Table 3– Significant results (p<0.05) from linear regression analysis of pulmonary function tests and computed tomography-scan data with changes in mRNA in response to stimuli

Gene	Stimulus	Outcome	r²	p-value
*MMP9*	TNF-α	FEV₁ % pred	0.3150	0.0005
*CTSL*	LPS	Semiquantitative score for emphysema	0.0653	0.0162
*TIMP1*	LPS	FEV₁/FVC %	0.1445	0.0219
*TIMP3*	LPS	Semiquantitative score for emphysema	0.0582	0.0407

MMP: metalloproteinase; CTSL: cathepsin L; TIMP: tissue inhibitor of metalloproteinase; TNF-α: tumour necrosis factor-α; LPS: lipopolysaccharide; FEV₁: forced expiratory volume in 1 s; % pred: % predicted; FVC: forced vital capacity. The mRNA was obtained after 24 h of culture with the various stimuli, and the change of mRNA from cells cultured with no stimuli was analysed. Coefficients of determination (r²) and p-values were calculated from regression analysis of each clinical outcome including age, sex, race, pack-years and mRNA expression as covariates. r² values are for the whole model, p-values are for the mRNA expression level. FEV₁ % pred and FEV₁/FVC % were measured post-bronchodilator. An ordinal logistic regression was performed for the semiquantitative emphysema scores. The p-value threshold to correct for multiple corrections is 0.05/(9 (number of single nucleotide polymorphisms)×3 (number of conditions)×4.45 (number of phenotypes))=0.00042. Complete results are shown in online supplementary table S8.