Stable Mixed Hematopoietic Chimerism Permits Tolerance of Vascularized Composite Allografts Across a Full MHC Mismatch in Swine.

Transplant international : official journal of the European Society for Organ Transplantation

PubMedID: 24963743

Mathes DW, Solari MG, Gazelle GS, Butler PE, Wu A, Nazzal A, Nielsen GP, Huang CA, Sachs DH, Lee WP, Randolph MA. Stable Mixed Hematopoietic Chimerism Permits Tolerance of Vascularized Composite Allografts Across a Full MHC Mismatch in Swine. Transpl Int. 2014;.
This study tested the hypothesis that vascularized composite allografts (VCA) could be accepted in a robust model of hematopoietic chimerism by injecting allogeneic bone marrow cells (BMC) into swine fetuses. Outbred Yorkshire sows and boars were screened to ensure the absence of the MHC allele SLA(cc) of inbred MGH miniature swine and then mated. Bone marrow harvested from an SLA(cc) swine donor was T-cell depleted and injected intravenously into the fetuses between days 50-55 of gestation. After birth, the piglets were studied with flow cytometry to detect donor cells, and mixed lymphocyte reactions (MLR) and cell-mediated lympholysis (CML) assays to assess their response to donor. Donor-matched VCAs from SLA(cc) donors were performed on four chimeric and two non-chimeric swine. The results showed donor cell engraftment and multi-lineage macrochimerism after the in utero transplantation of adult BMC, and chimeric animals were unresponsive to donor antigens in vitro. Both control VCAs were rejected by 21 days and were alloreactive. Chimeric animals accepted the VCAs and never developed anti-donor antibodies or alloreactivity to donor. These results confirm that the intravascular, in utero transplantation of adult BMC leads to donor cell chimerism and donor-specific tolerance of VCAs across a full MHC barrier in this animal model. This article is protected by copyright. All rights reserved.