Comprehensive domain-specific analysis and immunoglobulin G profiling of anti-factor VIII antibodies using a bead-based multiplex immunoassay.

Antibodies against factor (F)VIII are a major complication in the treatment of patients with severe hemophilia A. The Nijmegen-Bethesda assay (NBA) is the gold standard for detection of neutralizing antibodies (inhibitors), whereas both inhibitors and nonneutralizing antibodies can be detected by immunoassays such as enzyme-linked immunosorbent assay (ELISA) and multiplex bead-based assays. Evaluation of an in-house Luminex bead-based assay (LumiTope) compared with a commercially available ELISA and NBA. The LumiTope method comprised full-length and B-domain-deleted FVIII as well as 9 purified FVIII single or multidomains. The respective proteins were coupled to magnetic beads to detect domain-specific immunoglobulin (IgG; IgG1-4) anti-FVIII antibodies in a large cohort of patients with hemophilia A with and without inhibitors. Overall, LumiTope assay had a high sensitivity (94.9%) and specificity (91.2%), particularly in patients with low-titer inhibitors compared with ELISA (sensitivity of 72.2% vs 27.7%). IgG4 was the most abundant IgG subclass in NBA-positive patients. NBA-positive and -negative patients showed different domain profiles. Patients with genetic variants in the heavy chain predominantly exhibited antibodies specific to this chain, while those with a light-chain variant showed a more diverse distribution of antibody specificities. Patients with an intron 22 inversion resembled those with a light-chain defect, with a majority of antibodies targeting the light chain. LumiTope assay provides a sensitive and specific method for not only detection but also domain specification of anti-FVIII-antibodies. Implementation of bead-based assays could improve antibody detection, profiling, and comparability of results and complement NBA. Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.

Citation

Behnaz Pezeshkpoor, Ann-Cristin Berkemeier, Kerstin Herbst, Thilo Albert, Jens Müller, Johannes Oldenburg. Comprehensive domain-specific analysis and immunoglobulin G profiling of anti-factor VIII antibodies using a bead-based multiplex immunoassay. Journal of thrombosis and haemostasis : JTH. 2024 Jun;22(6):1591-1604

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PMID: 38453023

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