History of Acquired Immune Deficiency Syndrome
Acquired Immune Deficiency Syndrome (AIDS), specific group of diseases or conditions that result from suppression of the immune system, related to infection with the human immunodeficiency virus (HIV). A person infected with HIV gradually loses immune function along with certain immune cells called CD4 T-lymphocytes or CD4 T-cells, causing the infected person to become vulnerable to pneumonia, fungus infections, and other common ailments. With the loss of immune function, a clinical syndrome (a group of various illnesses that together characterize a disease) develops over time and eventually results in death due to opportunistic infections (infections by organisms that do not normally cause disease except in people whose immune systems have been greatly weakened) or cancers.
In the early 1980s deaths by opportunistic infections, previously observed mainly in organ transplant recipients receiving therapy to suppress their immune responses, were recognized in otherwise healthy homosexual men. In 1983 French cancer specialist Luc Montagnier and scientists at the Pasteur Institute in Paris isolated what appeared to be a new human retrovirus—a special type of virus that reproduces differently from other viruses—from the lymph node of a man at risk for AIDS (see Lymphatic System). Nearly simultaneously, scientists working in the laboratory of American research scientist Robert Gallo at the National Cancer Institute in Bethesda, Maryland, and a group headed by American virologist Jay Levy at the University of California at San Francisco isolated a retrovirus from people with AIDS and from individuals having contact with people with AIDS. All three groups of scientists isolated what is now known as human immunodeficiency virus (HIV), the virus that causes AIDS.
Infection with HIV does not necessarily mean that a person has AIDS, although people who are HIV-positive are often mistakenly said to have AIDS. In fact, a person can remain HIV-positive for more than ten years without developing any of the clinical illnesses that define and constitute a diagnosis of AIDS. In 1997 an estimated 30.6 million people worldwide were living with HIV or AIDS—29.5 million adults and 1.1 million children. The World Health Organization (WHO) estimates that between 1981, when the first AIDS cases were reported, and the end of 1997, more than 12.9 million adults and children had developed AIDS. In this same period there were 11.7 million deaths worldwide from AIDS or HIV. About 430,000 of these deaths occurred in the United States.
II CLINICAL PROGRESSION OF AIDS
The progression from the point of HIV infection to the clinical diseases that define AIDS may take six to ten years or more. This progression can be monitored using surrogate markers (laboratory data that correspond to the various stages of disease progression) or clinical endpoints (illnesses associated with more advanced disease). Surrogate...