IN SIBLINGS OF CELIAC CHILDREN, RECTAL GLUTEN CHALLENGE REVEALS GLUTEN SENSITIZATION NOT RESTRICTED TO CELIAC HLA

Background & Aims: Inflammatory changes in the rectum of patients with celiac disease after local instillation of gluten have been reported. The aim of this study was to examine rectal mucosa after local gluten challenge in children with celiac disease and their siblings. Methods : Rectal biopsy specimens were obtained before and 6 hours after recta l challenge with a peptictryptic digest of gliadin in 33 children with treated celiac disease, 12 controls, and 19 siblings of children with celiac disease. Epithelium and lamina propria volumes were determined , and CD3(+) and gamma delta(+) lymphocytes were counted. Results: Aft er local instillation of gliadin, a significant increment in the absol ute number of intraepithelial lymphocytes was noted in patients with c eliac disease but not in controls. Immunohistochemical analysis showed a significant increase in CD3(+) and gamma delta(+) cells, with the g amma delta CD3 ratio remaining unchanged after challenge. A discrimina nt analysis allowed correct classification of 100% of patients with ce liac disease and controls. The same analysis was used to classify 6 of 13 siblings as having celiac disease. The positivity was not associat ed with the presence of the heterodimer encoded by the DQA0501 DQB1*0 201 alleles in any of the siblings. Conclusions: All patients with cel iac disease were identified by rectal gluten challenge. Approximately half of the siblings reacted to rectal instillation of gluten. The gen etic background of such sensitization to gluten remains to be elucidat ed.