title: Catalytic IgG from patients with hemophilia A inactivate therapeutic factor VIII.
abstract: Factor VIII (FVIII) inhibitors are anti-FVIII IgG that arise in up to 50% of the patients with hemophilia A, upon therapeutic administration of exogenous FVIII. Factor VIII inhibitors neutralize the activity of the administered FVIII by sterically hindering its interaction with molecules of the coagulation cascade, or by forming immune complexes with FVIII and accelerating its clearance from the circulation. We have shown previously that a subset of anti-factor VIII IgG hydrolyzes FVIII. FVIII-hydrolyzing IgG are detected in over 50% of inhibitor-positive patients with severe hemophilia A, and are not found in inhibitor-negative patients. Although human proficient catalytic Abs have been described in a number of inflammatory and autoimmune disorders, their pathological relevance remains elusive. We demonstrate here that the kinetics of FVIII degradation by FVIII-hydrolyzing IgG are compatible with a pathogenic role for IgG catalysts. We also report that FVIII-hydrolyzing IgG from each patient exhibit multiple cleavage sites on FVIII and that, while the specificity of cleavage varies from one patient to another, catalytic IgG preferentially hydrolyze peptide bonds containing basic amino acids.
authors.affiliation: Institut National de la Santé et de la Recherche Médicale (INSERM) Unité 681 and Université Pierre et Marie Curie (UPMC)-Paris 6, Institut des Cordeliers, 15 rue de l'Ecole de Médecine, 75006 Paris, France. sebastien.lacroix-desmazes@umrs681.jussieu.fr
authors.forename: Sébastien
authors.initials: S
authors.lastname: Lacroix-Desmazes
authors.forename: Bharath
authors.initials: B
authors.lastname: Wootla
authors.forename: Suryasarathi
authors.initials: S
authors.lastname: Dasgupta
authors.forename: Sandrine
authors.initials: S
authors.lastname: Delignat
authors.forename: Jagadeesh
authors.initials: J
authors.lastname: Bayry
authors.forename: Joseph
authors.initials: J
authors.lastname: Reinbolt
authors.forename: Johan
authors.initials: J
authors.lastname: Hoebeke
authors.forename: Evgueni
authors.initials: E
authors.lastname: Saenko
authors.forename: Michel D
authors.initials: MD
authors.lastname: Kazatchkine
authors.forename: Alain
authors.initials: A
authors.lastname: Friboulet
authors.forename: Olivier
authors.initials: O
authors.lastname: Christophe
authors.forename: Valakunja
authors.initials: V
authors.lastname: Nagaraja
authors.forename: Srini V
authors.initials: SV
authors.lastname: Kaveri
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D017151:Antibodies, Catalytic / Q000096:biosynthesis / Q000097:blood / Q000502:physiology*; D001120:Arginine / Q000378:metabolism; D001666:Binding Sites, Antibody; D001777:Blood Coagulation / Q000276:immunology; D002648:Child; D003374:Coumarins / Q000378:metabolism; D005169:Factor VIII / Q000037:antagonists & inhibitors* / Q000378:metabolism* / Q000627:therapeutic use; D006467:Hemophilia A / Q000276:immunology* / Q000628:therapy; D006801:Humans; D006868:Hydrolysis; D007074:Immunoglobulin G / Q000378:metabolism / Q000502:physiology*; D008875:Middle Aged; D009842:Oligopeptides / Q000378:metabolism; D010649:Phenylalanine / Q000378:metabolism; D011392:Proline / Q000378:metabolism
chemical_list: D017151:Antibodies, Catalytic; D003374:Coumarins; D007074:Immunoglobulin G; D009842:Oligopeptides; D010649:Phenylalanine; D005169:Factor VIII; D001120:Arginine; D011392:Proline; C030123:coumarin