IL22 and Alzheimer disease: In line with this, Zhou et al. [18], in a large cross-sectional study that encompassed patients with AD (n = 5246) and healthy controls (n = 571), showed an age-specific decrease in IL-22 expression levels only in patients with AD, but not in the control group, whereas an increase in IFN-γ with age in both groups and positive correlation between IFN-γ and age was found.