ABSTRACT
Systemic Lupus Erythematosus [SLE] is an autoimmune disorder affecting multiple organ systems. Antiphospholipid [aPL] antibodies are frequently found in plasma of SLE patients and venous thromboembolism VTE is common manifestation. This work was designed to assess the level of antiphospholipid antibodies [B2 glycoprotein I antibodies, anti prothrombin antibodies and lupus anticoagulant], protein C resistance and factor V Leiden in SLE patients and evaluate the correlation to thrombotic tendency in those patients. 50 SLE patients and 30 normal controls were included and subjected to measurement of antibodies to B2 glycoprotein I and antiprothrombin antibodies using ELISA technique, Lupus anticoagulant was estimated using diluted Russell Viper Venom Test [dRVVT], activated protein C resistance APC-R was measured by modified coagulometric technique and Factor V Leiden by PCR technique. Acquired APC-R was present in 17 out of 50 patients [34%] and all of them are not found to have Factor V Leiden mutations. The presence of acquired APC-R was a strong risk Factor for venous thromboembolism VTE. [OR 5.63 CI 1.8 - 11.2 P < 0.001] Raised level of all aPL antibodies found in patient group Anti B2GPI in 30%, anti PT in 50% and LA activity in 46% of SLE patients. A significant association was observed between APC-R and co-existence of anti- B2GPIAb and LA activity or of antiprothombin antibodies and LA activity. There was no association between APC-R and presence of anti-B2GPIAb, antiprothrombin Abs or LA activity alone. However, multivariate logistical regression analysis was performed it was clear that only the coexistence of antiprothrombin antibodies and LA activity was a significant risk factor for APC-R. [OR 3 - 53 95% CI 1.45 - 8.58.] There was no significant differences between SLE patient and control group as regard Protein C, Protein S or AT III levels. Coexistence of only antiprothrombin Abs and LA activity was a significant risk factor for APC-R and it may be important for pathogenesis of VTE in patients with SLE