The escape of the immune system from the regulatory affects of the body, induced by immunotoxicants or pathogenic microorganisms, may lead to hypersensitivity, autoimmunity or immunosuppression. Immunosuppression causes failure of the immune system to respond properly to invading foreign microbes. It may occur due to lack of the cells or the organs of the immune system or their proper functioning. Suppression of the immune system causes an increased susceptibility of an individual to infections from pathogens, cancer as well as opportunistic microbes. Organisms that our body would normally be able to ward off will be able to infect tissues causing life threatening conditions.