Introduction: The presence of anti-HLA antibodies have a major impact on allograft survival and it is a barrier in renal transplantation (RT). A combined use of techniques such as flow cytometric crossmatch (FCXM) with complement-dependent cytotoxicity (CDC) has improved immunological risk analysis. FCXM allows direct evaluation of the immunological risk in the recipient-donor couple, independently of the resolution level of the donor's HLA typing and the representativeness of all the HLA variants arranged in the beads of the antibody specificity kits. The policy of our renal transplant program does not include restrictions for access to the transplant due to the degree of HLA sensitization. We show the results of this strategy in the present scenario in transplant patients (P) with HLA sensitization.

Patients and methods: In the period between January 2017 and December 2021, 248 deceased RT were performed in our center. Fourty seven P presented some degree of HLA sensitization (19%): 21 P did not have donor specific antibodies (DSA) at the time of transplantation and 26 P did have at least 1 DSA (virtual crossmatch at the serological level) with mean MFI: 9.300 (1.157-27.994). FCXM was negative for T and B cells. Age of this cohort: 45.7 (range 18-78), re-RT 55%, PRA Class I: 39%, Class II: 57%, female 55%, MM: 3.2 (0-5). The induction scheme included antithymocyte globulin in 100%, 32% received IvIG and 10% PF, post-TR IS was mostly with TAC and MMF.

Results: The mean follow-up was 24.2 months (1-59). In the period studied, 28 biopsy-confirmed rejections were recorded: 0.6 episodes/patient, of which 18 were humoral. 64% of the patients did not develop acute rejection (n: 30) until the end of follow-up. Among patients with rejection, 1.6 episodes/patient were recorded. Graft survival at 2 years was 84% while patient survival in the same period was 90%. In patients with DSA (+) IVIg was used more frequently (46% vs. 14%) as induction and plasmapheresis was used only in DSA + patients (15%). The presence of DSA was not associated with significant differences in organ survival (89% vs. 79% p: n.s.) and patient survival: 95% vs. 86% (p: n.s.). The rejection rate in DSA (+) was 55.3% and in DSA (-) 44.7% (chi-square p: n.s.). DSA + group was divided into MFI<5000 (n: 14, mean 2.918 MFI) and MFI ≥5000 (n: 12, mean 16.205 MFI) with no significant differences in P and graft survival. We also did not observe differences in those P with PRA > 85% and presence of DSA with MFI > 5000.

Conclusion: The results at 24 months in sensitized patients do not seem to be significantly influenced by the type and intensity of HLA sensitization as long as they have a negative FCXM. The future distribution of organs in our country according to unacceptable antigens will make possible to compare the results of both strategies.