Potential future requirements for immunotoxicology testing of pesticides.

The thoughts presented above comprise a possible approach for revising Subdivision F guidelines with respect to testing of chemical pesticides as immunotoxicants. The main points of this report can be summarized as follows: 1. The tier system approach to Subdivision M guidelines allows for an effective screen (Tier I), and for in-depth (Tier II) evaluation of biochemical pesticides as immunotoxic agents. 2. Subchronic and chronic studies in Subdivision F guidelines can be modified to provide a more effective screen for evaluating the immunotoxic potential of chemical pesticides. 3. Addition to Subdivision F of studies to measure certain specific and non-specific cell-mediated immune responses might be considered appropriate for an immunotoxicity screen and, if included, would render Subdivision F data requirements analogous to those of Subdivision M. 4. When considered necessary, further studies can be done with chemical pesticides to provide sufficient data for an in-depth immunotoxicological risk evaluation. These studies would not necessarily be performed routinely (i.e., would not be included as data requirements in Subdivision F), but rather would be reserved for pesticides for which the immune system is shown to be a sensitive target of toxicity.