Diagnostic value of anti-nucleosome antibodies in the assessment of disease activity of systemic lupus erythematosus:: A prospective study comparing anti-nucleosome with anti-dsDNA antibodies

Objective. To determine the diagnostic value of anti-nucleosome antibodies in the assessment of clinically active systemic lupus erythematosus (SLE) and active nephritis. Methods. A 12 month prospective study of 87 patients diagnosed with SLE. At each evaluation, disease activity was scored by SLE Disease Activity Index and Lupus Activity Criteria Count, and blood samples were collected for laboratory tests. Autoantibodies were detected by ELISA. Results. Nearly all patients were female (96.6%). The mean age was 33 years and the mean disease duration was 60.7 months. About half the patients presented with nephritis (49.4%) and active SLE (50.6%) at the first clinical examination. During the study period, the prevalence of active SLE decreased from 50.6% to 29.1%. The prevalence of anti-nucleosome and anti-dsDNA antibodies was 40.0%-58.6% and 10.9%-21.8%, respectively, throughout the study period. The sensitivity of antinucleosome and anti-dsDNA antibodies for active SLE was 72.7%-100% and 31.3%-54.8%, respectively. The specificity of anti-nucleosome and anti-dsDNA antibodies for active SLE was 66.7%-83.7% and 88.7%-100%, respectively. The sensitivity and specificity of anti-nucleosome antibodies for active nephritis were 32.0%-67.5% and 46.2%-67.3%, respectively. The sensitivity and specificity for anti-dsDNA antibodies for active nephritis were 16.0%-35.4% and 85.1-97.5%, respectively. Conclusion. Anti-nucleosome antibodies are more sensitive than anti-dsDNA antibodies to active SLE and active nephritis. Thus, anti-nucleosome antibody reactivity may be a useful marker in the diagnosis and assessment of active SLE.