Novel insights into human T‐lymphotropic virus type‐1 (HTLV‐1) pathogenesis‐host interactions in the manifestation of HTLV‐1‐associated myelopathy/tropical spastic paraparesis.

Human T‐lymphotropic virus type‐1 (HTLV‐1) was the first discovered human oncogenic retrovirus, the etiological agent of two serious diseases have been identified as adult T‐cell leukaemia/lymphoma malignancy and HTLV‐1‐associated myelopathy/tropical spastic paraparesis (HAM/TSP), a debilitating chronic neuro‐myelopathy. Despite more than 40 years of molecular, histopathological and immunological studies on HTLV‐1‐associated diseases, the virulence and pathogenicity of this virus are yet to be clarified. The reason why the majority of HTLV‐1‐infected individuals (∼95%) remain asymptomatic carriers is still unclear. The deterioration of the immune system towards oncogenicity and autoimmunity makes HTLV‐1 a natural probe for the study of malignancy and neuro‐inflammatory diseases. Additionally, its slow worldwide spreading has prompted public health authorities and researchers, as urged by the WHO, to focus on eradicating HTLV‐1. In contrast, neither an effective therapy nor a protective vaccine has been introduced. This comprehensive review focused on the most relevant studies of the neuro‐inflammatory propensity of HTLV‐1‐induced HAM/TSP. Such an emphasis on the virus‐host interactions in the HAM/TSP pathogenesis will be critically discussed epigenetically. The findings may shed light on future research venues in designing and developing proper HTLV‐1 therapeutics. [ABSTRACT FROM AUTHOR]