Circulating cell free DNA as a predictor of systemic lupus erythematosus severity and monitoring of therapy

BackgroundSystemic lupus erythematosus (SLE) is the most heterogeneous chronic autoimmune disease; it is characterized by the presence of auto reactive B and T cells, responsible for the aberrant production of a broad and heterogeneous group of autoantibodies. Recent studies using various detection methods have demonstrated the elevations of circulating DNA in SLE patients.Aim of the studyThe current study aimed to measure cell-free DNA (cf-DNA) in SLE patients as a potential tool to predict disease activity and treatment follow up.Subjects and methods52 of SLE patients with age ranging from 10 to 48 years were randomly selected and 25 healthy subjects with age and gender matched with the patients were included as a control group. Thorough clinical examination stressing on the central nervous system, vascular, renal, rash, musculoskeletal, mucocutaneous manifestations, and fever was done for patients. The following investigations were done: Complete blood count (CBC), kidney function tests, C-reactive protein (CRP), routine autoantibodies for autoimmune diseases, complements (C3 & C4), anti-nucleosome antibodies and cf-DNA by real time PCR (RT-PCR).ResultsThe levels of anti-double stranded DNA (anti-dsDNA), anti-nucleosome Ab, and cf-DNA were significantly increased in SLE patients compared to controls. The cf-DNA level was correlated to markers of disease severity namely CRP and anti-nucleosome. A significant reduction in levels of cf-DNA, anti-nucleosome Ab and anti-dsDNA was noticed after therapy.ConclusionOur findings support that the measurement of cf-DNA appears to be a useful marker in addition to laboratory tests used in SLE diagnosis. High correlation with markers of disease severity suggesting its role in disease pathogenesis and decreasing its level after therapy makes it to be a marker of treatment follow-up.