IL-27 synergizes with IL-12 in IFN-γ production from naïve CD4+ T cells and plays an important role in host defence against infection; defects in the IL-27 receptor causes increased susceptibility to different intracellular pathogens and it has been reported that Th1 responses can be controlled by intra-cellular glutathione redox status in dendritic cells (DCs) through IL-27 production [8], [23], [24]. The gene discussed is CD4; the disease is infection.