Genetics of kidney allograft survival in dogs. I. Relevance of subregions of the major histocompatibility complex in recipients without immunosuppressive therapy.

The influence of subregions of the canine major histocompatibility complex (MHC) on renal allograft survival is assessed in recipients without immunosuppressive therapy. Results in six beagle littermate donor-recipient pairs in which the donor or recipient had a recombination in the MHC are compatible with the concept of a predominant role for the subregion containing the major mixed lymphocyte reaction (MLR) locus in determining allograft survival. Results in unrelated mongrel dogs indicate that compatibility for MLR induces a longer kidney allograft survival than compatibility for the serologically defined (SD) antigens. However, the effect of combined matching for MLR and SD antigens in unrelated donor-recipient pairs is slight in comparison to the effect of MLR and/or SD matching in littermate-related dogs. This indicates that other important histocompatibility systems probably exist in this species.