Abstract
Human T-cell lymphotropic virus Type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a chronic progressive inflammatory neurological disease. It is considered that virus–host immunological interactions are an important cause of this disease. Coexisting high HTLV-I proviral load and HTLV-I-specific T-cells is an important feature of HAM/TSP. The immune response to HTLV-I probably contributes to the inflammatory process of CNS lesions in HAM/TSP patients. Therefore, treatments for HAM/TSP aim to reduce HTLV-I proviral load and normalize the abnormal immune responses to HTLV-I.