Chronic Activation of the Immune System in HIV Infection: Contribution to T Cell Apoptosis and Vβ Selective T Cell Anergy

Since the initial isolation in 1983 of the human immunodeficiency virus (HIV) that is known to cause AIDS (acquired immune deficiency syndrome) (Barre-Sinoussi et al. 1983) and despite an extensive knowledge of the molecular characteristics of this virus, one of the main questions is still not answered: what causes the immune system collapse in HIV infection? Indeed the hallmark of AIDS is the progressive disappearance of CD4+ helper T lymphocytes which, in addition to being the targets of the virus (Klatzmann et al. 1984), play a major role in the immune system. There is no question that the presence of the virus in lymphoid organs and its active replication associated with direct killing of the target is at least associated with CD4+ T cell depletion. However it has become clear for many investigators that direct mechanisms, even if they play a role, are inadequate to explain the extent of immunosuppression. HIV disease is now considered as a multifactorial process and the immunopathogenic mechanisms involved appear to be very complex (Fauci 1988, 1993; Gougeon and Montagnier 1993; Levy 1993).