Professor Satish Keshav

Research Area: Cell and Molecular Biology
Technology Exchange: Cellular immunology, Immunohistochemistry and In situ hybridisation
Scientific Themes: Immunology & Infectious Disease
Keywords: Paneth cell, Inflammatory Bowel Disease, Chemokines, Clinical trials and Biomarkers
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Professor Satish Keshav is a Consultant Physician and Gastroenterologist and Honorary Senior Lecturer specializing in Inflammatory Bowel Disease (IBD). He also has extensive experience in general gastroenterology, endoscopy, nutrition, and small bowel and liver transplantation. He provides specialist care for IBD at the John Radcliffe Hospital, running a busy multi-disciplinary clinical service with consultant colleagues, specialist registrars, clinical training and research fellows, and clinical nurse specialists. He also provides support for patients at the Lysosomal Storage Disorders Unit at the Royal Free Hospital, which is funded by the National Commissioning Group (NCG).

Dr Keshav received his Clinical training at the University of the Witwatersrand in Johannesburg, South Africa, and then completed a DPhil at the Sir William Dunn School of Pathology under the supervision of Professor Siamon Gordon FRS. Subsequently he went on to train in Gastroenterology and Internal Medicine at the John Radcliffe Hospital and Royal Free Hospital in London. He returned to the John Radcliffe Hospital and Nuffield Department of Medicine to take up his current post in 2007.

Dr Keshav's research encompasses laboratory-based investigation of gastrointestinal immunity and inflammation as well as clinical studies and trials. The research is translational, aiming to use clinical investigation to understand basic mechanisms, and to take this knowledge into clinical practice. His main interest is in understanding the mechanisms of organ-specific immunity and inflammation in the gastrointestinal tract, and particularly in determining the role of specialised epithelial cells, such as Paneth cells that maintain host defence and mediate between extrinsic micro-organisms and the innate and adaptive immune systems. Recent advances from his work includes identifying Paneth cells as potential mediators of the effect of the NOD2 gene in Crohn’s disease, and elucidating the role of the chemokine receptor CCR9 in inflammatory bowel disease.

There are no collaborations listed for this principal investigator.

Wendt E, White GE, Ferry H, Huhn M, Greaves DR, Keshav S. 2016. Glucocorticoids Suppress CCR9-Mediated Chemotaxis, Calcium Flux, and Adhesion to MAdCAM-1 in Human T Cells. J Immunol, 196 (9), pp. 3910-3919. | Show Abstract | Read more

CCR9 expressed on T lymphocytes mediates migration to the small intestine in response to a gradient of CCL25. CCL25-stimulated activation of α4β7 integrin promotes cell adherence to mucosal addressin cell adhesion molecule-1 (MAdCAM-1) expressed by vascular endothelial cells of the intestine, further mediating gut-specific homing. Inflammatory bowel disease is a chronic inflammatory condition that primarily affects the gastrointestinal tract and is characterized by leukocyte infiltration. Glucocorticoids (GCs) are widely used to treat inflammatory bowel disease but their effect on intestinal leukocyte homing is not well understood. We investigated the effect of GCs on the gut-specific chemokine receptor pair, CCR9 and CCL25. Using human peripheral blood-derived T lymphocytes enriched for CCR9 by cell sorting or culturing with all-trans retinoic acid, we measured chemotaxis, intracellular calcium flux, and α4β7-mediated cell adhesion to plate-bound MAdCAM-1. Dexamethasone (DEX), a specific GC receptor agonist, significantly reduced CCR9-mediated chemotaxis and adhesion to MAdCAM-1 without affecting CCR9 surface expression. In contrast, in the same cells, DEX increased CXCR4 surface expression and CXCL12-mediated signaling and downstream functions. The effects of DEX on human primary T cells were reversed by the GC receptor antagonist mifepristone. These results demonstrate that GCs suppress CCR9-mediated chemotaxis, intracellular calcium flux, and α4β7-mediated cell adhesion in vitro, and these effects could contribute to the efficacy of GCs in treating intestinal inflammation in vivo.

Travis S, Corte C, Keshav S. 2015. Does Disease Extent Matter when Scoring the UCEIS? J Crohns Colitis, 9 (8), pp. 694. | Read more

Bryant RV, Burger DC, Delo J, Walsh AJ, Thomas S, von Herbay A, Buchel OC, White L, Brain O, Keshav S et al. 2016. Beyond endoscopic mucosal healing in UC: histological remission better predicts corticosteroid use and hospitalisation over 6 years of follow-up. Gut, 65 (3), pp. 408-414. | Show Abstract | Read more

BACKGROUND: Endoscopic mucosal healing is an established treatment target for UC, yet the value of achieving histological remission remains unclear. AIMS: To evaluate histological remission compared to endoscopic mucosal healing for predicting patient outcomes in UC. METHODS: Blinded assessment of endoscopic and histological measures of disease activity was performed on patients with established UC at baseline. Concordance and prognostic values of endoscopic mucosal healing (defined by Baron score ≤1) and histological remission (defined by Truelove and Richards' index) for predicting outcomes of corticosteroid use, hospitalisation and colectomy were determined over a median 6 years follow-up, including κ statistics and Cox regression multivariate analysis. RESULTS: 91 patients with UC were followed up for a median 72 months (IQR 54-75 months). Overall, concordance between endoscopic and histological remission was moderate (κ=0.56, 95% CI 0.36 to 0.77); 24% patients had persistent inflammation despite endoscopic remission. Histological remission predicted corticosteroid use and acute severe colitis requiring hospitalisation over the follow-up period (HR 0.42 (0.2 to 0.9), p=0.02; HR 0.21 (0.1 to 0.7), p=0.02; respectively), whereas endoscopic mucosal healing did not (HR 0.86, 95% CI 0.5 to 1.7, p0.65; HR 0.83 95% CI 0.3 to 2.4, p0.74; respectively). CONCLUSIONS: Histological remission is a target distinct from endoscopic mucosal healing in UC and better predicts lower rates of corticosteroid use and acute severe colitis requiring hospitalisation, over a median of 6 years of follow-up. Our findings support the inclusion of histological indices in both UC clinical trials and practice, towards a target of 'complete remission'.

Corte C, Fernandopulle N, Catuneanu AM, Burger D, Cesarini M, White L, Keshav S, Travis S. 2015. Association between the ulcerative colitis endoscopic index of severity (UCEIS) and outcomes in acute severe ulcerative colitis. J Crohns Colitis, 9 (5), pp. 376-381. | Show Abstract | Read more

BACKGROUND: The Ulcerative Colitis Endoscopic Index of Severity (UCEIS) accounts for 86% of the variance between observers in the overall assessment of endoscopic severity, but has not been correlated with outcomes. METHODS: Consecutive cases of acute severe colitis (ASC) defined by Truelove and Witts (TW) criteria were retrospectively evaluated. Demographic details, number of TW criteria, prior medical therapy, UCEIS and inpatient medical therapy were recorded. Pre-specified (adverse) endpoints included rescue therapy, colectomy and readmission. RESULTS: Eighty-nine patients, 48 (54%) male, mean age 38 years, all received intravenous hydrocortisone 400mg/d (median 5 days [range 1-11]). Median follow-up was 14 months (2-33). Forty-eight (54%) were diagnosed the year prior to or at the time of admission. Thirty-six (40%) required rescue therapy (infliximab 25/36, ciclosporin 12/36, one receiving both). Twenty-one (24%) underwent colectomy on the index admission (9/21) or during follow-up (12/21). Median UCEIS score (possible range 0-8) was 5 (3-8). UCEIS was higher in patients requiring rescue therapy or colectomy (median score 6 [range 4-8] versus 5/8 [3-8], both p < 0.005). For UCEIS ≥5, 27/54 (50%) required rescue therapy, compared with 9/33 (27%) for UCEIS ≤4 (p = 0.037). When UCEIS was ≥5, 18/54 (33%) came to colectomy during follow-up, compared with 3/33 (9%) with UCEIS ≤4. Of 14 patients with UCEIS 7 or 8, 11/14 needed rescue therapy and 13/14 met any adverse endpoint. CONCLUSION: Endoscopic severity is associated with a worse outcome in ASC. When the UCEIS is ≥7 on admission, almost all patients will need treatment with infliximab or ciclosporin beyond steroids. This may mark a threshold for an early decision to use infliximab or ciclosporin.

Cesarini M, Collins G, Ronnblom A, Santos A, Sjoberg D, Parkes M, Keshav S, Travis S. 2015. Predicting the risk of acute severe colitis (ASC) at diagnosis of Ulcerative Colitis (UC): external validation JOURNAL OF CROHNS & COLITIS, 9 pp. S117-S118.

Wendt ER, Ferry H, Greaves DR, Keshav S. 2015. Ratiometric analysis of fura red by flow cytometry: a technique for monitoring intracellular calcium flux in primary cell subsets. PLoS One, 10 (3), pp. e0119532. | Show Abstract | Read more

Calcium flux is a rapid and sensitive measure of cell activation whose utility could be enhanced with better techniques for data extraction. We describe a technique to monitor calcium flux by flow cytometry, measuring Fura Red calcium dye by ratiometric analysis. This technique has several advantages: 1) using a single calcium dye provides an additional channel for surface marker characterization, 2) allows robust detection of calcium flux by minority cell populations within a heterogeneous population of primary T cells and monocytes 3) can measure total calcium flux and additionally, the proportion of responding cells, 4) can be applied to studying the effects of drug treatment, simultaneously stimulating and monitoring untreated and drug treated cells. Using chemokine receptor activation as an example, we highlight the utility of this assay, demonstrating that only cells expressing a specific chemokine receptor are activated by cognate chemokine ligand. Furthermore, we describe a technique for simultaneously stimulating and monitoring calcium flux in vehicle and drug treated cells, demonstrating the effects of the Gαi inhibitor, pertussis toxin (PTX), on chemokine stimulated calcium flux. The described real time calcium flux assay provides a robust platform for characterizing cell activation within primary cells, and offers a more accurate technique for studying the effect of drug treatment on receptor activation in a heterogeneous population of primary cells.

Wendt E, Keshav S. 2015. CCR9 antagonism: potential in the treatment of Inflammatory Bowel Disease. Clin Exp Gastroenterol, 8 pp. 119-130. | Show Abstract | Read more

Inflammatory Bowel Disease (IBD), mainly comprising Crohn's disease (CD) and ulcerative colitis (UC), is a chronic condition that primarily affects the intestine and is characterized by leukocytic infiltration. Blocking the migration of leukocytes from the circulation is therefore a reasonable therapeutic goal. Recent clinical trials using this approach have shown promise, with the monoclonal antibody to α4β7 integrin, vedolizumab, and previously with the monoclonal antibody to the α4 subunit, natalizumab. Directly targeting the subset of α4β7 expressing cells that co-express CC chemokine receptor 9 (CCR9), using the orally administered antagonist, CCX282-B, also known as vercirnon, has also been evaluated in Phase II and III trials that have produced mixed results. Although CCX282-B showed efficacy in inducing response in active CD in early studies, this was not confirmed in a Phase III study. CCX282-B was also more effective than placebo in maintaining remission, and this result has yet to be confirmed in Phase III. The efficacy of blocking CCR9 in UC, where vedolizumab was effective, has not been tested. The prospect of targeting CCR9 in IBD remains attractive. Much of the local accumulation of inflammatory cells in the intestine arises from migration rather than local proliferation and genetic and pharmacological targeting of CCR9 or its ligand in preclinical models that mimic UC and CD ameliorate inflammation in some cases. Furthermore, binding of chemokine ligands to receptor is a critical step in activating integrin binding, so there is a potential for synergistic action between integrin and chemokine antagonists. CCR9 is expressed on a smaller proportion of circulating cells than α4β7 integrin, which may offer greater specificity of effect, particularly in long term use. Furthermore, while α4β7 is widely expressed on T and B cell subsets, CCR9 is mainly expressed on effector memory Th1 cells. Indications for the use of intestine-specific integrin and chemokine receptor targeting may also extend beyond IBD, to include, for example, postoperative ileus, and primary sclerosing cholangitis.

Danese S, Rudziński J, Brandt W, Dupas J-L, Peyrin-Biroulet L, Bouhnik Y, Kleczkowski D, Uebel P, Lukas M, Knutsson M et al. 2015. Tralokinumab for moderate-to-severe UC: a randomised, double-blind, placebo-controlled, phase IIa study. Gut, 64 (2), pp. 243-249. | Show Abstract | Read more

OBJECTIVE: Interleukin-13 (IL-13) has been implicated as a key driver of UC. This trial evaluates the efficacy and safety of tralokinumab, an IL-13-neutralising antibody, as add-on therapy in adults with moderate-to-severe UC despite standard treatments. DESIGN: Non-hospitalised adults with UC (total Mayo score ≥6) were randomised to receive tralokinumab 300 mg or placebo subcutaneously every 2 weeks for 12 weeks. The primary end point was the rate of clinical response at week 8. Secondary efficacy end points included clinical remission and mucosal healing rates at week 8 and changes in total Mayo score, total modified Riley score, partial Mayo score and disease activity markers. RESULTS: Clinical response rate was 38% (21/56) for tralokinumab vs. 33% (18/55) for placebo (p=0.406). Clinical remission rate was 18% (10/56) vs. 6% (3/55) (p=0.033) and mucosal healing rate was 32% (18/56) vs. 20% (11/55) (p=0.104) for tralokinumab vs placebo. Changes to week 8 in total Mayo score and total modified Riley score were similar for tralokinumab and placebo (least-squares mean difference between groups: -0.49 (p=0.394) and 0.25 (p=0.449), respectively). Partial Mayo score at week 4 was lower with tralokinumab than placebo (least-squares mean difference between groups: -0.90 (p=0.041)). No consistent patterns were observed for disease activity markers. Tralokinumab had an acceptable safety profile. CONCLUSIONS: Add-on therapy with tralokinumab did not significantly improve clinical response. However, the higher clinical remission rate with tralokinumab than placebo suggests that tralokinumab may benefit some patients with UC. Tralokinumab was well tolerated. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov number: NCT01482884.

Tripathi M, Fryer E, Williamson KD, Karydis I, Gupta A, Keshav S, Middleton M. 2014. Ipilimumab associated colitis: a modern mimic of Inflammatory Bowel Disease (IBD) VIRCHOWS ARCHIV, 465 pp. S235-S236.

Kent A, Keshav S. 2014. Managing intractable proctitis and the problematic pouch. Dig Dis, 32 (4), pp. 427-437. | Show Abstract | Read more

Proctitis accounts for a significant proportion of cases of ulcerative colitis (UC), and some patients subsequently develop more extensive disease. However, most patients continue to have limited inflammation, although the changes in the distal colon and rectum can occasionally be severe, and symptoms of increased frequency, rectal bleeding and urgency can be as disabling as they are for patients with more extensive colitis. Furthermore, although symptoms are typically well controlled with standard medications, medically refractory proctitis poses particular problems. Patients generally are not systemically unwell, and there is no added fear of cancer. Therefore, the prospect of colectomy for such limited disease is resisted by patients, physicians and surgeons alike. Unusual therapies, often delivered locally by enema or suppository, have been tested in small case series without definitive outcomes. The pathogenesis of such limited, yet intractable inflammation remains unclear, and the differential diagnosis should be carefully reviewed to ensure that local disease, whether it is infectious, vascular, or a result of injury or degeneration, is not overlooked. Ileo-anal pouch formation is the surgery of choice for about 20% of patients with UC who undergo colectomy. In the majority of cases, this surgery results in an acceptable quality of life and freedom from a stoma. However, in a sizeable minority of cases, pouch dysfunction can cause intractable problems. The causes of pouch dysfunction are varied and must all be considered carefully, particularly in refractory cases. Pouchitis is a common issue and is usually transient and easily treated. However, refractory and chronic pouchitis can be challenging. Ischaemia, injury, infection and Crohn's disease can all cause refractory pouch dysfunction. In a minority of cases, there appears to be no apparent organic pathology, and the presumptive diagnosis is that of a functional pouch disorder. Although it is much rarer, neoplastic changes in the pouch must also be considered, and the risk managed appropriately. The management of both intractable proctitis and the problematic pouch is made more challenging by the wide differential diagnosis that must be considered and by the paucity of high-quality clinical trials to support any one therapy. Key strategies to overcoming these limitations include methodical and systematic investigation and review, and a willingness to tailor therapy to the individual patient. Clinical trials of new treatments should be supported, and data from the experience with small cohorts of patients should be meticulously collected, critically analysed and widely disseminated.

Walsh AJ, Ghosh A, Brain AO, Buchel O, Burger D, Thomas S, White L, Collins GS, Keshav S, Travis SPL. 2014. Comparing disease activity indices in ulcerative colitis. J Crohns Colitis, 8 (4), pp. 318-325. | Show Abstract | Read more

BACKGROUND: Comparisons between disease activity indices for ulcerative colitis (UC) are few. This study evaluates three indices, to determine the potential impact of inter-observer variation on clinical trial recruitment or outcome as well as their clinical relevance. METHODS: One hundred patients with UC were prospectively evaluated, each by four specialists, followed by videosigmoidoscopy, which was later scored by each specialist. The Simple Clinical Colitis Activity (SCCAI), Mayo Clinic and Seo indices were compared by assigning a disease activity category from published thresholds for remission, mild, moderate and severe activity. Inter-observer variation was evaluated using Kappa statistics and its effect for each patient on recruitment and outcome measures for representative clinical trials calculated. Clinical relevance was assessed by comparing an independently assigned clinical category, taking all information into account as if in clinic, with the disease activity assigned by the indices. RESULTS: Inter-observer agreement for SCCAI (κ=0.75, 95% CI 0.70-0.81), Mayo Clinic (κ=0.72, 95% CI 0.67-0.78) and Seo (κ=0.89, 95% CI 0.83-0.95) indices was good or very good as was the agreement for rectal bleeding (κ=0.77) and stool frequency (κ=0.90). Endoscopy in the Mayo Clinic index had the greatest variation (κ=0.38). Inter-observer variation alone would have excluded up to 1 in 5 patients from recruitment or remission criteria in representative trials. Categorisation by the SCCAI, Mayo Clinic and Seo indices agreed with the independently assigned clinical category in 61%, 67% and 47% of cases respectively. CONCLUSIONS: Trial recruitment and outcome measures are affected by inter-observer variation in UC activity indices, and endoscopic scoring was the component most susceptible to variation.

Reenaers C, Louis E, Belaiche J, Seidel L, Keshav S, Travis S. 2013. Letter: should immunosuppressive therapy be started with adalimumab in Crohn's disease? Authors' reply. Aliment Pharmacol Ther, 37 (7), pp. 752-753. | Read more

Keshav S, Vaňásek T, Niv Y, Petryka R, Howaldt S, Bafutto M, Rácz I, Hetzel D, Nielsen OH, Vermeire S et al. 2013. A randomized controlled trial of the efficacy and safety of CCX282-B, an orally-administered blocker of chemokine receptor CCR9, for patients with Crohn's disease. PLoS One, 8 (3), pp. e60094. | Show Abstract | Read more

UNLABELLED: CCX282-B, also called vercirnon, is a specific, orally-administered chemokine receptor CCR9 antagonist that regulates migration and activation of inflammatory cells in the intestine. This randomized, placebo-controlled trial was conducted to evaluate the safety and efficacy of CCX282-B in 436 patients with Crohn's disease. Crohn's Disease Activity Index (CDAI) scores were 250-450 and C-reactive protein >7.5 mg/L at study entry. In addition to stable concomitant Crohn's medication (85% of subjects), subjects received placebo or CCX282-B (250 mg once daily, 250 mg twice daily, or 500 mg once daily) for 12 weeks. They then received 250 mg CCX282-B twice daily, open-label, through week 16. Subjects who had a clinical response (a ≥ 70 point drop in CDAI) at week 16 were randomly assigned to groups given placebo or CCX282-B (250 mg, twice daily) for 36 weeks. Primary endpoints were clinical response at Week 8 and sustained clinical response at Week 52. During the 12-week Induction period, the clinical response was highest in the group given 500 mg CCX282-B once daily. Response rates at week 8 were 49% in the placebo group, 52% in the group given CCX282-B 250 mg once daily (odds ratio [OR] = 1.12; p = .667 vs placebo), 48% in the group given CCX282-B 250 mg twice daily (OR = 0.95; p = .833), and 60% in the group given CCX282-B 500 mg once daily (OR = 1.53; p = .111). At week 12, response rates were 47%, 56% (OR = 1.44; p = .168), 49% (OR = 1.07; p = .792), and 61% (OR = 1.74; p = .039), respectively. At the end of the Maintenance period (week 52), 47% of subjects on CCX282-B were in remission, compared to 31% on placebo (OR = 2.01; p = .012); 46% showed sustained clinical responses, compared to 42% on placebo (OR = 1.14; p = .629). CCX282-B was well tolerated. Encouraging results from this clinical trial led to initiation of Phase 3 clinical trials in Crohn's disease. TRIAL REGISTRATION: ClinicalTrials.gov NCT00306215.

Cited:

38

Scopus

Leedham SJ, Rodenas-Cuadrado P, Howarth K, Lewis A, Mallappa S, Segditsas S, Davis H, Jeffery R, Rodriguez-Justo M, Keshav S et al. 2013. A basal gradient of Wnt and stem-cell number influences regional tumour distribution in human and mouse intestinal tracts Gut, 62 (1), pp. 83-93. | Show Abstract | Read more

Objective: Wnt signalling is critical for normal intestinal development and homeostasis. Wnt dysregulation occurs in almost all human and murine intestinal tumours and an optimal but not excessive level of Wnt activation is considered favourable for tumourigenesis. The authors assessed effects of pan-intestinal Wnt activation on tissue homeostasis, taking into account underlying physiological Wnt activity and stem-cell number in each region of the bowel. Design: The authors generated mice that expressed temporally controlled, stabilised β-catenin along the crypt-villus axis throughout the intestines. Physiological Wnt target gene activity was assessed in different regions of normal mouse and human tissue. Human intestinal tumour mutation spectra were analysed. Results: In the mouse, β-catenin stabilisation resulted in a graduated neoplastic response, ranging from dysplastic transformation of the entire epithelium in the proximal small bowel to slightly enlarged crypts of non-dysplastic morphology in the colorectum. In contrast, stem and proliferating cell numbers were increased in all intestinal regions. In the normal mouse and human intestines, stem-cell and Wnt gradients were non-identical, but higher in the small bowel than large bowel in both species. There was also variation in the expression of some Wnt modulators. Human tumour analysis confirmed that different APC mutation spectra are selected in different regions of the bowel. Conclusions: There are variable gradients in stem-cell number, physiological Wnt activity and response to pathologically increased Wnt signalling along the cryptvillus axis and throughout the length of the intestinal tract. The authors propose that this variation influences regional mutation spectra, tumour susceptibility and lesion distribution in mice and humans.

Reenaers C, Louis E, Belaiche J, Seidel L, Keshav S, Travis S. 2012. Does co-treatment with immunosuppressors improve outcome in patients with Crohn's disease treated with adalimumab? Aliment Pharmacol Ther, 36 (11-12), pp. 1040-1048. | Show Abstract | Read more

BACKGROUND: There is clear benefit from combination therapy with infliximab and immunosuppressive drugs (IS), but few data are available for adalimumab (ADA). AIM: To assess the efficacy of ADA monotherapy and ADA+IS for induction and maintenance therapy in Crohn's disease. METHODS: Retrospective study of patients with Crohn's disease treated with ADA in Oxford, UK or Liège, Belgium. Treatment periods were divided into 6-month semesters. A combination therapy semester was defined as ADA+IS for at least 3 months; successful induction meant clinical response; a semester with flare as ADA dose escalation, starting steroids, perianal complication, or surgery; and ADA failure as ADA withdrawal for secondary loss of response or intolerance. Semesters with and without flares were compared through univariate and multivariate analysis. RESULTS: Successful induction was achieved in 171/207 (83%) patients, with no significant difference between ADA+IS and ADA monotherapy (85% vs. 82%, P = 0.50). Five hundred and sixty-two semesters in 181 patients were included for maintenance analysis. ADA+IS was not associated with fewer semesters with flare (34% vs. 35%, P = 0.96), or with ADA failure (6% vs. 8%, P = 0.43). Nevertheless, combination therapy in the first semester was associated with a lower risk of ADA failure (5% vs. 10%, P = 0.04, OR = 0.48) and combination therapy beyond 6 months was associated with fewer semesters with flares (14% vs. 36%, P = 0.02, OR = 0.31). CONCLUSIONS: There may be a benefit from adalimumab+immunosuppressive drugs combination therapy during the first semester of initiating adalimumab, with a slight decrease in adalimumab failure and lower need for adalimumab dosage escalation.

Leedham SJ, Rodenas-Cuadrado P, Howarth K, Lewis A, Mallappa S, Segditsas S, Davis H, Jeffery R, Rodriguez-Justo M, Keshav S et al. 2013. A basal gradient of Wnt and stem-cell number influences regional tumour distribution in human and mouse intestinal tracts. Gut, 62 (1), pp. 83-93. | Show Abstract | Read more

OBJECTIVE: Wnt signalling is critical for normal intestinal development and homeostasis. Wnt dysregulation occurs in almost all human and murine intestinal tumours and an optimal but not excessive level of Wnt activation is considered favourable for tumourigenesis. The authors assessed effects of pan-intestinal Wnt activation on tissue homeostasis, taking into account underlying physiological Wnt activity and stem-cell number in each region of the bowel. DESIGN: The authors generated mice that expressed temporally controlled, stabilised β-catenin along the crypt-villus axis throughout the intestines. Physiological Wnt target gene activity was assessed in different regions of normal mouse and human tissue. Human intestinal tumour mutation spectra were analysed. RESULTS: In the mouse, β-catenin stabilisation resulted in a graduated neoplastic response, ranging from dysplastic transformation of the entire epithelium in the proximal small bowel to slightly enlarged crypts of non-dysplastic morphology in the colorectum. In contrast, stem and proliferating cell numbers were increased in all intestinal regions. In the normal mouse and human intestines, stem-cell and Wnt gradients were non-identical, but higher in the small bowel than large bowel in both species. There was also variation in the expression of some Wnt modulators. Human tumour analysis confirmed that different APC mutation spectra are selected in different regions of the bowel. CONCLUSIONS: There are variable gradients in stem-cell number, physiological Wnt activity and response to pathologically increased Wnt signalling along the crypt-villus axis and throughout the length of the intestinal tract. The authors propose that this variation influences regional mutation spectra, tumour susceptibility and lesion distribution in mice and humans.

Cited:

58

Scopus

Reenaers C, Louis E, Belaiche J, Seidel L, Keshav S, Travis S. 2012. Does co-treatment with immunosuppressors improve outcome in patients with Crohn's disease treated with adalimumab? Alimentary Pharmacology and Therapeutics, 36 (11-12), pp. 1040-1048. | Show Abstract | Read more

Background: There is clear benefit from combination therapy with infliximab and immunosuppressive drugs (IS), but few data are available for adalimumab (ADA). Aim: To assess the efficacy of ADA monotherapy and ADA+IS for induction and maintenance therapy in Crohn's disease. Methods: Retrospective study of patients with Crohn's disease treated with ADA in Oxford, UK or Liège, Belgium. Treatment periods were divided into 6-month semesters. A combination therapy semester was defined as ADA+IS for at least 3 months; successful induction meant clinical response; a semester with flare as ADA dose escalation, starting steroids, perianal complication, or surgery; and ADA failure as ADA withdrawal for secondary loss of response or intolerance. Semesters with and without flares were compared through univariate and multivariate analysis. Results: Successful induction was achieved in 171/207 (83%) patients, with no significant difference between ADA+IS and ADA monotherapy (85% vs. 82%, P = 0.50). Five hundred and sixty-two semesters in 181 patients were included for maintenance analysis. ADA+IS was not associated with fewer semesters with flare (34% vs. 35%, P = 0.96), or with ADA failure (6% vs. 8%, P = 0.43). Nevertheless, combination therapy in the first semester was associated with a lower risk of ADA failure (5% vs. 10%, P = 0.04, OR = 0.48) and combination therapy beyond 6 months was associated with fewer semesters with flares (14% vs. 36%, P = 0.02, OR = 0.31). Conclusions: There may be a benefit from adalimumab+immunosuppressive drugs combination therapy during the first semester of initiating adalimumab, with a slight decrease in adalimumab failure and lower need for adalimumab dosage escalation. © 2012 Blackwell Publishing Ltd.

Minassian A, Jeffery K, Conlon C, Keshav S. 2011. DIAGNOSTIC DIFFICULTY IN THE GUT: A GRANULOMATOUS DILEMMACATEGORY: CLINICAL LESSON JOURNAL OF INFECTION, 63 (6), pp. E118-E119. | Read more

Stoesser N, Crook DW, Fung R, Griffiths D, Harding RM, Kachrimanidou M, Keshav S, Peto TE, Vaughan A, Walker AS, Dingle KE. 2011. Molecular epidemiology of Clostridium difficile strains in children compared with that of strains circulating in adults with Clostridium difficile-associated infection. J Clin Microbiol, 49 (11), pp. 3994-3996. | Show Abstract | Read more

Molecular analysis of Clostridium difficile (28 isolates) from children (n = 128) in Oxfordshire, United Kingdom, identified eight toxigenic genotypes. Six of these were isolated from 27% of concurrent adult C. difficile-associated infections studied (n = 83). No children carried hypervirulent PCR ribotype 027. Children could participate in the transmission of some adult disease-causing genotypes.

Culver EL, Winearls C, Roberts I, Keshav S. 2012. A rare cause of bloody diarrhoea. Gut, 61 (1), pp. 94-168. | Read more

Vradelis S, Maynard N, Warren BF, Keshav S, Travis SPL. 2011. Quality control in upper gastrointestinal endoscopy: detection rates of gastric cancer in Oxford 2005-2008. Postgrad Med J, 87 (1027), pp. 335-339. | Show Abstract | Read more

BACKGROUND: Gastric cancer (GC) represents the sum of advanced gastric cancer (AGC) and early gastric cancer (EGC). Endoscopy (with biopsies) is the gold standard for detection of GC, but a false-negative rate of up to 19% is reported. AIM: To determine whether patients with GC had had an oesophagogastroduodenoscopy (OGD) in the year preceding diagnosis that might reasonably have been expected to detect the cancer, as a measure of quality assurance of endoscopic practice. METHODS: Patients with histologically proven GC were identified from pathology records. Endoscopy reports and case notes were examined to identify any OGD before diagnosis, the interval and endoscopic findings. A false-negative OGD was defined as one where GC was neither suspected nor shown at pathology, but where a diagnosis of GC was made within 12 months. RESULTS: Between January 2005 and February 2008, 9764 OGDs were performed. GC was diagnosed in 74 patients (male/female ratio 2.89; median age 76, range 38-95). Nine (12%) patients had EGC. There were no differences in age, sex or symptoms between the EGC and AGC group. Sixty-eight of the 74 patients with GC (92%) presented with alarm symptoms. Ten of the 74 had had an OGD within 12 months before definitive diagnosis; all these were planned because of suspicious lesions. Significantly fewer biopsies were performed at OGDs preceding definitive diagnosis (median 2 (0-10) vs 6 (2-12); p=0.002). CONCLUSION: False-negative rates of 0% (within 12 months) and 8% (within 3 years) for diagnosis of GC are reassuring, but an inadequate number of biopsies compromises the quality assurance of endoscopy. GC presents without alarm symptoms in <10%.

Walters MJ, Wang Y, Lai N, Baumgart T, Zhao BN, Dairaghi DJ, Bekker P, Ertl LS, Penfold MET, Jaen JC et al. 2010. Characterization of CCX282-B, an orally bioavailable antagonist of the CCR9 chemokine receptor, for treatment of inflammatory bowel disease. J Pharmacol Exp Ther, 335 (1), pp. 61-69. | Show Abstract | Read more

The chemokine system represents a diverse group of G protein-coupled receptors responsible for orchestrating cell recruitment under both homeostatic and inflammatory conditions. Chemokine receptor 9 (CCR9) is a chemokine receptor known to be central for migration of immune cells into the intestine. Its only ligand, CCL25, is expressed at the mucosal surface of the intestine and is known to be elevated in intestinal inflammation. To date, there are no reports of small-molecule antagonists targeting CCR9. We report, for the first time, the discovery of a small molecule, CCX282-B, which is an orally bioavailable, selective, and potent antagonist of human CCR9. CCX282-B inhibited CCR9-mediated Ca(2+) mobilization and chemotaxis on Molt-4 cells with IC(50) values of 5.4 and 3.4 nM, respectively. In the presence of 100% human serum, CCX282-B inhibited CCR9-mediated chemotaxis with an IC(50) of 33 nM, and the addition of α1-acid glycoprotein did not affect its potency. CCX282-B inhibited chemotaxis of primary CCR9-expressing cells to CCL25 with an IC(50) of 6.8 nM. CCX282-B was an equipotent inhibitor of CCL25-directed chemotaxis of both splice forms of CCR9 (CCR9A and CCR9B) with IC(50) values of 2.8 and 2.6 nM, respectively. CCX282-B also inhibited mouse and rat CCR9-mediated chemotaxis. Inhibition of CCR9 with CCX282-B results in normalization of Crohn's disease such as histopathology associated with the TNF(ΔARE) mice. Analysis of the plasma level of drug associated with this improvement provides an understanding of the pharmacokinetic/pharmacodynamic relationship for CCR9 antagonists in the treatment of intestinal inflammation.

Cassinotti A, Keshav S, Ardizzone S, Mortensen N, Sampietro G, Fociani P, Duca P, George B, Lazzaroni M, Manes G et al. 2009. IBD care in Europe: A comparative audit of the inpatient management of Crohn's disease and ulcerative colitis using the national UK IBD audit tool. J Crohns Colitis, 3 (4), pp. 291-301. | Show Abstract | Read more

BACKGROUND AND AIMS: The National UK IBD audit tool is an electronic database created to improve the quality and safety of care for IBD patients by auditing individual patient care, service resources and organisation against national standards. We used the National UK IBD audit tool to compare the organisation and process of IBD care between services in Oxford (UK) and Milan (Italy), as a pilot study to evaluate its application outside national boundaries. METHODS: Clinical and demographic data of patients with CD and UC, consecutively admitted during a 2month period, were collected and compared between the centres, to each other and to the UK IBD standards obtained by previous audit analyses performed in Oxford in 2006. RESULTS: 20 and 26 patients with UC were admitted in Oxford and Milan, as well as 21 and 20 patients with CD, respectively. Most admissions in Milan were planned admissions for moderately active treatment-refractory disease. No patient died. Oxford had a higher surgery rate. Endoscopy for UC consisted mainly of colonoscopy in Milan (92%) and flexible sigmoidoscopy in Oxford (64%). In CD, Oxford data revealed a higher use of immununomodulators and CT scan, compared with higher use of bowel ultrasound in Milan. CRP was the preferred biomarker of disease activity. The following areas did not reach the standards set for the 2006 UK IBD Audit: the lack in Milan of IBD specialist nurses and few dietitian visits, as well as little attention to heparin prophylaxis and abdominal radiography in UC. Both sites paid little attention to stool cultures and revealed a high rate of active smokers in CD and little attention to bone protection in steroids users. Since the 2006 audit in Oxford, improvements include IBD specialist nurse visits, dietitian visits, number of active smokers, stool samples, prophylactic heparin, bone protection and nutritional assessment. CONCLUSIONS: Consistent procedural differences between Oxford and Milan identified by audits of both UC and CD could be resolved by organisational change, with an improvement in the service. The UK IBD audit tool is an easy instrument to assess the processes and outcomes of care delivery in IBD and can be applied also outside UK.

Walsh AJ, Brain AOS, Keshav S, Buchel OC, Jacobovits S, Thomas S, White L, Von Herbay A, Altman DG, Travis SPL. 2009. Which activity index for ulcerative colitis? evaluation of the size and effect of inter_observer variation in clinical, endoscopic and composite indices JOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, 24 pp. A321-A321.

Brain O, von Herbay A, Keshav S. 2009. Clinical challenges and images in GI. Intestinal posttransplant lymphoproliferative disorder. Gastroenterology, 136 (5), pp. 1506-1845. | Read more

Vradelis S, Kalaitzakis E, Sharifi Y, Buchel O, Keshav S, Chapman RW, Braden B. 2009. Addition of senna improves quality of colonoscopy preparation with magnesium citrate. World J Gastroenterol, 15 (14), pp. 1759-1763. | Show Abstract | Read more

AIM: To prospectively investigate the effectiveness and patient's tolerance of two low-cost bowel cleansing preparation protocols based on magnesium citrate only or the combination of magnesium citrate and senna. METHODS: A total of 342 patients who were referred for colonoscopy underwent a colon cleansing protocol with magnesium citrate alone (n = 160) or magnesium citrate and senna granules (n = 182). The colonoscopist rated the overall efficacy of colon cleansing using an established score on a 4-point scale. Patients were questioned before undergoing colonoscopy for side effects and symptoms during bowel preparation. RESULTS: The percentage of procedures rescheduled because of insufficient colon cleansing was 7% in the magnesium citrate group and 4% in the magnesium citrate/senna group (P = 0.44). Adequate visualization of the colonic mucosa was rated superior under the citramag/senna regimen (P = 0.004). Both regimens were well tolerated, and did not significantly differ in the occurrence of nausea, bloating or headache. However, abdominal cramps were observed more often under the senna protocol (29.2%) compared to the magnesium citrate only protocol (9.9%, P < 0.0003). CONCLUSION: The addition of senna to the bowel preparation protocol with magnesium citrate significantly improves the cleansing outcome.

Brain O, von Herbay A, Keshav S. 2009. Clinical Challenges and Images in GI Gastroenterology, 136 (5), pp. 1506-1845. | Read more

Cummings JRF, Keshav S, Travis SPL. 2008. Medical management of Crohn's disease. BMJ, 336 (7652), pp. 1062-1066. | Read more

Mayor NP, Shaw BE, Hughes DA, Maldonado-Torres H, Madrigal JA, Keshav S, Marsh SGE. 2008. NOD2/CARD15 polymorphisms in allogeneic stem-cell transplantation from unrelated donors: T depletion matters - Reply JOURNAL OF CLINICAL ONCOLOGY, 26 (2), pp. 339-339. | Read more

Mayor NP, Shaw BE, Hughes DA, Maldonado-Torres H, Madrigal JA, Keshav S, Marsh SGE. 2008. In Reply Journal of Clinical Oncology, 26 (2), pp. 339-339. | Read more

Hoffmann B, Schwarz M, Mehta A, Keshav S, Fabry Outcome Survey European Investigators. 2007. Gastrointestinal symptoms in 342 patients with Fabry disease: prevalence and response to enzyme replacement therapy. Clin Gastroenterol Hepatol, 5 (12), pp. 1447-1453. | Show Abstract | Read more

BACKGROUND & AIMS: Fabry disease is an X-linked deficiency of alpha-galactosidase A, resulting in lysosomal deposition of globotriaosylceramide in nearly all tissues. The disease frequently causes diarrhea and abdominal pain, which are assumed to arise from malfunction of enteric neurons and which mimic diarrhea-predominant irritable bowel syndrome (IBS). There are limited data about the prevalence and nature of gastrointestinal symptoms in patients with Fabry disease and the response to enzyme replacement therapy (ERT) in large cohorts. The aims of this study were to evaluate the nature and prevalence of gastrointestinal symptoms and their impact on health-related quality of life (HRQoL) in patients with Fabry disease and to analyze changes after 12 and 24 months of treatment with agalsidase alfa. METHODS: Information about gastrointestinal symptoms was obtained from regular interviews before and during the time of ERT. Data on HRQoL were collected by using the EQ-5D questionnaire. RESULTS: The overall prevalence of gastrointestinal symptoms was 52%, with abdominal pain and diarrhea being most frequent. Female patients were more frequently affected than male patients, and there was a high prevalence in children (abdominal pain, 49.3%; diarrhea 25.4%). ERT with agalsidase alfa reduced the prevalence of abdominal pain, with a statistically significant decrease in male patients and in children after 12 months of treatment. CONCLUSIONS: The gastrointestinal symptomatology of Fabry disease is very similar to diarrhea-predominant IBS; however, pathophysiologic similarities remain to be elucidated. ERT reduced the prevalence of gastrointestinal symptoms in Fabry disease, particularly in children and male patients.

Mayor NP, Shaw BE, Keshav S, Madrigal JA, Marsh SGE. 2007. A novel technique for NOD2/CARD15 genotyping using PCR-SSP. J Immunol Methods, 327 (1-2), pp. 82-87. | Show Abstract | Read more

The Nucleotide-binding Oligomerisation Domain (NOD) 2 protein is encoded by the Caspase Recruitment Domain (CARD) 15 gene and has a critical role in innate immunity. Recent studies have implicated Single Nucleotide Polymorphisms (SNPs) of the NOD2/CARD15 gene with the onset of several Inflammatory Bowel Disorders (Crohn's Disease, Blau syndrome) and the progression of several malignant diseases. The identification of SNPs in the genotypes of donor and recipient pairs prior to haematopoietic stem cell transplantation have also been shown to predict for a worse outcome, specifically causing increases in the incidence and severity of acute Graft-versus-Host disease, disease relapse and mortality. In light of these widespread areas of interest, we have developed a Polymerase Chain Reaction assay using Sequence Specific Primers (PCR-SSP) to identify the three SNPs that have been implicated, (SNPs 8, 12 and 13). The assay has proven to be a rapid and accurate method of performing NOD2/CARD15 genotyping when compared to other techniques described to date.

Mayor NP, Shaw BE, Hughes DA, Maldonado-Torres H, Madrigal JA, Keshav S, Marsh SGE. 2007. Single nucleotide polymorphisms in the NOD2/CARD15 gene are associated with an increased risk of relapse and death for patients with acute leukemia after hematopoietic stem-cell transplantation with unrelated donors. J Clin Oncol, 25 (27), pp. 4262-4269. | Show Abstract | Read more

PURPOSE: Hematopoietic stem cell transplantation (HSCT) is an important option in the management of acute leukemia, but the risk of disease relapse and death remains appreciable. Recent studies have suggested that nucleotide-binding oligomerization domain 2 (NOD2)/caspase recruitment domain 15 (CARD15) gene single nucleotide polymorphisms (SNPs), implicated in innate immunity and Crohn's disease, may also affect immune function post-HSCT. PATIENTS AND METHODS: NOD2/CARD15 genotypes were analyzed in 196 patients diagnosed with acute leukemia and their unrelated donors. The pairs are part of a previously well-characterized cohort with a median follow-up of 2.2 years (range, 0.42 to 6.61 years). T-cell depletion was used in 83% of pairs. RESULTS: NOD2/CARD15 SNPs were associated with a reduction in overall survival (44% v 22%; log-rank P = .0087) due to an increase in disease relapse (32% v 54%; Gray's test P = .001) as compared with wild-type pairs. In multivariate analyses, the two most significant factors impacting outcome were transplantation in relapse and the presence of SNPs. The incidence of acute graft-versus-host disease was low and there was no significant difference due to the presence of SNPs. CONCLUSION: These data indicate an unrecognized role for the NOD2/CARD15 gene in unrelated donor HSCT for acute leukemia. The increased risk of disease relapse suggests that the wild-type gene product may contribute to a graft-versus-leukemia effect. These data suggest that NOD2/CARD15 genotyping before transplantation may contribute to prognosis and influence clinical management.

Mayor NP, Shaw BE, Hughes DA, Maldonado-Torres H, Madrigal JA, Keshav S, Marsh SGE. 2007. Single nucleotide polymorphisms (SNPs) of the NOD2/CARD15 gene are associated with significant increases in disease relapse and death in recipients of an unrelated donor haematopoietic stem cell transplant for acute leukaemia INTERNATIONAL JOURNAL OF IMMUNOGENETICS, 34 (4), pp. 295-295.

Bekker P, Keshav S, Wei Z, Ertl L, Wang Y, Lai N, Wright J, Ungashe S, Schall T. 2007. Pharmacological inhibition of CCR9 is a novel approach in the treatment of inflammatory bowel disease INFLAMMATION RESEARCH, 56 pp. S350-S350.

Brennan M, Rao M, Sercombe J, Keshav S, Heuschkel R. 2007. Transitional care in IBD - What is best? Experiences of patients and families JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION, 44 pp. 10-10.

Hoffmann B, Keshav S. 2007. Gastrointestinal symptoms in Fabry disease: everything is possible, including treatment. Acta Paediatr, 96 (455), pp. 84-86. | Show Abstract | Read more

UNLABELLED: Gastrointestinal symptoms in Fabry disease were first described independently by William Anderson and Johannes Fabry. Case reports and case series suggest that the whole gastrointestinal tract may be affected in patients with Fabry disease. The Fabry Outcome Survey (FOS) database supports these observations. The overall prevalence of gastrointestinal involvement reported in a study of 342 patients (271 adults; 71 children) enrolled in FOS was 52% (49.8% in adults, 60.8% in children). Abdominal pain was the most prevalent symptom. The median age at onset of gastrointestinal symptoms was 14 years, similar to the age at onset of acroparaesthesia. The prevalence of gastrointestinal symptoms was reduced in patients after receiving enzyme replacement therapy with agalsidase alfa for 12 and 24 months. There was no correlation between gastrointestinal symptoms and body mass index. CONCLUSION: Gastrointestinal symptoms in Fabry disease may have been underestimated. The FOS database supports previous reports of beneficial effects of enzyme replacement therapy on gastrointestinal symptoms in Fabry disease.

Lala S, Dheda K, Chang J-S, Huggett JF, Kim LU, Johnson MA, Rook GAW, Keshav S, Zumla A. 2007. The pathogen recognition sensor, NOD2, is variably expressed in patients with pulmonary tuberculosis. BMC Infect Dis, 7 (1), pp. 96. | Show Abstract | Read more

BACKGROUND: NOD2, an intracellular pathogen recognition sensor, modulates innate defences to muropeptides derived from various bacterial species, including Mycobacterium tuberculosis (MTB). Experimentally, NOD2 attenuates two key putative mycobactericidal mechanisms. TNF-alpha synthesis is markedly reduced in MTB-antigen stimulated-mononuclear cells expressing mutant NOD2 proteins. NOD2 agonists also induce resistance to apoptosis, and may thus facilitate the survival of MTB in infected macrophages. To further define a role for NOD2 in disease pathogenesis, we analysed NOD2 transcriptional responses in pulmonary leucocytes and mononuclear cells harvested from patients with pulmonary tuberculosis (PTB). METHODS: We analysed NOD2 mRNA expression by real-time polymerase chain-reaction in alveolar lavage cells obtained from 15 patients with pulmonary tuberculosis and their matched controls. We compared NOD2 transcriptional responses, in peripheral leucocytes, before and after anti-tuberculous treatment in 10 patients. In vitro, we measured NOD2 mRNA levels in MTB-antigen stimulated-mononuclear cells. RESULTS: No significant differences in NOD2 transcriptional responses were detected in patients and controls. In some patients, however, NOD2 expression was markedly increased and correlated with toll-like-receptor 2 and 4 expression. In whole blood, NOD2 mRNA levels increased significantly after completion of anti-tuberculosis treatment. NOD2 expression levels did not change significantly in mononuclear cells stimulated with mycobacterial antigens in vitro. CONCLUSION: There are no characteristic NOD2 transcriptional responses in PTB. Nonetheless, the increased levels of NOD2 expression in some patients with severe tuberculosis, and the increases in expression levels within peripheral leucocytes following treatment merit further studies in selected patient and control populations.

Keshav S. 2006. Paneth cells: leukocyte-like mediators of innate immunity in the intestine. J Leukoc Biol, 80 (3), pp. 500-508. | Show Abstract | Read more

Paneth cells are secretory intestinal epithelial cells located at the base of the crypts of Lieberkühn in the small intestine. They display prominent cytoplasmic granules, containing antibacterial proteins such as lysozyme, secretory phospholipase A2 type IIA, and alpha-defensins, which are released into the intestinal lumen in response to a range of stimuli. In this, they resemble circulating leukocytes, which also elaborate and secrete lysozyme and alpha-defensins as part of an antibacterial defense function, and the resemblance is sustained at other levels. The cells also strongly and specifically express the NOD2 gene product, one of an emerging family of critical, intracellular mediators of innate immune responses, which is also highly expressed in peripheral blood mononuclear cells, and they express RNA for tumor necrosis factor alpha, a major myelomonocytic cell-derived cytokine, which has a crucial role in the pathogenesis of diseases such as rheumatoid arthritis and Crohn's disease (CD). Thus, these cells, which are derived from the pluripotent intestinal epithelial stem-cell lineage, are sessile, resident host-defense cells, which may share with leukocytes the beneficial function of secreting antimicrobial peptides, as well as the potentially harmful capacity for promoting inflammation and tissue damage. Paneth cells are most abundant in the distal small intestine, which is the region most frequently affected by CD, and there is great interest in the potential role of these cells in this condition. This brief review summarizes current knowledge and speculates on how the study of these fascinating cells might be advanced.

Orchard T, Probert CS, Keshav S. 2006. Review article: maintenance therapy in patients with ulcerative colitis. Aliment Pharmacol Ther, 24 Suppl 1 (s1), pp. 17-22. | Show Abstract | Read more

British Society of Gastroenterology guidelines recommend that all patients with ulcerative colitis should receive long-term therapy with a 5-aminosalicylic acid compound to maintain remission. Recent studies have shown that time spent in remission is longer when the maintenance dose is increased from 1.2 to 2.4 g/day, with patients with extensive disease benefiting most from an increase with dosage. A retrospective analysis also found that the frequency of relapse was lower in patients taking more than the median dose of 5-aminosalicylic acid (1.6 g/day) compared with those taking less than the median dose. Similarly, when 5-aminosalicylic acids are used to induce remission, continuing the induction dosage for an extra 4 weeks prolongs remission and reduces the frequency of relapse. However, patients rarely comply fully with the prescribed dose regimen, which can lead to effective under-dosing. The recent discovery that 5-aminosalicylic acids may act in ulcerative colitis by activating peroxisome proliferator-activated receptor-gamma, a nuclear receptor that plays a role in the control of cell proliferation and apoptosis, has given new impetus to the idea that long-term therapy with 5-aminosalicylic acid may reduce the risk of colorectal cancer. Epidemiological studies are beginning to provide evidence to support this view. Accumulating evidence suggests that the next revision of the clinical guidelines should suggest life-long doses of 5-aminosalicylic acid of > or =2 g/day for maintenance of remission in patients with ulcerative colitis.

Hoffmann B, Schwarz M, Mehta A, Keshav S, Investigators FOSE. 2006. Gastrointestinal symptoms in Fabry disease: Data from the Fabry outcome survey JOURNAL OF INHERITED METABOLIC DISEASE, 29 pp. 72-72.

Hughes DA, Li A, Holmes AM, Reed MC, Baker RJ, Milligan A, Richfield L, Bruce R, Goodwin S, Blincoe M et al. 2006. Anaemia in Anderson-Fabry disease: the role of hepcidin ACTA PAEDIATRICA, 95 pp. 131-132.

Martinez-Pomares L, Hanitsch LG, Stillion R, Keshav S, Gordon S. 2005. Expression of mannose receptor and ligands for its cysteine-rich domain in venous sinuses of human spleen. Lab Invest, 85 (10), pp. 1238-1249. | Show Abstract | Read more

The mannose receptor (MR) is a type I membrane molecule with two lectin activities. Mannose recognition takes place through the C-type lectin-like carbohydrate recognition domains, while recognition of sulphated glycans is mediated by the cysteine-rich domain (CR). In murine spleen CR ligands are present in a subpopulation of macrophages (Mphi) placed in the marginal zone whereas MR-expressing cells consisting of Mphi and nonvascular endothelia are located in the red pulp. No colocalisation of MR with CR ligands has been observed in murine tissues. In this manuscript we describe the distribution of MR and CR ligands in human spleen. In this organ we have detected a perfect colocalisation of MR with CR ligands in Lyve-1+ cells lining venous sinuses. These cells form a physical barrier for blood cells as they need to migrate through the sinuses in order to exit the splenic parenchyma and, in this way, contribute to the unique filtration function of this organ. Furthermore, unlike murine spleen, CD68+ red pulp Mphi lack MR expression. Our results suggest an unexpected contribution of MR to splenic function through the recognition of sulphated ligands that could influence the filtering capability of this organ.

Ala A, Schiano T, Burroughs A, Keshav S. 2004. Recognition of nonhepatic coma in the setting of acetaminophen overdose. Dig Dis Sci, 49 (11-12), pp. 1977-1980. | Read more

Ogura Y, Lala S, Xin W, Smith E, Dowds TA, Chen FF, Zimmermann E, Tretiakova M, Cho JH, Hart J et al. 2003. Expression of NOD2 in Paneth cells: a possible link to Crohn's ileitis. Gut, 52 (11), pp. 1591-1597. | Show Abstract | Read more

BACKGROUND AND AIMS: Genetic variation in NOD2 has been associated with susceptibility to Crohn's disease (CD) and specifically with ileal involvement. The reason for the unique association of NOD2 mutations with ileal disease is unclear. To identify a possible link, we tested expression of NOD2 in intestinal tissue of CD patients and controls. PATIENTS AND METHODS: Fifty five specimens of ileum or colon from 21 CD patients, seven ulcerative colitis (UC) patients, and five controls with pathology other than CD or UC were stained for NOD2 using an immunoperoxidase method. RESULTS: Using a monoclonal antibody against NOD2 developed in our laboratory, we detected uniform expression of NOD2 in terminal ileum Paneth cells from controls and patients as well as in metaplastic Paneth cells in the colon. Mechanical purification showed enriched expression of NOD2 mRNA in ileal crypts. In Paneth cells, NOD2 was located in the cytosol in close proximity to the granules that contain antimicrobial peptides. We detected minimal NOD2 in the villous epithelium of the ileum or in the colonic epithelium from both CD patients and controls. CONCLUSIONS: These results suggest a role for NOD2 in the regulation of Paneth cell mediated responses against intestinal bacteria and a plausible mechanism to explain the selective association of NOD2 mutations with ileal disease. The impaired capacity of CD associated mutations to sense luminal bacteria may result in increased susceptibility to certain gut microbes.

Lala S, Ogura Y, Osborne C, Hor SY, Bromfield A, Davies S, Ogunbiyi O, Nuñez G, Keshav S. 2003. Crohn's disease and the NOD2 gene: a role for paneth cells. Gastroenterology, 125 (1), pp. 47-57. | Show Abstract | Read more

BACKGROUND & AIMS: The NOD2 gene, which is strongly associated with susceptibility to Crohn's disease (CD) of the terminal ileum, interacts with bacterial lipopolysaccharide (LPS), inducing cellular activation. However, the mechanisms by which NOD2 mutations cause terminal ileitis are unknown, and NOD2 is expressed most highly by peripheral blood monocytes, which are distributed ubiquitously and readily respond to LPS via cell-surface receptors. Paneth cells on the other hand, are most numerous in the terminal ileum, are critically important in enteric antibacterial defense, and respond to LPS through as yet undefined pathways. We therefore determined if these specialized intestinal epithelial cells also expressed the NOD2 gene. METHODS: In situ hybridization, immunohistochemistry, and laser-capture microdissection were used to determine RNA and protein expression in tissue sections, and real-time reverse-transcription polymerase chain reaction (RT-PCR) was used to quantitate gene expression in intestinal epithelial cells and peripheral blood mononuclear cells. RESULTS: NOD2 was detected readily in monocytes, but not in mature macrophages in the lamina propria or within granulomas, and levels declined as monocytes differentiated into macrophages in vitro, so that Caco-2 cells expressed more NOD2 mRNA than macrophages. NOD2 mRNA was enriched in crypts compared with villi, and in situ, Paneth cells were the most prominent cells expressing NOD2 in normal and CD-affected intestinal tissue, where they also strongly expressed tumor necrosis factor alpha (TNFalpha) RNA. CONCLUSIONS: The NOD2 gene product is most abundant in Paneth cells in the terminal ileum, which could therefore play a critical and hitherto unrecognized role in the pathogenesis of NOD2-associated CD.

Lala SG, Turton D, Keshav S. 2002. Expression of tumour necrosis factor alpha (TNF alpha) and lysozyme in necrotizing enterocolitis (NEC) GUT, 50 pp. A27-A27.

Osborne CLE, Davies S, Ogunbiye O, Keshav S. 2002. Phosphoinositide signalling in inflammatory bowel disease and colorectal neoplasia GUT, 50 pp. A77-A78.

Pastacaldi S, Butler P, Keshav S, Burroughs AK, Rolles K. 2001. Isolation of liver associated leukocytes (LAL) from human liver graft perfusates JOURNAL OF HEPATOLOGY, 34 pp. 36-37.

Papatheodoridis GV, Chung S, Keshav S, Pasi J, Burroughs AK. 1999. Correction of both prothrombin time and primary haemostasis by recombinant factor VII during therapeutic alcohol injection of hepatocellular cancer in liver cirrhosis. J Hepatol, 31 (4), pp. 747-750. | Show Abstract | Read more

We evaluated the efficacy of recombinant factor VII to correct impaired haemostasis in a patient with liver cirrhosis requiring an invasive procedure. A test intravenous bolus of 80 microg/kg of recombinant factor VII was given to a Jehovah's Witness, with a solitary 4.4-cm hepatocellular carcinoma and underlying hepatitis C virus cirrhosis, in an attempt to correct his haemostatic disorders and safely inject the tumour with alcohol. An extensive portal block had precluded consideration of liver transplantation. Haemostasis was evaluated by clotting assays, bleeding time and thromboelastography 10 min before and 10 min and 1, 2, 4, 8 and 24 h after factor VII infusion. Parameters of both coagulation (prothrombin time) and platelet function (bleeding time and the alpha and ma parameters of thrombelastography) were improved 10 min after factor VII infusion; improvements lasted 4 to 8 h or more. Platelet count did not change and there was no evidence of disseminated intravascular coagulation. The improvements in haemostatic parameters correlated significantly with the increases in factor VII plasma concentrations (p<0.04). Factor VII clearance was 25.1 U/h/kg and its half-life was 5.8 h. The same dose of recombinant factor VII was given to the patient 1 week later, just before the alcohol injections. The patient had no subsequent bleeding or other complication, with no change in haemoglobin levels over 24 h. Thus, recombinant factor VII represents a therapeutic advance, as it can correct fully both coagulation and platelet function defects in cirrhosis and allow invasive procedures to be performed safely.

Papatheodoridis G, Chung S, Keshav S, Hardaker L, Pasi J, Burroughs AK. 1999. Recombinant factor VIIA is used in a Jehova's Witness with liver cirrhosis to correct prothrombin time, bleeding time, and thromboelastographic parameters, enabling safe percutaneous injection of hepatocellular carcinoma THROMBOSIS AND HAEMOSTASIS, pp. 620-620.

Papatheodoridis GV, Chung S, Keshav S, Pasi J, Burroughs AK. 1999. Correction of both prothrombin time and primary haemostasis by recombinant factor VII during therapeutic alcohol injection of hepatocellular cancer in liver cirrhosis GASTROENTEROLOGY, 116 (4), pp. A1260-A1260.

Dalton D, Haynes L, Chu C, Keshav S, Gordon S, Swain S, Wittmer S. 1999. Interferon-gamma is required to stop proliferation and promote apoptosis of CD4 T cells during BCG infection. FASEB JOURNAL, 13 (5), pp. A982-A982.

Haworth R, Platt N, Keshav S, Hughes D, Darley E, Suzuki H, Kurihara Y, Kodama T, Gordon S. 1997. The macrophage scavenger receptor type A is expressed by activated macrophages and protects the host against lethal endotoxic shock. J Exp Med, 186 (9), pp. 1431-1439. | Show Abstract | Read more

During gram-negative bacterial infections, lipopolysaccharide (LPS) stimulates primed macrophages (Mphi) to release inflammatory mediators such as tumor necrosis factor (TNF)-alpha, which can cause hypotension, organ failure, and often death. Several different receptors on Mphi have been shown to bind LPS, including the type A scavenger receptor (SR-A). This receptor is able to bind a broad range of polyanionic ligands such as modified lipoproteins and lipoteichoic acid of gram-positive bacteria, which suggests that SR-A plays a role in host defense. In this study, we used mice lacking the SR-A (SRKO) to investigate the role of SR-A in acquired immunity using a viable bacillus Calmette Guérin (BCG) infection model. We show that activated Mphi express SR-A and that this molecule is functional in assays of adhesion and endocytic uptake. After BCG infection, SRKO mice are able to recruit Mphi to sites of granuloma formation where they become activated and restrict BCG replication. However, infected mice lacking the SR-A are more susceptible to endotoxic shock and produce more TNF-alpha and interleukin-6 in response to LPS. In addition, we show that an antibody which blocks TNF-alpha activity reduces LPS-induced mortality in these mice. Thus SR-A, expressed by activated Mphi, plays a protective role in host defense by scavenging LPS as well as by reducing the release by activated Mphi of proinflammatory cytokines. Modulation of SR-A may provide a novel therapeutic approach to control endotoxic shock.

Keshav S, McKnight AJ, Arora R, Gordon S. 1997. Cloning of intestinal phospholipase A2 from intestinal epithelial RNA by differential display PCR. Cell Prolif, 30 (10-12), pp. 369-383. | Show Abstract | Read more

Differential display polymerase chain reaction (DD-PCR) is a powerful technique for comparing gene expression between cell types, or between stages of development or differentiation. Differentially expressed genes may be cloned and analysed further. Here we extend the use of DD-PCR to analyse differences in gene expression between two complex epithelia: that of the small intestine and of the large intestine. The aim of this study was to identify genes expressed preferentially in Paneth cells. Paneth cells are secretory epithelial cells putatively involved in host defense and regulation of crypt cell proliferation and are found at the base of the small intestinal crypts adjacent to the stem cell zone. Of 34 clones that were analysed, partial sequencing identified two clones related to known Paneth cell products: a homologue of secretory phospholipase A2 (clone B1) and a homologue of a neutrophil defensin (clone C5). B1 was strongly expressed in Paneth cells, as demonstrated by in-situ hybridization. B1 was also expressed at a lower level in the large intestinal epithelium. A full length B1 cDNA clone was isolated and sequenced, and shown to be highly homologous to type II secretory phospholipase A2 genes, and almost identical to the enhancing factor gene and the putative gene for the MOM-1 locus. B1 expression is limited to the intestinal tract, and we propose that it be designated intestinal phospholipase A2, or i-PLA2. The method we describe is well suited to the rapid identification of genes expressed exclusively or predominantly in Paneth cells.

Mistry PK, Butler P, Keshav S, Elstein D, Zimran A. 1997. Effect of macrophage-targeted glucocerebrosidase(alglucerase) on hypolipidaemia of type 1 Gaucher disease(GD) HEPATOLOGY, 26 (4), pp. 1015-1015.

Dalton DJ, Haynes L, Jardieu P, Gordon S, Swain SL, Keshav S. 1997. A possible role for interferon-gamma as a regulator of B cell proliferation during an immune response. JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY, 99 (1), pp. 1549-1549.

MCGOWAN I, RADFORDSMITH G, KESHAV S, JEWELL DP. 1994. QUANTITATIVE ASSESSMENT OF CYTOKINE GENE-EXPRESSION IN HIV-INFECTED INTESTINAL-MUCOSA GASTROENTEROLOGY, 106 (4), pp. A732-A732.

RADFORDSMITH G, MCGOWAN I, KESHAV S, JEWELL DP. 1994. INVESTIGATION OF CYTOKINE MESSENGER-RNA PRODUCTION IN THE NORMAL HUMAN INTESTINAL-MUCOSA GASTROENTEROLOGY, 106 (4), pp. A757-A757.

Herbein G, Keshav S, Collin M, Montaner LJ, Gordon S. 1994. HIV-1 induces tumour necrosis factor and IL-1 gene expression in primary human macrophages independent of productive infection. Clin Exp Immunol, 95 (3), pp. 442-449. | Show Abstract | Read more

Cytokines such as tumour necrosis factor-alpha (TNF-alpha) and IL-1 beta may play a role in immunopathogenesis of AIDS. We studied early effects (0.5-48 h) of monocytotropic (ADA) or lymphotropic (IIIB) strains of HIV-1 on TNF-alpha and IL-1 beta mRNA expression in primary human macrophages by a semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) assay. Three-day-old monocyte-derived macrophages were exposed either to tissue culture supernatants containing virus (at multiplicity of infection (m.o.i.) of 0.05) or to control supernatants free of virions and gp120. ADA strain, but not IIIB, replicated in primary tissue culture-differentiated macrophages (TCDM). Soluble CD4 (sCD4) was used to inhibit binding of both strains to macrophages. We found that TNF-alpha and IL-1 beta gene expression was induced by both strains 0.5-3 h after addition of virus, and that enhanced expression of both cytokines was inhibited by sCD4. We conclude that CD4-dependent binding to the cell surface is sufficient to enhance TNF-alpha and IL-1 beta mRNA, whereas productive viral replication in primary human macrophages is not required. Therefore, similar pathways regulate gene expression of TNF-alpha and IL-1 beta by macrophages during initial infection by HIV-1 in vitro.

MCGOWAN I, RADFORDSMITH G, KESHAV S, JEWELL DP. 1993. CYTOKINE PROFILES IN HIV-INFECTED INTESTINAL-MUCOSA GASTROENTEROLOGY, 104 (4), pp. A740-A740.

RADFORDSMITH G, MCGOWAN I, KESHAV S, JEWELL DP. 1993. INVESTIGATION OF MUCOSAL CYTOKINE MESSENGER-RNA TRANSCRIPTS IN PATIENTS WITH ULCERATIVE-COLITIS (UC) AND CROHNS-DISEASE (CD) GASTROENTEROLOGY, 104 (4), pp. A767-A767.

HERBEIN G, KESHAV S, COLLIN M, MONTANER L, GORDON S. 1993. DIFFERENTIAL REGULATION OF CYTOKINE MESSENGER-RNA DURING ACUTE INFECTION OF PRIMARY MONONUCLEAR PHAGOCYTES BY HIV-1 JOURNAL OF CELLULAR BIOCHEMISTRY, pp. 15-15.

MCGOWAN I, KESHAV S, RADFORDSMITH G, JEWELL DPJ. 1993. TH1/TH2 CYTOKINE PROFILES IN HIV-INFECTED INTESTINAL-MUCOSA JOURNAL OF CELLULAR BIOCHEMISTRY, pp. 91-91.

Dalton DK, Pitts-Meek S, Keshav S, Figari IS, Bradley A, Stewart TA. 1993. Multiple defects of immune cell function in mice with disrupted interferon-gamma genes. Science, 259 (5102), pp. 1739-1742. | Show Abstract | Read more

Interferon-gamma (IFN-gamma) is a pleiotrophic cytokine with immunomodulatory effects on a variety of immune cells. Mice with a targeted disruption of the IFN-gamma gene were generated. These mice developed normally and were healthy in the absence of pathogens. However, mice deficient in IFN-gamma had impaired production of macrophage antimicrobial products and reduced expression of macrophage major histocompatibility complex class II antigens. IFN-gamma-deficient mice were killed by a sublethal dose of the intracellular pathogen Mycobacterium bovis. Splenocytes exhibited uncontrolled proliferation in response to mitogen and alloantigen. After a mixed lymphocyte reaction, T cell cytolytic activity was enhanced against allogeneic target cells. Resting splenic natural killer cell activity was reduced in IFN-gamma-deficient mice. Thus, IFN-gamma is essential for the function of several cell types of the murine immune system.

de Sauvage FJ, Keshav S, Kuang WJ, Gillett N, Henzel W, Goeddel DV. 1992. Precursor structure, expression, and tissue distribution of human guanylin. Proc Natl Acad Sci U S A, 89 (19), pp. 9089-9093. | Show Abstract | Read more

Heat-stable enterotoxins (STa) are small, cysteine-rich peptides secreted by Escherichia coli that are able to induce diarrhea through the stimulation of an intestine-specific receptor-guanylyl cyclase known as STaR. A 15-amino acid peptide, guanylin, was recently purified from rat jejunum and proposed to be a potential endogenous activator of this receptor. We describe here the cloning and characterization of human and mouse cDNAs encoding precursor proteins of 115 and 116 amino acids, respectively, having guanylin present at their C termini. Expression of the human cDNA in mammalian cells leads to the secretion of proguanylin, an inactive 94-amino acid protein. Guanylin generated by either trypsin or acid treatment of proguanylin was purified and found to bind to, and activate, STaR. Northern blot and in situ hybridization show high-level expression of guanylin mRNA restricted to the intestine, with localization to Paneth cells at the base of the small intestinal crypts. These results demonstrate that guanylin is an endogenous activator of STaR.

Cappello M, Keshav S, Prince C, Jewell DP, Gordon S. 1992. Detection of mRNAs for macrophage products in inflammatory bowel disease by in situ hybridisation. Gut, 33 (9), pp. 1214-1219. | Show Abstract | Read more

In situ hybridisation has been used to detect mRNAs to the macrophage secretory products, lysozyme, interleukin 1 beta and tumour necrosis factor-alpha. Sections of paraformaldehyde fixed, frozen colonoscopic biopsies from patients with ulcerative colitis, Crohn's disease or normal controls were hybridised with specific radiolabelled probes and the signal detected by autoradiography. Lysozyme mRNA expression was more common in ulcerative colitis (22/27) and Crohn's disease (eight of eight) compared with controls (17/27). Positive cells were found mainly in the subepithelial region in normal colon, while in inflammatory bowel disease they also appeared in the deeper lamina propria. Immunocytochemistry in parallel sections showed that lysozyme mRNA was expressed only in macrophages or in metaplastic Paneth cells in longstanding inflammatory bowel disease. Tissue neutrophils did not express the lysozyme mRNA, though they have large stores of the protein. Tumour necrosis factor mRNA was detected in four of nine controls compared with 11/15 inflammatory bowel disease patients. For interleukin 1 beta, three of eight controls were positive compared with 10/13 with ulcerative colitis. The tumour necrosis factor signal was located mainly in the deeper lamina propria whereas the interleukin 1 beta was seen in subepithelial macrophages. These results confirm increased macrophage activation in inflammatory bowel disease and suggest functional heterogeneity within the intestinal macrophage population.

Stamp GW, Poulsom R, Chung LP, Keshav S, Jeffery RE, Longcroft JA, Pignatelli M, Wright NA. 1992. Lysozyme gene expression in inflammatory bowel disease. Gastroenterology, 103 (2), pp. 532-538. | Show Abstract | Read more

Riboprobe in situ hybridization (rISH) demonstrates active lysozyme synthesis in ulcerative colitis and Crohn's disease. Maximal labeling was seen in Paneth cells, macrophages, and granulomas. Diffuse infiltration of the mucosa by lysozyme-rich polymorphs characterizes ulcerative colitis but obscures reactivity in other cell lineages in immunohistochemical studies; lysozyme mRNA is not detected in polymorphs, rISH giving a clearer picture than immunohistochemical studies of the active synthesis of lysozyme within the gut in inflammatory bowel disease. In ulcerative colitis, strong signals localized to Paneth cell metaplasia were found in 11 of 20 cases and to a lesser degree in non-Paneth cell lineages in regenerative mucosa in 13 of 20 cases. In Crohn's disease, abundant labeling was seen in tuberculoid granulomas (5 of 20) and over macrophage aggregates in the lamina propria in another 7, characteristic patterns not encountered in ulcerative colitis. Low levels of lysozyme messenger RNA were found in the ulceration-associated cell lineage ("pseudopyloric metaplasia"). These results support the view that neutrophils are largely responsible for elevated fecal lysozyme levels in ulcerative colitis and macrophages for elevated serum lysozyme levels in Crohn's disease.

Stein M, Keshav S, Harris N, Gordon S. 1992. Interleukin 4 potently enhances murine macrophage mannose receptor activity: a marker of alternative immunologic macrophage activation. J Exp Med, 176 (1), pp. 287-292. | Show Abstract | Read more

Expression of the macrophage mannose receptor is inhibited by interferon gamma (IFN-gamma), a T helper type 1 (Th-1)-derived lymphokine. Interleukin 4 (IL-4), a Th-2 lymphocyte product, upregulates major histocompatibility class II antigen expression but inhibits inflammatory cytokine production by macrophages. We have studied the effect of IL-4 on expression of the macrophage mannose receptor (MMR) by elicited peritoneal macrophages. We found that recombinant murine IL-4 enhances MMR surface expression (10-fold) and activity (15-fold), as measured by the respective binding and degradation of 125I-mannose-bovine serum albumin. Polymerase chain reaction analysis of cDNAs from purified primary macrophage populations revealed that MMR, but not lysozyme or tumor necrosis factor alpha, mRNA levels were markedly increased by IL-4. The above effects were associated with morphologic changes. These data establish IL-4 as a potent and selective enhancer of murine MMR activity in vitro. IL-4 induces inflammatory macrophages to adopt an alternative activation phenotype, distinct from that induced by IFN-gamma, characterized by a high capacity for endocytic clearance of mannosylated ligands, enhanced (albeit restricted) MHC class II antigen expression, and reduced proinflammatory cytokine secretion.

Reichman CT, Mayer BJ, Keshav S, Hanafusa H. 1992. The product of the cellular crk gene consists primarily of SH2 and SH3 regions. Cell Growth Differ, 3 (7), pp. 451-460. | Show Abstract

We have cloned and sequenced a complementary DNA encoding the cellular homologue of the transforming oncogene v-crk of avian sarcoma virus CT10. This complementary DNA contains an open reading frame of 915 base pairs that encodes a polypeptide of 305 amino acids. The first 205 amino acids of this c-Crk protein were identical to those of the CT10 encoded v-Crk protein, with the exception of 5 amino acids. Like v-Crk, this portion of c-Crk contained one each of the Src homology domains SH2, SH2', and SH3. The 100 carboxy-terminal amino acids of c-Crk protein, which are not coded for in the CT10 viral genome, contain another SH3 region. We found limited sequence homology between c-crk and the avian retrovirus genome, which explains recombination events in the transduction of this protooncogene. Using a polyclonal antiserum made against bacterially expressed v-crk, we identified a 35-kilodalton protein in normal chicken embryo fibroblasts and in all embryonic chicken tissues examined. This 35-kilodalton protein was indistinguishable from a polypeptide made by in vitro translation of c-crk complementary DNA.

Stein M, Keshav S. 1992. The versatility of macrophages. Clin Exp Allergy, 22 (1), pp. 19-27. | Read more

Keshav S, Chung P, Milon G, Gordon S. 1991. Lysozyme is an inducible marker of macrophage activation in murine tissues as demonstrated by in situ hybridization. J Exp Med, 174 (5), pp. 1049-1058. | Show Abstract | Read more

This study demonstrates the induction of lysozyme mRNA expression in situ in tissue macrophages (M phi) of mice following in vivo stimulation. The resting resident tissue M phi of most tissues do not contain enough lysozyme mRNA to be detected by in situ hybridization using 35S-labeled RNA probes. Following Bacille Calmette Guerin or Plasmodium yoelli infection, however, M phi recruited to liver and spleen hybridize strongly to the lysozyme probe. Within 24 h of infection, cells found in the marginal zone of the spleen begin to produce lysozyme mRNA. This response is also evoked by a noninfectious agent (intravenously injected sheep erythrocytes), and is possibly the result of an early phagocytic interaction. Later in the infection, other cells in the red and white pulp of the spleen, and cells in granulomas in the liver, become lysozyme-positive. Kupffer cells are rarely lysozyme-positive. Lysozyme mRNA levels in liver granulomas remain relatively constant during the infection, and lysozyme is produced by most granuloma cells. This contrasts with tumor necrosis factor alpha (TNF alpha) mRNA, which is produced by fewer cells in the granuloma, and which can be massively induced by lipopolysaccharide administration. The production of lysozyme, previously considered a constitutive function of M phi, is therefore an indicator of M phi activation in vivo, where immunologically specific and nonspecific stimuli both stimulate lysozyme production at high levels in subpopulations of cells occupying discrete anatomical locations.

STAMP GWH, KESHAV S, CHUNG P, WRIGHT NA. 1990. EXPRESSION OF LYSOZYME IN INFLAMMATORY BOWEL-DISEASE JOURNAL OF PATHOLOGY, 160 (2), pp. A170-A170.

Keshav S, Lawson L, Chung LP, Stein M, Perry VH, Gordon S. 1990. Tumor necrosis factor mRNA localized to Paneth cells of normal murine intestinal epithelium by in situ hybridization. J Exp Med, 171 (1), pp. 327-332. | Show Abstract | Read more

Paneth cells in normal murine small intestine contain TNF mRNA that is readily detectable by in situ hybridization, unlike resident macrophages in lamina propria, which are negative. Northern blot analysis of whole tissue shows the presence of mRNA that has the same electrophoretic mobility as TNF mRNA from activated macrophages. A low level of TNF bioactivity, but no immunoreactivity, was detected in normal small intestine, and TNF production in resting Paneth cells appears to be post-transcriptionally controlled. Typical leukocyte surface membrane markers were not found on Paneth cells, but were expressed by the surrounding lamina propria macrophages. Paneth cells are thus epithelial cells with leukocyte-like secretory potential that may be important in intestinal physiology and pathology.

Gordon S, Keshav S, Chung LP. 1988. Mononuclear phagocytes: tissue distribution and functional heterogeneity. Curr Opin Immunol, 1 (1), pp. 26-35. | Read more

Chung LP, Keshav S, Gordon S. 1988. Cloning the human lysozyme cDNA: inverted Alu repeat in the mRNA and in situ hybridization for macrophages and Paneth cells. Proc Natl Acad Sci U S A, 85 (17), pp. 6227-6231. | Show Abstract | Read more

Lysozyme is a major secretory product of human and rodent macrophages and a useful marker for myelomonocytic cells. Based on the known human lysozyme amino acid sequence, oligonucleotides were synthesized and used as probes to screen a phorbol 12-myristate 13-acetate-treated U937 cDNA library. A full-length human lysozyme cDNA clone, pHL-2, was obtained and characterized. Sequence analysis shows that human lysozyme, like chicken lysozyme, has an 18-amino-acid-long signal peptide, but unlike the chicken lysozyme cDNA, the human lysozyme cDNA has a greater than 1-kilobase-long 3' nontranslated sequence. Interestingly, within this 3' region, an inverted repeat of the Alu family of repetitive sequences was discovered. In RNA blot analyses, DNA probes prepared from pHL-2 can be used to detect lysozyme mRNA not only from human but also from mouse and rat. Moreover, by in situ hybridization, complementary RNA transcripts have been used as probes to detect lysozyme mRNA in mouse macrophages and Paneth cells. This human lysozyme cDNA clone is therefore likely to be a useful molecular probe for studying macrophage distribution and gene expression.

Danese S, Rudziński J, Brandt W, Dupas J-L, Peyrin-Biroulet L, Bouhnik Y, Kleczkowski D, Uebel P, Lukas M, Knutsson M et al. 2015. Tralokinumab for moderate-to-severe UC: a randomised, double-blind, placebo-controlled, phase IIa study. Gut, 64 (2), pp. 243-249. | Show Abstract | Read more

OBJECTIVE: Interleukin-13 (IL-13) has been implicated as a key driver of UC. This trial evaluates the efficacy and safety of tralokinumab, an IL-13-neutralising antibody, as add-on therapy in adults with moderate-to-severe UC despite standard treatments. DESIGN: Non-hospitalised adults with UC (total Mayo score ≥6) were randomised to receive tralokinumab 300 mg or placebo subcutaneously every 2 weeks for 12 weeks. The primary end point was the rate of clinical response at week 8. Secondary efficacy end points included clinical remission and mucosal healing rates at week 8 and changes in total Mayo score, total modified Riley score, partial Mayo score and disease activity markers. RESULTS: Clinical response rate was 38% (21/56) for tralokinumab vs. 33% (18/55) for placebo (p=0.406). Clinical remission rate was 18% (10/56) vs. 6% (3/55) (p=0.033) and mucosal healing rate was 32% (18/56) vs. 20% (11/55) (p=0.104) for tralokinumab vs placebo. Changes to week 8 in total Mayo score and total modified Riley score were similar for tralokinumab and placebo (least-squares mean difference between groups: -0.49 (p=0.394) and 0.25 (p=0.449), respectively). Partial Mayo score at week 4 was lower with tralokinumab than placebo (least-squares mean difference between groups: -0.90 (p=0.041)). No consistent patterns were observed for disease activity markers. Tralokinumab had an acceptable safety profile. CONCLUSIONS: Add-on therapy with tralokinumab did not significantly improve clinical response. However, the higher clinical remission rate with tralokinumab than placebo suggests that tralokinumab may benefit some patients with UC. Tralokinumab was well tolerated. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov number: NCT01482884.

Keshav S, Vaňásek T, Niv Y, Petryka R, Howaldt S, Bafutto M, Rácz I, Hetzel D, Nielsen OH, Vermeire S et al. 2013. A randomized controlled trial of the efficacy and safety of CCX282-B, an orally-administered blocker of chemokine receptor CCR9, for patients with Crohn's disease. PLoS One, 8 (3), pp. e60094. | Show Abstract | Read more

UNLABELLED: CCX282-B, also called vercirnon, is a specific, orally-administered chemokine receptor CCR9 antagonist that regulates migration and activation of inflammatory cells in the intestine. This randomized, placebo-controlled trial was conducted to evaluate the safety and efficacy of CCX282-B in 436 patients with Crohn's disease. Crohn's Disease Activity Index (CDAI) scores were 250-450 and C-reactive protein >7.5 mg/L at study entry. In addition to stable concomitant Crohn's medication (85% of subjects), subjects received placebo or CCX282-B (250 mg once daily, 250 mg twice daily, or 500 mg once daily) for 12 weeks. They then received 250 mg CCX282-B twice daily, open-label, through week 16. Subjects who had a clinical response (a ≥ 70 point drop in CDAI) at week 16 were randomly assigned to groups given placebo or CCX282-B (250 mg, twice daily) for 36 weeks. Primary endpoints were clinical response at Week 8 and sustained clinical response at Week 52. During the 12-week Induction period, the clinical response was highest in the group given 500 mg CCX282-B once daily. Response rates at week 8 were 49% in the placebo group, 52% in the group given CCX282-B 250 mg once daily (odds ratio [OR] = 1.12; p = .667 vs placebo), 48% in the group given CCX282-B 250 mg twice daily (OR = 0.95; p = .833), and 60% in the group given CCX282-B 500 mg once daily (OR = 1.53; p = .111). At week 12, response rates were 47%, 56% (OR = 1.44; p = .168), 49% (OR = 1.07; p = .792), and 61% (OR = 1.74; p = .039), respectively. At the end of the Maintenance period (week 52), 47% of subjects on CCX282-B were in remission, compared to 31% on placebo (OR = 2.01; p = .012); 46% showed sustained clinical responses, compared to 42% on placebo (OR = 1.14; p = .629). CCX282-B was well tolerated. Encouraging results from this clinical trial led to initiation of Phase 3 clinical trials in Crohn's disease. TRIAL REGISTRATION: ClinicalTrials.gov NCT00306215.

Walters MJ, Wang Y, Lai N, Baumgart T, Zhao BN, Dairaghi DJ, Bekker P, Ertl LS, Penfold MET, Jaen JC et al. 2010. Characterization of CCX282-B, an orally bioavailable antagonist of the CCR9 chemokine receptor, for treatment of inflammatory bowel disease. J Pharmacol Exp Ther, 335 (1), pp. 61-69. | Show Abstract | Read more

The chemokine system represents a diverse group of G protein-coupled receptors responsible for orchestrating cell recruitment under both homeostatic and inflammatory conditions. Chemokine receptor 9 (CCR9) is a chemokine receptor known to be central for migration of immune cells into the intestine. Its only ligand, CCL25, is expressed at the mucosal surface of the intestine and is known to be elevated in intestinal inflammation. To date, there are no reports of small-molecule antagonists targeting CCR9. We report, for the first time, the discovery of a small molecule, CCX282-B, which is an orally bioavailable, selective, and potent antagonist of human CCR9. CCX282-B inhibited CCR9-mediated Ca(2+) mobilization and chemotaxis on Molt-4 cells with IC(50) values of 5.4 and 3.4 nM, respectively. In the presence of 100% human serum, CCX282-B inhibited CCR9-mediated chemotaxis with an IC(50) of 33 nM, and the addition of α1-acid glycoprotein did not affect its potency. CCX282-B inhibited chemotaxis of primary CCR9-expressing cells to CCL25 with an IC(50) of 6.8 nM. CCX282-B was an equipotent inhibitor of CCL25-directed chemotaxis of both splice forms of CCR9 (CCR9A and CCR9B) with IC(50) values of 2.8 and 2.6 nM, respectively. CCX282-B also inhibited mouse and rat CCR9-mediated chemotaxis. Inhibition of CCR9 with CCX282-B results in normalization of Crohn's disease such as histopathology associated with the TNF(ΔARE) mice. Analysis of the plasma level of drug associated with this improvement provides an understanding of the pharmacokinetic/pharmacodynamic relationship for CCR9 antagonists in the treatment of intestinal inflammation.

Hoffmann B, Schwarz M, Mehta A, Keshav S, Fabry Outcome Survey European Investigators. 2007. Gastrointestinal symptoms in 342 patients with Fabry disease: prevalence and response to enzyme replacement therapy. Clin Gastroenterol Hepatol, 5 (12), pp. 1447-1453. | Show Abstract | Read more

BACKGROUND & AIMS: Fabry disease is an X-linked deficiency of alpha-galactosidase A, resulting in lysosomal deposition of globotriaosylceramide in nearly all tissues. The disease frequently causes diarrhea and abdominal pain, which are assumed to arise from malfunction of enteric neurons and which mimic diarrhea-predominant irritable bowel syndrome (IBS). There are limited data about the prevalence and nature of gastrointestinal symptoms in patients with Fabry disease and the response to enzyme replacement therapy (ERT) in large cohorts. The aims of this study were to evaluate the nature and prevalence of gastrointestinal symptoms and their impact on health-related quality of life (HRQoL) in patients with Fabry disease and to analyze changes after 12 and 24 months of treatment with agalsidase alfa. METHODS: Information about gastrointestinal symptoms was obtained from regular interviews before and during the time of ERT. Data on HRQoL were collected by using the EQ-5D questionnaire. RESULTS: The overall prevalence of gastrointestinal symptoms was 52%, with abdominal pain and diarrhea being most frequent. Female patients were more frequently affected than male patients, and there was a high prevalence in children (abdominal pain, 49.3%; diarrhea 25.4%). ERT with agalsidase alfa reduced the prevalence of abdominal pain, with a statistically significant decrease in male patients and in children after 12 months of treatment. CONCLUSIONS: The gastrointestinal symptomatology of Fabry disease is very similar to diarrhea-predominant IBS; however, pathophysiologic similarities remain to be elucidated. ERT reduced the prevalence of gastrointestinal symptoms in Fabry disease, particularly in children and male patients.

Mayor NP, Shaw BE, Hughes DA, Maldonado-Torres H, Madrigal JA, Keshav S, Marsh SGE. 2007. Single nucleotide polymorphisms in the NOD2/CARD15 gene are associated with an increased risk of relapse and death for patients with acute leukemia after hematopoietic stem-cell transplantation with unrelated donors. J Clin Oncol, 25 (27), pp. 4262-4269. | Show Abstract | Read more

PURPOSE: Hematopoietic stem cell transplantation (HSCT) is an important option in the management of acute leukemia, but the risk of disease relapse and death remains appreciable. Recent studies have suggested that nucleotide-binding oligomerization domain 2 (NOD2)/caspase recruitment domain 15 (CARD15) gene single nucleotide polymorphisms (SNPs), implicated in innate immunity and Crohn's disease, may also affect immune function post-HSCT. PATIENTS AND METHODS: NOD2/CARD15 genotypes were analyzed in 196 patients diagnosed with acute leukemia and their unrelated donors. The pairs are part of a previously well-characterized cohort with a median follow-up of 2.2 years (range, 0.42 to 6.61 years). T-cell depletion was used in 83% of pairs. RESULTS: NOD2/CARD15 SNPs were associated with a reduction in overall survival (44% v 22%; log-rank P = .0087) due to an increase in disease relapse (32% v 54%; Gray's test P = .001) as compared with wild-type pairs. In multivariate analyses, the two most significant factors impacting outcome were transplantation in relapse and the presence of SNPs. The incidence of acute graft-versus-host disease was low and there was no significant difference due to the presence of SNPs. CONCLUSION: These data indicate an unrecognized role for the NOD2/CARD15 gene in unrelated donor HSCT for acute leukemia. The increased risk of disease relapse suggests that the wild-type gene product may contribute to a graft-versus-leukemia effect. These data suggest that NOD2/CARD15 genotyping before transplantation may contribute to prognosis and influence clinical management.

Ogura Y, Lala S, Xin W, Smith E, Dowds TA, Chen FF, Zimmermann E, Tretiakova M, Cho JH, Hart J et al. 2003. Expression of NOD2 in Paneth cells: a possible link to Crohn's ileitis. Gut, 52 (11), pp. 1591-1597. | Show Abstract | Read more

BACKGROUND AND AIMS: Genetic variation in NOD2 has been associated with susceptibility to Crohn's disease (CD) and specifically with ileal involvement. The reason for the unique association of NOD2 mutations with ileal disease is unclear. To identify a possible link, we tested expression of NOD2 in intestinal tissue of CD patients and controls. PATIENTS AND METHODS: Fifty five specimens of ileum or colon from 21 CD patients, seven ulcerative colitis (UC) patients, and five controls with pathology other than CD or UC were stained for NOD2 using an immunoperoxidase method. RESULTS: Using a monoclonal antibody against NOD2 developed in our laboratory, we detected uniform expression of NOD2 in terminal ileum Paneth cells from controls and patients as well as in metaplastic Paneth cells in the colon. Mechanical purification showed enriched expression of NOD2 mRNA in ileal crypts. In Paneth cells, NOD2 was located in the cytosol in close proximity to the granules that contain antimicrobial peptides. We detected minimal NOD2 in the villous epithelium of the ileum or in the colonic epithelium from both CD patients and controls. CONCLUSIONS: These results suggest a role for NOD2 in the regulation of Paneth cell mediated responses against intestinal bacteria and a plausible mechanism to explain the selective association of NOD2 mutations with ileal disease. The impaired capacity of CD associated mutations to sense luminal bacteria may result in increased susceptibility to certain gut microbes.

Lala S, Ogura Y, Osborne C, Hor SY, Bromfield A, Davies S, Ogunbiyi O, Nuñez G, Keshav S. 2003. Crohn's disease and the NOD2 gene: a role for paneth cells. Gastroenterology, 125 (1), pp. 47-57. | Show Abstract | Read more

BACKGROUND & AIMS: The NOD2 gene, which is strongly associated with susceptibility to Crohn's disease (CD) of the terminal ileum, interacts with bacterial lipopolysaccharide (LPS), inducing cellular activation. However, the mechanisms by which NOD2 mutations cause terminal ileitis are unknown, and NOD2 is expressed most highly by peripheral blood monocytes, which are distributed ubiquitously and readily respond to LPS via cell-surface receptors. Paneth cells on the other hand, are most numerous in the terminal ileum, are critically important in enteric antibacterial defense, and respond to LPS through as yet undefined pathways. We therefore determined if these specialized intestinal epithelial cells also expressed the NOD2 gene. METHODS: In situ hybridization, immunohistochemistry, and laser-capture microdissection were used to determine RNA and protein expression in tissue sections, and real-time reverse-transcription polymerase chain reaction (RT-PCR) was used to quantitate gene expression in intestinal epithelial cells and peripheral blood mononuclear cells. RESULTS: NOD2 was detected readily in monocytes, but not in mature macrophages in the lamina propria or within granulomas, and levels declined as monocytes differentiated into macrophages in vitro, so that Caco-2 cells expressed more NOD2 mRNA than macrophages. NOD2 mRNA was enriched in crypts compared with villi, and in situ, Paneth cells were the most prominent cells expressing NOD2 in normal and CD-affected intestinal tissue, where they also strongly expressed tumor necrosis factor alpha (TNFalpha) RNA. CONCLUSIONS: The NOD2 gene product is most abundant in Paneth cells in the terminal ileum, which could therefore play a critical and hitherto unrecognized role in the pathogenesis of NOD2-associated CD.

Keshav S, McKnight AJ, Arora R, Gordon S. 1997. Cloning of intestinal phospholipase A2 from intestinal epithelial RNA by differential display PCR. Cell Prolif, 30 (10-12), pp. 369-383. | Show Abstract | Read more

Differential display polymerase chain reaction (DD-PCR) is a powerful technique for comparing gene expression between cell types, or between stages of development or differentiation. Differentially expressed genes may be cloned and analysed further. Here we extend the use of DD-PCR to analyse differences in gene expression between two complex epithelia: that of the small intestine and of the large intestine. The aim of this study was to identify genes expressed preferentially in Paneth cells. Paneth cells are secretory epithelial cells putatively involved in host defense and regulation of crypt cell proliferation and are found at the base of the small intestinal crypts adjacent to the stem cell zone. Of 34 clones that were analysed, partial sequencing identified two clones related to known Paneth cell products: a homologue of secretory phospholipase A2 (clone B1) and a homologue of a neutrophil defensin (clone C5). B1 was strongly expressed in Paneth cells, as demonstrated by in-situ hybridization. B1 was also expressed at a lower level in the large intestinal epithelium. A full length B1 cDNA clone was isolated and sequenced, and shown to be highly homologous to type II secretory phospholipase A2 genes, and almost identical to the enhancing factor gene and the putative gene for the MOM-1 locus. B1 expression is limited to the intestinal tract, and we propose that it be designated intestinal phospholipase A2, or i-PLA2. The method we describe is well suited to the rapid identification of genes expressed exclusively or predominantly in Paneth cells.

Dalton DK, Pitts-Meek S, Keshav S, Figari IS, Bradley A, Stewart TA. 1993. Multiple defects of immune cell function in mice with disrupted interferon-gamma genes. Science, 259 (5102), pp. 1739-1742. | Show Abstract | Read more

Interferon-gamma (IFN-gamma) is a pleiotrophic cytokine with immunomodulatory effects on a variety of immune cells. Mice with a targeted disruption of the IFN-gamma gene were generated. These mice developed normally and were healthy in the absence of pathogens. However, mice deficient in IFN-gamma had impaired production of macrophage antimicrobial products and reduced expression of macrophage major histocompatibility complex class II antigens. IFN-gamma-deficient mice were killed by a sublethal dose of the intracellular pathogen Mycobacterium bovis. Splenocytes exhibited uncontrolled proliferation in response to mitogen and alloantigen. After a mixed lymphocyte reaction, T cell cytolytic activity was enhanced against allogeneic target cells. Resting splenic natural killer cell activity was reduced in IFN-gamma-deficient mice. Thus, IFN-gamma is essential for the function of several cell types of the murine immune system.

de Sauvage FJ, Keshav S, Kuang WJ, Gillett N, Henzel W, Goeddel DV. 1992. Precursor structure, expression, and tissue distribution of human guanylin. Proc Natl Acad Sci U S A, 89 (19), pp. 9089-9093. | Show Abstract | Read more

Heat-stable enterotoxins (STa) are small, cysteine-rich peptides secreted by Escherichia coli that are able to induce diarrhea through the stimulation of an intestine-specific receptor-guanylyl cyclase known as STaR. A 15-amino acid peptide, guanylin, was recently purified from rat jejunum and proposed to be a potential endogenous activator of this receptor. We describe here the cloning and characterization of human and mouse cDNAs encoding precursor proteins of 115 and 116 amino acids, respectively, having guanylin present at their C termini. Expression of the human cDNA in mammalian cells leads to the secretion of proguanylin, an inactive 94-amino acid protein. Guanylin generated by either trypsin or acid treatment of proguanylin was purified and found to bind to, and activate, STaR. Northern blot and in situ hybridization show high-level expression of guanylin mRNA restricted to the intestine, with localization to Paneth cells at the base of the small intestinal crypts. These results demonstrate that guanylin is an endogenous activator of STaR.

Stamp GW, Poulsom R, Chung LP, Keshav S, Jeffery RE, Longcroft JA, Pignatelli M, Wright NA. 1992. Lysozyme gene expression in inflammatory bowel disease. Gastroenterology, 103 (2), pp. 532-538. | Show Abstract | Read more

Riboprobe in situ hybridization (rISH) demonstrates active lysozyme synthesis in ulcerative colitis and Crohn's disease. Maximal labeling was seen in Paneth cells, macrophages, and granulomas. Diffuse infiltration of the mucosa by lysozyme-rich polymorphs characterizes ulcerative colitis but obscures reactivity in other cell lineages in immunohistochemical studies; lysozyme mRNA is not detected in polymorphs, rISH giving a clearer picture than immunohistochemical studies of the active synthesis of lysozyme within the gut in inflammatory bowel disease. In ulcerative colitis, strong signals localized to Paneth cell metaplasia were found in 11 of 20 cases and to a lesser degree in non-Paneth cell lineages in regenerative mucosa in 13 of 20 cases. In Crohn's disease, abundant labeling was seen in tuberculoid granulomas (5 of 20) and over macrophage aggregates in the lamina propria in another 7, characteristic patterns not encountered in ulcerative colitis. Low levels of lysozyme messenger RNA were found in the ulceration-associated cell lineage ("pseudopyloric metaplasia"). These results support the view that neutrophils are largely responsible for elevated fecal lysozyme levels in ulcerative colitis and macrophages for elevated serum lysozyme levels in Crohn's disease.

Stein M, Keshav S, Harris N, Gordon S. 1992. Interleukin 4 potently enhances murine macrophage mannose receptor activity: a marker of alternative immunologic macrophage activation. J Exp Med, 176 (1), pp. 287-292. | Show Abstract | Read more

Expression of the macrophage mannose receptor is inhibited by interferon gamma (IFN-gamma), a T helper type 1 (Th-1)-derived lymphokine. Interleukin 4 (IL-4), a Th-2 lymphocyte product, upregulates major histocompatibility class II antigen expression but inhibits inflammatory cytokine production by macrophages. We have studied the effect of IL-4 on expression of the macrophage mannose receptor (MMR) by elicited peritoneal macrophages. We found that recombinant murine IL-4 enhances MMR surface expression (10-fold) and activity (15-fold), as measured by the respective binding and degradation of 125I-mannose-bovine serum albumin. Polymerase chain reaction analysis of cDNAs from purified primary macrophage populations revealed that MMR, but not lysozyme or tumor necrosis factor alpha, mRNA levels were markedly increased by IL-4. The above effects were associated with morphologic changes. These data establish IL-4 as a potent and selective enhancer of murine MMR activity in vitro. IL-4 induces inflammatory macrophages to adopt an alternative activation phenotype, distinct from that induced by IFN-gamma, characterized by a high capacity for endocytic clearance of mannosylated ligands, enhanced (albeit restricted) MHC class II antigen expression, and reduced proinflammatory cytokine secretion.

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