TREM2 and Alzheimer disease: Performing qPCR on the established the Alzheimer's disease-linked gene trem2 and the inflammatory genes for nlrp3 and il-1β, we confirmed that transcriptional changes were largely confined to the periplaque regions (Fig. 3I) (periplaque main effect: trem2 χ2(1) = 28.40, p < 0.001; il-1β χ2(1) = 32.21, p < 0.001; nlrp3 χ2(1) = 13.93, p < 0.001).