Genes separating chronic inflammatory diseases from controls. (a) Venn diagram shows all of those genes that show significant differences between each disease group and control samples. Each set contains genes that separate control samples only from the particular disease or diseases. Underlined genes were down-regulated compared to healthy controls. (b) Gene interaction analysis in GeneSpring GX in Direct Interactions mode highlights 28 genes that have direct interactions with each other while 25 genes have no direct interactions. Genes with the highest number of interactions are shown in extended size. Cyclooxygenase 2 enzyme is located in the middle of this pathway network. The genes that showed significant differences between one of the diseased groups and healthy controls have color codes in which blue represents RA, green represents IBD and red codes for psoriasis-related genes.