HLA-B and -DR match reduces the allograft reaction after keratoplasty.

Since 1983, corneal grafts have been routinely obtained from multiorgan donors and allocated to the patient with the greatest HLA compatibility. At follow-ups in 248 primarily clear corneal grafts, grouping according to the HLA mismatch rate revealed that the incidence of allograft reactions did not differ significantly for HLA-A but certainly did for HLA-B (P < 0.01) and, in patients with a poor prognosis, for HLA-DR as well (P < 0.05). Grouping the patients according to the mismatch rate of the total of four HLA-B and -DR antigens disclosed the incidence of allograft reactions to be markedly increased by a mismatch of more than two antigens (P < 0.05). The relative risk of an allograft reaction is increased by factors of 5.1 in patients with a good prognosis and 5.5 in those with a poor prognosis. The adverse influence of a postoperative inflammation on the occurrence of an allograft reaction as seen in nonmatched donor material is no longer present in matched donor material if the prognosis is good and no longer significant if it is poor (P < 0.09). The inflammation-promoted expression of HLA antigens is of less importance for graft survival if the difference in the HLA antigens is reduced by the match.