Interestingly, soluble TREM2 (the secreted ectodomain of TREM2, sTREM2) has been found in cerebrospinal fluid (CSF) from AD patients, where it exerts a proinflammatory action (Zhong et al., 2017), in a higher level when compared to controls (Shen et al., 2019). The gene discussed is TREM2; the disease is Alzheimer disease.