Virological and immunological features of long-term human immunodeficiency virus-infected individuals who have remained asymptomatic compared with those who have progressed to acquired immunodeficiency syndrome.

Infection with the human immunodeficiency virus (HIV) leads to a decrease in CD4(+) T cells and disease progression within a decade of seroconversion. However, a small group of infected people, despite being infected by HIV for 10 or more years, remain clinically asymptomatic and have stable CD4(+) cell counts without taking antiretroviral medication. To determine why these individuals, known as long-term survivors (LTS), remain healthy, the hematological profiles, viral load and properties, HIV coreceptor genotype, and anti-HIV immune responses of these people were compared with those of individuals who have progressed to disease (Progressors) over the same time period. Unlike Progressors, LTS have a low circulating viral load and a low number of HIV-infected cells. These differences in the levels of the viral load were not associated with a dominant biologic viral phenotype, varying growth kinetics of the virus, mutation in the cellular CCR5 gene, or the presence of neutralizing antibodies. Importantly, the difference in viral load could be explained by the enhanced ability of CD8(+) cells from LTS to suppress HIV replication.