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Kidney Week

Abstract: TH-OR73

Spatiotemporal Immune Atlases of Two Gene-Edited, Pig-to-Human Kidney Xenotransplants

Session Information

Category: Transplantation

  • 2101 Transplantation: Basic

Authors

  • Cheung, Matthew David, The University of Alabama at Birmingham Heersink School of Medicine, Birmingham, Alabama, United States
  • Asiimwe, Rebecca, The University of Alabama at Birmingham Heersink School of Medicine, Birmingham, Alabama, United States
  • George, James F., The University of Alabama at Birmingham Heersink School of Medicine, Birmingham, Alabama, United States
  • Locke, Jayme E., The University of Alabama at Birmingham Heersink School of Medicine, Birmingham, Alabama, United States
  • Porrett, Paige Marie, The University of Alabama at Birmingham Heersink School of Medicine, Birmingham, Alabama, United States
Background

Xenotransplantation is a promising solution for the organ shortage, but enthusiasm to proceed to clinical trials is tempered by persistent knowledge gaps about the human immune response to porcine kidney xenografts and how best to control it. Preliminary data from our group and others have suggested a role for complement immune-mediated injury of the xenograft. We used state-of-the-art single-cell technologies to characterize the human immune response to porcine kidney xenografts in two brain-dead human recipients, one of whom received the C5a inhibitor eculizumab.

Methods

Kidneys from 10-gene modified pigs were transplanted into two nephrectomized brain-dead human recipients in the setting of standard immunosuppression (induction: anti-thymocyte globulin and rituximab; maintenance: tacrolimus, mycophenolate mofetil, prednisone). Decedent 2 also received eculizumab. Xenograft core biopsies were taken pre- and post-transplant (days 1, 2, and at termination on day 3) and assessed by spatial transcriptomics. Porcine and human CD45+ cells were sorted from the explanted xenograft and analyzed using single-cell RNA seq. Data were aligned to a custom porcine-human reference genome to distinguish porcine and human transcripts and analyzed using Seurat and cell2location.

Results

Human immune cells were uncommon in the xenograft biopsies; few human neutrophils and macrophages were detected 3 days after transplant. Human neutrophils were reduced by 7-fold in decedent 2. Myeloid cells were the predominant lineage in the porcine and human compartments, and both human and porcine macrophages expressed an anti-inflammatory gene signature. Notably, human B and T cells were absent in the xenograft cortex at all time points assessed in both decedents.

Conclusion

Limited human immune cells infiltrate the porcine kidney early after xenotransplantation. Eculizumab administration was associated with a decrease in neutrophils in the xenograft. These data suggest that the addition of a complement inhibitor to conventional immunosuppression may limit further innate immune cell graft infiltration in a preclinical human model of xenotransplantation. These data may help inform the immunosuppression design for upcoming clinical trials.

Funding

  • Commercial Support – United Therapeutics Corporation