HIV is a virus that attacks your immune system, which is made up of millions of cells that help fight against infection and disease. One of the most important of these infection-fighting cells is called the
CD4 cell or T-helper cell.
When HIV enters the body, the virus infects CD4 cells and copies its own genetic code into the cell's DNA. The CD4 cell is then "programmed" to create new copies of HIV (referred to as
replication). The new viruses are released from infected CD4 cells into the blood and go on to infect and destroy other CD4 cells. As CD4 cells are attacked and destroyed by HIV, the immune system becomes less able to fight infection and disease.
Without treatment, the number of CD4 cells will most likely go down and the immune system will become less able to fight certain infections and cancers. These infections are called
opportunistic infections (OIs). Once the immune system becomes seriously damaged or weakened, or OIs occur, HIV infection has progressed to
AIDS (Acquired Immunodeficiency Syndrome).
To learn about the different types, or "classes," of HIV medications that are used to fight the virus,
click here.
