Tregs are CD4+CD25+FOXP3+ cells, which are key immunomodulators with established relevance and therapeutic potential in many disease settings such as infections, cancer, autoimmune diseases and transplantation (Josefowicz, Lu, & Rudensky, 2012; Pandiyan et al., 2011; Pandiyan & Lenardo, 2008; Pandiyan, Zheng, Ishihara, Reed, & Lenardo, 2007; Pandiyan & Zhu, 2015). Here, CD4 is linked to infection.