Once activated, in acute inflammation of RA, neutrophils release high concentrations of oxidants and cytotoxic products, such as ROS, cytokine (such as TNF-α) and granules containing proteases, phospholipases, defensins and myeloperoxidase, in the synovial fluid or directly onto the surface of articular cartilage [166, 167, 169]. The gene discussed is MPO; the disease is rheumatoid arthritis.