Purpose of review: To discuss current understanding of the mechanisms of human T-lymphotropic virus type-1 (HTLV-1) tumorigenesis and current and potential treatment strategies for adult T-cell leukaemia/lymphoma (ATL), an aggressive malignant disease of CD4 cells caused by HTLV-1.
Recent findings: Treatment of the aggressive subtypes of ATL remains inadequate, with little improvement in overall survival in the 30 years since HTLV-1 was discovered. Detailed analysis of the clonal expansion of HTLV-1 has provided new insight into pathogenesis. Most HTLV-1-infected cells, including ATL, express CCR4 which can be targeted. Reports of antitumour effects with allogeneic bone marrow transplantation provide a rationale for novel immunotherapy approaches. Progress has been made in the indolent subtypes of ATL with the use of 'antiviral' therapies.
Summary: ATL has poor prognosis. There is a major, urgent, unmet clinical need to identify HTLV carriers who will develop ATL to develop biomarkers of transforming disease and disease progression and to provide novel treatment approaches within the context of clinical trials. Several strategies now include putative or actual antiviral therapy. Potentially, the risk of ATL would be reduced by eliminating some or all infected clones. HTLV-1 infection, and hence ATL, can be prevented by antenatal HTLV-1 screening.