Prolonged bleeding time in patients with lupus anticoagulant.
Platelet adhesion to collagen under flow conditions was studied in 18 patients with lupus anticoagulant, seven of which showed a prolonged bleeding time in the presence of a normal platelet count. The effect of patient plasma, IgG and purified anticardiolipin antibodies on platelet adhesion was also examined. We found a significant reduction of platelet adhesion in patients with lupus anticoagulant, which was more evident in patients with prolonged bleeding time. This platelet adhesion defect could be attributed to a plasma factor. In fact, patients' platelets regained normal adhesion when mixed with normal plasma, whereas controls' platelets showed abnormal adhesion in the presence of patient plasma. A causative role of antiphospholipid antibodies was demonstrated in experiments using purified immunoglobulins and anticardiolipin antibodies.
Orlando
E
E
Department of Hematology, Ospedali Riuniti di Bergamo, Italy.
Cortelazzo
S
S
Marchetti
M
M
Sanfratello
R
R
Barbui
T
T
D000328:Adult; D000368:Aged; D017153:Antibodies, Anticardiolipin / Q000097:blood; D001760:Bleeding Time; D005260:Female; D006470:Hemorrhage / Q000209:etiology; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D066298:In Vitro Techniques; D016682:Lupus Coagulation Inhibitor / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010973:Platelet Adhesiveness
D017153:Antibodies, Anticardiolipin; D007074:Immunoglobulin G; D016682:Lupus Coagulation Inhibitor