Increased expression of non-interleukin-2 T cell growth factors and their implications during liver allograft rejection in rats

IL-15 induces alloreactive CD28(-) memory CD8 T cell proliferation and CTLA4-Ig resistant memory CD8 T cell activation

The presence of CD28(-) memory CD8 T cells in the peripheral blood of renal transplant patients is a risk factor for graft rejection and resistance to CTLA-4Ig induction therapy. In vitro analyses have indicated poor alloantigen-induced CD28(-) memory CD8 T cell proliferation, raising questions about mechanisms mediating their clonal expansion in kidney grafts to mediate injury. Candidate proliferative cytokines were tested for synergy with alloantigen in stimulating CD28(-) memory CD8 T cell proliferation. Addition of IL-15, but not IL-2 or IL-7, to co-cultures of CD28(-) or CD28(+) memory CD8 T cells and allogeneic B cells rescued proliferation of the CD28(-) and enhanced CD28(+) memory T cell proliferation. Proliferating CD28(-) memory CD8 T cells produced high amounts of interferon gamma and tumor necrosis factor alpha and expressed higher levels of the cytolytic marker CD107a than CD28(+) memory CD8 T cells. CTLA-4Ig inhibited alloantigen-induced proliferation of CD28(+) memory CD8 T cell proliferation but had no effect on alloantigen plus IL-15-induced proliferation of either CD28(-) or CD28(+) memory CD8 T cells. These results indicate the ability of IL-15, a cytokine produced by renal epithelial during inflammation, to provoke CD28(-) memory CD8 T cell proliferation and to confer memory CD8 T cell resistance to CTLA-4Ig-mediated costimulation blockade.

Effectiveness of topical immunosuppressants in prevention and treatment of rejection in face allotransplantation

BACKGROUND

The use of topical immunosuppressants has been anecdotally reported for the treatment of rejection in vascularized composite allotransplantation. The aim of this study was to evaluate the effectiveness of topical tacrolimus and clobetasol in the prevention and treatment of rejection.

METHODS

Seventy-six hemiface allotransplants, between ACI (RT1) donors and Lewis (RT1) recipients, were performed in 11 groups and treated with topical tacrolimus or clobetasol, or in combination with systemic cyclosporine A and anti-αβ-T-cell receptor antibody for 1 week. Topical treatment increased the survival of the allograft in all groups.

RESULTS

Best outcomes were obtained in the groups treated with systemic therapy and topical tacrolimus. Expression of proinflammatory cytokines interleukin 2, interferon γ, tumor necrosis factor α, and transforming growth factor β correlated with clinical signs of rejection and the final outcomes. Clobetasol application was associated with a marked depletion of lymphocytic populations, and dermal and epidermal atrophy.

CONCLUSIONS

Both topical tacrolimus and clobetasol were effective in treating episodes of acute rejection, and the best outcomes were achieved when their application was initiated after systemic immunosuppression. Topical tacrolimus proved to be a preferable adjunct agent to the systemic therapy by preventing both the local and systemic complications.