Crohn's disease (CD) involves intensive immunologic responses to food antigens. Exclusive enteral nutrition (EEN) showed efficacy in inducing disease remission. However, relapse commonly occurred when normal diet was reintroduced. We aimed to investigate the food-specific IgG antibodies of CD, and clarify the effects of exclusion diet guided by food-specific antibodies on remission maintenance after EEN.

All available data of food-specific antibodies were retrieved from the database and analyzed for the diagnostic value. Thereafter, we retrospectively recruited qualified patients who reintroduced their diet excluding the moderately and strongly immunoreactive foods with prospective follow-up data. Matched patients without diet intervention after EEN served as control. CD activity index (CDAI), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and endoscopic score were compared.

A significantly enhanced immune response to rice, tomato, egg white/egg yolk and maize was observed in CD patients. The number of IgG-positive items had the greatest power to discriminate CD from ulcerative colitis and the control group with area under the curve of 0.819 and 0.828. Each diet group included 32 patients, and disease relapsed in 12.5% of the exclusion group compared with 25% of the control. The increase of CDAI and ESR was more remarkable in the control group than in the exclusion diet group (P<0.05).

CD patients presented intensive immune responses to food antigens. The number of IgG-positive food items had potential to be a diagnostic marker of CD. Diet guided by food antibody test might help maintain disease remission.