부산대학교 도서관

Introduction Approximately, 25% of haemophilia A ( HA) patients treated by factor VIII ( FVIII), develop antibodies, known as inhibitors, neutralizing the activity of infused FVIII. This immune response involves B cells ( BC), including FVIII-specific memory B cells ( MBC). Production of anti- FVIII antibodies after stimulation of FVIII-specific MBC suggests a role of these cells in the immune response to FVIII. Animal models allowed the study of circulating FVIII-specific cells, however few data are available on HA patients. Aim and methods In the present study, we simultaneously detected, via ELISpot assay, different isotypes of MBC in the blood of HA patients, after polyclonal activation. Patients included: three with active inhibitors; three with a history of inhibitors; six without any past or active inhibitor. Results FVIII-specific MBC were detected in peripheral blood of HA patients: (i) patients with active inhibitors (IgG: 4-5.2/106 BC; IgA: 2.9-4/106 BC) (ii) patients with a past of inhibitors (no IgG BC; IgA: 5-7.5/106 BC) (iii) patients without inhibitors (no IgG BC or IgA BC except one patient had two FVIII-specific IgA BC/106 BC). Conclusion FVIII-specific IgA MBC were detected in HA patients with past and current immune responses against FVIII and FVIII-specific IgG MBC were found only in those with positive inhibitors. This study shows the possibility to detect and characterize easily and simultaneously the MBC from patient blood and that MBC seem different according to anti- FVIII immune history. It could be a useful tool to study anti- FVIII response and Immune Tolerance Induction cellular mechanisms. [ABSTRACT FROM AUTHOR]