Immunology

The key factor in HIV pathogenesis is the decline in CD4+ T cells with resultant immunodeficiency and chronic inflammation. Depletion of CD4+ T cells from the gastrointestinal mucosa followed by microbial translocation and subsequent immune activation are components of disease progression in untreated patients. Symptomatic and occult opportunistic infections including cytomegalovirus contribute to chronic inflammation in persons infected with HIV. Antiretroviral therapy (ART) results in immune reconstitution, with increases in peripheral CD4+ T cell lymphocytes in most persons infected with HIV, although immune recovery is quite variable. A subset of patients with AIDS will develop immune reconstitution inflammatory syndromes after initiation of ART. Approximately 1% of persons with HIV are able to control infection without the need for ART (“elite” controllers). A variety of immune-based therapies, including hydroxyurea, growth hormone, and statins, are being studied in clinical trials and may ultimately play a role in treating persons with HIV infection.