4th Congress of the Spanish Society of TransplantationKidney transplantationKidney Transplantation Results in Very Highly Sensitized Patients Included in a Virtual Crossmatch Program: Analysis of Kidney Pairs

- Kidney transplant (KT) in highly-sensitized (HS) patients can improve with organ-exchange strategies based on virtual crossmatch (V-XM). Experience in very-HS patients is still limited.
- In June 2012 Andalusia (a European region in the south of Spain) started a V-XM protocol for very-HS patients (calculated-PRA≥95%). After organ allocation a cytotoxic-XM done immediately before transplantation had to be negative for surgery to proceed. We analyzed the results of this V-XM protocol up to December 2015. Whenever possible we also compared the course of these very HS patients with the recipient (not very HS) of the other kidney from the same donor (data source: regional transplant registry, SICATA Registry).
- In conclusion, although a few patients still developed AMR, our V-XM based protocol with a final pre-transplant cytotoxic-XM achieved very satisfactory results. In most cases the HLA-DSA considered to be involved in the development of AMR were already present before transplantation, which reflects the difficulty to establish an adequate threshold for the MFI. Though the number of patients was limited, the initial survival of these high-risk recipients was comparable to the controls.

BackgroundKidney transplantation in highly-sensitized (HS) patients can improve with organ-exchange strategies based on virtual crossmatch (V-XM). Experience in very-HS patients is limited.MethodsIn June 2012, Andalusia started a V-XM protocol for very-HS patients (calculated panel reactive antibodies ≥95%). After organ allocation a cytotoxic-XM performed immediately before transplantation had to be negative for surgery to proceed. We analyzed results up until December 2015. Whenever possible we also compared the course of the recipient (non-HS) of the other kidney from the same donor.ResultsOf the 57 grafts, 52 kidney transplantations were performed (the pretransplantation cytotoxic-XM was positive in 5; predictive value 91.3%). Five patients (9.6%) experienced acute rejection (4 antibody-mediated rejections [AMRs]; 7.6%). Donor-specific antibodies developed in 10 patients. No patient died. One-year graft survival was 98%. We compared the course of the non-HS recipient of the other kidney, excluding cases with no pair (n = 5), pairs who were children recipients (n = 3), pancreas-kidney recipients (n = 5), or pairs already included in the V-XM protocol (n = 4). Finally, 35 pairs were studied. More HS-patients developed donor-specific antibodies (P = .016). No significant differences were seen in acute rejection, but AMR was more common (P = .057). No deaths occurred in either group, and there were no differences in graft survival or renal function.ConclusionsAlthough a few patients still developed AMR, our V-XM based protocol with a final pretransplantation cytotoxic-XM achieved very satisfactory results. Although the number of patients was limited, the initial survival of these high-risk recipients was comparable to the controls.