Human T-lymphotropic virus type 1 (HTLV-1) (HTLV-1)

Human T-lymphotropic virus type 1 (HTLV-1) is a complex deltaretrovirus that primarily infects CD4+ T-lymphocytes and is estimated to infect 5 to 10 million people worldwide (Gessain & Cassar, 2012). It is the etiological agent of Adult T-cell leukemia/lymphoma (ATL), an aggressive CD4+ T-cell malignancy, and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), a chronic progressive neurological disease (Bangham et al., 2015). Unlike other retroviruses, HTLV-1 induces the clonal expansion of infected cells through the actions of its regulatory proteins, Tax and HTLV-1 basic leucine zipper factor (HBZ), which dysregulate cell cycle control and apoptosis (Tagaya & Gallo, 2017). Therapeutic interventions include the use of zidovudine and interferon-alpha for ATL, and the anti-CCR4 monoclonal antibody mogamulizumab, which targets the high expression of CCR4 on the surface of infected cells (Martin et al., 2018). Management of HTLV-1-associated diseases remains challenging due to the high proviral load and the persistence of the virus in the host genome (WHO, 2021).

Other names

Human T-cell leukemia virus type 1Human T-cell lymphotropic virus type 1HTLV-I

Reverse transcriptase inhibition, inhibition of viral replication, depletion of CCR4-positive T-cells via antibody-dependent cellular cytotoxicity, and modulation of host immune response.