Approaches to detecting immunotoxic effects of environmental contaminants in humans.

Experimental animal studies indicate that environmental contaminants can have adverse effects on several organs and tissues of the immune system. Such effects are known to lead to increased host susceptibility to microbial infections and to compromised immunosurveillance mechanisms normally instrumental in the elimination of neoplastic cells and the prevention of autoimmune diseases. Evaluation of the potential risk environmental contaminants pose to the human immune system is currently accomplished via extrapolation of experimentally derived animal data to humans. Presently, this process requires that uncertainty factors such as interspecies differences and genetic variability be considered. Naturally, the process of risk assessment would be greatly facilitated if it were based on clinically relevant data derived from studying humans known to be exposed to environmental contaminants. However, the existing human data are scarce and often described as very limited in scope. To generate the much-needed human data we need to identify a set of clinically relevant immunologic end points that, when adequately standardized, can be incorporated easily into the design of prospective epidemiologic studies.