Britannica
Sources used in this answer
Why are Kaposi sarcoma and Pneumocystis pneumonia common among people with AIDS?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
immune system disorder
False-color scanning electron micrograph of a T cell infected with HIV (human immunodeficiency virus), the agent that causes AIDS (acquired immunodeficiency syndrome).
Kaposi sarcoma and Pneumocystis pneumonia are common among people with AIDS because the condition causes a severe breakdown of the immune system.12
HIV, the virus that causes AIDS, selectively infects and destroys helper T cells, which are essential for coordinating the body's immune response. When the count of these cells drops significantly, the body loses its ability to defend against opportunistic pathogens—microbes that typically live benignly in the body or are easily cleared by a healthy immune system but cause disease when immunity is suppressed.234
- Pneumocystis pneumonia is an opportunistic infection that arises specifically because the compromised immune system cannot prevent the pathogen from causing severe illness.24
- Kaposi sarcoma is considered an opportunistic tumor. Its development is linked to the loss of immune surveillance, the process by which the immune system identifies and destroys abnormal or cancerous cells. Additionally, the sarcoma's occurrence may be encouraged by the production of growth factors from HIV-infected white blood cells and infection by the herpes virus HHV-8.15