CCR4 and tropical spastic paraparesis: Therefore, we investigated the intracellular proinflammatory cytokine expression in the CD4+CD25+CCR4+ T cells in 8 HDs, 11 HAM/TSP patients, and 5 ATL patients after phorbol 12-myristate 13-acetate (PMA) and ionomycin stimulation and compared the expression levels with those of Foxp3 (Figure 4A, B).