Related Experiment Video
Updated: May 14, 2026
Methods for Quantitative Detection of Antibody-induced Complement Activation on Red Blood Cells
Published on: January 29, 2014
Systematic comparison of four cell- and Luminex-based methods for assessment of complement-activating HLA antibodies
Nils Lachmann1, Kremena Todorova, Harald Schulze
1Charité-Universitätsmedizin Berlin, Center for Tumor Medicine and ZTB Zentrum für Transfusionsmedizin und Zelltherapie Berlin, Tissue Typing Laboratory, Berlin, Germany.
Background:
Efforts to increase the specificity and sensitivity of human leukocyte antigen (HLA) antibody detection assays recently led to the establishment of two novel Luminex bead-based assays to detect complement-activating antibodies by the assessment of complement products C1q or C4d. Here, we present a systematic comparison of the four methods, complement-dependent lymphocytotoxicity (CDC) and C1q-, C4d-, and IgG-Luminex, to assess or predict the complement-binding capability of HLA IgG antibodies.
Methods:
Forty-five sera of highly immunized patients have been assessed by in-house modified C1q- and C4d-Luminex assays and compared with standard CDC and IgG-Luminex.
Results:
Antibody specificities assigned by the C1q- and C4d-Luminex assay revealed an excellent concordance of 94% and 97% for HLA class I and II, respectively. Complement-fixing HLA class II antibodies were found less frequently among IgG antibodies compared with class I. Both C1q- and C4d-Luminex detected, on average, three times more specificities than CDC. Although we found a high correlation of mean fluorescence intensity values between C1q- and C4d-Luminex assays, IgG mean fluorescence intensity was not a suitable surrogate marker for the prediction of complement binding.
Conclusions:
C1q- and C4d-Luminex assays are characterized by an increased sensitivity and specificity compared with CDC, the current standard in detecting complement-fixing HLA antibodies. Pretransplantation risk assessment for transplantation but also posttransplantation monitoring are important applications for both assays to improve overall allograft survival.
