IL6 and Alzheimer disease: Furthermore, when monocytes were stimulated with Pg extracts, pro-inflammatory cytokines such as IL-1β, IL-6 and TNFα showed an increased production in the SMC group but a significant decrease in AD group, whereas in MCI group there is no change in IL-1β and TNFα levels except for IL-6 which showed significant reduction (Fig 2 f through h).