Subsequently, the 10 statistically significant variables were analyzed by multiple linear regression analysis, and the multiple linear regression equation established was statistically significant (P < 0.05; Figure 3B), only ESR and TNF-α levels were positively associated with cf-DNA concentration and were found to be independent variables, implying that TNF-α is a major inducer in triggering NET formation in JIA patients, and further verifying that cf-DNA concentration could be a biomarker for monitoring disease activity. Here, ESR1 is linked to juvenile idiopathic arthritis.