We propose that such effects are, at least in part, due to their impact on macrophages and/or DCs, be it upstream, as in the case of bone marrow transplantation, where HD myeloid cells are replaced by wild type cells14, or downstream, where specific macrophage-upregulated cytokines are inhibited, such as peripheral IL6 neutralization and TNFα signalling inhibition15,16. This evidence concerns the gene IL6 and Huntington disease.