Potential role of immune modulation in the effective long-term control of HIV-1 infection

Recent advances in HIV-1 pathogenesis, and in defining virological and immunological responses to highly active antiretroviral therapy (HAART), along with the identification of the numerous drawbacks of HAART, have clearly demonstrated that the eradication of the virus is not a feasible therapeutic goal, and that there is an urgent need to develop other approaches to fight HIV-1 infection. Novel therapeutic approaches of immune modulation have recently been evaluated in pilot clinical trials. First, treating primary HIV-1 infection with cyclosporin A (CsA) coupled with HAART to target massive immune activation extends the benefits achieved with HAART during primary HIV-1 infection and might contribute to the establishment of a more favourable immunological set-point affecting the ultimate pattern and rate of disease progression. Second, treating chronic HIV-1 infection in patients with long-term suppression of virus replication induced by HAART, with the addition of mycophenolate mofetil (MMF) reduces the pool of activated CD4+ T lymphocytes able to support productive HIV-1 infection, and might have an indirect impact on the pool of resting, latently infected CD4+ T cells, contributing to its depletion in vivo. The important question is clearly whether these results will have an impact on the clinical management of patients with HIV-1 infection, determining the precise therapeutic function of drugs like CsA and MMF, thus investigating the effects of these drugs on residual viral replication and the decay of the latent reservoir, on long-term immunological benefit, and, ultimately, on clinical benefit.