Immunotoxicology is the dysfuntion of immune system because of exposure of organism to extrinsic factors. The immune system is a target following exposure to a diverse group of xenobiotic including chemical pollutants, recreational drugs, ultraviolet radiation and therapeutics. There is a well-established cause and effect relationship between suppression of the immune response and reduced resistance to infections. Xenobiotic exposure may result in stimulation of immune function. Xenobiotic can act as allergens and elicit hypersensitivity responses, or they can modulate hypersensitivity responses to other allergens. The immune dysfunction may take the form of immunosuppression or alternatively, allergy or autoimmunity or any number of inflammatory-based diseases..
Immunotoxicity can be regarded as one of several distinct immunopathologies that include allergic disease, immunodeficiency and autoimmunity. In immunopathologies, the immune system responds to the agent as an allergen of low (hapten) or high molecular weight, that result in allergic contact dermatitis, food hypersensitivity or respiratory hyper-sensitivity. In immunodeficiency, the immune system acts as a passive target for the agent and this may lead to increased incidence or severity of infectious disease. Autoimmunity which is a break-down in self-tolerance occurs when an agent directly or indirectly induces an immune response to autologous constituents that result in pathological consequences. As the immune system plays a critical role in host resistance to disease as well as in normal homeostasis of an organism, identificantion of immunotoxic risk is significant in the protection of human, animal and wildlife health.
Last date updated on January, 2021