To determine the presence of Lin− CD123+ (IL-3Rα) population in the PB of HD, cells with a lymphoid morphology and linage negative (Lin−) for T cells (CD3−), B cells (CD19−), monocytes (CD14−), NK cells (CD94−), and dendritic cells (HLA-DR−) were evaluated. The gene discussed is KLRD1; the disease is Huntington disease.