Figure 7.

Cytokine principal component plots showing clusters at baseline (in nonsmokers) in NELF samples from the primary cohort (left) and separate validation cohort (right). Cytokine concentration distributions were transformed using data reduction approaches (i.e., PCA) to illustrate the overall trends in cytokine groupings in 2-D. The illustrated principal components show the resulting reduced values, which captured the majority of variance in data across NELF samples. Cytokine clusters are shown as shaded shapes within these PCA plots. NELF, nasal epithelial lining fluid; PCA, principal component analysis; 2-D, two dimensional.