In the absence of treatment, most patients with HIV infection progress to AIDS after a chronic phase lasting from 7 to 10 years, but there are exceptions. In rapid progressors, the middle, chronic phase is telescoped to 2 to 3 years after primary infection. About 5% to 15% of infected individuals are long-term nonprogressors, defined as untreated HIV-1–infected individuals who remain asymptomatic for
A.Asymptomatic:acuteA1A2A3(primary)HIV,orpersistentgeneralizedlymphadenopathy
B.Symptomatic:noAorB1B2B3Cconditions
C.AIDSindicatorconditions:includingconstitutionaldisease,neurologicdisease,orneoplasm
DatafromCentersforDiseaseControlandPrevention:1993revisedclassificationsystemandexpandedsurveillancedefinitionforAIDSamongadolescentsandadults.MMWR 41(RR-17):1,1992.
http://ebooksmedicine.net response, but the immune correlates of protection are still unknown. Some of these individuals have high levels of HIV-specific CD4+ and CD8+ T-cell responses, and these levels are maintained over the course of infection. The inheritance of particular HLA alleles seems to correlate with resistance to disease progression, perhaps reflecting the ability to mount anti-viral T cell responses.
In the following section, we summarize the clinical manifestations of the terminal phase of the disease, full-blown AIDS.
In the United States, the typical adult patient with AIDS presents with fever, weight loss, diarrhea, generalized lymphadenopathy, multiple opportunistic infections, neurologic disease, and, in many cases, secondary neoplasms.
Opportunistic infections account for the majority of deaths in untreated patients with AIDS. Many of these infections represent reactivation of latent infections, which are normally kept in check by a robust immune system but are not completely eradicated because the infectious agents have evolved to coexist with their hosts. The actual frequency of infections varies in different regions of the world, and has been markedly reduced by the advent of highly active anti-retroviral therapy (called HAART or ART), which relies on a combination of three or four drugs that block different steps of the HIV life cycle.
Approximately 15% to 30% of untreated HIV-infected individuals develop pneumonia caused by the fungus Pneumocystis jiroveci at some time during the course of the disease. Before the advent of HAART, this infection was the presenting feature in about 20% of cases, but the incidence is much less in patients who respond to HAART.
Candidiasis is the most common fungal infection in patients with AIDS, and infection of the oral cavity, vagina, and esophagus are its most common clinical manifestations. In HIV-infected individuals, oral candidiasis is a sign of immunologic decompensation, and often heralds the transition to AIDS. Invasive candidiasis is infrequent in patients with AIDS, and it usually occurs when there is drug-induced neutropenia or use of indwelling catheters.
Cytomegalovirus (CMV) may cause disseminated disease, but more commonly affects the eye and gastrointestinal tract. Chorioretinitis used to be seen in approximately 25% of patients, but has decreased dramatically after the initiation of HAART. CMV retinitis occurs almost exclusively in patients with CD4+ T cell counts less than 50 per microliter. Gastrointestinal CMV infection, seen in 5% to 10% of cases, manifests as esophagitis and colitis, the latter associated with multiple mucosal ulcerations.