The importance of FoxP3+CD25+CD4+ Tregs in regulating and maintaining homeostasis between both the immune system and the brain is demonstrated by their roles in CNS diseases, especially neurodegenerative diseases, such as MS, Parkinson's disease (PD) and Alzheimer's disease (AD) [9, 10, 66, 67]. The gene discussed is CD4; the disease is Alzheimer disease.