The molecular immunogenetics of celiac disease continues to be a major area of study. CertainHLA-DQgenes appear to be the main HLA susceptibility marker in the various populations studied, although interest has been shown in related genes that are involved in antigen processing. The role of γ/δ T-cell receptor positive lymphocytes in the intestinal epithelium continues to be investigated; cytotoxicity seems possible but whether this occursin vivois not known.