Predisposing HLA-DQ2 and HLA-DQ8 haplotypes of coelialc disease and associated enteropathy in microscopic colitis

Objective To assess the presence of both genetic and serological markers of coeliac disease in patients with microscopic colitis, and whether there was associated enteropathy. Methods HLA-DQ2, HLA-DQ8, serum immunoglobulin A-antiendomysial and immunoglobulin A-anti-tissue transglutaminase antibodies were investigated in 59 patients with microscopic colitis. Seventy healthy subjects acted as the control group. Endoscopic biopsies from the distal duodenum were obtained in DQ2-positive or DQ8-positive patients. Patients with histological changes compatible with gluten-sensitive enteropathy were started on a gluten-free diet. Results Seventeen of 70 (24.3%) healthy controls were DQ2-positive. Twelve of 25 (48%) patients with lymphocytic colitis (P = 0.027 versus controls), and 11 of 34 (32.3%) with collagenous colitis (P = 0.38 versus controls) were DQ2-positive. There were no differences in the frequency of DQ8-positivity. The coeliac serology was positive in one patient. Duodenal biopsies were performed in 23 DQ2-positive and/or DQ8-positive patients. None had villous atrophy (Marsh III lesion) (0%; 95% confidence interval, 0-6.1). A Marsh type I lesion was found in four patients. Three of these patients were put on a gluten-free diet with disappearance of diarrhoea. Conclusions The results suggest that there is an association of lymphocytic colitis with HLA-DQ2 genes, which might be relevant in the pathogenesis of this disease. The association of microscopic colitis with Marsh type III coeliac disease seems to be rare, making it unnecessary to routinely screen for coeliac disease in microscopic colitis patients.