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.
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.
Carmona
E
E
Research Center, La Fe Hospital, Valencia, Spain.
Aznar
J A
JA
Jorquera
J I
JI
Villanueva
M J
MJ
Sánchez-Cuenca
J M
JM
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
D001323:Autoantibodies; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D014841:von Willebrand Factor; D005169:Factor VIII