Figure 6.

MSU crystal induced NET formation is independent of ROS. (A) Neutrophils were pre-treated with the NADPH-oxidase inhibitors DPI (10 μM) or GSK (20 µM) and thereafter stimulated with MSU crystals (300 μg/mL) or PMA (50 nM) before NET formation was evaluated by Sytox green measurement after 3 h. As opposed to PMA stimulated neutrophils, MSU treated neutrophils formed NETs also in the presence of the inhibitors. Mean +/− SEM of three independent experiments are shown, a paired t-test was used for statistical comparisons. (B) Neutrophils from one patient with CGD (left) as well as from one individual with complete MPO-deficiency (MPO-, right) formed NETs in response to MSU (300 μg/mL), dotted lines, but not to PMA (50 nM, solid lines). * p ≤ 0.05 and ** p ≤ 0.01. ns = not significant.