High levels of circulating cell‐free DNA are a biomarker of active SLE

Background High levels of circulating cell‐free DNA (cfDNA) have been reported in patients with inflammatory conditions. The aim of the study was to investigate the levels of cfDNA in patients with systemic lupus erythematosus (SLE). Materials and methods Comparative groups comprised 22 nonpregnant and 36 pregnant women with SLE (test groups) and 60 nonpregnant and 199 pregnant women with no history of SLE (control groups). The levels of cfDNA in plasma were quantitated by a fluorometric dsDNA assay. Results Compared to controls, the median levels of cfDNA were significantly higher in nonpregnant SLE patients (7.38 ng/mL vs 4.6 ng/mL, P = 0.033) and in pregnant SLE patients (7.65 ng/mL vs 5.25 ng/mL, P = 0.003). Based on SLE disease activity index (SLEDAI) scores, the median cfDNA levels were significantly higher in patients with active disease (4