CD4 and AIDS: In the absence of antiretroviral therapy (ART), the hallmark of human immunodeficiency virus type 1 (HIV-1) infection is the gradual destruction of the naive and memory CD4+ T-lymphocytes and the associated immunological abnormalities leading to the acquired immunodeficiency syndrome (AIDS) [1,2,3,4,5,6,7,8,9,10,11] (Figure 1, progressors immune system damage, top box).