While costimulatory molecule CD28, essential for cytokine expression, proliferation and survival of T cells [17, 18], is lost in HIV infection and aging [19, 20], terminal differentiation marker CD57 on T cells, commonly associated with conditions of chronic antigenic exposure, is expressed at higher levels and inversely related to CD28 expression [1, 21]. The gene discussed is B3GAT1; the disease is HIV infectious disease.