CD4 and tropical spastic paraparesis: This bloodborne pathogen has the potential to induce adult T-cell leukemia (ATL), an extremely aggressive CD4+ T-cell malignancy [1,3], HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), a progressive neurodegenerative disease [4,5], and several other inflammatory diseases (uveitis, keratitis, dermatitis, and conjunctivitis) [6].