Food‐specific IgG4‐guided exclusion diets improve symptoms in Crohn’s disease: a pilot study

AIM: Exclusion diets have been shown to prolong remission in Crohn's disease (CD). We assessed IgG4-targeted exclusion diets in patients with CD. METHOD: Forty patients with symptomatic CD were recruited. Their sera were tested for IgG4 antibodies to 14 specific food antigens and each subject's four most reactive foods were excluded for 4 weeks. Disease activity was assessed using a modified CD activity index (mCDAI). Questionnaire and inflammatory markers were measured before and on completion of the exclusion diet. RESULTS: Eleven patients did not complete the study, leaving 29 for analysis. Of these, 26 (90%) reported symptomatic improvement with a reduction in mCDAI from a mean of 171-97.5 (P = 0.0001). The ESR fell from 23 to 17 mm/h (P = 0.021) and the IgG4 titres for the excluded foods fell from a mean of 3015-2306 mcgA/l (P = 0.003). CONCLUSION: IgG4-guided exclusion diets resulted in significant symptomatic improvement with an objective fall in an inflammatory marker. This approach may be useful in clinical practice.