Specific MHC antigens are identified during HLA typing for organ and tissue transplant compatibility. The genes and/or antigens of transplant recipients are compared to those of potential donors. Results indicate how many antigens match or how many mismatches are present. The greater the number of matches the more likely the transplant will succeed. “0 mismatches” indicates a high probability that the organ or tissue will not be rejected by the recipient.
The absence of HLA antibodies to the donor HLA is very important. Matching a donor with a recipient who has developed antibodies must be carefully considered because the more HLA antibodies a person has developed, the higher the probability for rejection.
A positive (reactive) crossmatch result is usually interpreted as a high risk transplant. These patients are at risk for rejection of the transplant, which may or may not be treatable with various immunosuppressant drugs.