The anti-nucleosome antibodies were evaluated in the serum of 200 Tunisian SLE patients at disease onset by a sensitive immunodot assay. Serum samples from each patient were also tested for ANA and anti-ds DNA antibody by IIF on Hep 2 cells and Crithidia luciliae respectively. During the follow-up, the patients were regularly monitored for clinical parameters. Global SLE activity was measured by the European Consensus Lupus Activity Measurement (ECLAM).
The prevalence of anti-nucleosome and anti-dsDNA antibodies was 69 % and 63.5 % respectively. Anti-nucleosome antibodies were found to be 30.1 % positive in SLE patients lacking anti-dsDNA antibody. 79.5 % patients had active SLE at the first clinical examination. Anti-nucleosome antibodies were more sensitive than anti-dsDNA antibodies to detect active SLE (78 % vs. 71.7 % , P =0.19). 52.5 % of SLE patients had renal involvement. Among these patients, the rate of anti-nucleosome positivity and anti-dsDNA were 77.1 % and 67.6 % respectively. The positivity of anti-nucleosome antibodies was significantly higher in patients with renal disease than the subjects without renal disease (P = 0.009). Anti-nucleosome and anti-ds DNA antibodies were significantly correlated with disease activity (P < 0.001 and P < 0.001 respectively).
Anti-nucleosome antibody reactivity may be a useful marker in the diagnosis and assessment of active SLE.