The main danger of AIDS is that the virus attacks the body’s immune system. As the virus continues to replicate in the infected person, the immune system is gradually compromised and the CD4+ T-lymphocyte count decreases, resulting in the development of secondary infections such as pneumocystis pneumonia, cryptococcal meningitis, giant cell retinitis, etc. The decline in immune function also leads to the development of specific tumors, such as malignant lymphoma and Kaposi’s sarcoma. Most people with AIDS eventually die from secondary infections, so once AIDS is diagnosed, treatment with antiretroviral drugs should be started as soon as possible to avoid the decline of immune function.