Chronic progressive myelopathy associated with elevated antibodies to human T‐lymphotropic virus type I and adult T‐cell leukemialike cells

Abstract Six adult patients had a chronic progressive myelopathy that possessed the following features: (1) high antibody titers to human T‐lymphotropic virus type I (HTLV‐I) in serum and cerebrospinal fluid (CSF); (2) predominantly upper motor neuron disorder, symmetrical, with mild sensory and bladder disturbances; and (3) presence of adult T‐cell leukemia–like cells in both peripheral blood and CSF. We refer to this entity as HTLV‐I–associated myelopathy (HAM). Electrophoretic studies of immunoglobulin G in CSF using Western blot analysis characteristically demonstrated p24 and p32 bands. Rates of intra‐blood–brain barrier synthesis were determined and found increased in the patients with HAM. Corticosteroid treatment produced clinical improvement in all of 4 patients. A retrospective survey of CSF samples was carried out in 287 patients with neurological disorders, and 6 additional patients with HAM were identified.