TREM2 and Alzheimer disease: To assess whether the gene expression signature associated with XO4+ microglia is present in microglia isolated from human brains, we performed a comprehensive integration and analysis of microglia from the publicly available single-nucleus datasets from the brains of AD patients and non-AD individuals (Fig. 5a), comprising single cells from 102 human entorhinal and prefrontal cortex samples from 4 independent datasets51–54 (total 11,931 microglial nuclei, 2988 controls, 1591 mild AD, 5891 AD, 1458 with TREM2 R62H variant, and 3 nuclei of Other Dementia).