The human body normally harbors a number of viruses and bacteria that have no effect if the immune system is functioning properly. A damaged or weakened immune system presents an opportunity for these viruses and bacteria to cause diseases, which are called opportunistic infections. In patients who have HIV/AIDS, opportunistic infections usually develop years after the initial HIV infection when the immune system has weakened.
Generally, opportunistic infections are difficult to treat. For example, although vaginal yeast infections are common in all women, the risk for developing this type of infection is much greater in women with HIV/AIDS and the infection often is more difficult to treat.
The use of potent combination antiretroviral therapy has made HIV-related infections much less common than they were in the early days of the HIV/AIDS epidemic. Antiretrovirals also boost the immune system, which makes it easier to treat these infections once they develop.
If a patient's CD4+ count falls below 100 cells/mL, he or she is at great risk for developing any of a number of HIV-related opportunistic infections. Types of infections include central nervous system disorders, sexually transmitted diseases, and systemic disorders.
Viruses and AIDS-Related Cancers
Some cancers are also associated with HIV/AIDS. For example, Kaposi's sarcoma, lymphomas, cervical cancer, and anal cancer may have a viral origin. Oncogenic (tumor-causing) viruses are fairly common, but infection with one of these viruses, doesn't necessarily mean that developing cancer is inevitable.
Some of these associations include the following:
- Kaposi's sarcoma is associated with human herpesvirus 8 (HHV-8).
- Lymphomas (e.g., NHL, primary CNS lymphoma) are associated with Epstein-Barr virus (EBV).
- Anogenital cancers (e.g., cervical cancer, anal squamous cell carcinoma) are associated with human papillomavirus (HPV).
How Does a Virus Cause Cancer?
Some viruses may alter the genetic makeup of cells and cause them to become cancerous (malignant). The risk that an oncogenic viral infection will eventually lead to cancer is higher in patients who have HIV/AIDS because a weakened immune system is less able to suppress tumor growth. Patients who have an AIDS-related cancer should find a cancer specialist (oncologist) who is also expert in the care and treatment of people with HIV/AIDS.