[Role of DNA-associated autoantibodies to cell membrane in the diagnosis of juvenile systemic lupus erythematosus].

Objective: To establish a method of indirect immunofluorescence (IIF) to measure DNA (mDNA)-associated autoantibodies to cell membrane, and to evaluate diagnostic value of the anti-mDNA antibodies in patients with juvenile systemic lupus erythematosus (SLE) in comparison with anti-dsDNA antibody.

Methods: Forty-four children with SLE were enrolled in this study. As a control group, 30 children with other rheumatic diseases were also enrolled. Anti-mDNA and anti-dsDNA antibodies were measured by IIF. Anti-smooth muscle (Sm) antibodies were measured by immuno-double diffusion (ID) and IIF.

Results: Out of 44 juvenile SLE patients, 34 (77.27%) were seropositive for anti-mDNA, which was significantly higher than that of patients with other rheumatic diseases (20.00%, P<0.05). The sensitivity and specificity of anti-mDNA for juvenile SLE diagnosis were 77.27% and 80.00%, respectively. The positive predictive value and negative predictive value were 85.00% and 70.59%, respectively. The positive rate of anti-mDNA in SLE lacking of anti-dsDNA and anti-Sm antibodies were 68.00% (17/25) and 79.49% (31/39), respectively.

Conclusion: The detection of anti-mDNA antibodies is useful for diagnosis of juvenile SLE, especially in patients who are negative for anti-dsDNA antibodies and anti-Sm antibodies.