CCL2 and Huntington disease: Maintenance HD patients have a higher proportion of inflammation-related monocytes with a pre-activation phenotype [17] which, together with neutrophils, overproduce pro-inflammatory cytokines like interleukin (IL)-1β, IL-6, IL-8, tumour necrosis factor-alpha (TNF-α), monocyte chelator protein-1 (MCP-1), and interferon gamma (IFN-γ) [18,19,20].