While NO is involved in the blood pressure regulation, smooth muscle relaxation, platelet aggregation, neurotransmission, long-term potentiation, penile erection, apoptosis and immune response, over-expression of inducible nitric oxide synthase (iNOS) plays an important role in systemic or local, acute or chronic inflammation such as septic shock and rheumatoid arthritis [4,5]. The gene discussed is NOS2; the disease is rheumatoid arthritis.