TGFB1 and chronic obstructive pulmonary disease: TGF-β1 stained vessels in the Rbm were increased in smokers with normal lung function, current smoking COPD and ex-smokers with COPD compared to controls [median (range) for number of vessels/mm Rbm 2.5 (0.0–12.7), 3.4 (0.0–8.1) and 1.0 (0.0–6.3) vs. 0.0 (0.0–7.0), p<0.05].