TREM2 and Alzheimer disease: Patients taking non-steroidal anti-inflammatory drugs (NSAIDs) are significantly less likely to develop AD [8]; several genetic risk factors for AD have been identified which also have roles within the immune system, such as the myeloid cell receptor TREM2 [9], and genome-wide association studies (GWAS) suggest that there is widespread dysfunction of the immune system in AD [10].