Gene expression signature of regional emphysema severity. (a) Supervised heatmap of genes whose expression is associated with Lm (FDR <0.10). Samples are organized from low to high Lm. Each row corresponds to a gene and each column corresponds to a sample. Green represents lower relative expression and red represents higher relative expression. (b,c) Expression of CD79A (b) and ACVRL1 (c) are plotted against the natural log of Lm with the color of each point indicating the subject from which the sample was derived.