However, this high level of LIP may not occur during healthy aging, and it can only be reached during premature CD4+ T cell aging in autoimmune-prone condition, in which all lymphopenia, Treg detects, autoreactive T cells, and IL-6 are present, either in early-onset diseases in the young or in late-onset diseases in the middle-aged or aged animals or humans. The gene discussed is CD4; the disease is lymphopenia.