Successful nerve regeneration and persistence of donor cells after a limited course of immunosuppression in rat peripheral nerve allografts.

BACKGROUND

The origin of Schwann cells and effect of a limited course of immunosuppression using cyclosporine (CsA) were examined in rat peripheral nerve allotransplants.

METHODS

Phenotypes of Schwann cells in groups without, with continuing, and with limited (12 weeks) CsA treatment were examined immunohistochemically in allogeneically and syngeneically transplanted animals from 4 to 36 weeks after transplantation.

RESULTS

In the group receiving no CsA, little nerve regeneration was obtained; donor Schwann cells were rejected and replaced by recipient cells. In continuing and limited-course CsA groups, successful nerve regeneration was achieved at postoperative week 36, as was also observed in the syngeneic group. Schwann cells in the continuing CsA group remained donor-derived. In the limited-course CsA group, graft rejection and loss of function occurred after the withdrawal of CsA, and donor Schwann cells were replaced by recipient cells in the part of the graft where rejection had been complete. However, many donor Schwann cells remained at week 36, when the rejection response subsided.

CONCLUSION

Possible clinical use of a limited course of immunosuppression was supported by this demonstration of long term persistence of donor Schwann cells.