High prevalence of celiac sprue-like HLA-DQ genes and enteropathy in patients with the microscopic colitis syndrome

OBJECTIVE: Celiac sprue is associated with specific HLA-DQ genes (mainly DQ 2). Because there are epidemiological and histopathological similarities be tween celiac sprue and microscopic colitis, we hypothesized that these synd rome may share an HLA genetic predisposition and pathogenesis. METHODS: The HLA-DQ genes of 25 patients with celiac sprue, 53 patients wit h the microscopic colitis syndrome, and 429 normal controls were typed and compared. Serum was analyzed for antigliadin and antiendomysial antibodies. Small intestinal biopsies were analyzed for signs of histopathology. RESULTS: HLA-DQ2 or DQ1,3 (the latter as DQ1,7,DQ1,8, or DQ1,9) were seen m ore frequently in both patient groups relative to controls. In patients wit h the microscopic colitis syndrome, serological tests for celiac sprue were weakly positive in 17%; mild inflammation of the small intestine without v illous atrophy was present in 43%, and inflammation plus partial or subtota l villous atrophy was present in 27%. CONCLUSIONS: A shared set of predisposing HLA-DQ genes account for the epid emiological overlap of celiac sprue and microscopic colitis. Mild to modera te mononuclear cell inflammation of the small intestine, often accompanied by partial or subtotal villous atrophy, is frequent in patients with the mi croscopic colitis syndrome. Although further studies will be necessary to d etermine if this enteropathy is induced by dietary gluten, we speculate tha t the small intestinal but not colonic histopathology in patients with micr oscopic colitis is caused by immunological gluten sensitivity. (C) 2000 by Am. Cell. of Gastroenterology.