HLA class II peptide-binding and autoimmunity.

The HLA class II locus is located in the 6p21.3 region on the short arm of chromosome 6 and encompasses approximately 700 kb. It consists of over 30 gene loci including the major class II structural genes DP, DQ and DR. While autoimmune disease correlates to specific DP, DQ or DR alleles have been documented, due to the strong linkage disequilibrium between the different HLA alleles, especially between the DR and DQ, the precise identification of susceptible MHC alleles for a number of autoimmune diseases remains elusive.