Insights into immunopathogenic mechanisms of HIV infection: high levels of immune activation and HIV fitness.

Progressive diminution in the number, and decline in the function of CD4+ T cells are the hallmarks of HIV infection. The pathogenic mechanisms responsible for the progression of the disease to acquired immunodeficiency syndrome (AIDS) are not well understood, but it appears that HIV-induced immune activation and increase in HIV viral fitness play an essential role in the pathogenesis of HIV infection. In this paper HIV fitness in relation to the chronic immune activation in HIV infection will be discussed.