We identified GM-CSF as one such factor that is upregulated in the blood of RA patients and found that subcutaneous injection of GM-CSF for 20 days increased microglial activation, reduced amyloid pathology by more than 50%, and completely reversed the cognitive impairment of transgenic AD mice (Boyd et al., 2010), which has been replicated by other groups (Castellano et al., 2017; Kiyota et al., 2018). Here, CSF2 is linked to Alzheimer disease.