MAJOR HISTOCOMPATIBILITY (MHC) ASSAYS
Using sera obtained first from multi transfused patients and later from multiparous women (alloantigens), the early work of Dauset and others in the 1950s and 1960s identified a series of antigens present on mononuclear cells called the human leucocyte antigens (HLAs). Using a somewhat crude agglutination assay of leucocytes from unrelated donors and that the pattern of such co-aggulutination demonstrated definitive antigens in human populations. After extensive research and workshop meetings, it became apparent that these antigens were present on all tissues of the body, but their high concentration on peripheral blood lymphocytes enabled investigators to perform immunogenetic studies more easily on these cells. While most of the original testing for the antigens on cells and for use in transplantation relied on serological techniques using purified antibodies to detect these antigens, the introduction of the PCR assay changed the rapidity with which these antigens could be identified, and both MHC class I and class II antigens are now routinely identified by the method.