Correlations between antinucleosome antibodies and anti-double-stranded DNA antibodies, C3, C4, and clinical activity in lupus patients.

OBJECTIVE To examine the correlations between antinucleosome antibodies and anti-double-stranded (ds) DNA antibodies, complement (C) 3 and 4 levels, and clinical activities in SLE patients. METHODS Antinucleosome antibodies and anti-dsDNA antibodies were detected by enzyme-linked immunosorbent assays (ELISA). The levels of C3 and C4 were measured by nephelometry. Clinical activities were determined by SLE Disease Activity Index (SLEDAI). RESULTS Of 65 SLE patients, the prevalence of antinucleosome antibodies were higher than anti-ds DNA antibodies (52.3 vs 36.9%, respectively, p < 0.05). Similar results were obtained in 45 active SLE patients, 64.4% for antinucleosome antibodies and 46.7% for anti-ds DNA antibodies. Of 34 patients lacking anti-ds DNA antibodies, 16 (47.1%) were shown antinucleosome antibodies. Activity of antinucleosome antibodies was significantly correlated with the SLEDAI scores and inversedly correlated with the C3 levels but not with the C4 levels. CONCLUSION Antinucleosome antibodies could be one of the earliest and most sensitive markers in diagnosis of SLE, particularly in anti-dsDNA antibodies-negative patients. More importantly, antinucleosome antibodies is correlated with clinical activities and C3 levels.