CD4 and Huntington disease: According to the nodal state of BCP, we found an increase in CD4+ T cells and a decrease in CD8+ T cells in PLN compared with HD patients (Fig. 3K), an increase in Tregs in negative lymph node (NLN) patients but a more marked increase in PLN patients (Fig. 3L), and a decrease in the ratio of CD8+ T cells to Tregs in NLN and PLN patients (Supplementary Figure 2D).