CXCL2 and amyotrophic lateral sclerosis: Some of the most important pro-inflammatory mediators secreted by monocytes are chemokines C-X-C Motif Chemokine Ligand 1 (CXCL1) and C-X-C Motif Chemokine Ligand 2 (CXCL2), as well as FosB Proto-Oncogene, AP-1 Transcription Factor Subunit, Interleukin (IL)-1β, and Il-8, which unequivocally indicates that monocytes tend to polarize towards a pro-inflammatory phenotype in ALS (Du et al., 2020).