Extension of Composite Tissue Allograft Survival Across Major Histocompatibility Barrier Under Short Course of Anti-Lymphocyte Serum and Cyclosporine A Therapy

ABSTRACT In this study, the authors investigated the effects of combined use of cyclosporine A (CsA) and anti-lymphocyte serum (ALS) on the survival of rat hindlimb allografts across a fully allogeneic major histocompatibility complex (MHC) barrier between Brown-Norway rats (BN, RT1 n ) and Lewis rats (LEW, RT1 l ). Thirty transplantations were performed in five groups of six rats each: Group 1 was the isograft control; Group 2 was the allograft control; Group 3 received ALS, Group 4 received CsA, and Group 5 received CsA and ALS. Treatment was started 2 hr before surgery and was then given for 21 days. Donor-derived chimerism was monitored by FACS analysis. Survival time was calculated as the number of post-transplant days until the first signs of rejection. The allografts in Group 2, Group 3, and Group 4 survived a mean of 5, 6, and 33 days, respectively. The longest mean survival time-51 days-was noted in Group 5 (P