IL-17A is produced by Th17 cells and plays a critical role in mediating inflammation during early infection and prior to the onset of adaptive T cell responses against infectious pathogens in a variety of in vivo mammalian infection model systems (Steinman, 2007; Chen and O’Shea, 2008; McGeachy and Cua, 2008; Ivanov et al., 2009; Iwakura et al., 2011). The gene discussed is IL17A; the disease is infection.