title: Prediction of Complement-Binding Capacity of HLA Antibodies Based on Mean Fluorescence Intensity.
abstract: BACKGROUND
  Human leukocyte antigen (HLA) antibodies estimated by Luminex single-antigen beads, especially those that fix complement, are associated with antibody-mediated rejection and graft failure. However, the relationship between HLA antibody strength and complement-binding ability is controversial.
  
  
  METHODS
  Serum samples of 31 sensitized renal patients waiting for renal transplantation were retrospectively analyzed by IgG-Luminex to identify HLA antibodies and in parallel by C1q-Luminex to determine the complement binding of HLA antibodies.
  
  
  RESULTS
  The percentage of HLA class I antibodies binding with C1q was lower than that of HLA class II antibodies (43.2% vs. 51.3%, P = .006). The mean fluorescence intensities (MFI) of IgG-Luminex correlated with the MFI of C1q-Luminex for the same antibodies (Spearman correlation; class I, r = 0.665, P < .01; class II, r = 0.761, P < .01). Receiver operating characteristic (ROC) curve analysis showed that the MFIs of HLA antibodies by IgG-Luminex predicted their C1q-binding abilities (area under the curve [AUC] class I = 0.917; AUC class II = 0.927). Using MFI cutoff values of 8238 and 6754 in IgG-Luminex 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.
  
  
  CONCLUSIONS
  The MFI of HLA antibodies by IgG-Luminex predicts the complement-binding capability to a certain extent before transplantation.
authors: Department of Urology, The Second Hospital of Tianjin Medical University, Tianjin, China; Department of Transplant Surgery, Tianjin First Central Hospital, Tianjin, China.
authors: J
authors: J
authors: Zhao
authors: Department of Transplant Surgery, Tianjin First Central Hospital, Tianjin, China.
authors: Y X
authors: YX
authors: Fu
authors: Department of Transplant Surgery, Tianjin First Central Hospital, Tianjin, China.
authors: T
authors: T
authors: Yang
authors: Department of Transplant Surgery, Tianjin First Central Hospital, Tianjin, China.
authors: Z Y
authors: ZY
authors: Shen
authors: Department of Urology, The Second Hospital of Tianjin Medical University, Tianjin, China. Electronic address: changliwu2014@aliyun.com.
authors: C L
authors: CL
authors: Wu
mesh_terms: D000328:Adult; D000906:Antibodies / Q000097:blood / Q000276:immunology*; D015922:Complement C1q / Q000276:immunology; D003168:Complement Fixation Tests; D005260:Female; D005453:Fluorescence; D005455:Fluorescent Antibody Technique / Q000379:methods; D006084:Graft Rejection / Q000276:immunology; D006680:HLA Antigens / Q000097:blood / Q000276:immunology*; D015395:Histocompatibility Antigens Class I / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D007676:Kidney Failure, Chronic / Q000097:blood / Q000276:immunology* / Q000601:surgery; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012372:ROC Curve; D012016:Reference Values; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014850:Waiting Lists
chemical_list: D000906:Antibodies; D006680:HLA Antigens; D015395:Histocompatibility Antigens Class I; D007074:Immunoglobulin G; D015922:Complement C1q