Early Donor-Specific HLA Antibodies Detected by Screening in the First Month Posttransplant and Kidney Graft Outcomes

Donor-specific HLA antibodies (DSA) are related to antibody-mediated rejection (ABMR) and graft failure. The rationale and frequency of screening for anti-HLA antibodies in stable patients are not established. The aim of our study is to evaluate the impact of early DSA appearance in the first month post-transplant on graft outcomes. All kidney transplant recipients between 1/1/2012-12/31/2022 with anti-HLA antibody screening by Luminex during the first month post-transplant were included. Patients with preformed or historical DSA and those with DSA detection after graft loss were excluded. The mean fluorescence intensity cut-off was 1,500. Three hundred fifty-three patients were included and the median time from transplant to first antibody sample was 30.0 days. During 3.8 years of follow-up, graft loss occurred in 9.1% and 19.5% had ABMR. A total of 8.5% developed early-DSA in the first month. Patients with early-DSA detection had more HLA sensitization at the time of transplant (p < 0.001). Multivariable analysis showed that the presence of early-DSA was an independent risk factor for ABMR. In conclusion, sensitized patients at the time of transplant have a higher risk of DSA formation in the first month, probably reflecting alloimmune memory, therefore early HLA antibody screening should be performed in this high-risk population.