A COMPARISON OF IMMUNE-RESPONSE TO NERVE AND SKIN ALLOGRAFTS

Research in limb reconstruction using peripheral nerve tissue has been hampered by tissue rejection, Not all tissues express major histocomp atibility class I and class II antigens to the same extent. Allogenic and isogenic peripheral nerve grafts and split-thickness skin grafts w ere performed using C57BL/6 and Balb/c mice, which are inbred strains that differ at both major histocompatibility (MHC) class I and class I I antigens. The cellular and humoral immune responses of the nerve tra nsplants were compared with studies of skin transplants. Skin allograf ts represent a ''gold standard'': they are clearly rejected, with a ti ssue failure that is easily observed and closely correlated with cellu lar and humoral projection responses. A significant cellular immune re sponse was noted following both the nerve (p <.04) and skin (p <.03) a llografts. The peak response occurred by day 14 following the transpla ntation. The humoral response with rising antibody titers followed a s imilar pattern, with peak response at 14 and 21 days post-transplantat ion. Isogenic transplants did not produce a cellular or humoral immune responses. There was no significant difference between the immune res ponses produced by the skin transplants, compared to the nerve transpl ants. Because of the difficulty in producing accurate models of animal function following nerve transplantation, quantitative studies of hos t immune response to transplantation have not correlated well with the recipient's final functional result. A comparison of the immune respo nses between clearly rejected skin allografts and nerve allografts sug gests that the immune response resulting from nerve allografts could d ecrease the functional performance of the nerve grafts. Of clinical re levance is the fact that tissue typing to minimize differences between the major histocompatibility complexes of the donor and recipient mig ht be necessary, in order to optimize final recovery of patients recei ving nerve transplants, and in order to avoid immunosuppression of the host.