Virtual HLA Crossmatching as a Means to Safely Expedite Transplantation of Imported Pancreata.

BACKGROUND: Imported pancreata accumulate cold ischemia time (CIT), limiting utilization and worsening outcomes. Flow cytometric crossmatching (FXM) is a standard method to assess recipient and donor compatibility, but can prolong CIT. Single-antigen bead assays allow for detection of recipient donor-specific HLA antibodies, enabling prediction of compatibility through a "virtual crossmatch" (VXM). This study investigates the utility and outcomes of VXM after transplantation of imported pancreata.

METHODS: We retrospectively compared outcomes of 153 patients undergoing pancreas transplantation at our institution over a 3.5-year period.

RESULTS: Three patient groups were analyzed based on geographic source of the pancreas graft and the type of prospective crossmatch performed: (1) imported VXM-only, n = 39; (2) imported VXM + FXM, n = 12; and (3) local VXM + FXM, n = 102. There were no episodes of hyperacute rejection and 1 episode of early antibody-mediated rejection (<90 days) in the imported VXM group. Death-censored graft survival, patient survival, and rejection rates were comparable among the recipient groups. For pancreata imported from United Network of Organ Sharing regions 3 and 4, proceeding to surgery without an FXM reduced CIT by 5.1 hours (P < 0.001). The time from organ arrival at the hospital to operation start was significantly shorter in the VXM-only group compared with the VXM + FXM group (P < 0.001).

CONCLUSIONS: Virtual crossmatch helps minimize CIT without increasing rejection or adversely affecting graft survival, making it a viable method to increase pancreas graft utilization across distant organ sharing regions.