Figure 1. Differential expression of iron-related genes in human monocyte subsets.

Monocyte subset-specific differences in expression of iron metabolism–related genes were analyzed in 3 whole-genome microarray studies using ANOVA, as described in Methods, Supplemental Figure 1A, and Supplemental Table 1 (GSE25913: n = 4, GSE66936: n = 4, and E-MEXP-2544: n = 3 healthy monocyte donors). Genes proving significant in at least 2 studies were further investigated. (A) Relationship among monocyte populations in terms of iron-related gene expression was visualized with principal coordinate analysis. Expression values for the entire iron-related gene set in each study were transformed to Z-scores and used to calculate Pearson’s distance between human monocyte samples in a 2-dimensional space. Each point represents 1 sample. Red: classical monocytes; gray: intermediate monocytes; blue: nonclassical monocytes. (B) Venn diagram showing significantly regulated iron-related genes.