Since the first leukocyte antigen group was described in 1958 by Dausett,1 the HL-A system became the major tool in the studies of human histocompatibility. It gained great importance in human organ transplantation, in prevention of transplant rejection, and in the fight against the host vs graft reaction.
The HL-A system had its beginning in the detection in the serum of polytransfused patients of antibodies capable of agglutinating leukocytes, which were independent of blood group antibodies, and with a second observation that such antigens were L antigens distributed in group fashion in the population.
Today, with the expansion of HL-A system studies, the emphasis began shifting into other areas of medical science. An increasing number of diseases have been shown to be associated with the HL-A system. Various manifestations of the hay fever-allergy syndrome are inherited in families with HL-A chromosomes. Illnesses with immunological components, such as myasthenia gravis