Effects of airway exposure to di-(2-ethylhexyl) phthalate on allergic rhinitis

Recent epidemiological studies have suggested a positive link between atopy morbidity and exposure to phthalate esters, which are environmental chemicals mainly involved in house dust. Nevertheless, experimental studies applying several allergic in vivo models (in addition to epidemiological studies) are needed to prove the precise correlation between phthalates and facilitation of the allergic response/pathophysiology. Among the phthalate esters, di-(2-ethylhexyl) phthalate (DEHP) has been widely used in flexible polyvinyl chloride products, including vinyl flooring and wall covering, and has been widely suggested to have immunomodulating potential. In the present study, we examined the effects of airway exposure to DEHP on allergen (ovalbumin: OVA)-induced rhinitis in mice. The repeated administration of OVA via an intranasal route induced nasal inflammation characterized by the infiltration of granulocytes (neutrophils and eosinophils) into the nasal cavity. In this experimental setting, DEHP did not exaggerate OVA-related inflammatory pathology. However, local (nasal) IL-13 levels were significantly higher in mice treated with allergen plus DEHP than with allergen alone. Taken together, phthalate esters including DEHP have the potential to exacerbate the allergic milieu in the nasal system, as well as dermal and respiratory systems.