Lupus anticoagulants (LA) are IgG or IgM antibodies against phospholipids which in
vivo represent an important thrombophilic factor despite their in vitro anticoagulant
activity. We investigated the fibrinolytic system of 20 patients with connective tissue
disease and positive LA, compared to a control group of 24 age- and disease-matched
patients without LA. There was no statistically significant difference of alpha2-antiplasmin, plasminogen, fibrinogen, t-PA activity, D-dimers and heparin cofactor
II, between the two groups. Although t-PA was uniformly low in both groups, plasminogen
activator inhibitor activity (PAI) was significantly higher in LA cases (p <0.001).
Increased PAI levels represent an inhibitory factor of the fibrinolytic defense mechanism,
which together with other functional deviations may contribute to the thrombophilic
tendency of LA patients.
Keywords
Lupus anticoagulant - Fibrinolysis - Plasminogen activator inhibitor - Tissue plasminogen
activator - Alpha
2-antiplasmin - Plasminogen - D-dimers - Heparin cofactor II - Antithrombin III - C
4 complement component
