Figure 5 shows the most appropriate significant models at the 5% level for each cytokine. Although the regressions were significant, the amount of variation explained was low because age was the only explanatory variable considered. There were significantly different responses with age within the disease/infection groups for all cytokines. Separate lines with significantly different gradients were necessary for IDO, IL-10, and IFN-γ, in contrast to FOXP3, where the separate lines had the same gradient. The gene discussed is IDO1; the disease is infection.