HLA matching: maximizing the number of compatible transplants

1. Less than 10% of the cadaver kidneys currently allocated have 0-B,DR mismatches. 2. Up to 15% of the kidneys could be regionally allocated using the UNOS algorithm to 0-B,DR-mismatched recipients with a projected 67% 5-year graft survival. 3. Twice the number (32%) of recipients can be identified with zero of 10 A,B residues mismatched with the same 67% 5-year survival. 4. Another doubling (68%) of compatible recipients can be identified with zero of 7 DR supertypic determinants (4 DQ and 3 DRB) and zero of the A,B residues mismatched with a 66% 5-year graft survival. 5. Compressing A,B, and DR antigens to supertypic determinants reduces the racial differences in HLA to the point that 90% of kidneys can be allocated to Black recipients with zero of 3 DRB and zero A,B residues mismatched.