[Composite tissue allograft limb in rats immunosuppressed with cyclosporine A]

The purpose of this study was to examine the mechanism of rejection after limb allografts and the effect of Cyclosporine A (CYA) on this process. Male F344 rats were used as recipients, Lew and WKAH as donors. After transplantation, CYA (15mg/kg/day s.c.) was administered for 21 days. It was possible to achieve a long-term survival of allograft limbs with CYA, but the skin was soon rejected after the termination of CYA administration. Without immunosuppression skin was rapidly rejected. It is conceivable that this rejection process takes place both by direct destruction of epithelial cells, by non-helper T lymphocytes and through injury to the microvascular endothelium of dermis. The mechanism of the microvascular injury remains unknown. The skin of some of the animals enhanced with CYA was transformed, but immunohistologically represented no sign of classic rejection. After termination of CYA treatment, a degenerative change of skin was observed. It is considered that this change proceeds through direct destruction of epithelial cells by non-helper T lymphocytes.