Allograft transduction of IL-10 prolongs survival following orthotopic liver transplantation

Interleukin-10 (IL-10) is an ideal candidate cytokine for suppressing the alloimmune response in transplantation. To determine whether genetic modulation of the hepatic graft with IL-10 could prolong survival following orthotopic liver transplantation, we constructed a replication-deficient adenovirus vector expressing human IL-10 (AdCMVhIL-10). Intraportal injection of this vector into a donor rat 24–48 h before grafting resulted in efficient release of IL-10 into the circulation of a recipient rat after transplantation. Moreover, levels of hIL-10 from the suprahepatic vena cava were significantly (1.48-fold) higher than those from the infrahepatic vena cava (P = 0.013), indicating local IL-10 production within the transduced hepatic graft. AdCMVhIL-10 induced a prolongation of median survival to more than 87 days, with two of five transduced grafts showing more than 100 days of ongoing survival, when compared with 11 days for grafts transduced with a control adenovirus vector carrying the E. coli β-galactosidase gene (P = 0.0021) and 11 days for untreated grafts (P = 0.0021). Pathological findings occurring in the AdCMVhIL-10-transduced hepatic grafts revealed no evidence of progressive rejection reaction resulting in graft failure. These results demonstrate that hepatic grafts modulated by IL-10 gene transfer make local and effective immunosuppression feasible in the transplantation setting.