High Circulating Frequencies of Tumor Necrosis Factor Alpha- and Interleukin-2-Secreting Human T-Lymphotropic Virus Type 1 (HTLV-1)-Specific CD4⁺T Cells in Patients with HTLV-1-Associated Neurological Disease

Significantly higher frequencies of tumor necrosis factor alpha- and interleukin-2-secreting human T-lymphotropic virus type 1 (HTLV-1)-specific CD4(+) T cells were present in the peripheral blood mononuclear cells of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) patients than in those of asymptomatic carriers with similar provirus loads. The data suggest that HTLV-1-specific CD4(+) T cells play a role in the pathogenesis of HAM/TSP.