Prevalence and clinical significance of antiprothrombin antibodies in patients with systemic lupus erythematosus or with primary antiphospholipid syndrome

Background and Objectives. Antibodies to prothrombin (aII) have been identi fied in patients with antiphospholipid antibodies, but their clinical signi ficance is not well known. The aim of our study was investigate their preva lence and association with Clinical manifestations of the antiphospholipid syndrome (APS) in patients with primary APS or with systemic lupus erythema tosus (SLE), Design and Methods. A series of 177 patients with autoimmune diseases was s tudied: 70 with primary APS and 107 with systemic lupus erythematosus, A Co ntrol group of 87 healthy volunteers were included in the study, aII were i nvestigated in sera by an ELISA, using human prothrombin as antigen fixed i n irradiated polystyrene plates. Results, all prevalence in patients with autoimmune : disease was 47% (57% and 40% in patients with primary APS or with SLE, respectively) significant ly higher than in controls (5%) (p<0.0001). In the whole series, thrombotic events were more prevalent in patients with aII (45% vs 28%; p=0.02), More over, all was found to be an independent risk factor for arterial thrombosi s (OR=2.4; p=0.04). Similarly, in patients with SLE, all were associated wi th both arterial and venous thrombosis (35% vs 14%; p=0.01), although only IgG-aII (OR=3.7; p=0.01) had an independent value as a risk factor for thro mbosis, However, a relationship between aII and;thrombosis was not found in primary APS. aII were associated with thrombocytopenia only in patients wi th primary APS (OR=6.7; p=0.007). Interpretation and Conclusions. aII seem to be a serologic marker of thromb osis in autoimmune diseases, mainly in SLE patients and/or in the arterial territory.(C)2000, Ferrata Storti Foundation.