Dietary allergy evaluated by PRIST and RAST in inflammatory bowel disease.

The role of allergic responses to dietary antigens in the pathogenesis of inflammatory Bowel Disease (IBD) remains speculative. We studied 50 patients with Ulcerative Colitis (UC), 50 patients with Crohn's Disease (CD) and 100 healthy controls (HC) matched for sex and age. In these patients total serum IgE and specific IgE to ten selected foods were estimated using Phadebas PRIST and RAST. There was no significant difference in the total serum IgE level between UC, CD and HC. The percentage of positive reaction to specific IgE was significantly lower in HC (score 1-2: 7%; score 2: 3%) compared with UC (score 1-2: 24%, p less than 0.004; score 2: 8%, n.s.) and CD (score 1-2: 16%, n.s.; score 2: 12%, p less than 0.03). In CD with colic or ileocolic involvement, the percentage of patients with a positive response to RAST was significantly greater (score 1-2: 26%; score 2: 21%) than in CD with ileal involvement. The considerable increase in positive results to RAST in IBD may be due to a greater absorption of antigens through the diseased wall.