The first description of the human T-lymphotropic virus type 1 (HTLV-1) was made in 1980, followed closely by the discovery of HTLV-2, in 1982. Since then, the main characteristics of these viruses, commonly referred to as HTLV-1/2, have been thoroughly studied. Central and South America and the Caribbean are areas of high prevalence of HTLV-1 and HTVL-2 and have clusters of infected people. Th...

Human T-cell leukemia virus type 1 (HTLV-1) was the first human retrovirus discovered. Studies on HTLV-1 have been instrumental for our understanding of the molecular pathology of virus-induced cancers. HTLV-1 is the etiological agent of an adult T-cell leukemia (ATL) and can lead to a variety of neurological pathologies, including HTLV-1-associated-myelopathy/tropical spastic paraparesis (HAM/...

Adult T-cell leukemia (ATL), a disorder associated with high mortality rates, arises from human T-lymphotropic virus type I (HTLV-I)-infected CD4+ T cells. We designed a retroviral vector-based gene therapy approach to ATL. The long terminal repeat (LTR) of HTLV-I is transactivated by the viral tax protein. We constructed a hybrid gene consisting of herpes simplex virus thymidine kinase (HSV TK...

Human T-cell leukemia virus type 1 (HTLV-1) is the etiologic agent of adult T-cell leukemia (ATL), an aggressive and fatal leukemia of T cells. Interferon regulatory factor (IRF)-5 plays a critical role in the induction of interferon genes in viral infected cells. We examined the specific mechanisms underlying the expression and regulation of IRF-5 in HTLV-1-infected T cells. IRF-5 was constitu...

Adult T-cell leukemia (ATL), a CD4+-T-cell malignancy caused by human T-cell leukemia virus type 1 (HTLV-1), is difficult to cure, and novel treatments are urgently needed. Apo2 ligand (Apo2L; also tumor necrosis factor-related apoptosis-inducing ligand [TRAIL]) has been implicated in antitumor therapy. We found that HTLV-1-infected T-cell lines and primary ATL cells were more resistant to Apo2...

PURPOSE In a recent study to purify adult T-cell leukemia-lymphoma (ATL) cells from acute-type patients by flow cytometry, three subpopulations were observed in a CD3 versus CD7 plot (H: CD3(high)CD7(high); D: CD3(dim)CD7(dim); L: CD3(dim)CD7(low)). The majority of leukemia cells were enriched in the L subpopulation and the same clone was included in the D and L subpopulations, suggesting clona...

We report the clinical, hematologic, and immunologic features of 18 preleukemic adult T cell leukemia (pre-ATL) cases with abnormal T lymphocytosis induced by human adult T cell leukemia-lymphoma virus (HTLV/ATLV). The patients were from the Nagasaki district, which is one of the most endemic areas of ATL in Japan. Pre-ATL is a subclinical T cell abnormality differing from ATL. It is characteri...

Human T cell lymphotrophic Virus 1 (HTLV-1) is endemic in the Caribbean, parts of South America, West Africa, Asia and Oceania but rare in North America. After a prolonged latency, HTLV-1 is associated with development of acute T cell leukemia/lymphoma (ATL) in 2–5% of infected individuals and HTLV-1-associated myelopathy (HAM) in a smaller percentage. Screening tests do not distinguish between...

Detection methods for the human T-cell leukemia virus type-I (HTLV-I) for blood screening and diagnosis generally rely on antibody tests that use the structural proteins of HTLV-I as antigen. We have found an unusual pattern of antibody reactivity among people who are at high risk of HTLV infection due to being a family member of an adult T-cell leukemia (ATL) patient: a specific antibody react...

HTLV-1 (human T-cell leukaemia virus type 1) is the causative agent for ATL (adult T-cell leukaemia). HTLV-1 Tax can activate the PI3K (phosphoinositide 3-kinase)/Akt signalling pathway, which is responsible for survival of HTLV-1-infected T-cells. HIFs (hypoxia-inducible factors) are transcriptional regulators that play a central role in the response to hypoxia. Overexpression of HIF-1alpha in...