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. Author manuscript; available in PMC: 2013 Mar 11.
Published in final edited form as: Int J Clin Rheumtol. 2011 Apr 1;6(2):157–171. doi: 10.2217/ijr.11.9

Figure 2. Dysregulation of anticoagulant and fibrinolytic systems in antiphospholipid syndrome.

Figure 2

aPC, an important anticoagulant, functions by inactivating activated forms of factors V (Va) and VIII (VIIIa). Antibodies acting against aPC inhibit its function. The function of anti-thrombin III, another major regulator of coagulation factors, is also inhibited by antibodies isolated from antiphospholipid syndrome patients. Ultimately this results in increased thrombin generation and subsequent fibrin formation. Dysregulation of the fibrinolytic system can also occur in antiphospholipid syndrome due to antibodies that inhibit tPA-mediated conversion of plasminogen to plasmin and those that directly inhibit plasmin function.

aPC: Activated protein C; tPA: Tissue plasminogen activator.