To determine whether gene expression levels of these two genes not previously described in association with COPD – RIN3 and TGFB2 – were different in lung tissue samples from COPD cases versus controls, we performed real-time quantitative reverse transcription PCR in 18 control samples and 15 COPD samples – 8 with moderate (FEV1 < 80% predicted), and 7 with severe (FEV1 < 50% predicted) disease) – from the NHLBI Lung Tissue Research Consortium. RIN3 expression was significantly lower in COPD cases versus controls (P = 0•003, Figure S3). Differences in TGFB2 expression were not significant when comparing all cases versus controls (P = 0•5), but were significant when the cases were limited to those with severe disease (P = 0•002, Figure S4).
