T-cell dysfunction in HIV infection: anergy due to defective antigen-presenting cell function?

Before CD4⁺ T cells are depleted, T cells in asymptomatic HIV-infected individuals are functionally abnormal. These T cells are programmed for death, are nonresponsive and fail to produce interleukin-2 after antigenic stimulation. Our view is that these different T-cell abnormalities are explained by the effects of HIV on antigen-presenting cells. Alteration of the functions of the antigen-presenting cell may program T cells for activation-induced death, and may induce anergy in interleukin-2 and interferon-γ secreting T_H1 cells. This results in predominance of T_H2 allergic responses instead of cellular immunity dependent on T_H1 cells.