HLA-A, HLA-B and HLA-DR matching reduces the rate of corneal allograft rejection.

PURPOSE

The purpose of this study is to determine the effectiveness of HLA typing in preventing corneal allograft rejection.

METHODS

This retrospective single-center study analyzed 459 consecutive HLA-typed patients who underwent perforating keratoplasty (PKP) between 1983 and 2001. Grafts were postoperatively transparent after donor-recipient selection by HLA-A, -B and -DR typing. Patients were divided into a low- and a high-risk group based on their preoperative diagnosis.

RESULTS

The estimated 1-, 5- and 10-year graft survival (Kaplan-Meier) was 93, 88 and 67% in low-risk patients and 73, 43 and 38% in high-risk patients. We found a significant correlation between the number of HLA mismatches and the rate of allograft rejections: a donor-recipient match of two or more alleles in HLA-A, -B or -DR reduces the rejection rate by at least 10% in low-risk (10 years after PKP; P<0.04) and 40% in high-risk patients (3 years after PKP; P<0.0001). Especially HLA-B mismatches are important prognostic factors for both low- ( P<0.008) and high-risk patients ( P<0.003). Considering both HLA-B and -DR mismatches significantly reduces the rate of allograft rejection, particularly in high-risk patients ( P<0.0001). Matching on a split typing level offers no significant advantage over broad level matching.

CONCLUSION

Clinical results confirm theories developed to explain the function of the HLA (MHC) receptor. The closest possible donor-recipient match of HLA antigens based on broad level typing significantly reduces the rate of allograft rejection and thus improves the prognosis for long-term transparency of corneal grafts in both high- and low-risk patients.