Objective: To determine thft correlation of anti-dsDNA level and clinical activity of systemic lupus erythematosus disease and lupus nephritis. Materials and methods: A cross-sectional study was conducted to 160 SLE patients. The patients were measured levels of anti-dsDNA by ELISA method, C3, C4. Clinical activity of SLE disease and lupus nephritis was evaluated by SELANA-SLEDAI and SLICC score, respectively. Results: In groups of SLE patients with highly active, intermediately active and inactive disease, the median concentration of anti-dsDNA (lU/ml) were 67.92 + or - 122.9
139.33 + or - 146.87 and 269.76 + or - 231.3, respectively. SLEDAI score had a stronger correlation with the level of anti-dsDNA (r = 0.61) than C3 (r = -0.48), C4 (r = -0.47) and SLICC score (r = 0.296). Levels of anti-dsDNA in groups of patient with lupus nephritis or renal flares were higher than in group of patients with non-renal lupus or inactive nephritis, respectively. Conclusion: The level of anti-dsDNA in SLE patients is highly correlative with the clinical activity of SLE and lupus nephritis.