Also, previous reports have shown that downregulation of Bach2 expression in CD4 + T cells leads to dysregulation of cytokine production and cellular immune responses in vivo [14, 17–20], which is a characteristic feature of the inflammatory disease HAM/TSP and is an important finding that contributes to our understanding of the pathogenesis of HAM/TSP. This evidence concerns the gene CD4 and tropical spastic paraparesis.