The US Air Force uses approximately 2.5 billion gallons of jet propellant-8 fuel per year. As a result, a considerable number of military personnel are exposed to JP-8 fuel during refueling and servicing of aircrafts, and maintenance of fuel storage tanks. Those exposed have increased incidence of headaches, blocked nasal passages, ear infections, skin irritation, or fatigue. In rodent studies, we have previously reported that 7-day dermal or oral exposure to JP-8 suppresses humoral immunity and decreases thymus weight and cellularity. Additionally, other published studies have demonstrated that a single, dermal exposure to JP-8 modulated serum cytokine levels in mice, thereby accounting for a possible mechanism of immunosuppression. To determine if alterations in serum cytokines occurred after 7 days of exposure to JP-8, the following study was performed. B6C3F1 female mice aged 7-10 weeks of age were exposed to JP-8 dermally (50 uL applied to the clipped dorsal thorax of mice with an average weight of 20 g) or orally (2000 mg/kg/day) for a duration of 7 days. Serum was collected 24 hours after the last exposure to JP-8. Using ELISA and Cytometric Bead Array methods, it was determined that levels of IL-2, IL-4, IL-5, IL-6, IL-10, and TNF-alpha were not significantly altered after exposure to JP-8 via the oral or dermal route. It was also learned that, when used as a negative control in the dermal study, acetone as compared to olive oil induced a suppressive effect on IL-4 and IL-6 serum cytokine levels. Consequently, interpretation of immunological dermal studies utilizing acetone should be made with caution. Overall, these findings indicate that serum cytokine levels were not elevated after a 7-day exposure to JP-8, regardless of the route of administration. These observations indicate that serum cytokine levels are not sustained above normal levels following repeat exposure to JP-8.
The Toxicologist. Society of Toxicology 42nd Annual Meeting and ToxExpo, Cutting-Edge Science, Networking, New Perspectives, March 9-13, 2003, Salt Lake City, Utah