title: Interaction between platelets and lupus anticoagulant.
abstract: 10 consecutive patients fulfilled the diagnostic criteria for lupus anticoagulant. 4 had concomitant systemic lupus erythematosus, 1 Waldenstrom's disease and 5 had no apparent underlying disease. Only the case with Waldenstrom's disease presented a bleeding tendency, with bleeding time greater than 20 min; the others had a history of thrombotic complications. A defect of platelet aggregation induced by ADP, epinephrine, collagen and arachidonic acid was documented in the Waldenstrom's disease case whose lupus anticoagulant was an IgM. In the others, lupus anticoagulant, identified as IgG immunoglobulins, produced no aggregation abnormalities. However, beta-thromboglobulin levels in platelets, plasma and urine were consistent with a pattern of platelet activation in all cases. IgG immunoglobulins separated from sera of 6 patients showed lupus anticoagulant activity, with no effects on platelet aggregation of normal platelet-rich plasma, but they induced secretion of beta-thromboglobulin from normal platelets.
authors.affiliation: Division of Hematology, Ospedall Riuniti di Bergamo, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Galli
authors.forename: S
authors.initials: S
authors.lastname: Cortelazzo
authors.forename: P
authors.initials: P
authors.lastname: Viero
authors.forename: G
authors.initials: G
authors.lastname: Finazzi
authors.forename: G
authors.initials: G
authors.lastname: de Gaetano
authors.forename: T
authors.initials: T
authors.lastname: Barbui
mesh_terms: D000328:Adult; D001778:Blood Coagulation Disorders / Q000503:physiopathology*; D001779:Blood Coagulation Factors / Q000032:analysis / Q000276:immunology*; D001792:Blood Platelets / Q000187:drug effects / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis; D007075:Immunoglobulin M / Q000032:analysis; D016682:Lupus Coagulation Inhibitor; D008297:Male; D008875:Middle Aged; D010974:Platelet Aggregation; D010976:Platelet Count; D012701:Serotonin / Q000032:analysis; D001620:beta-Thromboglobulin / Q000032:analysis
chemical_list: D001779:Blood Coagulation Factors; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D016682:Lupus Coagulation Inhibitor; D001620:beta-Thromboglobulin; D012701:Serotonin