Background Systemic Lupus Erythematosus (SLE) is an autoimmune disease, characterized by the production of a wide range of autoantibodies, resulting from polyclonal B cells activation, impaired apoptotic pathways, or idiotypic network dysregulation. The anti-double stranded DNA antibodies (anti-dsDNA) are considered a specific marker for SLE, due to their high frequency, sensitivity and specificity (57.3% and 97.4%, respectively). Moreover, their identification in other pathological conditions and in healthy subjects is very rare (less than 0.5%). These antibodies have been associated with kidney involvement and disease activity, however, a comparison between large cohorts of SLE patients with or without anti-dsDNA is lacking.
Objectives We aimed at evaluating the demographic, clinical, and laboratory features of SLE patients according with the anti-dsDNA status.
Methods According with the anti-dsDNA status, we identified three groups of patients: Group 1 (persistently positive); Group 2 (positive at diagnosis who became negative); Group 3 (persistently negative). Disease activity was assessed using the European Consensus Lupus Activity Measurement (ECLAM).
Results We evaluated 393 SLE patients (Group 1: 62.3%; Group 2: 13.3%; Group 3: 24.4%). The renal involvement was significantly more frequent in those patients who were persistently positive for anti-dsDNA (P=0.001). Conversely, serositis resulted significant more frequent in those persistently negative (P<0.0001). The anti-RNP and the reduction of C4 serum levels were found significantly more frequently in Group 1 and 2 (P=0.04, P=0.005). The anti-dsDNA status did not influence disease activity (ECLAM group 1 vs group 2 vs group 3 =NS). Finally, the therapeutic approach was not different between the groups except for the use of cyclosporine A which was more frequently prescribed in the persistently positive patients (60 patients, 24.5%) compared to Group 2 and 3 [9 (17.3%) and 12 (12.5%) patients, respectively; P=0.01].
Conclusions The main clinical feature associated with anti-dsDNA positivity is the kidney involvement. Nonetheless, disease activity evaluated with ECLAM, thus with an index which does not include anti-dsDNA evaluation, does not seem to be influenced by the presence of anti-dsDNA.
Disclosure of Interest None declared