Cancer risk in HIV-infected persons: influence of CD4(+) count.

Persons infected with HIV are at increased risk for all cancers known or suspected to have an infectious cause, an effect believed to be primarily mediated by lowered host immunity via the depletion of CD4(+) cells. Whereas Kaposi sarcoma and non-Hodgkin lymphoma were recognised as AIDS-defining illnesses early in the HIV epidemic, the influence of declining CD4(+) count on other infection-related cancers has taken longer to establish, undoubtedly because the association is weaker and the dose-response relationship is less steep. However, following improved survival made possible by combined antiretroviral therapy, declining CD4(+) count starts showing an impact on the natural history of various carcinogenic infections and on the risk for an increasingly wide range of cancers, including Hodgkin lymphoma, cervical, anal and liver cancers.