CD4 and tropical spastic paraparesis: Analysis of these T cell subsets based on Foxp3 expression in CD4+CD25+CCR4+ cells demonstrated a significant elevation in the frequency of CD4+CD25+CCR4+Foxp3− T cells in the total PBMCs in HAM/TSP patients (n = 11) as compared to that in HDs (n = 8) (left panel, Figure 3A; p = 0.001).