TREM2 and Alzheimer disease: The role of the immune system in AD pathogenicity has been previously shown22, 25 and previous pathway analysis of the AD GWAS we assessed here showed enrichment in immune‐related pathways.24 Findings are strongest for the innate immune response, for instance association with the TREM2 gene, which in brain cells are primarily expressed on microglia.45, 46 Our findings further support the role of immune variation in AD susceptibility.