Fig. 5

Neutrophil effector functions are impaired in JIA blood and synovial fluid. a Phagocytosis of fluorescently labeled opsonized E. coli in neutrophils from paired samples of JIA blood and synovial fluid (SF). b Phagocytosis of fluorescently labeled opsonized E. coli in healthy control neutrophils in a mixture of 10% whole blood and 90% serum or cell-free synovial fluid from four JIA patients. The results are presented as phagocytosis, measured as MFI, in serum/SF-treated samples compared to non-treated whole blood. c, d Neutrophil ROS production, quantified using DHR-123 fluorescence, after stimulation with c PMA or d opsonized E. coli. e–g Pearson r correlation analysis of the proportion of CD206⁺ neutrophils in the synovial fluid with e phagocytosis of opsonized E. coli, f ROS production by PMA-stimulation, and g ROS production by opsonized E. coli stimulation. ***p < 0.001, Wilcoxon signed-rank test. MFI, median fluorescence intensity