FMO5 and juvenile idiopathic arthritis: Notably, NET formation in JIA patients might occur through activation of the PI3K-Akt-dependent and MAPK-ERK signaling pathways, followed by the production of ROS by NADPH oxidase and the subsequent activation of MPO, and CDKs, which was proven by increases in basal ROS production, the levels of phosphorylated PI3K and AKT, phosphorylated MAPK-CDKs and ERK1/2, and MPO expression in JIA-derived neutrophils (Figures 5B, 6C, D).