Human leucocyte antigens

Group of proteins present on the surface of white blood cells (leucocytes) and other nucleated cells (containing a nucleus). These proteins help the body’s immune system to identify its own cells and to distinguish between “self” and “nonself.” Each person has an inherited combination of HLA antigens and, while not as unique as a fingerprint, the presence or absence of each antigen creates a distinctive HLA combination for each person. HLA antigens are divided into types: Class I (A, B, C) and Class II (DR, DP, DQ).