ABSTRACT
Objective To investigate the relationship between HLA antibodies strength and complement-binding ability in sensitized renal patients waiting for renal transplantation.Method Serum samples of 31 sensitized renal patients waiting for renal transplantation were retrospectively analyzed by single-antigen bead array (SAB) to identify HLA antibodies and in parallel by C1q-SAB to determine the complement binding of HLA antibodies.Result C1q-positive HLA antibodies had significantly higher MFI than C1q-negative HLA antibody (for Class Ⅰ,11052 ± 3291 vs.4506 ± 2960,P＜0.05;for Class Ⅱ,13347 ± 4076 vs.4448 ± 3602,P＜0.05).The mean fluorescence intensities (MFI) of IgG-SAB were correlated with the MFI of C1q-SAB for the same antibodies (Spearman correlation; Class Ⅰ,r =0.665,P ＜ 0.01 ; Class Ⅱ,r =0.761,P ＜ 0.01).Receiver operating characteristics (ROC) curve analysis showed that the MFIs of HLA antibodies by IgG-SAB could predict their C1q-binding abilities [area under the curve (AUC)Class Ⅰ =0.917; AUCclass Ⅱ =0.927).Using MFI cut-off value of 8238 and 6754 for HLA Class Ⅰ and Class Ⅱ antibodies,respectively,the sensitivity and specificity for C1q binding were 82.4％ and 87.4％ for Class Ⅰ antibodies,and 90.9％ and 82％ for Class Ⅱ antibodies,respectively.Conclusion The MFI of HLA antibodies by IgG-SAB can predict the C1q binding capability at a certain extent before transplantation.