Our data revealed that CSF macrophages in patients with ALS expressed not only classic macrophage markers, such as CSF1R and C1QC, but also BAM markers, such as LYVE1.44 However, they also expressed microglia-specific markers, such as TMEM119 and P2RY12, in non-negligible proportions.44 Taken together, these CSF macrophages might represent a potential population of CSF-floating BAMs or microglia that have migrated from the parenchyma into the CSF. This evidence concerns the gene LYVE1 and amyotrophic lateral sclerosis.