Human T-lymphotropic virus type 1 infection.
Human T-cell lymphotropic virus type-1 (HTLV-1) is aetiologically associated with adult T-cell leukaemia/lymphoma (ATL). HTLV-1 infection can also lead to various non-malignant diseases, for example, HTLV-1 associated myelopathy/tropical spastic paraparesis and HTLV-1 uveitis. HTLV-1 is endemic in southern Japan and the Caribbean. HTLV-1 infection is mainly transmitted by either breast-feeding, sexual intercourse or blood transfusions. Primary prevention of HTLV-1 in endemic areas by screening of blood and by refraining from breast-feeding have been successful. The incidence of ATL is rather low among HTLV-1 carriers (<5%). The precise mechanism of development of ATL remains unknown. It is a multiple-step process which does not require viral expression in the later stages of leukaemogenesis. Many samples have mutations of the tumour suppressor genes, p53 and/or p16(INK4A). Four subtypes of ATL have been identified, each having distinctive clinical features. Monoclonal integration of HTLV-1 proviral DNA into tumour cells is found in each of the subtypes. At present, no effective therapy for ATL exists.
Tsukasaki
K
K
Department of Medicine, UCLA School of Medicine, CA, USA.
Koeffler
P
P
Tomonaga
M
M
D001773:Blood Cells / Q000473:pathology / Q000821:virology; D018450:Disease Progression; D015490:HTLV-I Infections; D006801:Humans; D015459:Leukemia-Lymphoma, Adult T-Cell / Q000145:classification / Q000175:diagnosis / Q000473:pathology