Immunologic alterations by environmental chemicals: relevance of studying mechanisms versus effects

A number of environmental chemicals are known to modify the immune responses via a number of different mechanisms. Immunologic systems are vital to the well-being of individuals and a number of toxic effects are likely to be produced by chemical alteration of its processes. A variety of tests have been suggested for screening existing or new chemicals with regards to their potential to modify the immune responses. It is well recognized that immune responses are highly temporal (time-related) and the outcome of a test is likely to be influenced by the specific protocol employed and other factors that may involve the test organism. Although standardization of tests will probably reduce some of this variability, test standardization is not expected to provide more valuable information than can be already predicted by the routine evaluation of chronic toxicity and clinical parameters. The need for studying the mechanisms involved in the modification of immunologic processes by exogenous and even endogenous chemicals is emphasized in this report.