Ligand–receptor interaction analysis revealed strong interactions between macrophages (CCL3 and CCL4) and CD8 GZMKhi TEMs (CCR4 and CCR5) within the CSF, indicating proinflammatory crosstalk between macrophages and cytotoxic T cells that may contribute to the initiation of inflammation in the CNS of patients with ALS (Fig. 4G). This evidence concerns the gene CCR4 and amyotrophic lateral sclerosis.