[Decreased DNase1L3 secretion and associated antibodies induce impaired degradation of NETs in patients with sporadic SLE].

Objective To evaluate the correlation between alterations in DNase1 and DNase1L3 enzyme activities and impairment of NET degradation in patients with sporadic SLE, and to investigate the underlying mechanism. Methods 46 sporadic SLE patients and 30 age- and sex-matched healthy individuals were recruited. Serum levels of DNase1, DNase1L3 and corresponding autoantibodies were detected by ELISA. DNase1 and DNase1L3 were isolated by immunoprecipitation; NETs and enzyme degradation activities were detected using a modified immunofluorescence. DNase1L3 secretion by PBMCs was analyzed by ELISPOT, Western blotting and reverse transcription PCR. Results Levels of H3-dsDNA and Ela-dsDNA complexes were significantly elevated in SLE patients. LDGs in SLE population was significantly higher than in the control group, and LDGs was positively correlated with H3-dsDNA and Ela-dsDNA NETs complexes. The ability of SLE patients to degrade NET in vitro was significantly lower than that of the control group. Degradation experiments of DNase1 and DNase1L3 in different proportions showed that the decrease in DNase1L3 activity was the primary contributor to the elevated NET residue level. The concentration of DNase1L3 autoantibodies in SLE patients was significantly elevated compared to the control group. In addition, the capacity of PBMCs to secrete DNase1L3 was significantly lower in the SLE patients compared to the control group. Conclusion Decreased secretion of DNase1L3 and the presence of relevant autoantibodies notably impede NET degradation in patients with SLE, offering new directions for the monitoring and treatment of SLE patients.