Figure 1.

Hierarchical clustering of cytokine-PAMP combinations by subject.

Notes: In the heatmap, each column corresponds to an individual patient. The presence or absence (Y/N) of chronic bronchitis or severe COPD (FEV₁<50%) is indicated at the top for each patient. Each row corresponds to cytokine production in response to a specific PAMP. Several cytokines formed distinct clusters in response to multiple PAMPs (IL-1RA, G-CSF, MCP-1, IL-10, IL-8) and have been highlighted. Note the aggregation of multiple subjects with severe COPD in the “low responder” group.

Abbreviations: PAMP, pathogen-associated molecular pattern; IL, interleukin; G-CSF, granulocyte-colony stimulating factor.