Elucidating the elite: mechanisms of control in HIV-1 infection

In patients with progressive disease, untreated HIV-1 infection is characterized by high viral loads and decreasing CD4(+)T cell counts which lead to opportunistic infection and other AIDS-defining illness. A rare subset of patients termed 'elite controllers' (ECs) maintain control over viremia and often retain normal CD4(+)T cell levels without treatment with antiretroviral drugs. For the most part these patients are infected with replication-competent, fit virus. Factors such as strong, polyfunctional cytotoxic T lymphocyte (CTL) responses and retention of T cell proliferative ability appear to be important in control of HIV-1. Defining what enables ECs to control viral replication will aid in the development of effective vaccine and treatment regimens. This review will discuss differences between ECs and progressors while emphasizing recent findings on the immunological response of ECs to HIV-1.