Peter M. Irving

Gluten Causes Gastrointestinal Symptoms in Subjects Without Celiac Disease: A Double-Blind Randomized Placebo-Controlled Trial

OBJECTIVES:Despite increased prescription of a gluten-free diet for gastrointestinal symptoms in individuals who do not have celiac disease, there is minimal evidence that suggests that gluten is a trigger. The aims of this study were to determine whether gluten ingestion can induce symptoms in non-celiac individuals and to examine the mechanism.METHODS:A double-blind, randomized, placebo-controlled rechallenge trial was undertaken in patients with irritable bowel syndrome in whom celiac disease was excluded and who were symptomatically controlled on a gluten-free diet. Participants received either gluten or placebo in the form of two bread slices plus one muffin per day with a gluten-free diet for up to 6 weeks. Symptoms were evaluated using a visual analog scale and markers of intestinal inflammation, injury, and immune activation were monitored.RESULTS:A total of 34 patients (aged 29–59 years, 4 men) completed the study as per protocol. Overall, 56% had human leukocyte antigen (HLA)-DQ2 and/or HLA-DQ8. Adherence to diet and supplements was very high. Of 19 patients (68%) in the gluten group, 13 reported that symptoms were not adequately controlled compared with 6 of 15 (40%) on placebo (P=0.0001; generalized estimating equation). On a visual analog scale, patients were significantly worse with gluten within 1 week for overall symptoms (P=0.047), pain (P=0.016), bloating (P=0.031), satisfaction with stool consistency (P=0.024), and tiredness (P=0.001). Anti-gliadin antibodies were not induced. There were no significant changes in fecal lactoferrin, levels of celiac antibodies, highly sensitive C-reactive protein, or intestinal permeability. There were no differences in any end point in individuals with or without DQ2/DQ8.CONCLUSIONS:“Non-celiac gluten intolerance” may exist, but no clues to the mechanism were elucidated.

Fermentable Carbohydrate Restriction Reduces Luminal Bifidobacteria and Gastrointestinal Symptoms in Patients with Irritable Bowel Syndrome

Preliminary studies indicate that dietary restriction of fermentable short-chain carbohydrates improves symptoms in irritable bowel syndrome (IBS). Prebiotic fructo-oligosaccharides and galacto-oligosaccharides stimulate colonic bifidobacteria. However, the effect of restricting fermentable short-chain carbohydrates on the gastrointestinal (GI) microbiota has never been examined. This randomized controlled trial aimed to investigate the effects of fermentable carbohydrate restriction on luminal microbiota, SCFA, and GI symptoms in patients with IBS. Patients with IBS were randomized to the intervention diet or habitual diet for 4 wk. The incidence and severity of symptoms and stool output were recorded for 7 d at baseline and follow-up. A stool sample was collected and analyzed for bacterial groups using fluorescent in situ hybridization. Of 41 patients randomized, 6 were withdrawn. At follow-up, there was lower intake of total short-chain fermentable carbohydrates in the intervention group compared with controls (P = 0.001). The total luminal bacteria at follow-up did not differ between groups; however, there were lower concentrations (P < 0.001) and proportions (P < 0.001) of bifidobacteria in the intervention group compared with controls when adjusted for baseline. In the intention-to-treat analysis, more patients in the intervention group reported adequate control of symptoms (13/19, 68%) compared with controls (5/22, 23%; P = 0.005). This randomized controlled trial demonstrated a reduction in concentration and proportion of luminal bifidobacteria after 4 wk of fermentable carbohydrate restriction. Although the intervention was effective in managing IBS symptoms, the implications of its effect on the GI microbiota are still to be determined.

Comparison of symptom response following advice for a diet low in fermentable carbohydrates (FODMAPs) versus standard dietary advice in patients with irritable bowel syndrome

BACKGROUND Emerging evidence indicates that the consumption of fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs) may result in symptoms in some patients with irritable bowel syndrome (IBS). The present study aimed to determine whether a low FODMAP diet is effective for symptom control in patients with IBS and to compare its effects with those of standard dietary advice based on the UK National Institute for Health and Clinical Excellence (NICE) guidelines. METHODS Consecutive patients with IBS who attended a follow-up dietetic outpatient visit for dietary management of their symptoms were included. Questionnaires were completed for patients who received standard (n = 39) or low FODMAP dietary advice (n = 43). Data were recorded on symptom change and comparisons were made between groups. RESULTS In total, more patients in the low FODMAP group reported satisfaction with their symptom response (76%) compared to the standard group (54%, P = 0.038). Composite symptom score data showed better overall symptom response in the low FODMAP group (86%) compared to the standard group (49%, P < 0.001). Significantly more patients in the low FODMAP group compared to the standard group reported improvements in bloating (low FODMAP 82% versus standard 49%, P = 0.002), abdominal pain (low FODMAP 85% versus standard 61%, P = 0.023) and flatulence (low FODMAP 87% versus standard 50%, P = 0.001). CONCLUSIONS A low FODMAP diet appears to be more effective than standard dietary advice for symptom control in IBS.

Review article: malignancy on thiopurine treatment with special reference to inflammatory bowel disease

Aliment Pharmacol Ther 2010; 32: 119–130

Optimising outcome on thiopurines in inflammatory bowel disease by co-prescription of allopurinol ☆

BACKGROUND AND AIMS Azathioprine and mercaptopurine remain first line immunomodulatory treatments for inflammatory bowel disease. Toxicity and non-response are significant issues. Co-prescription of allopurinol with reduced-dose (25-33%) azathioprine or mercaptopurine may overcome these problems. We present the outcome of co-prescription in a large single-centre cohort. METHOD Patients on thiopurine/allopurinol co-prescription were identified. Indication for and outcome on combination treatment were established. Blood parameters and metabolite results were compared on single agent and combination treatment. Toxicity associated with combination treatment was sought. RESULTS 110 patients on combination treatment were identified. Clinical remission was achieved in 60/79 (76%) of patients in whom the effect of thiopurine could be studied in isolation. 20/25 patients with hepatotoxicity tolerated combination treatment and normalised their liver function tests. 24/28 patients with atypical side effects tolerated co-therapy. 13/20 non-responders responded to combination treatment. In patients started on combination treatment as first line therapy, 15/23 achieved clinical remission. Thioguanine nucleotides were significantly higher and methylated metabolites significantly lower on combination therapy. Mean cell volume was higher and total white cell and neutrophil counts lower on combination treatment. 13 adverse events occurred, including 6 specific to co-therapy (3 rash, 2 abnormal liver function tests, 1 dosing error). All were minor and self-limiting. CONCLUSION This is the largest published experience of the use of allopurinol to optimise outcomes on thiopurine treatment. Combination therapy permitted successful treatment of a significant number of patients who would otherwise have been labelled as thiopurine failures. A few self-limiting side effects were encountered.

HLA-DQA1-HLA-DRB1 variants confer susceptibility to pancreatitis induced by thiopurine immunosuppressants

Pancreatitis occurs in approximately 4% of patients treated with the thiopurines azathioprine or mercaptopurine. Its development is unpredictable and almost always leads to drug withdrawal. We identified patients with inflammatory bowel disease (IBD) who had developed pancreatitis within 3 months of starting these drugs from 168 sites around the world. After detailed case adjudication, we performed a genome-wide association study on 172 cases and 2,035 controls with IBD. We identified strong evidence of association within the class II HLA region, with the most significant association identified at rs2647087 (odds ratio 2.59, 95% confidence interval 2.07–3.26, P = 2 × 10−16). We replicated these findings in an independent set of 78 cases and 472 controls with IBD matched for drug exposure. Fine mapping of the HLA region identified association with the HLA-DQA1*02:01–HLA-DRB1*07:01 haplotype. Patients heterozygous at rs2647087 have a 9% risk of developing pancreatitis after administration of a thiopurine, whereas homozygotes have a 17% risk.

Epithelia Use Butyrophilin-like Molecules to Shape Organ-Specific γδ T Cell Compartments

Summary Many body surfaces harbor organ-specific γδ T cell compartments that contribute to tissue integrity. Thus, murine dendritic epidermal T cells (DETCs) uniquely expressing T cell receptor (TCR)-Vγ5 chains protect from cutaneous carcinogens. The DETC repertoire is shaped by Skint1, a butyrophilin-like (Btnl) gene expressed specifically by thymic epithelial cells and suprabasal keratinocytes. However, the generality of this mechanism has remained opaque, since neither Skint1 nor DETCs are evolutionarily conserved. Here, Btnl1 expressed by murine enterocytes is shown to shape the local TCR-Vγ7+ γδ compartment. Uninfluenced by microbial or food antigens, this activity evokes the developmental selection of TCRαβ+ repertoires. Indeed, Btnl1 and Btnl6 jointly induce TCR-dependent responses specifically in intestinal Vγ7+ cells. Likewise, human gut epithelial cells express BTNL3 and BTNL8 that jointly induce selective TCR-dependent responses of human colonic Vγ4+ cells. Hence, a conserved mechanism emerges whereby epithelia use organ-specific BTNL/Btnl genes to shape local T cell compartments.

Optimizing quality of outpatient care for patients with inflammatory bowel disease : the importance of specialist clinics

Background Most patients with inflammatory bowel disease (IBD) undergo long-term outpatient follow up. However, quality of care provided by specialist and non-specialist IBD clinics is rarely critically audited. Objective To compare the standard of outpatient care provided by general gastroenterology and specialist IBD clinics within a single hospital using defined quality criteria. Methods The case notes of 60 consecutive patients with IBD attending general gastroenterology clinics and of 100 patients attending the specialist IBD clinic were reviewed for fulfilment of six quality criteria over the preceding 18 months. Results The proportion of patients fulfilling all six criteria was higher in the specialist IBD clinic. In the specialist IBD clinic, compared with the general gastroenterology clinics, blood tests were performed with appropriate frequency during the initiation of immunosuppressive treatment in 7/11 versus 2/12 patients (P=0.04) and during maintenance in 24/31 versus 6/21 patients (P=0.001); bone protection with oral steroids were given to 25/53 versus 4/24 patients (P=0.01); a screening colonoscopy at 8–10 years was performed in 25/27 versus 11/20 patients with ulcerative colitis (P=0.004); annual serum urea and creatinine concentrations were measured in 82/89 versus 31/45 patients prescribed 5-aminosalicylates (P=0.001); annual liver function tests were performed in 96/100 versus 38/60 patients (P=0.001); and annual haematinics were measured in 37/47 versus 18/33 patients with Crohns disease (P=0.03). Conclusion By these criteria, the specialist IBD clinic provided better care than the non-specialist general gastroenterology clinics. Even in the specialist clinic, however, the care of a minority of patients did not fulfil certain criteria, emphasizing the need for a critical audit of outpatient management of IBD.

Effects of Concomitant Immunomodulator Therapy on Efficacy and Safety of Anti–Tumor Necrosis Factor Therapy for Crohn’s Disease: A Meta-analysis of Placebo-controlled Trials

BACKGROUND & AIMS There is debate over whether patients with Crohns disease who start anti-tumor necrosis factor (TNF) therapy after failed immunomodulator therapy should continue to receive concomitant immunomodulators. We conducted a meta-analysis of subgroups from randomized controlled trials (RCTs) of anti-TNF agents to compare the efficacy and safety of concomitant immunomodulator therapy vs anti-TNF monotherapy. METHODS We performed a systematic review of literature published from 1980 through 2008 and identified 11 RCTs of anti-TNF agents in patients with luminal or fistulizing Crohns disease. We excluded RCTs of patients who were naive to anti-TNF and immunomodulator therapy. The primary end points were clinical response at weeks 4-14 and 24-30 and remission at weeks 24-30. Secondary end points included infusion site or injection site reactions and selected adverse events. A priori subgroup analyses were performed to evaluate fistula closure and the efficacy and safety of combination therapy with different anti-TNF agents. RESULTS Overall, combination therapy was no more effective than monotherapy in inducing 6-month remission (odds ratio [OR], 1.02; 95% confidence interval [CI], 0.80-1.31), inducing a response (OR, 1.08; 95% CI, 0.79-1.48), maintaining a response (OR, 1.53; 95% CI, 0.67-3.49), or inducing partial (OR, 1.25; 95% CI, 0.84-1.88) or complete fistula closure (OR, 1.10; 95% CI, 0.68-1.78). In subgroup analyses of individual anti-TNF agents, combination therapy was not more effective than monotherapy in inducing 6-month remission in those treated with infliximab (OR, 1.73; 95% CI, 0.97-3.07), adalimumab (OR, 0.88; 95% CI, 0.58-1.35), or certolizumab (OR, 0.93; 95% CI, 0.65-1.34). Overall, combination therapy was not associated with an increase in adverse events, but inclusion of infliximab was associated with fewer injection site reactions (OR, 0.46; 95% CI, 0.26-0.79.) CONCLUSIONS On the basis of a meta-analysis, continued use of immunomodulator therapy after starting anti-TNF therapy is no more effective than anti-TNF monotherapy in inducing or maintaining response or remission. RCTs are needed to adequately assess the efficacy of continued immunomodulator therapy after anti-TNF therapy is initiated.

Developing in vitro expanded CD45RA+ regulatory T cells as an adoptive cell therapy for Crohn's disease

Background and aim Thymus-derived regulatory T cells (Tregs) mediate dominant peripheral tolerance and treat experimental colitis. Tregs can be expanded from patient blood and were safely used in recent phase 1 studies in graft versus host disease and type 1 diabetes. Treg cell therapy is also conceptually attractive for Crohns disease (CD). However, barriers exist to this approach. The stability of Tregs expanded from Crohns blood is unknown. The potential for adoptively transferred Tregs to express interleukin-17 and exacerbate Crohns lesions is of concern. Mucosal T cells are resistant to Treg-mediated suppression in active CD. The capacity for expanded Tregs to home to gut and lymphoid tissue is unknown. Methods To define the optimum population for Treg cell therapy in CD, CD4+CD25+CD127loCD45RA+ and CD4+CD25+CD127loCD45RA− Treg subsets were isolated from patients’ blood and expanded in vitro using a workflow that can be readily transferred to a good manufacturing practice background. Results Tregs can be expanded from the blood of patients with CD to potential target dose within 22–24 days. Expanded CD45RA+ Tregs have an epigenetically stable FOXP3 locus and do not convert to a Th17 phenotype in vitro, in contrast to CD45RA− Tregs. CD45RA+ Tregs highly express α4β7 integrin, CD62L and CC motif receptor 7 (CCR7). CD45RA+ Tregs also home to human small bowel in a C.B-17 severe combined immune deficiency (SCID) xenotransplant model. Importantly, in vitro expansion enhances the suppressive ability of CD45RA+ Tregs. These cells also suppress activation of lamina propria and mesenteric lymph node lymphocytes isolated from inflamed Crohns mucosa. Conclusions CD4+CD25+CD127loCD45RA+ Tregs may be the most appropriate population from which to expand Tregs for autologous Treg therapy for CD, paving the way for future clinical trials.