Objective: To investigate whether serial anticardiolipin determination contributes to the clinical management of patients with systemic lupus erythematosus (SLE) with no previous sign of the antiphospholipid syndrome (APS).
Methods: In 90 patients with SLE with no previous clinical manifestations of the APS, repeated clinical evaluations were performed, and serial blood samples (obtained over a 30 month period, range 13-53 mo) were screened for antiphospholipid antibodies (aPL). Anticardiolipin antibodies (aCL) were detected using an ELISA and considered positive if the result was >25 GPL on 2 separate occasions. Patients were not required to be on a specific treatment regimen during the study.
Results: Thirty-four patients (37%) had at least one positive ELISA and 11 (11/90, 12%) 2 positive ELISA for IgG aCL during the study. Lupus anticoagulant (LAC) was found in 16 patients, and a false positive VDRL in 5. At study completion, the total number of clinical or laboratory events associated with APS was 30. In univariate analysis, aCL was significantly associated only with LAC (p<0.012). Presence of aCL also correlated with hemoglobin level, anti-DNA antibody, leukocyte count, and the SLE Disease Activity Index (SLEDAI). LAC and aCL were significantly associated with each other (OR 5.17; 95% CI 1.5-17.7), but LAC had a better positive predictive value than aCL for arterial thrombosis and neurological events.
Conclusion: Among our patients with SLE without previous clinical manifestations of APS, positive aCL did not predict the occurrence of APS within the next 3 years, but was statistically related to the clinical disease activity (SLEDAI).