University of Wisconsin School of Medicine and Public Health
Virtual HLA crossmatching using single antigen bead Luminex assays safely expedites transplantation of imported pancreata
Brian Eby1, Robert R Redfield1, Tom M Ellis2, Glen E Leverson3, Abby R Shenian1, Jon S Odorico1.
1Division of Transplantation, Department of Surgery, University of Wisconsin - Madison School of Medicine and Public Health, Madison, WI, United States; 2HLA Laboratory, Department of Pathology, University of Wisconsin Hospital and Clinics, Madison, WI, United States; 3Department of Surgery, University of Wisconsin - Madison School of Medicine and Public Health, Madison, WI, United States
Introduction: Cold ischemia time (CIT) accumulates with imported pancreata, limiting organ utilization, and adversely affecting outcomes. Flow cytometric HLA crossmatching (FXM) is a standard method to assess donor-recipient histocompatibility before transplantation; yet may add 4-6 hours of CIT to organs that are imported, worsening ischemia-reperfusion injury. A ‘virtual crossmatch’ (VXM) can be performed before organ transport comparing the anti-HLA antibody results by single antigen bead (SAB) Luminex assay to the donor HLA typing thereby assessing the presence, specificities, and strengths of recipient antibodies against donor HLA antigens. This study investigates the utility of VXM in reducing CIT and optimizing outcomes following transplantation of imported pancreata.
Methods: We retrospectively compared surgical outcomes of 153 patients that received solitary pancreas (SP) or simultaneous pancreas-kidney (SPK) transplantation at our institution during a 2.5-year span. Three patient groups were analyzed based on geographic source of the pancreas graft and type of prospective XM performed (i.e. VXM and FXM or only VXM) [Group 1: Imported VXM only (n=39), Group 2: Imported VXM + FXM (n=12), and Group 3: Local VXM + FXM (n=102)]. Transplantations that began based solely on VXM results did have a FXM performed retrospectively. Outcomes of interest were graft and patient survival, early rejection rates and CIT.
Results: In all 153 cases, the VXM result was predictive of a negative FXM and in no circumstance was the retrospective FXM positive in the VXM negative cases that proceeded to transplantation. Despite the imported groups (G1, G2) comprising higher immunological risk groups overall (greater proportions of SP transplant, more previous transplants, and higher panel reactive antibody in the recipients), graft survival, death-censored graft survival, and antibody mediated rejection rates did not differ between groups. When we compared the CITs of imported pancreata transplanted after VXM only (G1) vs. after VXM and FXM (G2), we found that pancreata imported from UNOS regions 3 and 4 which proceeded to surgery without a FXM saved 5.1 hours (95% CI [3.25, 6.98]) (Fig. 1, p = 0.0001).
Conclusion: By omitting the FXM and proceeding to surgery with only a negative VXM, CIT can be minimized without adversely affecting graft outcomes. If this practice is widely adopted, it could facilitate increased utilization of pancreas grafts.
UW SMPH Shapiro Summer Research Program with grant support from NIH T35DK062709. UW Department of Surgery Data Office Personnel (Bridget Welch).
15:30 - 17:00
|Pancreas and Islet Transplantation: Antibodies, Immunosuppression, and Outcomes||Virtual HLA crossmatching using single antigen bead Luminex assays safely expedites transplantation of imported pancreata||Room 110|