Modulation of type I allergy by environmental anthropogenic factors and the endocannabinoid system.

Several exogenous and endogenous factors might influence allergic diseases. Environmental airborne pollution such as diesel exhaust particles (DEP) have been described as potent adjuvant during allergic inflammation. Here, it was demonstrated that highly polluted DEP interfere with dendritic cell maturation and even their function to suppress B cell isotype switching to IgE in vitro, thus suggesting a role in Th2 immune deviation. Further, the role of the endocannabinoid system (ECS) in allergic airway inflammation was investigated in a mouse model. The impairment of the ECS was studied using cannabinoid receptor double-knockout mice and the activation by treatment with the ligand Δ9-Tetrahydrocannabinol. As the impairment led to an exacerbation and the activation to an improvement of the allergen-induced airway inflammation, these data sugget a potential protective role of the activated ECS in type I hypersensitivity