Since CD4 T-cell-specific PDPK1 deletion induces lymphoid atrophy, and PDPK1 deficiency in Treg cells generates severe spontaneous autoimmune diseases [31], which resemble the phenotypes observed in our KO and Treg-KO mice, we then examined PDPK1 and its downstream signaling molecules. The gene discussed is CD4; the disease is autoimmune disease.