CD4 and tropical spastic paraparesis: Furthermore, FoxP3+CD4+ T cells in HAM/TSP patient contain an increased FoxP3+ non-Treg population (Figure 5F), which would contribute to the inflammatory phenotype of HAM/TSP via generation of pro-inflammatory cytokine-producing CD4+ T cells such as THAM cells [46] or exFoxp3 cells [47].