UC San Diego

Numerous military personnel from Iraq and Afghanistan have reported health concerns and chronic clinical respiratory problems after returning home from overseas, and they attribute these to significant exposure to the burning of waste in open-air, “burn pits.” Those chronic respiratory problems suggest that burn pits may associate with histopathologic evidence of lung damage and asthma. In addition, burn pits are one of the allergens that cause unknown signaling pathways in asthma, and we only found limited research on the burn pits' effect on asthma and the effects of burn pits components. We first tested 2,3,7,8-tetrachlorodibenzodioxin (TCDD), one of the individual components of burn pits. However, after wild-type mice were given TCDD intranasally, this agent reduced the number and percentage of eosinophils in an Alternaria-induced (Alt) asthma model. Interestingly, when wild-type mice were intranasally given Burn Pit Constituents (BPC), including TCDD, particulate matter 4.0 (PM4.0), and benzo[a]pyrene (BaP), BPC increased the neutrophil population and shifted the Group 2 Innate Lymphoid Cell to Group 1 Innate Lymphoid Cell (ILC). In conclusion, TCDD alone may not be enough to promote burn pit airway disease responses, but BPC may be more relevant to the patterns found in deployed troops. To better understand mechanisms, we will plan to test the effects of other burn pits constituents in combination or separately by using the same models as TCDD or BPC, as well as the roles of Aryl Hydrocarbon Receptor (AhR) and stimulator of interferon genes (STING) knockout mice and AhR through the use of knockout mice.