Major histocompatibility complex: its role in the pathogenesis of autoimmune rheumatic diseases

Abstract

In order to allow early diagnosis and more efficient treatments, many studies have been trying to define genetic markers of rheumatic diseases. Amongst them, antigens and alleles of the HLA (Human Leukocyte Antigens) system are distinguished. Located in the short arm of chromosome 6, the HLA system exerts genetic influence on the susceptibility and severity of these diseases. The discovery of new molecular methods to typify HLA alleles and the recent nomenclature updates have been contributing to a better understanding of this system. Unfortunately, this information has not been adequately published in the clinical literature. The present work aimed at presenting the function, nomenclature and methods of detection of the HLA polymorphism; and to review its associations with rheumatic fever, systemic erythematosus lupus, rheumatoid arthritis, juvenile idiopathic arthritis and spondyloarthropathies. Articles that were published between 1980 and 2005 were searched in the MEDLINE and LILACS data basis. This review demonstrated that although the HLA association is well established for some rheumatic diseases (e.g., HLA-B27 and spondyloarthropathies, HLA DR-3 and HLA-DR4 with rheumatoid arthritis, HLA-DR4 and lupus) others vary in different ethnic-racial group and illnesses, due to its polymorphism. It is necessary to study populations from different ethnic backgrounds to identify new associations or to strengthen associations with the ones already identified. This knowledge will contribute to future prophylactic or therapeutic interventions in patients with rheumatic disorders or at risk to develop them.