‘of Mice and menʹ (John steinbeck)—How do we determine the potential for immunotoxicity in humans?

PURPOSE: Immunotoxicology is most simply defined as the study of adverse effects on the immune system resulting from exposure to drugs, environmental and industrial chemicals, and in some instances, biological materials. The science of immunotoxicology has validated animal models to conduct risk assessment. However, approaches to characterize immunotoxicity in humans are poorly defined. Animal models have indicated that a primary immune response is most predictive of immunotoxicity. Because vaccines can trigger a primary immune response, this approach may have utility in humans. The purpose of this project was to determine if the response to the influenza vaccine can be validated as an objective measurement of immune status in the workplace. METHODS: We randomly selected employees to receive the influenza vaccine and employees, matched according to age and gender, to receive the placebo. The participants (32 test group and 19 placebo group) completed a brief questionnaire to identify potential confounding factors. Specific anti-influenza antibodies were measured in the serum via an ELISA 30 days after administering the vaccine or placebo. RESULTS: Only 50% (16 of 32 subjects) produced a positive response which is defined by the Centers for Disease Control as a four-fold increase in serum titers. Not unexpectedly, all samples contained antibody to influenza prior to vaccination, and a number of the participants who did not achieve a positive response started with high serum titers. CONCLUSIONS: The influenza vaccine was originally selected for this study because of costs, acceptability to the population and proven safety and efficacy. However, the results of the present investigation suggest that this approach will have little utility as a workplace monitor of human immunotoxicity because most individuals would not be making a primary antibody response. Other technical limitations with the influenza vaccine will be presented; and the alternatives for other biomonitors of human immunotoxicity will be discussed.