M. Hu1, J. Ladowski1, J. Kwun1, S. Knechtle1 1Duke University Medical Center, Durham, NC, USA
Introduction: As the field prepares for clinical xenotransplantation, it is imperative we understand the reagents available to support xenograft recipients perioperatively. It has been previously demonstrated that intravenous immunoglobulin can carry xenoantibodies that are potentially detrimental to the xenograft. It is unknown if other blood products contain similar xenoantibodies.
Methods: Individual units of discarded blood products from our institutional blood bank were obtained: eleven fresh frozen plasma (FFP), seven cryoprecipitate (cryo), and three packed red blood cells. A T cell flow cytometry crossmatch was performed and IgG and IgM antibody binding against Alpha-1,3-Galacosyltransferase gene-knockout (GTKO) pig splenocytes. WT pig RBCs were isolated from porcine whole blood and incubated with each sample for 1 hour at 37C and the adsorbed sera was tested in a similar flow cytometry crossmatch.
Results: Average IgG levels (quantified by median fluorescence intensity) on T cell crossmatch were 391.3, 679.6, 165.7 (cryo, FFP, pRBCs) and 287.9, 227.3, and 166.7 after adsorption. Average IgM levels were 4063.4, 5459.7, 433 and 1286.4, 1275.5, and 320 after adsorption. There was a statistically significant decrease in both IgG and IgM levels in FFP following adsorption (p=0.004), but not cryo or pRBCs.
Conclusion: Human FFP, cryoprecipitate, and pRBCs contain variable levels of anti-GTKO pig antibodies, which may contribute to xenograft rejection if given during xenotransplantation. Further exploration is needed to explore antibody binding to pigs of other genetic backgrounds.