SEOPF high-grade match algorithm: the effect of HLA matching with ROP trays in transplanting highly sensitized...

The SEOPF high-grade match (HGM) algorithm for sharing kidneys was designed to increase utilization of kidneys for excellent HLA matches, decrease sharing for poor HLA matches, and improve the chances for highly sensitized patients to receive a kidney transplant through the use of ROP crossmatch trays. All retrieved kidneys from participating centers were offered to the system to be shared for high-grade HLA matches after six-antigen match obligations were satisfied with UNOS. Kidneys were shared according to HLA matches in the following priority: 1) 0-ABDR mismatch six - Antigen Matches. 2) 0-AB mismatch PRA > 40%, ROP tray negative crossmatch. 3) 0-BDR mismatch PRA > 40%, ROP tray negative crossmatch. 4) 0-BDR mismatch PRA < 40%. All patients with PRA's > 40% must be represented on the ROP tray to be considered for a shared kidney. Preliminary ROP tray crossmatch results must have been known for these patients in order to access the system. Here we report results of 126 shared kidneys using the HGM algorithm from January 1994 to September 1995. HLA typing concordance between the initial typing of cadaver donors by the donor center and repeat typing by recipient center was 94.7%. There were six (5.3%) typing discrepancies: HLA-A, no typing discrepancies; HLA-B, 2 (1.8%) typing discrepancies; and HLA-DR, 4 (3.5%) discrepancies. A total of 34 of 126 (27%) kidneys were shared for patients with high grade HLA matches, PRA's > 40% and a negative ROP tray. Twenty-eight of 34 (82.4%) shared kidneys were final crossmatch negative and transplanted into the intended recipient. Six of 34 (17.6%) shared kidneys were transplanted into backup recipients. All six of the intended recipients had positive final crossmatches using enhanced crossmatch procedures, such as antiglobulin and flow cytometry. In conclusion, the HLA concordance rate for shared kidneys within SEOPF was 94.7%. Kidney sharing using the HGM algorithm was very effective in transplanting highly sensitized patients when good HLA matching was combined with a negative ROP tray result.