Associations of MHC class II alleles in Norwegian primary Sjogren's syndrome patients: Implications for development of autoantibodies to the Ro52 autoantigen

Sjogren's syndrome (SS) is a chronic autoimmune disease characterized by dr yness of the eyes and mouth. Currently, the highly polymorphic major histoc ompatibility complex (MHC) genes are the best documented genetic risk facto r for the development of autoimmune disease. We examined the MHC class II a lleles DRB1, DRB3, DRB4, DRB5, DQA1 and DQB1 in a group of Norwegian pSS pa tients and compared with a group of healthy controls. Because a number of s tudies have shown that some of the MHC class II alleles are not associated with the disease as a whole, but rather to the development of autoantibodie s, anti-Ro52 autoantibodies in serum were measured and compared to MHC clas s II allele status. A clear association with pSS was detected for the DRB1* 0301 and DRB3*0101 alleles, but these alleles were more closely associated with the presence of anti-Ro52 autoantibodies than with pSS itself. Moreove r, the DQA1*0501 and DQB1*0201 alleles were only associated with the presen ce of anti-Ro52 autoantibodies. This study shows that the production of ant i-Ro52 autoantibodies in pSS is associated with the DRB1*0301, DRB3*0101, D QA1*0501 and DQB1*0201 alleles which are in strong linkage disequilibrium.