IL-6 plays an important role in host defense mechanisms and can act as both a pro-inflammatory cytokine by stimulating the production of IL-4 and IL-5—predominant Th2 cytokines in acute AD—and as an anti-inflammatory cytokine by inhibiting IL-1 and TNF and activating IL-10 and IL1Rα. The gene discussed is IL4; the disease is Alzheimer disease.