Histocompatibility Antigens: A Laboratory and Epidemiologic Tool

The value of HL-A antigens as genetic markers and epidemiologic tools in various disease states is becoming increasingly apparent. The antigens of the HL-A system (the major histocompatibility locus in man) are found on most human cells, especially the leukocytes and cells of the epidermis and the dermis. Associations have recently been found for HL-A antigens in psoriasis, atopic dermatitis, systemic lupus ervthematosus, dermatitis herpetiformis, pemphigus vulgaris and malignant melanoma of the skin; in several other diseases, associations with HL-A antigens are also probably present. Two possible mechanisms of association of HL-A with various diseases are (1) a close linkage between a gene governing immunologic responsiveness to a disease and HL-A genes, or (2) antigenic (chemical) cross-reaction between HL-A antigens and the etiologic agent (e.g.. streptococci or viral capsular antigen) associated with the disease