IgE levels in faecal extracts of patients with food allergy.

IgE levels in faecal extracts (Copro-IgE levels) were investigated in food allergy (FA) patients before and after the challenge test administration of food allergens. IgE levels were measured by time-resolved fluoroimmunometric assay. In addition, the effects of administration of oral sodium cromoglycate (SCG) on the Copro-IgE levels were studied. Copro-IgE levels in patients with FA, who were placed on an elimination diet, did not differ from those of healthy children. After a challenge test immediate symptoms of urticaria and wheezing were observed in all FA patients. Copro-IgE levels in each patient increased markedly within 24 h of the challenge test. Moreover, FA patients treated orally with SCG showed neither the increase in Copro-IgE levels nor any remarkable symptoms after the challenge. Our results suggest that the increased Copro-IgE levels may be a specific consequence of the local immune response to food allergen stimulation in the gut mucosa.