Intragraft cytokine expression and tolerance induction in rat renal allografts

Background Intragraft cytokine expression was evaluated in a model of renal transplantation, ACl and Lewis rats were used as donors and recipients, re spectively, for heterotopic renal transplantation. Methods. Treated allograft rats (n=10) received a preoperative dose of rapa mycin and cyclosporine, followed by 7 days of cyclosporine postoperatively. Isograft rats (n=5) and control allograft rats (n=4) received no immunosup pression, Sacrifice was performed after 120 days, Expression of interleukin (IL)-4, IL-10, and interferon-gamma (IFN-gamma) transcripts was determined with semiquantitative reverse transcriptase-polymerase chain reaction. Results. All treated allograft rats had normal function with 50% histologic rejection. All isografts had normal function, IL-4 and IL-10 were in great er density in allografts with normal histology, whereas IFN-gamma was only seen in allografts with cellular rejection. No IL-10 was seen in isografts, but IL-4 was detected in 315 isografts. Conclusions. We conclude that the lymphocyte population's elaboration of IL -4 and IL-10 is associated with tolerance, whereas the production of IFN-ga mma and absence of IL-4 is associated with histology suggestive of acute ce llular rejection.