Acquired Immune Deficiency Syndrome (AIDS) is a disease characterized by
a progressive loss of immune system function, manifested by numerous
opportunistic infections, including tumors. Untreated, it is
universally fatal, but recent
advances in treatment have made the disease much more manageable and
many patients can lead relatively normal lives. Human immunodeficiency
virus (HIV) is the virus that causes AIDS. HIV is a retrovirus
infects immune cells and some neurons. There is no cure for AIDS and
there is no drug that can eliminate HIV from the body. There are many
anti-retroviral drugs however that can reduce HIV plasma levels to
very low levels and restore immune system function.
AIDS is the most severe manifestiation of HIV infection. AIDS occurs due to
the progressive destruction of CD4+ T cells. AIDS is defined as the
presence of a cluster of symptoms outlined below and often when CD4+ T
cells drop to fewer than 200 per microliter of blood.
Symptoms of AIDS involve infections and conditions that are not present
in those with healthy immune systems. Many of these conditions are
caused by bacteria, fungi, viruses and parasites. Patients with AIDS are
susceptible to cancers such as Kaposi's sarcoma, lymphomas and
cervical cancers. Systemic symptoms may include fevers, night sweats,
loss, weakness and swollen lymph glands. Some common opportunistic
infections and symptoms include: pneumocystitis pneumonia (PCP),
tuberculosis, esophagitis, chronic diarrhea due to bacterial
Neuropsychiatric disorders such as toxoplasma encephalitis,
cryptococcal meningitis, progressive multifocal leukoencephalopathy
(PML) and AIDS dementia complex can occur.
Other opportunistic infections that are common in patients with AIDS
include infection with Epstein-Barr virus (EBV),
Kaposi's sarcoma-associated herpesvirus (KSHV) and
human papillomavirus (HPV). EBV
and KSHV are common causes of high-grade lymphomas in AIDS patients.
Cervical cancer in HIV-infected women is also common. Other more mild
infections include mycobacterium avium-intracellulare and
cytomegalovirus (CMV). Penicillosis has become a common
infection in HIV-positive patients in southeast Asia.
There is no cure for AIDS, nor is there a vaccine for HIV infection.
standard of care is highly active antiretroviral therapy (HAART).
treatment involves a cocktail of at least 3 antiretroviral agents coming
from at least 2 different classes. The most common combination is 2
nucleoside analogue reverse transcriptase inhibitors (NRTIs) in
a protease inhibitor or a
non-nucleoside reverse transcriptase inhibitor
(NNRTI). In the assessment of treatment, viral load and CD4
common measures of both success and for the decision of when to initiate
HAART has resulted in a dramatic decrease in HIV-related
mortality (and morbidity). HAART seems to increase survival time by at
least 4 years and some studies suggest as much as 12 years. Without HAART,
the progression of HIV to AIDS occurs in about 10 years. Many HIV-positive
patients develop a drug-resistant strain of HIV. Side effects can
diarrhea, insulin resistance, cholesterol disorders and