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Human immunodeficiency virus (HIV)

Pathogenesis

The Human immunodeficiency virus is made up of Genetic material, Chemicals and a coating. The Genetic material is RNA and the Chemicals are enzymes which help the virus enter and use other cells to make copies of itself.

HIV mainly infects white blood cells called T-lymphocyte cells (T-cells). The virus infects a T-cell by attaching to a protein on the cell's surface called CD4+. Not all T-cells have this protein. The ones that do are called CD4+ cells, T4 cells, or T-helper cells.

 
After binding with the CD4+ cell, the virus enters the cell and, using an enzyme called reverse transcriptase, merges its RNA with the cell's genetic material (DNA). This causes the DNA in the CD4+ cell to make copies of HIV (replication). Another enzyme called protease helps the new viruses form. The new viruses then "bud" off the infected cells into the body, where they infect more CD4+ cells.

The presence of the virus causes a person's immune system to react by attacking the virus itself and any HIV-infected cells. This process results to formation of antibodies . A person is said to be HIV-positive if antibodies to the virus are detected by tests, indicating infection.

As HIV-infected CD4+ cells are destroyed or impaired, the person's immune system becomes less and less effective at fighting infection and disease. The person is said to be "immunocompromised" or "immunodeficient." Such people are more likely to develop unusual diseases called Opportunistic infections that they would not get if their immune systems were healthy.

As the number of CD4+ cells decreases, the person is more likely to get sick and have more serious illnesses. When this is the case, a person is usually diagnosed with acquired immunodeficiency syndrome (AIDS).

HIV enters T lymphocyte

HIV uses cell's own DNA and enzymes to copy its RNA

Enzymes divide RNA to make new HIV

New HIV then emerges out of the T lymphocyte

 

Natural History of HIV Infection

Laboratory Tests for HIV Infection

Manifestations of HIV

Human Immunodeficiency Virus (HIV)

Management of HIV infection

HIV Update


Dr. Manbir Singh