Figure 2. Effect of genetic modifications and treatment regimens on survival of pig kidneys in baboons.

Survival of life-supporting kidneys from wild-type (WT, n=24), hDAF transgenic (n=42), or GalT-KO pigs (n=20) in immunosuppressed baboons. With intensive conventional immunosuppression, with or without additional complement depletion, hDAF kidney recipients succumbed to infectious complications or developed DXR at a median of 15 to 25 days, significantly later than do similarly treated recipients of wild-type organs (~6-10 days). The incidence of early graft failure (<3 days) was reduced in recipients of GalT-KO kidneys. Six GalT-KO kidneys in baboons treated with conventional immunosuppression exhibited DXR associated with induction of anti-pig antibodies, demonstrating that the regimens tested in this experience were subtherapeutic. Using an anti-CD154 antibody, mycophenolate mofetil, T-cell depletion, and vascularized donor thymus tissue, 8 of 14 recipient baboons in the GalT-KO kidney group died with functioning grafts (serum creatinine <2.0mg/dL) from treatment complications. (Results in 3 recipients of hDAF kidneys treated with anti-CD154 antibody, which survived for 28, 29 and 29 days, are omitted from the figure due to the relatively small experience.)

Data for conventional immunosuppression is abstracted and aggregated from all peer-reviewed pig-to-baboon kidney transplant studies published since 1998. Pig phenotype (GalT-KO, hDAF, or WT) and treatment regimen (anti-CD154-based or conventional (Conv.) treatment (Rx)) are indicated. Similar results were achieved with conventional immunosuppression in over 250 cynomolgus recipients of hDAF kidneys that used comparable approaches.