title: A new variant of interaction between phospholipid antibodies and the protein C system.
abstract: The influence of 38 IgG fractions with either cardiolipin antibodies only (CLa) or both CLa and lupus anticoagulant activity (LA) on the response to activated protein C (APC) and on the snake venom activation of protein C were investigated. Five of eight IgG fractions with LA activity showed a tendency to reduce the effect of APC in the aPTT method and to simulate the APC-resistance phenomenon. This effect was not observed in IgG fractions without LA activity. The addition of IgG fractions did not decrease enzymatic activation of protein C in normal plasma. No correlation was found between sample protein C activity and CLa level or the extent of clotting time prolongation. These observations suggested that acquired resistance to APC in the presence of some types of phospholipid antibodies may be a cause of thrombophilia in such patients.
authors.affiliation: Department of Laboratory Medicine and Blood Coagulation, Karolinska Hospital, Stockholm, Sweden.
authors.forename: M I
authors.initials: MI
authors.lastname: Bokarewa
authors.forename: M
authors.initials: M
authors.lastname: Blombäck
authors.forename: N
authors.initials: N
authors.lastname: Egberg
authors.forename: S
authors.initials: S
authors.lastname: Rosén
mesh_terms: D000328:Adult; D000368:Aged; D017153:Antibodies, Anticardiolipin / Q000494:pharmacology; D017152:Antibodies, Antiphospholipid / Q000494:pharmacology*; D002850:Chromatography, Gel; D004789:Enzyme Activation; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000494:pharmacology; D016682:Lupus Coagulation Inhibitor / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D011486:Protein C / Q000378:metabolism*
chemical_list: D017153:Antibodies, Anticardiolipin; D017152:Antibodies, Antiphospholipid; D007074:Immunoglobulin G; D016682:Lupus Coagulation Inhibitor; D011486:Protein C