CD8A and tropical spastic paraparesis: Since the frequency of HTLV-1-specific CD8+ T cells was significantly higher in HAM/TSP patients than ACs [82, 83], and these cells have the potential to produce proinflammatory cytokines [84], there is a debate on the role of HTLV-1-specific-CD8+ T cells, that is, whether these cells contribute to the inflammatory and demyelinating processes of HAM/TSP, or whether the dominant effect of such cells in vivo is protective against disease.