Clinical importance of persistence of anticardiolipin antibodies in systemic lupus erythematosus.

The clinical importance of IgG anticardiolipin antibodies was investigated in systemic lupus erythematosus (SLE). IgG anticardiolipin antibodies were found in 69 of 155 (44.5%) patients with SLE. Serial measurements of IgG anticardiolipin antibodies allowed the patients to be classified into two groups: group A, persistently positive for IgG anticardiolipin antibodies; group B, positive only in active phases. The IgG anticardiolipin antibody titre in group A was significantly higher than in group B. The incidence of thromboses, spontaneous abortions, and lupus anticoagulant in group A was significantly higher than in group B (p less than 0.05). By contrast, the incidence of renal diseases and anti-dsDNA antibodies in group B was significantly higher than in group A (p less than 0.05). This study showed that group A formed a separate subgroup of patients with SLE who had a high risk of thromboses and spontaneous abortions despite having milder disease activity.