Some subgroup of T effector cells that expressed activation molecules such as HLADR+, CD40L, ICOS, or CD69 and belonged to one pattern of the activated lymphocytes were able to continuously mature into memory T cells for robust augmentation to fight EBV infection and overcome cytokines-related catastrophic response in persistent and un-eradicated pathogen reactivation [38], [40]. The gene discussed is ICOS; the disease is Epstein-Barr virus infection.