Does anti-DNA positivity increase the incidence of secondary antiphospholipid syndrome in lupus patients?

Aim of the workTo detect the incidence of secondary antiphospholipid syndrome (APS) among Systemic lupus erythematosus (SLE) patients with positive anti-DNA antibodies.Patients and methodsWe studied 342 SLE patients; Group I: anti-DNA positive SLE patients (n = 208) and Group II: anti-DNA negative SLE patients (n = 134), with a female to male ratio of 9.39:1 and a mean age of 27.49 ± 7.94 years and disease duration of 5.74 ± 3.97 years. Full history taking, thorough clinical examination, laboratory and relevant radiological investigations were performed. Disease activity was assessed using systemic lupus erythematosus disease activity index (SLEDAI). Anti-dsDNA tests were carried out by indirect Immunofluorescence (IF) technique. Anti cardiolipin antibodies (IgG and IgM) and Anti-β2 glycoprotein-I antibody of IgG and/or IgM isotype were detected by ELISA.ResultsThe clinical manifestations, disease activity and laboratory investigations of the SLE patients varied according to the anti-DNA antibodies. Thirty-six patients (17.3%) had secondary APS in those with positive anti-DNA antibodies while only16 (11.9%) had secondary APS in those with negative anti-DNA antibodies, with no significant differences between both groups.ConclusionApparent higher incidence of secondary APS was detected in anti-DNA positive SLE patients. The non significant differences between both groups may suggest that anti-DNA positivity cannot be considered as the only predictor of secondary APS and further studies may be needed to detect other factors which may increase the incidence of APS in SLE patients.