Immunogenetics of human T-cell leukemia virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP)

Abstract

Human T-cell leukemia virus type 1 (HTLV-1) is a replication-competent human retrovirus associated with two distinct types of disease: the malignancy known as adult T-cell leukemia (ATL) and a chronic inflammatory central nervous system disease HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), whereas the vast majority of infected individuals remain asymptomatic carriers of the virus in lifetime. It is not yet fully understood why do certain individuals develop ATL or HAM/TSP, and how does HTLV-1 persist in spite of host immune response. This review focuses on the complex virus-host interactions and the cellular immune responses to HTLV-1 infection seen in HAM/TSP patients, which are important factors in determining HTLV-1 proviral load and the risk of developing disease.