David H. Dewar

The toxicity of high molecular weight glutenin subunits of wheat to patients with coeliac disease

Objectives The ability of the gliadin fraction of wheat gluten to exacerbate coeliac disease is well documented. We investigated the possible toxicity of high molecular weight glutenin subunits (HMW-GS) in coeliac disease in vitro using gluten-sensitive T cells, and in vivo with challenge studies in patient volunteers. Methods A mixture of four HMW-GS was chemically separated from wheat flour and checked for purity by HPLC, SDS-PAGE and ELISA. T-cell lines, grown up from small intestinal biopsies from coeliac patients (n=17), were tested for their reactivity to HMW-GS. Adults with coeliac disease and who were on a gluten-free diet (n=3) underwent in-vivo challenges with HMW-GS. Duodenal biopsies, taken prior to the challenge and at intervals up to 6 h afterwards, were assessed for morphology, intra-epithelial lymphocyte count, and interleukin 15 (IL-15) expression, by immunohistochemistry. Results T-cell lines from 11 of 17 patients were stimulated by HMW-GS. There was a significant change in small intestinal morphology 4 h after commencing infusions with HMW-GS in all three subjects. For example villus height to crypt depth ratios were reduced in the three patients from 3.0±0.5 to 1.29±0.2, 2.53±0.7 to 0.81±0.6 and 3.0±0.7 to 1.85±0.3, P<0.0001 in all cases. There was increased expression of IL-15 in the small intestine from 2 h after the HMW-GS challenges. Conclusion Mixed HMW-GS stimulate T-cell lines from some coeliac patients and exacerbate coeliac disease in vivo, inducing expression, within 2 h, of IL-15. This suggests an innate immune response to these proteins.

Celiac disease: Management of persistent symptoms in patients on a gluten-free diet

AIM To investigate all patients referred to our center with non-responsive celiac disease (NRCD), to establish a cause for their continued symptoms. METHODS We assessed all patients referred to our center with non-responsive celiac disease over an 18-mo period. These individuals were investigated to establish the eitiology of their continued symptoms. The patients were first seen in clinic where a thorough history and examination were performed with routine blood work including tissue transglutaminase antibody measurement. They were also referred to a specialist gastroenterology dietician to try to identift any lapses in the diet and sources of hidden gluten ingestion. A repeat small intestinal biopsy was also performed and compared to biopsies from the referring hospital where possible. Colonoscopy, lactulose hydrogen breath testing, pancreolauryl testing and computed tomography scan of the abdomen were undertaken if the symptoms persisted. Their clinical progress was followed over a minimum of 2 years. RESULTS One hundred and twelve consecutive patients were referred with NRCD. Twelve were found not to have celiac disease (CD). Of the remaining 100 patients, 45% were not adequately adhering to a strict gluten-free diet, with 24 (53%) found to be inadvertently ingesting gluten, and 21 (47%) admitting non-compliance. Microscopic colitis was diagnosed in 12% and small bowel bacterial overgrowth in 9%. Refractory CD was diagnosed in 9%. Three of these were diagnosed with intestinal lymphoma. After 2 years, 78 patients remained well, eight had continuing symptoms, and four had died. CONCLUSION In individuals with NRCD, a remediable cause can be found in 90%: with continued gluten ingestion as the leading cause. We propose an algorithm for investigation.

Faecal calprotectin:a noninvasive diagnostic tool and marker of severity in pouchitis

Introduction In pouchitis, the mucosa is infiltrated by activated polymorphonuclear neutrophils capable of producing calprotectin, a stable antimicrobial myelomonocytic protein. Aim The aim is to assess the ability of faecal calprotectin to differentiate between inflamed and noninflamed ileal pouches, and to correlate this with inflammation severity using the newly developed Objective Pouchitis Score. Method Fifty-four stool samples were collected from patients who had undergone restorative proctocolectomy; 46 from patients with ulcerative colitis and eight from those with familial adenomatous polyposis coli. Faecal calprotectin concentrations were determined by quantitative enzyme-linked immunosorbant assay. Results Of the ulcerative colitis patients, six were diagnosed with pouchitis and pre-pouch ileitis (median faecal calprotectin: 865 μg/g, with a range of 95–2350 μg/g); 13 had pouchitis alone (145, 33–3350 μg/g) and 27 were uninflamed (56, 4–705 μg/g). Of the familial adenomatous polyposis patients, one had pouchitis and pre-pouch ileitis (305 μg/g), and seven had noninflamed pouches (9, 6–26 μg/g). Stool samples obtained from pouchitis patients had significantly higher calprotectin concentrations compared with those obtained from uninflamed pouches (Mann–Whitney: P<0.0001). Faecal calprotectin concentrations correlated closely with the Objective Pouchitis Score, the Pouch Disease Activity Index and endoscopic and histological inflammatory scores (Spearman rank test: P values <0.0001). Using a faecal calprotectin threshold of ≥92.5 μg/g to define a positive result, Receiver Operating Characteristic analysis demonstrated a sensitivity of 90% and a specificity of 76.5%. Conclusion Faecal calprotectin measurement is a useful noninvasive tool in the diagnosis of acutely inflamed ileal pouches and correlates well with the severity of pouchitis.

Faecal M2-pyruvate kinase: a novel, noninvasive marker of ileal pouch inflammation

Background Dimeric M2-pyruvate kinase (dM2-PK) is overexpressed in tumour cells with rapid cell turnover. Its concentrations correlate well with the staging and metastatic capability of the tumour cells. We investigated the use of faecal dM2-PK as a noninvasive marker of pouch inflammation (pouchitis) in patients having undergone restorative proctocolectomy. Methods Stool samples were obtained from 46 patients with ulcerative colitis (UC) and eight with familial adenomatous polyposis. Pouchitis was defined using the objective pouchitis score (OPS) and the pouch disease activity index. Faecal dM2-PK was measured using a quantitative sandwich-type enzyme immunoassay (ScheBo Biotech UK) and the results compared with reciprocal faecal calprotectin concentrations. Results Using the OPS, 6 of the 46 patients with UC had pouchitis and prepouch ileitis, 13 had UC pouchitis alone, and 27 had a non-inflamed UC pouch. One patient with familial adenomatous polyposis had pouchitis and prepouch ileitis and 7 had an non inflamed pouch. Respective median dM2-PK values (U/ml) for these five groups were 49.5 (4.5–110), 12 (1–192.3), 2.2 (0.1–95.2), 19.5 and 1 (0.1–3). Statistically significant differences were noted between inflamed and non inflamed pouches (P<0.0001). dM2-PK correlated significantly with the OPS, pouch disease activity index, endoscopic appearances, acute histological and neutrophil scores (<0.0001). The receiver operating characteristic analysis demonstrated a sensitivity and specificity of 80 and 70.6%, respectively. dM2-PK and faecal calprotectin concentrations correlated closely (r=0.87, P<0.0001). Conclusion This study demonstrates that faecal dM2-PK is a sensitive marker of pouch inflammation and that its concentration directly correlates with the objective markers of pouchitis severity.

Medical management of patients with ileal pouch anal anastomosis after restorative procto-colectomy

Restorative procto-colectomy with ileal pouch anal anastomosis has become the most common elective surgical procedure for patients with ulcerative colitis and is becoming popular in those with familial adenomatous polyposis coli. The procedure itself is primarily carried out in specialist surgical centres but an increasing number are being performed and followed up in district general hospitals. These patients are now filtering through general surgical and gastroenterology clinics and are frequently seen in primary care. Pouchitis, an inflammatory condition of the ileal pouch, has become the third most important form of inflammatory bowel disease. As research develops in this area, other complications are being found. The aim of this review is to provide an up-to-date, evidence-based approach to the clinical management of these patients.