Figure 2

<p><i>Panel A</i>: Principal component analysis (PCA) of those genes with the largest variability of expression values across the experimental groups (COPD patients, smokers (S) and non-smokers (NS)) at baseline (T0). Because the sex effect observed, further analysis was stratified by sex (right and left columns.<i>) Panels B1 (females) and B2 (males)</i> present the number of differentially expressed (DE) genes from T0 to T180 in the three groups of participants studied. Red and green figures indicate up and down-regulation, respectively. <i>Panels C1 (females) and C2 (males)</i> show a BioVenn diagram (<a href="http://www.cmbi.ru.nl/cdd/biovenn" target="_blank">www.cmbi.ru.nl/cdd/biovenn</a>) with the number of DE genes shared between COPD, S and NS controls. For further explanations, see text.