AIDS stands for acquired immune deficiency syndrome. It is a disorder of the cell-mediated immune system of the body. There is a reduction in the number of helper t cells which stimulate antibody production by b cells. This results in the loss of natural defense against viral infection. This is caused by the HIV virus which stands for Human Immunodeficiency Virus. Once the host is infected with the HIV virus the symptoms may or may not be visible at first but gradually with time the immunity weakens.