title: Detection of two different anti-factor VIII/von Willebrand factor antibodies of the IgA class in a hemophilic patient with a polyclonal factor VIII inhibitor of the IgG class.
abstract: A hemophilic patient treated with Factor VIII (F.VIII) concentrates developed a F.VIII inhibitory activity. The patient's plasma showed 2 anti-F.VIII/von Willebrand Factor (vWF) antibodies (Abs) of the IgG and IgA class respectively. The specific anti-F.VIII/vWF Abs were isolated and resulted to be IgG (20 micrograms/ml) and IgA (35 micrograms/ml). The plasma was subsequently fractionated by Protein A-Sepharose and the IgG and IgA containing fractions were separately analyzed for anti-F.VIII activity. Both fractions exhibited F.VIII inhibitory activity, but that corresponding to the IgA was lower than expected. Regarding the possible existence of a non-inhibitor Ab in the IgA containing sample, plasma was processed through an immunoadsorbent to which a F.VIII devoid vWF preparation had been previously coupled and further fractionated by Protein A-Sepharose, obtaining 2 IgA fractions. One of them exhibited F.VIII inhibitory activity while the other, which reacted with the F.VIII devoid vWF preparation, did not. Therefore, this latter one was considered as a true anti-vWF Ab. The IgG and IgA inhibitors were polyclonal and the IgG one was composed of the 4 IgG subclasses.
authors.affiliation: Research Center, La Fe Hospital, Valencia, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Carmona
authors.forename: J A
authors.initials: JA
authors.lastname: Aznar
authors.forename: J I
authors.initials: JI
authors.lastname: Jorquera
authors.forename: M J
authors.initials: MJ
authors.lastname: Villanueva
authors.forename: J M
authors.initials: JM
authors.lastname: Sánchez-Cuenca
mesh_terms: D000328:Adult; D001323:Autoantibodies / Q000097:blood*; D005169:Factor VIII / Q000037:antagonists & inhibitors* / Q000276:immunology / Q000627:therapeutic use; D006467:Hemophilia A / Q000188:drug therapy / Q000276:immunology*; D006801:Humans; D007070:Immunoglobulin A / Q000378:metabolism; D007074:Immunoglobulin G / Q000145:classification / Q000378:metabolism; D008297:Male; D014841:von Willebrand Factor / Q000037:antagonists & inhibitors* / Q000276:immunology
chemical_list: D001323:Autoantibodies; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D014841:von Willebrand Factor; D005169:Factor VIII