The impact of low donor-specific MLR versus HLA-DR compatibility on kidney graft survival

We have analyzed the predictive value on cadaver kidney graft survival of a low stabilized relative response (SRR) in donor-specific mixed lymphocyte culture (MLC). Thirty-eight recipients and donors of cadaver kidneys constituted the case material. The 12-month survival of cadaveric grafts was 83% when the SRR values of the mixed lymphocyte reaction (MLR) between recipient and donor were below or equal to 50 and 40% when the SRR values were above 50. The difference was statistically significant (P less than 0.006). A higher (though not significantly so) graft survival rate was obtained in transplant groups when the recipients and donors were well matched for DR antigens. The 12-month survival was 70% when no DR incompatibilities could be demonstrated and 50% when one or more DR antigens were incompatible. The primary role of MLR matching for the outcome of kidney graft survival is supported by the observation that the influence of the MLR is still significant when stratified for DR matching (P less than 0.05). In conclusion, when adequately stabilized, the specific MLC reactivity of the recipient against the donor is a very important predictive factor for the outcome of cadaver kidney transplantation, which stresses the importance of improvements in serological DR typing.