Immunosuppressive effect of 15-deoxyspergualin applied to peripheral nerve allotransplantation in the rat.

15-Deoxyspergualin (15-DSG), which has a unique immunosuppressive action, was applied to peripheral nerve allotransplantation. Its effects on graft survival were experimentally assessed using inbred rats. The sciatic nerve (20 mm) allotransplantation model was created in two different strains. An attempt was made to answer the following two questions: (1) can short-term immunosuppression alone produce sufficient immunological tolerance to maintain graft survival indefinitely? (2) can graft rejection be prevented by chronic intermittent low-dose 15-DSG administration (2.5 mg/kg/day), and to what extent does nerve regeneration occur? To evaluate the efficacy of 15-DSG, a comparison was made with autografts, allografts with no immunosuppression, and allografts immunosuppressed with cyclosporine (CsA), a strong immunosuppressant. The results indicate that short-term 15-DSG therapy is incapable of inducing immunotolerance of peripheral nerve allografts. Because nerve conduction in the rejected allografts was better preserved than in the CsA group, short-course 15-DSG therapy appeared to provide better results than CsA therapy for peripheral nerve allotransplantation.