HLA typing

determination of the human leukocyte antigens (HLA) possessed by an individual. Class I antigens (HLA-A, -B, and -C) are detected by lymphocyte microcytotoxicity assay using standard typing sera. Class II antigens are detected by one-way mixed lymphocyte cultures using panels of homozygous typing cells; they may also be identified by primed lymphocyte typing (q.v.). DR Class II antigens are also detected by lymphocyte microtoxicity assay using B lymphocytes and anti-DR antibody types. HLA typing is used to identify compatible donors and recipients for transplantation or platelet or granulocyte transfusion, to establish associations of human leukocyte antigens with diseases, and in paternity testing.