In Study Session 20, you learnt that HIV is a virus. In fact, there are many types of viruses. The classification of viruses is very complex, and explaining it here would go beyond the scope of this study session. For your work as a Health Extension Practitioner, you only need to know that HIV is a type of virus that is termed a retrovirus. Hence, drugs that are used to treat HIV infection are called antiretroviral drugs, which can be shortened to ARVs.
Antiretroviral therapy (HIV treatment), also known as ART, is a treatment that uses ARV drugs. The two main goals of ART are:
- to reduce the number of viruses in the patient's blood to a very low level
- to increase the number of CD4 lymphocytes in the patient as much as possible, to increase the body's immunity to infection, including immunity against HIV.
Lymphocytes are a type of white blood cell involved in the immune system; CD4 lymphocytes (or CD4 cells) are a specialised type of lymphocyte, which stimulate all the other defensive mechanisms in the immune system. For this reason, they are sometimes also called 'helper T cells'.
Remember from Section 20.2 that once inside the body, HIV first infects a previously uninfected CD4 lymphocyte. Then the HIV-infected CD4 lymphocyte produces many copies of the virus that are released into the blood to infect other CD4 lymphocytes, and so the process goes on, again and again. The ARV drugs work to stop this cycle by acting at different stages of the process.