T cell depletion in HIV-I infection: how CD4(+) T cells go out of stock

HIV-I infection is characterized by a gradual loss of CD4(+) T cells and pr ogressive immune deficiency that leads to opportunistic infections, otherwi se rare malignancies and ultimately death. Extensive research over the past two decades has increased our insight into the pathogenic mechanisms under lying these features of HIV-I infection. Here, we will give a brief overvie w of the most recent findings and present a model that fits most of the rel evant aspects of HIV-I infection as known. We hypothesize that HIV-I infect ion depletes T cell supplies (which are not replaced because of low and sta tic thymic function) by direct infection and killing of cells and through h yperactivation of the immune system.