Human leucocyte antigens (HLA) and rheumatic diseases: HLA class ii antigen-associated diseases

The association between genes of the major histocompatibility complex, HLA in man, and disease susceptibility is one of the most intriguing discoveries of modern genetics. These studies are important for understanding the genetic basis, pathogenesis and aetiology of human diseases. With progress in these areas, new and better forms of treatment as well as disease prevention will become possible. In the previous paper, we reviewed the literature on associations between HLA Class I (A,B,C) genes and rheumatic disease. In this article, we will now concentrate on rheumatic disorders associated with genes in the HLA Class II region, including DR, DQ, DP and the transporter associated with antigen processing (TAP) genes. In addition, the role of the pathogenic mechanism(s), which results in an aberrant expression(s) of HLA molecules on the cell surface, in causing disease susceptibility will be examined.