TGFB1 and chronic obstructive pulmonary disease: The area of vessels staining for TGF-β1, expressed per μm2/mm of Rbm, was also greater in S-N, S-COPD and ES-COPD [median (range) 379 (0–2132), 324 (0–2882) and 155 (0–4029)] compared to the healthy control group [median (range) 0 (0–545)], (p<0.01 for all comparisons).