Thus, although we established the role of combined βAR and GR activation using higher (non-therapeutic) doses in ozone-induced pulmonary and systemic effects, the purpose of the current study was to examine if ozone-induced lung injury, inflammation, lymphopenia and metabolic alterations were exacerbated in rats receiving more therapeutically relevant dosages of LABA (clenbuterol; CLEN) or the GR agonist, dexamethasone (DEX), as separate treatments. This evidence concerns the gene ADRB2 and lymphopenia.