Cumulative mean fluorescent intensities of HLA specific antibodies predict antibody mediated rejections after kidney transplantation

It is still not fully elucidated which pretransplant donor-specific HLA antibodies (DSA) are harmful after kidney transplantation. In particular, it needs to be clarified whether cumulative mean fluorescence intensities (MFI) against multiple HLA specificities have a predictive value for allograft function. Our retrospective single centre study analyzed preformed HLA antibodies determined by Luminex (TM) Single Antigen Bead (SAB) assay, including C1q addition, in relation to rejection and clinical outcome in 255 cross match negative kidney allograft recipients. Only 33 recipients (13%) of the total cohort showed early AMR during the first year posttransplant, but in patients with pre-transplant DSA the rate was increased to 15 out of 40 (38%). Three year graft survival was significantly shorter in patients with histological signs of AMR compared with patients without AMR or with no biopsy (74%, 92%, and 97%, respectively, p < 0.0001). In patients with HLA-DSA, a cumulative MFI value of all HLA antibodies of more than 103.000 indicated the highest risk for AMR posttransplant (p = 0.01). In conclusion, in patients with HLA-DSA, the cumulative MFI value may help to further stratify the risk of AMR after kidney transplantation.