Immune molecular profiling of whole blood drawn from a non-human primate cardiac xenograft model treated with anti-CD154 monoclonal antibodies.

Most studies of xenografts have been carried out with complex immunosuppressive regimens to prevent immune rejection; however, such treatments may be fatal owing to unknown causes. Here, we performed immune molecular profiling following anti-CD154 monoclonal antibody (mAb) treatment in heterotopic abdominal cardiac xenografts from α-1,3-galactosyltransferase-knockout pigs into cynomolgus monkeys to elucidate the mechanisms mediating the undesirable fatal side effects of immunosuppressive agents. Blood samples were collected from healthy monkeys as control and then at 2 days after xenograft transplantation and just before humane euthanasia; 94 genes related to the immune system were analyzed. The basic immunosuppressive regimen included cobra venom factor, anti-thymocyte globulin, and rituximab, with and without anti-CD154 mAbs. The maintenance therapy was followed with tacrolimus, MMF, and methylprednisolone. The number of upregulated genes was initially decreased on Day 2 (-/+ anti-CD154 mAb, 22/13) and then increased before euthanasia in recipients treated with anti-CD154 mAbs (-/+ anti-CD154 mAb, 30/37). The number of downregulated genes was not affected by anti-CD154 mAb treatment. Additionally, the number of upregulated genes increased over time for both groups. Interestingly, treatment with anti-CD154 mAbs upregulated coagulation inducers (CCL2/IL6) before euthanasia. In conclusion, immunosuppressive regimens used for cardiac xenografting affected upregulation of 6 inflammation genes (CXCL10, MPO, MYD88, NLRP3, TNFα, and TLR1) and downregulation of 8 genes (CCR4, CCR6, CD40, CXCR3, FOXP3, GATA3, STAT4, and TBX21).