In addition, the observation that neutrophils from RA cases exhibited increased spontaneous NET formation in vitro with enhanced NE and MPO expression and PAD-4-mediated citrullination of H3 (Sur Chowdhury et al., 2014) confirmed that NET formation is one of the mechanisms whereby neutrophils transmit immune responses in RA. The gene discussed is PADI4; the disease is rheumatoid arthritis.