Calcineurin inhibitors are effective immunosuppressants in organ transplantation clinical setting. However, they inhibit IL2 expression and this limits the maturation of Treg cells, reducing the instauration of immune tolerance required for graft acceptance. In this work, we assess the potential interest of "ex vivo" transferring the IL10 gene, which encodes the pleiotropic immunomodulatory protein interleukin 10, into the organ prior to its implantation in recipient.

With this aim, naked human IL10 gene was transferred to livers during bench surgery in a porcine model of liver transplantation with 10-days follow-up. Human IL10 mRNA and protein were quantified by qPCR and ELISA. Immune response during follow-up was studied in liver biopsies and by quantifying the plasmatic concentrations of other cytokines.

No change in biochemical parameters of control and treated animals was observed. Plasma levels of human IL10 protein remained stationary over 20 pg/ml during the entire follow-up in treated animals. Anti-inflammatory IL8 and TGFβ cytokines were significantly increased. Although most pro-inflammatory cytokines analyzed (IFNα, IL1β, TNFα, IL6, IL8) were also significantly higher in treated animals, no deleterious effect was detected in tissue.

In conclusion, gene transfection was safe and mediated efficacious stationary plasma levels of hIL10 protein. The augmented pro-inflammatory cytokines in treated animals did not result in a higher graft injury than in controls and we hypothesize that the sustained presence of IL10 and TGFβ in transfected group could contribute to reinstate the immune tolerance lost due to the undesired effect of tacrolimus, although longer-term studies will be required to confirm it.