Induction of immune tolerance and altered cytokine expression in skin transplantation recipients

Apoptotic lymphocytes can induce specific immune tolerance. This study aimed to investigate the influence of the preoperative transfusion of apoptotic lymphocytes on allograft survival after skin transplantation. In addition, we aimed to determine changes in IL-4, IL-10 and IFN-γ mRNA expression in the grafted skin. A total of 20 New Zealand white rabbits were randomly divided into two groups: lymphocyte preconditioned group (n = 10) and control group (n = 10). Rabbits in the lymphocyte preconditioned group were intravenously injected with 60Co γ-treated donor lymphocytes at seven days before the surgery. Rabbits in the control group were intravenously injected with normal lymphocytes at seven days before skin transplantation. The mRNA expression of IL-4, IL-10 and IFN-γ in the grafted skin was determined using real-time PCR. Skin allograft rejection time was 72.63 ± 2.65 days in the lymphocyte preconditioned group and 6.52 ± 0.64 days in the control group. IL-4, IL-10 and IFN-γ mRNA expression in the skin graft was 4.32 ± 0.48, 7.86 ± 0.56 and 2.63 ± 0.25 respectively in the lymphocyte preconditioned group, and 0.58 ± 0.07, 0.91 ± 0.14 and 8.68 ± 1.23 respectively in the control group. The preoperative transfusion of apoptotic lymphocytes induced immune tolerance in the grafted skin, as demonstrated by longer survival time of the grafts before rejection. This coincided with the increased mRNA expression of IL-4 and IL-10, and the decreased expression of IFN-γ.