The MHC region includes the following 3 regions: 1) Class I gene region controlling HLA-A, B, and C and antigens, which are found on eucaryotic cell membranes, 2) Class II region controlling cell-specific HLA-DP, DQ, and DR antigens, which are found on particular tissues or cells, such as B-cell and macrophage, and 3) Class III gene region controlling complement ingredients and 21-hydroxyilaze. [0