This has been confirmed by the observation that polymorphisms of key cytokines genes, such as TNF (Santos et al. 2002; Sapkota et al., 2010; Cardoso et al. 2011), IL-12 (Alvarado-Navarro et al. 2008), IL-4 (Yang et al. 2011; Sampaio et al. 2012), IL-10, TGF-B, IL-6, and their respective receptors (Aggarwal et al. 2011) have been associated with susceptibility to and severity of leprosy. The gene discussed is IL10; the disease is leprosy.