A molecule basis for the HLA association in rheumatoid arthritis.

Rheumatoid arthritis (RA) is a common chronic autoimmune disease that primarily affects the joints. The etiology of RA is unknown, and the pathogenesis is only poorly defined. One of the few clues to the understanding of the pathogenesis of RA is the observation that the disease is associated with genes in the major histocompatibility complex (MHC). Recent structural and functional studies provide molecular insight into the role of MHC genes in RA susceptibility. This insight provides an important basis for further understanding of the disease mechanism, generation of humanized animal models for RA, and the development of new immunomodulatory drugs with a minimum of unwanted side effects.