AB0111 The Underlying Pathogenic Effect of Impared Dnase I Activity on Rheumatoid Arthritis

Background

Aberrant formation of neutrophil extracellular traps (NETs) play important role in the pathogenesis of rheumatoid arthritis (RA) and Deoxyribonuclease I (DNase I) can remove NETs in vivo.

Objectives

We aimed to investigate the underlying pathogenic effect of DNase I on RA.

Methods

Serum DNase I activity was measured by radial enzyme diffusion method in 83 RA patients and 60 healthy volunteers, synovial fluid (SF) from 27 RA patients and 38 other inflammatory arthritis patients was measured by the same way. The SF cfDNA level was measured by Pico Green Kit. Correlation analysis were performed between DNase I activity, cfDNA level and clinical parameters of RA patients.

Results

Serum DNase I activity was significantly lower in RA group than in healthy control group [0.2913 (0.2029, 0.4064)U/ml vs 0.3980 (0.2864, 0.5484)U/ml, P<0.001] and negatively correlated with ESR (r=-0.2862, P=0.0122), CRP (r=-0.2790, P=0.0184) and neutrophil cell counts (r=-0.287, P=0.011). SF DNase I activity in RA group, ankylosing spondylitis (AS) group and gouty arthritis (GA) group were almost negative. SF cfDNA level in RA group was significantly higher than that in OA group [40.00 (12.47, 163.22) ug/ml vs 9.27 (4.62, 17.58) ug/ml, P=0.002], but there were no significant difference when compared to AS group [36.80 (4.84, 84.82) ug/ml, P=0.428] and GA group [156.72 (89.81, 257.11) ug/ml,P=0.132]. In inflammatory arthritis patients, SF cfDNA level was positively correlated to ESR (r=0.4106, P=0.0116)and CRP (r=0.5747, P=0.0002).

Conclusions

Impairment of DNase I activity may be responsible for the enhanced NETs generation and involve in the pathogenesis of RA.

References

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Disclosure of Interest

None declared