The clinical significance of anti-prothrombin antibodies for risk assessment of thromboembolism in patients with lupus anticoagulant

Introduction: Thromboembolism is a common manifestation of lupus anticoagulant (LA), however only a subgroup of LA-patients is affected by thrombosis. Study objective was to investigate whether anti-prothrombin antibodies can identify LA-patients at increased risk for thrombosis. Materials and Methods: In total 79 patients, 50 with (42 men/8 women) and 29 without thrombosis (21 men/8 women), were investigated for their presence of antiprothrombin IgG and IgM antibodies using assays from two different manufacturers (Aeskulisa =assay I, CoaChrom=assay II). Results: The prevalence of elevated levels of anti-prothrombin IgG, IgM as well as IgG and/or IgM antibodies was 66% [assayl] (36% [assayII]), 38% (24%) and 72% (50%) in patients with thrombosis and 55% (24%), 28% (28%) and 66% (41%) in patients without thrombosis, respectively. Neither anti-prothrombin IgG or IgM nor IgG and/or IgM antibodies were found to indicate an increased risk for thrombosis. In the subgroup of patients with arterial or venous thrombosis there was also no association between anti-prothrombin antibodies and thrombosis. The comparison of median levels of IgG and IgM anti-prothrombin antibodies between patients with and without thrombosis yielded a borderline statistically significant difference only for anti-prothrombin IgG antibodies by using assay II (p=0.033), all other comparisons were not statistically significant. Conclusions: In conclusion, presence of anti-prothrombin antibodies was not associated with thromboembolism in LA-patients. (C) 2007 Elsevier Ltd. All rights reserved.