HLA and Disease

Abstract

Publisher Summary This chapter discusses the relationships between HLA and diseases, which may be established by both population and family studies. In population studies, it is investigated whether one or more HLA characters occur with different frequencies in a group of unrelated patients as compared to the corresponding frequencies in healthy, unrelated individuals of the same ethnic group. If this is the case, there is association between the HLA factors in question and the disease. The strong association between HLA-A3 and idiopathic hemochromatosis indicates that immune mechanisms may not always be the basis for associations between HLA and disease. Idiopathic hemochromatosis is characterized by an abnormally high uptake of iron from the gut, and there is no evidence of aberrant immunity. The relationship to HLA suggests that the HLA system plays a role also in some biological phenomena not involving the immune system. HLA typing has already found a place as a diagnostic aid for a few of the HLA-associated diseases. HLA typing may have prognostic value. For example, multiple sclerosis seems to run a more severe course in Dw2-positive as compared to Dw2-negative patients, and the same may be true of rheumatoid arthritis in Dw4-positive patients.