In addition, although there was no significant correlation between the MPO-DNA complex levels and the JADAS27 in ERA patients, this was most likely due to the small sample size (n = 8), the plasma levels of MPO-DNA complex were associated with the JADAS27 in o-JIA and p-JIA patients (Figure 2F), and cf-DNA plasma concentrations were strongly and positively associated with the JADAS27 in patients with o-JIA, p-JIA and ERA (Figure 2E). Here, MPO is linked to enthesitis-related juvenile idiopathic arthritis.