The human immunodeficiency virus HIV primarily affects important cells of the body’s defense system, the T helper cells (also called T4 helper cells, CD4 cells or CD4 lymphocytes) and the phagocytes (macrophages). Nerve cells can also be affected. The viruses penetrate the cells, use their metabolism to multiply and thereby destroy the host cell. The newly formed viruses get into the blood and attack other cells, the infection spreads more and more in the body.
If an HIV infection is not treated, the viruses gradually gain the upper hand: the virus concentration in the blood increases and the T helper cells become less and less. After all, the immune system is so weakened that it can no longer fight diseases effectively. In this phase, the HIV infection becomes symptomatic, which means that there are increasing signs and symptoms that are a result of the increasing “immunodeficiency”. If left untreated, the immune system collapses to a large extent, resulting in illnesses and infections, the occurrence of which must be diagnosed as “AIDS”. Because “AIDS” stands for “Acquired Immune Deficiency Syndrome”, translated “acquired immune deficiency syndrome” – a group of often life-threatening infections and diseases, the cause of which is the immune deficiency caused by HIV. These include, for example, pneumonia, brain abscesses, tuberculosis or inflammation of the esophagus with difficulty swallowing and weight loss. They are caused by pathogens that cannot harm the healthy immune system and are therefore called “opportunistic pathogens”.