Reservoirs, sanctuaries, and residual disease: the hiding spots of HIV-1.

Highly active antiretroviral therapy (HAART) has profoundly decreased morbidity and mortality in human immunodeficiency virus type 1 (HIV-1)-infected individuals, at least in the developed world. Many infected individuals have plasma levels of HIV-1 RNA below the limits of detection of most clinical assays due to combination antiretroviral therapy. Nonetheless, HIV-1 has not been eradicated by HAART. This has been shown recently to be due to latent HIV-1 replication-competent provirus in resting CD4+ T-lymphocytes, cryptic viral replication below the limits of detection of most clinical assays, and viral sanctuary sites. An understanding of these sanctuaries and reservoirs for HIV-1 in the setting of virally suppressive HAART will be critical in developing new approaches to induce HIV-1 remissions or the possibility of viral eradication in the future.