AIDS Health Article

AIDS in women

HIV remains an important cause of death and illness in women. In the US, AIDS was the fifth leading cause of death among women aged 25-44 in 1998. In 1999, 32% of new HIV diagnoses were in women. Although HIV infected women have been observed to die earlier than men, it is believed that this difference in survival rates is caused by differences in access to care and delayed treatment rather than biological differences in disease progression.

AIDS in children

Since AIDS can be transmitted from an infected mother to the child during pregnancy, during the birth process, or through breast milk, all infants born to HIV-positive mothers are a high-risk group. In 1999, 78% of new HIV cases in women were in females of childbearing age. Without prenatal intervention, between 20-40% of children born to HIV-positive women will become infected with the virus.

AIDS is one of the 10 leading causes of death in children between one and four years of age. The interval between exposure to HIV and the development of AIDS is shorter in children than in adults. Infants infected with HIV have a 20-30% chance of developing AIDS within a year and dying before age three. In the remainder, AIDS progresses more slowly; the average child patient survives to seven years of age. Some survive into early adolescence.

Causes and symptoms

Because HIV destroys immune system cells, AIDS is a disease that can affect any of the body's major organ systems. HIV attacks the body through three disease processes: immunodeficiency, autoimmunity, and nervous system dysfunction.

Immunodeficiency describes the condition in which the body's immune response is damaged, weakened, or is not functioning properly. In AIDS, immunodeficiency results from the way that the virus binds to a protein called CD4, which is found on the surface of certain subtypes of white blood cells, including helper T cells, macrophages, and monocytes. Once HIV attaches to an immune system cell, it can replicate within the cell and

kill the cell in ways that are still not completely understood. In addition to killing some lymphocytes directly, the AIDS virus disrupts the functioning of the remaining CD4 cells. Because the immune system cells are destroyed, many different types of infections and cancers that take advantage of a person's weakened immune system (opportunistic) can develop.

Autoimmunity is a condition in which the body's immune system produces antibodies that work against its own cells. Antibodies are specific proteins produced in response to exposure to a specific, usually foreign, protein or particle called an antigen. In this case, the body produces antibodies that bind to blood platelets that are necessary for proper blood clotting and tissue repair. Once bound, the antibodies mark the platelets for removal from the body, and they are filtered out by the spleen. Some AIDS patients develop a disorder, called immune-related thrombocytopenia purpura (ITP), in which the number of blood platelets drops to abnormally low levels.

HIV also infects some susceptible cells in the central nervous system. The exact mechanism of HIV entry into the brain is unknown. Possible modes of entry across the blood-brain barrier include HIV entry as a single cell-free viral particle (virion), entry via infected monocyte or lymphocyte, and infection of endothelial cells (cells forming brain border). Regardless of the mechanism, evidence suggests that the cerebral spinal fluid is seeded with HIV very early in the infection process.

Although not all patients will follow them precisely, the course of AIDS generally progresses through the three stages (acute retroviral syndrome, latency period, and late-stage AIDS) that follow.