Showing papers by "Stephan R. Targan published in 2010"

Genome-wide meta-analysis increases to 71 the number of confirmed Crohn's disease susceptibility loci

Abstract: We undertook a meta-analysis of six Crohn's disease genome-wide association studies (GWAS) comprising 6,333 affected individuals (cases) and 15,056 controls and followed up the top association signals in 15,694 cases, 14,026 controls and 414 parent-offspring trios. We identified 30 new susceptibility loci meeting genome-wide significance (P < 5 × 10⁻⁸). A series of in silico analyses highlighted particular genes within these loci and, together with manual curation, implicated functionally interesting candidate genes including SMAD3, ERAP2, IL10, IL2RA, TYK2, FUT2, DNMT3A, DENND1B, BACH2 and TAGAP. Combined with previously confirmed loci, these results identify 71 distinct loci with genome-wide significant evidence for association with Crohn's disease.

Genome-wide association identifies multiple ulcerative colitis susceptibility loci

Abstract: Ulcerative colitis is a chronic, relapsing inflammatory condition of the gastrointestinal tract with a complex genetic and environmental etiology. In an effort to identify genetic variation underlying ulcerative colitis risk, we present two distinct genome-wide association studies of ulcerative colitis and their joint analysis with a previously published scan, comprising, in aggregate, 2,693 individuals with ulcerative colitis and 6,791 control subjects. Fifty-nine SNPs from 14 independent loci attained an association significance of P < 10(-5). Seven of these loci exceeded genome-wide significance (P < 5 x 10(-8)). After testing an independent cohort of 2,009 cases of ulcerative colitis and 1,580 controls, we identified 13 loci that were significantly associated with ulcerative colitis (P < 5 x 10(-8)), including the immunoglobulin receptor gene FCGR2A, 5p15, 2p16 and ORMDL3 (orosomucoid1-like 3). We confirmed association with 14 previously identified ulcerative colitis susceptibility loci, and an analysis of acknowledged Crohn's disease loci showed that roughly half of the known Crohn's disease associations are shared with ulcerative colitis. These data implicate approximately 30 loci in ulcerative colitis, thereby providing insight into disease pathogenesis.

Fucosyltransferase 2 (FUT2) non-secretor status is associated with Crohn's disease

Abstract: Genetic variation in both innate and adaptive immune systems is associated with Crohn's disease (CD) susceptibility, but much of the heritability to CD remains unknown. We performed a genome-wide association study (GWAS) in 896 CD cases and 3204 healthy controls all of Caucasian origin as defined by multidimensional scaling. We found supportive evidence for 21 out of 40 CD loci identified in a recent CD GWAS meta-analysis, including two loci which had only nominally achieved replication (rs4807569, 19p13; rs991804, CCL2/CCL7). In addition, we identified associations with genes involved in tight junctions/epithelial integrity (ASHL, ARPC1A), innate immunity (EXOC2), dendritic cell biology [CADM1 (IGSF4)], macrophage development (MMD2), TGF-beta signaling (MAP3K7IP1) and FUT2 (a physiological trait that regulates gastrointestinal mucosal expression of blood group A and B antigens) (rs602662, P=3.4x10(-5)). Twenty percent of Caucasians are 'non-secretors' who do not express ABO antigens in saliva as a result of the FUT2 W134X allele. We demonstrated replication in an independent cohort of 1174 CD cases and 357 controls between the four primary FUT2 single nucleotide polymorphisms (SNPs) and CD (rs602662, combined P-value 4.90x10(-8)) and also association with FUT2 W143X (P=2.6x10(-5)). Further evidence of the relevance of this locus to CD pathogenesis was demonstrated by the association of the original four SNPs and CD in the recently published CD GWAS meta-analysis (rs602662, P=0.001). These findings strongly implicate this locus in CD susceptibility and highlight the role of the mucus layer in the development of CD.

Blockade of cytotoxic T-lymphocyte antigen-4 by ipilimumab results in dysregulation of gastrointestinal immunity in patients with advanced melanoma.

Abstract: Blockade of cytotoxic T-lymphocyte antigen-4 (CTLA-4) by ipilimumab leads to immune-mediated tumor regression and immune-related adverse events (irAEs), including diarrhea and colitis. The current analyses were undertaken to promote an understanding of the underlying mechanism of action and to identify potential biomarkers that could help in the prediction and management of ipilimumab-induced gastrointestinal irAEs. Treatment-naive or previously treated patients with unresectable stage III/IV melanoma (n = 115) received open-label ipilimumab (10 mg/kg every 3 weeks for four doses) and were randomized to receive concomitant blinded prophylactic oral budesonide (9 mg/d with gradual taper through week 16) or placebo. Outcome measures included histologic assessment of bowel biopsies and assessment of serologic markers of inflammatory bowel disease (IBD), fecal calprotectin levels, and polymorphisms in immune-related genes. Ipilimumab resulted in dysregulation of gastrointestinal mucosal immunity as evidenced by altered antibody levels to enteric flora, inflammatory cell infiltration into gastrointestinal mucosa, and increased fecal calprotectin associated with diarrhea and clinical evidence of colitis. The pattern of ipilimumab-induced antibody titers to microbial flora and the histologic features and location of the inflammation were distinct from classic IBD. Prophylactic budesonide did not prevent ipilimumab-induced bowel inflammation. Despite an observed association between colonic inflammation and grade 2 or higher diarrhea, no baseline biomarkers could reliably predict development of gastrointestinal toxicity. Although classic IBD and ipilimumab-related gastrointestinal toxicity are both immune mediated, the observed pattern of biomarkers suggests ipilimumab-related gastrointestinal toxicity may be a distinct clinicopathologic entity.

Genetic predictors of medically refractory ulcerative colitis

Abstract: Background: Acute severe ulcerative colitis (UC) remains a significant clinical challenge and the ability to predict, at an early stage, those individuals at risk of colectomy for medically refractory UC (MR-UC) would be a major clinical advance. The aim of this study was to use a genome-wide association study (GWAS) in a well-characterized cohort of UC patients to identify genetic variation that contributes to MR-UC. Methods: A GWAS comparing 324 MR-UC patients with 537 non-MR-UC patients was analyzed using logistic regression and Cox proportional hazards methods. In addition, the MR-UC patients were compared with 2601 healthy controls. Results: MR-UC was associated with more extensive disease (P = 2.7 × 10−6) and a positive family history of UC (P = 0.004). A risk score based on the combination of 46 single nucleotide polymorphisms (SNPs) associated with MR-UC explained 48% of the variance for colectomy risk in our cohort. Risk scores divided into quarters showed the risk of colectomy to be 0%, 17%, 74%, and 100% in the four groups. Comparison of the MR-UC subjects with healthy controls confirmed the contribution of the major histocompatibility complex to severe UC (peak association: rs17207986, P = 1.4 × 10−16) and provided genome-wide suggestive association at the TNFSF15 (TL1A) locus (peak association: rs11554257, P = 1.4 × 10−6). Conclusions: A SNP-based risk scoring system, identified here by GWAS analyses, may provide a useful adjunct to clinical parameters for predicting the natural history of UC. Furthermore, discovery of genetic processes underlying disease severity may help to identify pathways for novel therapeutic intervention in severe UC. (Inflamm Bowel Dis 2010)

Anti-CD3 antibody visilizumab is not effective in patients with intravenous corticosteroid-refractory ulcerative colitis.

Abstract: Background and aims Pilot studies with visilizumab, a humanised monoclonal antibody to CD3, suggest efficacy for corticosteroid-refractory ulcerative colitis (UC). A placebo-controlled trial was warranted. Methods A randomised, double-blind, placebocontrolled study evaluated the efficacy of visilizumab induction treatment in 127 patients with severely active UC despite treatment with $5 days of intravenous corticosteroids. Patients received placebo or visilizumab 5 mg/kg intravenously on days 1 and 2. Corticosteroids were tapered according to disease activity. Patients were followed up for 90 days. The primary end point was induction of response at day 45. Secondary end points included remission and mucosal healing at day 45, symptomatic response at day 15 and colectomy. Results Response at day 45 occurred in 55% of patients receiving visilizumab compared with 47% of those who received placebo (p¼0.475). Remission at day 45 occurred in 8% of patients receiving visilizumab compared with 9% of those who received placebo (p¼0.704). Mucosal healing at day 45 occurred in 29% of patients receiving visilizumab compared with 26% of those who received placebo (p¼0.799). Symptomatic response at day 15 occurred in 82% of patients receiving visilizumab compared with 74% of those who received placebo (p¼0.244). Colectomy was performed in 18% of patients receiving visilizumab compared with 7% of those who received placebo (p¼0.130). Cardiac disorders and vascular disorders occurred more frequently in the patients who received visilizumab. Conclusion Visilizumab at a dose of 5 mg/kg for two consecutive days was not effective for severe, corticosteroid-refractory UC and was associated with increased cardiac and vascular adverse events. (Registered at http://www.clinicaltrials. govNCT00279422/).

Future biologic targets for IBD: potentials and pitfalls.

Abstract: IBD treatment has evolved towards biologic therapy, which seeks to target specific immune and biochemical abnormalities at the molecular and cellular level. Improved understanding of the pathogenesis of IBD has suggested future drug biologic targets, which are currently being investigated. This Review article discusses the potentials and pitfalls of biologic therapy for IBD as this field advances at a rapid pace.

Prospective randomized open-label multicenter phase I/II dose escalation trial of visilizumab (HuM291) in severe steroid-refractory ulcerative colitis.

Abstract: Background: Visilizumab is a humanized IgG2 monoclonal anti-CD3 antibody. We evaluated its safety and dose response in severe intravenous steroid-refractory ulcerative colitis (UC). Methods: In all, 104 patients were treated. In Stage I, 73 patients were randomly assigned to receive intravenous visilizumab 5, 7.5, 10, or 12.5 μg/kg/day for 2 consecutive days. In Stage II, 33 patients received visilizumab at the optimal clinical dose (OCD) of 5 μg/kg/day for 2 days. Symptomatic response and remission were defined by the modified Truelove–Witts severity index. Clinical response and remission were defined by the Mayo score. Results: The rates of symptomatic response at day 15 in the 5, 7.5, 10, or 12.5 μg/kg dose groups were 71%, 70%, 50%, and 61%, respectively, in Stage I and in 54% in Stage II. The symptomatic remission rates were 35%, 5%, 22%, and 11% in Stage I and 18% in Stage II. The rates of clinical response at day 30 in the 5, 7.5, 10, or 12.5 μg/kg dose groups were 71%, 65%, 50%, and 67%, respectively, in Stage I and 55% in Stage II. The clinical remission rates were 6%, 5%, 0%, and 11% in Stage I and 6% in Stage II. All patients experienced adverse events. Serious adverse events included abdominal abscess, cytomegalovirus infection, atrial fibrillation, herpes zoster, and esophageal candidiasis. Conclusions: Treatment with visilizumab induced symptomatic response and clinical response. Results with 5 μg/kg/day were similar to those observed with higher doses (NCT00267306 at www.clinicaltrials.gov). (Inflamm Bowel Dis 2009;)

Combination of innate and adaptive immune alterations increased the likelihood of fibrostenosis in Crohn's disease.

Abstract: Crohn’s disease (CD) is a heterogeneous disorder with variability in disease presentation as well as the response to medical and surgical therapies. The natural history of the disease is influenced by site of involvement (intestinal versus colonic), and disease behavior, uncomplicated (inflammatory), or complicated by stricture (fibrostenosis), or by abscess, mass, or fistula (penetrating). The prevailing pathogenic hypothesis of CD is hyperresponsiveness of the gut mucosal immune system to normal luminal bacteria. This aberrant response results from a combination of defects in innate and acquired immunity. The relationship between markers of altered immunity and the clinical features and phenotypes of CD has been extensively studied. NOD2 (nucleotide oligomerization domain 2) was the first gene to be linked to CD.1,2 From a meta-analysis of 42 studies, the odds ratio (OR) for a single allelic variant was 2.2–4.1 for non-Jewish Caucasians and 1.7–2.5 for Jewish patients.3 Three major NOD2 polymorphisms have been recognized in CD, referred to initially as single nucleotide polymorphisms 8, 12, and 13 (SNP8, SNP12, SNP13), more properly referred to as R702W, G908R, and 1007fs. Carriage of 2 alleles increased the OR to 17.1.3 All 3 mutations of the NOD2 gene, in vitro, are associated with impairment of muramyl dipeptide (MDP)-driven nuclear factor-kappa B activation (NF-κB).4 In mononuclear cells from homozygote CD subjects impaired secretion of MDP-induced interleukin 1-α and interleukin 8 was observed, indicating a defect in innate immunity in some CD patients.5 NOD2 has been primarily linked to 2 clinical features of CD, small bowel involvement and the fibrostenosis phenotype. The association with small bowel disease location has been found by most investigators; the overall OR was 2.5.6 However, there was some variability in the association of NOD2 expression and the fibrostenosis phenotype, overall OR of 1.9.3 In a recent review 10 studies examined the genotype/phenotype interaction; 6 reported a significant association.6 The sample size, allelic frequency, and ethnicity of the reported patients were comparable between the studies that found a significant association and those that did not. In 2 prospective studies, no association was found between the NOD2 genotype and progression from the inflammatory to the fibrostenosing phenotype.7,8 Ahmed et al9 reported that the fibrostenosis and NOD2 association in their study was not independent by logistic regression of the association with ileal disease. Many CD patients have serologic evidence of a loss of tolerance to luminal bacteria. Duchmann et al10 were the first to show that CD patients have reactivity to multiple bacterial antigens. Specific associations between antibody responses to oligomannan (anti-Saccharomyces cerevisiae [ASCA], Escherichia coli outer membrane protein C [anti-OmpC], a CD-related protein from Pseudomonas fluorescens anti-CD-related bacterial sequence [I2], and Cbir1 flagellin [anti-Cbir1]) and CD phenotypes have been described.10–12 The presence of antibody positivity and elevated antibody titer has been directly associated with small bowel disease, the fibrostenosis and internal penetrating phenotypes, and small bowel surgery, and is inversely correlated with colonic disease.11,12 These associations were strongest when the individual antibody responses were combined either as the number of positive antibodies or as the total antibody level. In the prospective study of Scottish patients the presence and the magnitude of antibody responses to ASCA, anti-I2, and anti-OmpC was associated with progression of disease type.7 The in vitro evidence of defective MDP recognition and NF-κB activation found with NOD2 mutations provides a theory for a defect in innate immunity. We have recently shown that the defect in innate immunity is associated with a presumed compensatory hyperresponse in adaptive immunity.14 CD phenotypes are likely associated with specific genetic defects as well as markers of loss of tolerance to luminal bacteria. The purpose of this study was to clarify the relationship between the presence of allelic variants to the NOD2 gene and the presence and titer of antibodies to microbial antigens, Cbir, I2, OmpC, and oligomannan and the fibrostenosis phenotype. Further, in those CD patients with fibrostenosis, we proposed that an association would be found between innate (NOD2 mutations) and adaptive (microbial antigens) immune alterations. Our findings indicate that the presence of NOD2 variants and elevated titers of antibody to microbial antigens both contribute individually and, further, act synergistically to increase the likelihood of fibrostenosis in CD patients.

A prospective analysis of clinical variables, serologic factors, and outcome of ileal pouch-anal anastomosis in patients with backwash ileitis.

Abstract: PURPOSE: The outcome of ileal pouch-anal anastomosis in patients with backwash ileitis is controversial. We prospectively compared the outcomes of ileal pouch-anal anastomosis in colitis patients with backwash ileitis and colitis patients without backwash ileitis. METHODS: Consecutive colitis patients undergoing ileal pouch-anal anastomosis were reviewed. All patients were classified after surgery as being either backwash ileitis-positive or backwash ileitis-negative. Serum drawn preoperatively was assayed, using enzyme-linked immunosorbent assay, for anti-Saccharomyces cerevisiae, anti-outer membrane of porin C, anti-CBir1, anti-I2, and perinuclear anti-neutrophil cytoplasmic antibody. Outcomes included acute pouchitis (antibiotic responsive), chronic pouchitis (antibiotic dependent or refractory), or de novo Crohn's disease (small inflammation above the pouch inlet or pouch fistula). RESULTS: Out of 334 patients, 39 (12%) were backwash ileitis-positive. Compared with backwash ileitis-negative patients, backwash ileitis-positive patients had a higher incidence of pancolitis (100% vs 74%; P = .0001), primary sclerosing cholangitis (15% vs 2%; P = .001) and high-level (>100 enzyme-linked immunosorbent assay units/ml) perinuclear anti-neutrophil cytoplasmic antibody expression (29% vs 9%; P = .001). After a median follow-up of 26 months, 53 patients (16%) developed acute pouchitis, 37 (11%) developed chronic pouchitis, and 40 (12%) developed de novo Crohn's disease. There was no significant difference between the backwash ileitis-positive and backwash ileitis-negative patient groups in the incidence of acute pouchitis, chronic pouchitis, or de novo Crohn's disease. CONCLUSION: There was a significantly higher incidence of pancolitis, primary sclerosing cholangitis, and high-level perinuclear anti-neutrophil cytoplasmic antibody expression in backwash ileitis-positive patients than in backwash ileitis-negative patients. The incidence of acute pouchitis, chronic pouchitis, and de novo Crohn's disease after ileal pouch-anal anastomosis does not differ significantly between backwash ileitis-positive and backwash ileitis-negative patients.

TL1A Selectively Enhances IL-12/IL-18-Induced NK Cell Cytotoxicity against NK-Resistant Tumor Targets

Abstract: Introduction TL1A (TNFSF15) augments IFN-γ production by IL-12/IL-18 responsive human T cells. Its ligand, death domain receptor 3 (DR3), is induced by activation on T and NK cells. Although IL-12/IL-18 induces DR3 expression on most NK cells, addition of TL1A minimally increases IFN-γ production.

Preoperative Wireless Capsule Endoscopy Does Not Predict Outcome After Ileal Pouch-anal Anastomosis

Abstract: PURPOSE: The extent of preoperative small-bowel mucosal inflammation may be an important predictor of pouchitis after ileal pouch-anal anastomosis. This study examined the value of preoperative wireless capsule endoscopy in predicting outcome of ileal pouch-anal anastomosis in patients with ulcerative colitis or indeterminate colitis. METHODS: Patients undergoing complete wireless capsule endoscopy before ileal pouch-anal anastomosis were identified. Findings on wireless capsule endoscopy were classified as positive (erosions, ulcers or erythema) or negative. Outcome was assessed prospectively and included no pouchitis, acute pouchitis, chronic pouchitis, or de novo Crohn disease. Patients with acute pouchitis, chronic pouchitis, or de novo Crohn disease were considered to have pouch inflammation. RESULTS: The 68 study patients (48 ulcerative colitis; 20 indeterminate colitis) had a median age of 38 years and included 34 males. Median follow-up time after ileostomy closure was 12 months (range, 3-63 months). Wireless capsule endoscopy was positive in 15 patients (22%) and negative in 53 patients (78%). Pouch inflammation was observed in 23 patients (34%), and included 8 patients with acute pouchitis, 3 patients with chronic pouchitis, and 12 patients with de novo Crohn disease. The incidence of acute pouchitis, chronic pouchitis, de novo Crohn disease, and pouch inflammation in the wireless capsule endoscopy-positive patient group was 7%, 7%, 20%, and 33% compared with 13%, 4%, 17%, and 34% in the wireless capsule endoscopy-negative patient group (all P = NS). CONCLUSION: There was no statistical association between the results of preoperative wireless capsule endoscopy and outcome after ileal pouch-anal anastomosis in patients with ulcerative colitis or indeterminate colitis. There seems to be little value of wireless capsule endoscopy in the preoperative evaluation of these patients.

Methods of using smad3 and jak2 genetic variants to diagnose and predict inflammatory bowel disease

Abstract: Disclosed are methods of diagnosing Inflammatory Bowel Disease by determining the presence or absence of genetic variants at SMAD3 and/or JAK2 loci Provided is a method of diagnosing a Crohn's Disease subtype in an individual by determining the presence or absence of a risk variant at the SMAD3 and/or JAK2 loci