Antiphospholipid antibodies in primary Sjögren's syndrome: prevalence and clinical significance in a series of 74 patients.

The aim of this study is to determine prevalence, clinical significance of antiphospholipid antibodies (aPL) including anticardiolipin antibodies (aCL), anti-beta2GP1 and lupus anticoagulant (LA) in a cohort of 74 patients with primary Sjögren's syndrome (pSS) according to revised European criteria. aPL were found in 25 (34%) patients; IgG in 23 (12 had low titres, six moderate titres and five high titres) and IgM in five (three and two had respectively moderate and high titres). Eight (11%) patients were found to have LA; anti-beta2GP1 antibodies were detected only in three (4%) patients. Only two patients with LA, aPL and beta2GP1 had recurrent venous thrombosis. One patient with moderate titres of aPL exhibited recurrent spontaneous foetal losses. Peripheral neuropathies without cryoglobulinemia were more frequent in the aPL group. Other systemic involvements of pSS were the same in both groups with or without aPL. Patients with aPL have more concurrent immunological diseases such as thyroiditis and primary biliary cirrhosis and a higher prevalence of hypergammaglobulinemia (P < 0.05). Even if aPL prevalence reached 30% in pSS, titres were usually low, with a close correlation with hypergammaglobulinemia but not with antiphospholipid syndrome, which is related to positivity of both LA and aPL.