Combined liver–kidney transplantation with positive crossmatch: Role of delayed kidney transplantation

Background Positive crossmatch (XM+) combined liver–kidney transplantation due to preformed donor-specific human leukocyte antigen antibodies has produced mixed results. We sought to understand the role of delayed kidney transplant approach in XM+ combined liver–kidney transplantations. Methods XM+ combined liver–kidney transplantations were retrospectively reviewed. T- and B-cell XM, complement-dependent cytotoxic crossmatch, and flow cytometric crossmatch were performed prospectively. Results Of 183 combined liver-kidney transplantations performed (2002–2019), 114 (62%) were with “delayed” kidney transplant approach and 19 (19 of 183, 10%) were XM+. Of 19 XM+ combined liver–kidney transplantations, kidney transplant was “delayed” in 14 by an average of 47 hours (range 24–64 hours) from liver transplant. There was a significant reduction in both class I (mean pre–liver transplant mean fluorescence intensity (MFI) 26,230 versus mean post–liver transplant and pre–delayed kidney transplant MFI 3,272, P = .01) and total MFI (mean pre–liver transplant MFI 27,233 vs mean post liver transplant and predelayed kidney transplant MFI 11,469, P = .01). However, there was no significant change in the MFI of class II donor-specific antibodies (mean pre–liver transplant MFI 17,899 versus post-liver transplant and pre–delayed kidney transplant MFI 14,341, P = .19). None of XM+ delayed kidney transplants had delayed graft function, and there was no antibody-mediated rejection. One-year patient survival for the XM+ combined liver–kidney transplantation with delayed kidney transplant approach was 92.9%, which is comparable to patient survival of XM– combined liver–kidney transplantation. Whereas patient survival in recipients before “delayed” approach (“simultaneous”; n = 5) was 40% when liver–kidney transplants were performed simultaneously (P = .06). Conclusion In sensitized combined liver-kidney transplantation recipients, the “delayed” kidney transplant approach is associated with a significant reduction in total and class I donor-specific antibodies after liver transplant before kidney transplant, enabling therapeutic interventions such as plasmapheresis, if needed, providing optimal outcomes similar to crossmatch recipients.