The spectrum of neutralizing and non-neutralizing anti-FVIII antibodies in a nationwide cohort of 788 persons with hemophilia A

Ilja Oomen, Marieke Verhagen, Mariarosaria Miranda, Peter Allacher, Erik A M Beckers, Nicole M A Blijlevens, Johanna G van der Bom, Michiel Coppens, Mariëtte Driessens, Jeroen C J Eikenboom, Karin Fijnvandraat, Shermarke Hassan, Waander L van Heerde, H Louise Hooimeijer, Joop H Jansen, Paul Kaijen, Frank W G Leebeek, Daniëlle Meijer, Helmut Paul, Sanna R RijpmaFrits R Rosendaal, Cees Smit, Lize F D van Vulpen, Jan Voorberg, Saskia E M Schols, Samantha C Gouw

Publikation: Beitrag in FachzeitschriftArtikelBegutachtung

Abstract

OBJECTIVES: Anti-factor VIII (FVIII) antibodies have been reported to exhibit both neutralizing and non-neutralizing characteristics. This is the first study investigating the full spectrum of FVIII-specific antibodies, including non-neutralizing antibodies, very-low titer inhibitors, and inhibitors, in a large nationwide population of persons with hemophilia A of all severities.

METHODS: All persons with hemophilia A (mild (FVIII > 5-40 IU/dL)/moderate [FVIII 1-5 IU/dL)/severe (FVIII < 1 IU/dL)] with an available plasma sample who participated in the sixth Hemophilia in the Netherlands study between 2018 and 2019 were included. The presence of anti-FVIII antibodies of the immunoglobulin A, M, and G isotypes and IgG subclasses, along with antibody titer levels, were assessed using direct-binding ELISAs. FVIII specificity was assessed using a competition-based ELISA approach. The inhibitor status was determined using the Nijmegen ultra-sensitive Bethesda assay (NusBA) and the Nijmegen Bethesda assay (NBA).

RESULTS: In total, 788 persons with hemophilia A (336 (42.6%) mild, 123 (15.6%) moderate, 329 (41.8%) severe hemophilia) were included. The median age was 45 years (IQR 24-60), and the majority (50.9%) had over 150 exposure days to FVIII concentrates. Within our population, 144 (18.3%) individuals had non-neutralizing FVIII-specific antibodies, 10 (1.3%) had very low-titer inhibitors (NusBA positive; NBA negative), and 13 (1.6%) had inhibitors (both NusBA and NBA positive). IgG1 was the most abundant FVIII-specific antibody subclass, and the highest titer levels were found for IgG4. In individuals without a reported history of inhibitor development, no clear differences were observed in antibody patterns between those who were minimally or highly exposed to FVIII concentrates. IgG4 subclass antibodies were only observed in persons with a reported history of FVIII inhibitor or in those with a currently detected (very low-titer) inhibitor.

CONCLUSION: In this cross-sectional study, we identified non-neutralizing antibodies in a relatively large proportion of persons with hemophilia A. In contrast, in our population, consisting of persons highly exposed to FVIII concentrates, (very low-titer) inhibitors were detected only in a small proportion of persons, reflecting a well-tolerized population. Hence, our findings suggest that only a small subpopulation of non-neutralizing FVIII-specific antibodies is associated with clinically relevant inhibitors.

OriginalspracheEnglisch
Aufsatznummer1355813
Seiten (von - bis)1355813
FachzeitschriftFrontiers in Immunology
Jahrgang15
DOIs
PublikationsstatusVeröffentlicht - 22 Feb. 2024

Fingerprint

Untersuchen Sie die Forschungsthemen von „The spectrum of neutralizing and non-neutralizing anti-FVIII antibodies in a nationwide cohort of 788 persons with hemophilia A“. Zusammen bilden sie einen einzigartigen Fingerprint.

Dieses zitieren