T cells from the peripheral blood of coeliac disease patients recognize gluten antigens when presented by HLA-DR, -DQ, or -DP molecules.

Coeliac disease (CD) is a T-cell mediated immunological disease of the small intestine which is precipitated in susceptible individuals by ingestion of gluten. We recently reported that gliadin-specific T cells can be found in the small intestinal mucosa of CD patients, and that a preponderance of these T cells was restricted by the CD-associated DQ(alpha 1*0501,beta 1*0201) heterodimer. Here we report studies on whether the same is found for gliadin specific T cells in the peripheral blood of CD patients. T-cell responses towards gluten antigens in vitro were found for both most CD patients and healthy controls. Gluten-specific T-cell clones (TCC) were established from four CD patients. Although a large proportion of these TCC were restricted by DQ molecules, including the CD-associated DQ(alpha 1*0501,beta 1*0201) heterodimer, several were restricted instead by DR or DP molecules. Thus, gluten-derived peptides can be presented to T cells by several different HLA class-II molecules, and the preferential DQ(alpha 1*0501,beta 1*0201) restriction of gluten-specific T cells in the small intestinal mucosa of CD patients is less pronounced than for similar T cells in the peripheral blood.