Evaluation of Anti-Nuclear Antibodies and Anti-dsDNA Serum Levels in Patients with Suspected Systemic Lupus Erythematosus

Background and objectives: Systemic lupus erythematosus (SLE) is a chronic autoimmune disease, caused by abnormal innate and adaptive immune responses. Anti-nuclear antibodies (ANA) and anti-double stranded DNA (anti-dsDNA) are reliable biomarkers for diagnosing SLE. Here, we aimed to investigate the serum levels of anti-dsDNA and ANA antibodies, their diagnostic utilities, and their relationship with disease activity and clinical/laboratory manifestations in patients with suspected. Methods: We evaluated the plasma levels of ANA and anti-dsDNA antibodies in all individuals with suspected SLE (n=668) who had been referred to rheumatology clinics in Gorgan, Iran. The level of antibodies as well as C3, C4, and CH50 were determined using commercially available enzyme-linked immunosorbent assay kits. Results: The mean level of ANA and anti-dsDNA antibodies differed significantly between the ANA-positive and ANA-negative groups (p 0.001). However, there was no significant difference in the mean values of C3 (p=0.233), C4 (p=0.415, and CH50 (p=0.482) between the two groups. Moreover, there was a significant positive correlation between ANA and anti-dsDNA levels (p 0.001, r=0.50). Conclusion: Our findings indicate that anti-dsDNA levels are higher in ANA-positive individuals, and there may be a positive correlation between ANA and anti-dsDNA levels. It is recommended to evaluate the diagnostic and prognostic values of ANA and anti-dsDNA antibodies in future studies.