Antibodies to β2-glycoprotein-I: Relation of anticardiolipin antibodies with clinical and laboratory parameters in patients with systemic lupus erythematosus

Objectives: There are controversial reports on the frequency of antiphospholipid antibodies (aPL) in patients with systemic lupus erythematosus (SLE). Thus, we aimed to determine the frequency and clinical importance of aPL isotypes in Turkish patients with SLE. Design and methods: Fifty-nine patients with SLE and 41 healthy controls were included. Serum aPL levels were measured both in patients and healthy subjects by ELISA. Results: Fifteen of the patients with SLE had the antiphospholipid syndrome (APS) (25.4%). The percentage of anticardiolipin antibody (aCL)-positive SLE patients among all patients was 56%. At least one isotype of anti-β2-glycoprotein I (β2-GPI) antibody was positive in 83% of patients. The positivity rates of aCL and anti-β2-GPI antibodies in patients with or without APS were higher than the healthy controls. There were positive correlations between isotypes of IgM aCL, IgG and IgM anti-β2-GPI and manifestations of APS. Conclusion: It seems that the isotypes of IgM aCL, IgG and IgM anti-β2-GPI are correlated with manifestations of APS. They may play a role in pathogenesis and may be helpful in establishing the diagnosis.