An HTLV-I Vaccine: Why, How, for Whom?

Abstract

Endemic infection with the human T cell leukemia/lymphoma viruses I and II (HTLV-I/II) is now recognized to be worldwide, and is becoming epidemic among intravenous drug abusers (IVDAs) in the United States and Europe. The number of people around the world infected with HTLV-I can be estimated as between 10 and 20 million (Table 1). HTLV-I causes a rapidly progressing adult T cell leukemia/lymphoma (ATLL), and an incurable progressive neuromyelopathy named tropical spastic paraparesis/HTLV-I-associated myelopathy (TSP/HAM), as well as a number of less well-studied syndromes. There is evidence that coinfection with HTLV-I or -II accelerates progression to AIDS. The cumulative lifetime risk of developing ATLL or TSP/HAM is around 5%, which, in terms of the induction of serious diseases, places HTLV-I in the same category of viruses for which efficient vaccines are made and used. Furthermore, there are factors favoring the feasibility of a vaccine against HTLV-I, in that the virus displays relatively low antigenic variability, natural immunity occurs in humans, and experimental vaccination with the envelope (Env) antigen is successful in animal models. A vaccine against HTLV-I would be of significant public health value in the fields of oncology, neurology, and AIDS, and it would serve as a pathfinder for a vaccine against HIV.

Seroprevalencia del virus linfotrópico humano de tipos I y II en donantes del Banco de Sangre de la Fundación Valle del Lili, Cali, Colombia, 2008-2014

“…La infección por HTLV en individuos asintomáticos no tiene ningún tratamiento establecido y solo algunas de las enfermedades relacionadas con el virus lo tienen (24). El hecho de ser el causante de enfermedades graves, como la leucemia o el linfoma de células T y la paraparesia espástica tropical, ubica al HTLV en la categoría de los virus contra los cuales se trata de elaborar vacunas eficaces (25). Aunque algunos grupos de investigadores han trabajado arduamente en la elaboración de una vacuna, su labor ha sido infructuosa hasta el momento.…”

Human T-cell Lymphotropic Virus types I and II (HTLV-I/II) in French Guiana: clinical and molecular epidemiology

“…High HTLV-I seroprevalence rates (> 2% in the adult population) have been described in Southern Japan, sub-Saharan Africa, the Caribbean Basin, parts of South America, and some areas of Melanesia and the Middle East (Gessain, 1996) where 15-20 million people are infected with this virus. An HTLV-I-associated disease will develop in 3-8% of these infected individuals once in their lifetime (de The & Bomford, 1993;Gessain, 1996). HTLV-II has been shown to be endemic among various American Indian populations, including Navajos and Pueblos (New Mexico) (Hjelle et al, 1993) and Seminoles (Florida) (Biggar et al, 1996;Levine et al, 1993) in North America and the Guaymi in Panama (Lairmore et al, 1990;Pardi et al, 1993).…”

Discrete serum protein signatures discriminate between human retrovirus-associated hematologic and neurologic disease

“…Globally, the estimated numbers of people infected with HTLV-1 approaches 20 million. 2,3 In endemic areas including southern Japan, the Caribbean basin and parts of western Africa and South America, where infection rates range from 2 to 30%, these diseases are the major causes of mortality and morbidity. 4 For example, ATL is the most common form of non-Hodgkin's lymphoma in Southwestern Japan and HAM/TSP is the most common form of neurodegenerative disorder in central Brazil.…”