Most of you are familiar with allergy problems, however, very few people understand the term "Immunology.” The immune system protects us from the outside environment so we can all lead a healthy life. Any dysfunction in the immune system can result in several diseases that we deal with in day-to-day life. The immune system consists of many different types of cells, and these cells make antibodies and mediators. The combination of these mediators and antibodies works to keep us healthy. If they do not function, people develop a group of diseases called immunodeficiency diseases. A common example that we all know now is AIDS, which is caused by the HIV virus that attacks the immune cells.