TREM2 and arthritic joint disease: Our results show that prior to amyloid plaque deposition in the spinal cord at 12 months of age15, and after the induction of arthritis, microglia express markers, such as CD68, TREM2, CD11c, MerTK, MHCII, and downregulate P2Y12, all of which are upregulated in response to rising levels of amyloid-β and amyloid plaques25,44.