RESUMEN
The objective of this study is to describe the chronic pain characteristics in individuals infected with human T cell lymphotropic virus type 1 (HTLV-1) per subgroup (asymptomatic, oligosymptomatic, and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP)) compared with controls with chronic pain without HTLV-1. This is a cross-sectional study investigating associations between pain profile, psychopathological symptoms, and quality of life. Individuals infected with HTLV-1 refer high-intensity pain compared with controls, with more severe characteristics being present in oligosymptomatic and HAM/TSP individuals. Oligosymptomatic individuals have a tendency of diffuse and frequent pain, mainly in the head/neck region and more depressive symptoms, resembling nociplastic pain. Neuropathic pain was localized in the lower limbs in all infected groups, worse in HAM/TSP individuals, and associated with a worse perception of quality of life. Pain was associated to higher levels of TNF-alpha and interferon-gamma. HTLV-1 pain is generally more severe when compared with other chronic pain syndromes, being present mainly in the lower limbs. Certain characteristics are typical, depending on the affected group. Oligosymptomatic and HAM/TSP individuals present more diffuse pain, with higher intensity and greater impact in quality of life. Increased levels of inflammatory cytokines are associated with HTLV-1-related pain.