Patients must have a diagnosis of HAM/TSP as defined by the WHO criteria, including a positive HTLV-I EIA and confirmatory pattern on Western Blot analysis. Other causes of chronic progressive myelopathy are excluded by tests for serum B12 level, Lyme disease serologies, RPR, anti-nuclear antibody (ANA), extractable nuclear antigen (ENA) screen and magnetic resonance images of brain and spinal cord.