In the late stages of AIDS, human immune function is severely deficient, with all tissues and organs of the body being compromised, accompanied by multiple and various opportunistic infections and the occurrence of malignant tumors. This leads to symptoms such as skin itching, muscle pain, fever, diarrhea, and weight loss. If the nervous system is affected, dementia, loss of discriminative ability, or motor dysfunction may occur. Therefore, the late stages are quite painful.