In addition, several authors have reported the spontaneous development of autoimmune diseases in mice; these diseases target the skin, lungs, liver, and tail when T-reg cells (CD4+, CD25+, and Foxp3+ cells) are absent (Foxp3 protein-deficient scurfy mice Sharma et al., 2007; Davies, 2008; Goodnow et al., 2005). The gene discussed is CD4; the disease is autoimmune disease.