We also noticed that Mrc1+ KRM had a very unique transcriptional signature including enriched expression of genes such as Trem2, Igf1, and Gas6. This is important as this signature has been ascribed to Trem2+ macrophages in other slowly progressing models of disease including Alzheimer’s disease (46, 47). Here, TREM2 is linked to early-onset autosomal dominant Alzheimer disease.