Immune Response to Exposure to Occupational and Environmental Agents

Recognition that xenobiotics can impair the function of the immune system has led to progress in immunotoxicology over the last two decades. Exposure to immunotoxic chemicals in the environment, however, may be expected to result in more subtle forms of immunosuppression that may be difficult to detect, leading to increased incidences of infections such as influenza and common cold. Studies on experimental animals and humans have shown that many environmental chemicals suppress the immune response. Immunotoxic xenobiotics are not restricted to a particular chemical class. Compounds that adversely affect the immune system are found among drugs, pesticides, solvents, halogenated and aromatic hydrocarbons, metals, etc. Therapeutic administration of immunostimulating agents can have adverse effects, and a few environmental chemicals that have immunostimulating properties (beryllium, silica, hexachlorobenzene) can have clinical consequences. Reports on the assessment of immunotoxicity in humans exposed to various agents as a part of occupational exposure are relatively scarce. Apart from various routine toxicological evaluations this is an important parameter that can provide information on body responses which may be responsible for a sequence of reactions leading to pathogenesis. Some of these parameters can be used as a biological marker for the early detection of disease due to occupational exposure to the agent.