FIGURE 2.

Rheumatoid arthritis (RA)‐derived neutrophils exhibited increased spontaneous NETosis and increased NETotic response to tumor necrosis factor (TNF)‐α. Neutrophils were isolated from patients with RA and healthy controls. Neutrophils from healthy controls and RA patients were stimulated with or without 10 ng/ml TNF‐α. NETs were detected in vitro by immunohistochemistry for NE (green) and 4′,6‐diamidino‐2‐phenylindole (DAPI; blue). Magnification, 20×; scale bar, 100 μm. Representative images demonstrating NETs formation are shown (A). Each experiment was performed in duplicate and two experienced observers quantified the NETs. At least 10 microscopic fields of view were quantified for each coverslip. The percentage area of NETs as a proportion of each microscopic field was recorded. The results were expressed as the mean ± SD (B)