HIV Support provides resources and information on HIV and AIDS including treatments, advice, forums and blogs. Find information on HIV treatments, cure and post questions to receive advice from others. What is HIV? During the past decade there have been many programs and health authorities who warned people about the impact and dangers of HIV. There are currently 50 million people living with HIV virus worldwide and according to world health organisation (WHO) in two years this number will increase to 70 million. Fig 1: People living with HIV and Aids HIV is a term which stands for the Human Immuno-deficiency Virus. HIV cannot grow or reproduce on its own. In order to make new copies of itself it must infect the cells of a living organism Viruses unlike bacteria infects the cells of living organism and use these cells to replicate. Virus can also damage the cells, which is one of the ways by which the infected person becomes ill. Not all viruses act the same and most of them can be eliminated from body by human immune system. Human immune system compose of a groups of cells and organs that protect the body by fighting disease. Human body can usually find different viruses and kill them although this does take time. One might ask, if the human immune response is so efficient why is it that HIV is not eliminated from body like other viruses. To answer this question, there have been many studies and observations. Not all viruses effect the same part of the body, and as body is comprised of so many different cell types, different viruses attack different parts of the body- some may attack the skin while some act on lung cells. Take common cold for example, a virus, which can make people ill for week or two but it is recognised by the body’s immune system and eliminated. What makes HIV so dangerous is it attacks the immune system itself, the very thing that is responsible for eliminating the virus. HIV virus attacks a specific cell type of immune system, known as CD4 lymphocyte. CD4 also known as T helper cells, are a sub-group of immune cells known as lymphocytes. This cells are unique in a sense that they do not pose the cytotoxic ability to kill the infected cells and without other immune cells they would usually be considered useless against an infection, however they are involved in activating and directing other immune cells, and are particularly important in the immune system. The importance of helper T cells can be seen from HIV, a virus that infects cells that are CD4+ (including helper T cells). Towards the end of an HIV infection the number of functional CD4+ T cells falls, which leads to the symptomatic stage of infection known as the acquired immune deficiency syndrome (AIDS). HIV virus has a number of tricks that help it to evade the body's defences, including very rapid mutation. This means that once HIV has taken hold, the immune system can never fully get rid of it.