DNase 1 and SLE: Possible Role in Etiology and Susceptibility

Background: Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the presence of autoan¬tibodies to nuclear constituents. Some of these antibodies are diagnostically important, whereas others act as disease- modifying factors. One clinically important factor is autoantibodies against dsDNA and nucleosomes, The activity of DNase 1, the enzyme responsible for nucleosome degradation, has been found to be decreased in patients with SLE.Objective: We aim to investigate the serum DNase 1 activity in SLE patients compared to healthy controls to explore its role in relation to susceptibility to SLE and the production of anti-dsDNA antibodies.Subjects and Methods: A total of 42 SLE patients, all fulfilled the revised criteria of the American College of Rheumatology for the diagnosis of SLE, were enrolled in the study and 17 healthy individuals with matching age and sex as a control group, 27 out of the 42 SLE patients had lupus nephritis proved by renal biopsy. Serum DNase activity was measured by an ELISA (Orgentec GmbH, Mainz, Germany), anti-dsDNA antibody level was measured by an enzyme- linked immunosorbent assay (ELISA; INOVA diagnostics, San diego, USA).Results: Our results showed that there was a significant decrease in DNase enzyme activity with higher percent activity reduction (%AR) of DNase enzyme activity and the titer of Anti ds DNA antibody was significantly higher in SLE patients compared to control gp with a statistically significant positive correlation between DNase enzyme (%AR) the titer of Anti ds DNA antibody. Comparing the results of lupus patients with and without nephritis revealed an increase in both DNase enzyme (%AR) the titer of Anti ds DNA antibody in the nephritis group but the difference is not statistically significant.Conclussion: Our results contribute to establishing the deficiency in DNase I activity as one of the defects in the clearance of cellular debris involved in the pathogenesis of SLE.