The sputum gene expression network enriched for cytotoxic CD8+ T-cell genes is decreased in type 2 inflammation–low asthma and associated with body mass index (BMI). (A) The cell surface markers of CD8+ T cells, CD3 and CD8, are strongly correlated to eigengene values for the royal blue module. (B) KLRB1 (killer cell lectin-like receptor B1) gene expression is strongly correlated to eigengene values for the royal blue module. (C) Genes for cytotoxic function, PRF1 (perforin 1) and GZMB (granzyme B), are strongly correlated to eigengene values for the royal blue module. (D) CD8+ T-cell transcription factors EOMES (eomesodermin) and TBX21 (T-box 21) are strongly correlated to eigengene values for the royal blue module. (E) Gene set enrichment analysis. The green curve displays the enrichment score for the royal blue network genes as the analysis walks down the ranked distribution of genes ordered by fold change in expression between CD8+ T cells relative to all other immune cell types. Genes are represented by the vertical black bars. (F) Eigengene values of the royal blue module are strongly negatively correlated to BMI and plasma IL-6 concentration. Red dots represent subjects with asthma, and blue dots represent healthy control subjects. KLRK1 = killer cell lectin-like receptor K1.