FOXP3 and tropical spastic paraparesis: In addition to investigating the association between HBZ and SS by using ISH, we also examined HBZ-induced Foxp3 expression due to the limited expression of HBZ in the salivary gland MNCs and duct epithelium of HAM-SS patients [81]; we observed that the expression of Foxp3 was infrequent in anti-HTLV-1 antibody-negative SS LSGs, as reported [84].