Spastic paraparesis and HTLV-I infection in Peru.

Three of 6 patients with spastic paraparesis in Lima, Peru, were found to have antibodies to human T-lymphotropic virus type I (HTLV-I). Blood and cerebrospinal fluid antibodies were confirmed by Western blot analysis. Multilobulated lymphocytes in blood and cerebrospinal fluid of the index case stained with monoclonal antibodies for T-helper cells and for T10, an activation marker. Blood mononuclear cells from patients with HTLV-I-associated myelopathy showed spontaneous proliferation in culture, evidence of interleukin-2 receptors, and decreased natural killer cell activity.