Patients with Essential Thrombocythaemia have an Increased Prevalence of Antiphospholipid Antibodies which may be associated with Thrombosis

Abstract

SummaryA significant proportion of patients with Essential Thrombocythaemia (ET) have thrombotic complications which have an important impact upon the quality, and duration of their life. We performed a retrospective cross sectional study of the prevalence of antiphospholipid antibodies (APA) in 68 ET patients. Compared to 200 “elderly” controls (> 50 years) there was a significant increase in anticardiolipin IgM (p < 0.0001) and anti β2 glycoprotein I (anti-β2GPI) IgM (p < 0.0001) antibodies in ET. Thrombosis occurred in 10/20 with APA and 12/48 without, p = 0.04, relative risk 2.0 (95% confidence intervals 1.03–3.86); these patients did not differ in terms of other clinical features. The prevalence of thrombosis in patients with dual APA (6/7) was significant when compared to those with single APA (p = 0.02) and the remaining patients (p < 0.0002). Also anti-β2GP1 IgM antibodies either alone, or in combination with another APA, were associated with thrombosis (p = 0.02). These results suggest that the prevalence of APA in ET and their influence upon thrombotic risk merit investigation in a larger study.