WHAT IS HUMAN LEUKOCYTE ANTIGEN (HLA) TYPING (TISSUE TYPING) TEST?
Human leukocyte antigens (HLAs) are glycoproteins found on all nucleated cells. They result from four closely linked genes on chromosome 6 and are important to histocompatibility complement and immune response. The antigens are divided into A, B, C (Class I, derived from T cells), D, and DR (D-related, Class II, derived from B cells). There are multiple antigens of each type, meaning that the combinations of antigens that identify any individual are infinite. The HLAs are inherited as two sets (one from each parent) of six antigens. This test is most commonly used in the bone marrow and renal transplantation. The antigens must match for transplantation to occur without organ rejection.