A previous study found that High mobility group protein B1 (HMGB1) A box inhibited the activation of microglia-mediated by HMGB1, inhibited the infiltration of Th17 cells, and decreased the proportion of Th17 in CD4+ T cells, indicating that HMGB1 A box may play a different role in protecting neurons in PD via influencing the activation of microglia cells, the infiltration of Th17 cells, and the differentiation of T cells to Th17 [136]. This evidence concerns the gene CD4 and Parkinson disease.