Clinical impact of the baseline donor-specific anti-human leukocyte antigen antibody measured by Luminex single antigen assay in living donor kidney transplant recipients after desensitization therapy

The aim of this study is to investigate the clinical impact of donor-specific anti-HLA-antibody (HLA-DSA) baseline levels, measured using the Luminex single antigen assay (LSA), in living donor kidney transplantation (LDKT). Total 129 cases of LDKT were divided into four groups according to baseline mean fluorescence intensity (MFI) HLA-DSA values: Strong (n=6), >10000; Moderate (n=8), 5000-10000; Weak (n=11), 1000-5000, Negative (n=104), <1000. Pretransplant desensitization (DSZ) was performed to decrease the MFI to weak or negative values before KT. Clinical outcomes in the four groups were compared. After DSZ, HLA-DSA decreased to weak or negative levels in all patients; Acute rejections developed more frequently in strong group [5/6 (83.3%)] compared with other three groups (P<0.05), and especially acute antibody-mediated rejection (AAMR) developed almost exclusively in strong group [4/6 (66.7%)]. Strong HLA-DSA levels at baseline were more predictive of AAMR than either type of XM (complement-dependent lymphocytotoxicity or flow cytometry) in ROC analysis. Allograft function in this group showed significant deterioration during follow-up compared with the other groups. In conclusion, strong HLA-DSA levels at baseline are associated with worse allograft outcome even after successful desensitization; therefore, strict monitoring and strong maintenance immunosuppression may be required in such patients.