HLA and autoimmune disease
Strong association between the HLA region and autoimmune disease has been established for over 50 years. Association of components of the HLA class II encoded HLA-DRB1-DQA1-DQB1 haplotype has been detected with several autoimmune diseases including reumathoid arthritis, type I diabetes and grave’s disease. Molecules encoded by this region play a key role in exogenous antigen presentation to CD4 Th cells, indicating the importance of this pathway in autoimmune disease initiation and progression. Association of the HLA class I region, independent of known HLA class II effects, has now been detected for several autoimmune diseases, including strong association of HLA-B with type I diabetes and HLA-C with multiple sclerosis and grave’s diseases. These results provide further evidence of a possible role for bacterial or viral infection and CD8 T cells in autoimmune disease onset.