Gliadin activates mucosal cell mediated immunity in cultured rectal mucosa from coeliac patients and a subset of their siblings

Background - CD3 and γδ cells in the rectal mucosa increase after local instillation of gluten in children with coeliac disease and in half of their siblings. Aim - To establish an in vitro system for assessing immunological changes induced by gluten in the rectum. Patients and Methods - Rectal biopsy specimens obtained from 13 treated coeliac children, nine of their siblings, and nine controls were cultured in vitro with a peptic- tryptic digest of gliadin or ovalbumin. CD3 and CD25 cells were counted, and the expression of adhesion molecules evaluated. Results - In the lamina propria of coeliac biopsy samples cultured with gliadin, but not in those from controls, the expression of vascular cell adhesion molecule 1 (VCAM-1) was enhanced, and the number of CD25 cells was significantly higher than in those cultured in medium alone; the density of intraepithelial CD3 cells was also significantly higher. No differences were noted in coeliac biopsy specimens cultured with ovalbumin. A discriminant analysis allowed correct classification of all controls and all coeliacs but one, but three of nine siblings were allocated to the coeliac group. Conclusions - Our data confirm that gliadin is able to activate cell mediated immunity in the rectal mucosa in coeliac patients and in a subset of their first degree relatives.