Homocysteine and antiphospholipid antibodies in rheumatoid arthritis patients: Relationships with thrombotic events

Objective To investigate the possible relationships between plasma homocyst eine levels and thrombotic events in a select population of rheumatoid arth ritis (RA) patients with or without antiphospholipid (aPL) antibody positiv ity. Methods 168 female RA patients attending the Extra-articular Involvement RA Clinic of University of Genova and 72 female subjects matched for age and vascular diseases as controls were included in the study. 30 of the RA pati ents showed aPL antibody positivity and 138 aPL antibody negativity on the basis of the concomitant presence or absence of high concentrations of anti cardiolipin (aCL) antibodies or the presence of lupus anticoagulant (LA). A ll subjects were evaluated,for plasma homocysteine concentrations and for t he occurrence of thrombotic events. Results Twenty-five RA patients and 5 controls reported a history of thromb otic events. Eleven and 5 of RA patients were found to have been previously affected by venous or arterial thrombosis, respectively. Plasma levels of homocysteine in aPL antibody positive patients with thrombosis were found t o be significantly higher than in aPL antibody positive RA patients without thrombosis (p < 0.001). When RA patients with thromboses were analyzed, a significant increase of plasma homocysteine levels was found in aPL antibod y-positive RA patients versus aPL antibody-negative RA patients (p < 0.04) and versus related controls (p < 0.003). Conclusions The association observed between aPL antibody positivity and hi gh levels of plasma homocysteine in RA patients may represent a possible ri sk factor for thrombotic events. Therefore, it is suggested that hyperhomoc ysteinemia might be involved in the vascular-related mortality observed in RA patients with a history of thrombosis.