Systemic immune response to peripheral nerve transplants across major histocompatibility class-I and class-II barriers.

The use of peripheral nerve transplantation in limb reconstruction has been limited by tissue rejection. In order to identify the major histocompatibility antigens involved in tissue rejection, mutant strains of inbred mice, differing from the parent strain (C57BL/6) by either major histocompatibility complex Class I (B6.C-H2bml mice) or Class II (B6.C-H2bml2 mice), were used in models of nerve transplantation. One, 2, and 3 weeks after nerve or skin transplantation, the immune response in the recipient animal was monitored with use of lymphocyte-dependent cytotoxicity and complement-dependent cytotoxicity assays. Skin transplants were used for comparison as the gold standard of a nonvascularized graft with an easily observable success or failure. There was no significant cellular immune response by the lymphocyte-mediated cytotoxicity assay when nerve or skin transplants involved an isolated Class-I or Class-II mismatch, but there was a significant response 2 weeks after transplantations across a combined Class-I and Class-II barrier for nerve (p < 0.04) or skin (p < 0.03). An antibody response to the grafts occurred for both skin and nerve transplants but only when a combined barrier was involved. This preliminary study, using a mouse model, suggests that nerve transplantation-may be performed without systemic evidence of rejection with only a partial cross match of the major histocompatibility complexes, thus decreasing the complexity of tissue typing necessary for tissue banking.