NATURAL INHIBITORS OF BLOOD-COAGULATION AND FIBRINOLYSIS IN PATIENTS WITH LUPUS ANTICOAGULANT

We studied the natural inhibitors (NI) of blood coagulation and fibrinolysis in 50 patients with lupus anticoagulant (LA), in order to identify possible alterations of these NI, that could favour thrombotic manifestations. We found no statistically significant difference in antithrombin III, protein C and alpha2-antiplasmin between controls and patients with 1,A, irrespective of their clinical manifestations. We found an increase of plasminogen activator inhibitor (PAI, P < 0.001) and a decrease of free protein S (PSf, P < 1) and total protein S (PSt, 0.01 < P < 0.05) in the patients with LA when compared with the control group. We found no difference in the levels of NI between patients with thrombosis (n = 19) and without thrombosis (n = 31) nor between patients with (n = 25) or without thrombosis and/or foetal loss(n = 25). In contrast, we observed a decrease of PS, in women with foetal loss (n = 10) as compared with women without foetal loss (n = 22, 0.01 < P < 0.05) and a decrease of PS, when comparing 19 patients with systemic lupus erythematosus (SLE) with 31 patients without SLE (0.01 < P < 0.05). These findings show that the patients with LA had several abnormalities in the NI system, but there was no significant association between levels of PAI, PSf, PSt and a history of thrombosis.