As a corollary, while the exact role of fibrocytes in asthma remains to be fully defined, in a previous study14 circulating fibrocytes are reported to have increased percentage in patients with chronic airway obstruction, while the serum levels of TGF-β1 were significantly higher in a group of ten patients with chronic obstructive asthma than in normal subjects and in asthmatic cases with normal lung function. This evidence concerns the gene TGFB1 and chronic obstructive pulmonary disease.