CD4+ T cells are the main target of HIV infection both in vitro and in vivo. While the progression of HIV disease is driven by the viral burden, the precise mechanisms of CD4+ T-cell depletion are not altogether understood.
The effects of HIV that predispose the patient to fungal infections also include impairment of neutrophil and mononuclear cell function, cytokine production, and B-cell function in addition to T-cell depletion. Disruption of skin and mucous membrane barriers, indwelling intravascular catheters, and broad-spectrum antibiotics all increase the risk of infection.
Incidence and Mortality
In HIV-infected patients, candidiasis is virtually always mucocutaneous, involving the oropharynx, the esophagus, and the vagina. It occurs in up to 90% of patients during the course of their disease . Disseminated candidiasis is uncommon except in those with advanced AIDS. Mucocutaneous candidiasis is related to the development of clinical cellular immunodeficiency. In fact, oropharyngeal candidiasis is an independent predictor of immunodeficiency in patients with AIDS . A CD4 lymphocyte count <200/µL is a major risk factor for the development of clinical thrush in HIV-infected persons . The alarming increase in the number of oropharyngeal infections caused by azole-resistant Candida species seems to have been halted with the introduction of highly active antiretroviral therapy (HAART).
Cryptococcosis was identified early in the HIV epidemic as one of the most common lifethreatening infections in AIDS patients , with the development of disease relating directly to the CD4 lymphocyte count . It occurs in 5% to 10% of HIV-infected patients in most areas of the world, although the incidence is significantly higher in Africa and Thailand . Invasive aspergillosis is becoming more prevalent in AIDS patients. Surveys of clinically diagnosed disease report an incidence of 0.9%8.6% . Endemic mycoses are problematic in this patient population, with primary infection of patients moving into an endemic area. Also, reactivation of infection can occur years after a person has left the endemic area. Histoplasmosis has been reported in 2% to 5% of patients with AIDS in areas of endemic infection in the US and up to 25% in selected cities .
Course Number: V035B.043001
This CME Expires on July 1, 2003; no tests will be accepted after this date.
This course is accredited by
The University of Pittsburgh School of Medicine, Center for Continuing Education