IL17A and Cognitive impairment: Zhang et al. (2021) found that gingival injection of Pg-LPS triggers Th17/Treg imbalance by activating the STAT3 signaling pathway, leading to cognitive impairment in mice. Among the observed changes, there was an upregulation in the expression of Th17-associated cytokines (IL-1β, IL-17A, IL-21, and IL-22). At the same time, a downregulation was noted in Treg-related cytokines (IL-2 and IL-10) both in peripheral blood and brain tissues. This shift resembles the immune imbalance observed in brain tissue of AD patients (Oberstein et al., 2018).