HLA and disease: current concepts.

The association between HLA and disease has a sound experimental foundation. Currently HLA has been implicated in the natural history of numerous diseases of varied pathogeneses. Efforts nor are being directed toward characterizations of the actual loci involved, but this is proving to be difficult because more than one and probably all the described mechanisms are playing a role. Nonetheless HLA appears to be a unique region for such analysis because it is highly polymorphic, which means that a gene and its linkage group may be traced not only through a family but also through a population and even a geographic region. In addition, the HLA region is a natural focus for the discovery of regulatory genes with one gene facilitating the discovery of the next. The identification of subsets and genetic antigenic polymorphisms expressed on these cells constitutes the best approach to the study of immune regulation and noseology today.