Background: Outstanding results from nonhuman primate study put islet xenotransplantation with immunosuppression closer to the clinical application. To establish successful immune suppressive protocols, immune monitoring by which the fate of graft could be predictable would be critical. However, there are few reports showing predictive immune parameters associated with the fate of the graft in pig to nonhuman primate islet xenotransplantation model.

Methods: Porcine islets were transplanted to diabetic nonhuman primate under immunosuppression (rabbit anti-thymocyte globulin (ATG) as induction immunosuppressant and various combinations of anti-CD154, anti-CD40, rapamycin, tacrolimus and tocilizumab as maintenance). During observation period, the number and ratio of T cell subsets were analyzed by flow cytometry from peripheral blood of 17 transplanted monkeys.

Results: CD3⁺T cells counts reached the 1,000 cells /[mu]l after 38.2 ± 47.7 days post transplantation following rATG treatment in 13/17 monkeys. CD4⁺ T cells were the dominant populations in CD3⁺ T cells before the transplantation. However, CD8⁺CD28^–CD95⁺ effector memory T cell's rapid expansion reversed the ratio of CD4⁺ versus CD8⁺ T cells. T lymphocyte subtype analysis with graft survival day revealed that CD4⁺/CD8⁺ T cell ratio was significantly associated with early graft failure.

Conclusions: CD4⁺/CD8⁺ T cell ratio could be used as a surrogate marker to predict early graft failure in porcine islet xenotransplantion in NHPs with immunosuppression.

CITATION INFORMATION: Choi S, Kim H.-J, Yoon I.-H, Kim J.-S, Kang S.-J, Nam H.-Y, Min B.-H, Shin J.-S, Kim J.-M, Kim Y.-H, Lee W.-W, Park C.-G. CD4⁺/CD8⁺ T Cell Ratio as a Predictive Marker for Early Graft Failure in Pig to Non-Human Primate Islet Xenotransplantation with Immunosuppression. Am J Transplant. 2017;17 (suppl 3).

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