Long-term administration of classic immunosuppressants can induce severe adverse effects. The development of novel immunosuppressants confronts great challenges and opportunities. Ibrutinib, an approved drug for B-cell lineages and chronic graft versus host disease (cGVHD), exhibits immunosuppressive efficacy in autoimmune diseases. Ibrutinib's potential as an immunosuppressant in organ transplantation has not been investigated to date. In a xeno-artery patch model ex vivo, ibrutinib inhibited the proliferation of PBMCs (POD 14-42), mainly CD3+CD4+ and CD3+CD8+ T cells ex vivo. The secretion of cytokines (IL-6, IL-2 and IFN-γ) was suppressed in response to ibrutinib. In allo-skin transplantation models, ibrutinib delayed the rejection of grafted skins. Ibrutinib decreased the amount of T/B cells and lymphocyte infiltration. Altogether, ibrutinib exhibited immunosuppressive potential through cytokine regulation and T cell inhibition ex vivo and in vitro. Repositioning of ibrutinib as an immunosuppressant will greatly facilitate novel immunosuppressant development.
Keywords: Allo-transplantation; Ibrutinib; Immune rejection; Immunosuppressant; Xeno-transplantation.