No induction of anti-avenin IgA by oats in adult, diet-treated coeliac disease

Objective. Coeliac disease is effectively treated with a gluten-free diet devoid of wheat, rye, barley and related cereals. Oats has until recently also been considered harmful but is now allowed in several countries. We have, however, identified three adult coeliac disease patients who developed a flare of active coeliac disease after ingestion of oats, which suggests that oats might not be entirely innocent in coeliac disease. It is known that patients with untreated coeliac disease have elevated IgA antibodies to oat prolamins. The objective of this study was to investigate whether levels of IgA against oats were increased in treated, adult coeliac disease patients. Material and methods. Serum was collected from 136 adult patients with treated coeliac disease and 139 controls. Eighty-two of the coeliac disease patients had been taking oats as part of their gluten-free diet for 6 months or more. IgA against oats avenin, wheat gliadin and tissue transglutaminase was tested with ELISA. Results. No significant differences were found in IgA against oats in oats-eating and non-oats-eating coeliac disease patients. Both groups had increased levels of IgA against wheat, oats and tissue transglutaminase compared to healthy controls. A significant positive correlation was found between anti-avenin and antigliadin IgA (p<0.0001), and between anti-avenin and anti-tissue transglutaminase IgA (p=0.0012). Conclusions. Ingestion of oats does not cause increased levels of IgA against oats in adult coeliac disease patients on a gluten-free diet. The findings support the notion that most adult coeliac disease patients can tolerate oats.