Furthermore, administration of the anticholinergic drug tiotropium bromide and the long-acting β2 agonist olodaterol to PBMCs from COPD patients has been shown to elevate the proportion of Foxp3+ Treg cells and reduce the proportion of T cells that express both acetylcholine IL-17A and acetylcholine RORγt in PBMCs. This evidence concerns the gene IL17A and chronic obstructive pulmonary disease.