Document 1064
 DOCN  M9471064
 TI    HTLV-I and -II natural history and disease associations (Meeting
       abstract).
 DT    9409
 AU    Blattner WA; Viral Epidemiology Section, NCI, Bethesda, MD
 SO    International Association for Comparative Research on Leukemia and
       Related Diseases, 16th Symposium. July 11-16, 1993, Montreal, Quebec,
       Canada, A52, 1993.. Unique Identifier : AIDSLINE ICDB/94698650
 AB    In 1980 HTLV-I and in 1982 HTLV-II were isolated. Considerable progress
       has been gained in defining the natural history of HTLV-I, while for
       HTLV-II progress has been slow. Recent studies have helped to clarify
       mechanisms of virus transmission. Breast milk feeding is the major route
       for transmission of HTLV-I in the first year, while for HTLV-II data is
       circumstantial. Prospective studies in Jamaica document a fall in
       maternal antibody titer in the first 6 months of life which coincides
       with subsequent seroconversion. Recently, a lymphadenopathy syndrome has
       been observed in children of HTLV-I positive mothers possibly reflecting
       immune response to initial infection. In the transfusion setting half of
       recipients seroconvert especially when the recipient is on
       immunosuppressant drugs supporting the concept that host immune
       responses contribute to clearing viral infection in some individuals.
       The major source of adult acquired infection results from sexual
       transmission especially in the setting of other sexually acquired
       diseases with male to female rather than female to male transmission
       predominating. Environmental cofactors which may amplify the
       proliferation of lymphocytes and create activation marker targets which
       amplify susceptibility have been suggested. The ATL syndrome appears to
       result from early life exposure perhaps involving immunosuppressive
       mechanisms as suggested by its possible link to Infective Dermatitis and
       markers of immunosuppression (ie, elevated levels of tumor growth
       factor-beta in cases). HAM/TSP and HAAP may involve heightened
       immunologic over response in their pathogenesis, although virologic
       factors are suggested by recent animal models. Several investigators
       have described HAM/TSP-like illnesses in HTLV-II infected persons, and
       large cell granulocytic cell leukemia has been reported as a possible
       HTLV-II associated leukemia. Recent studies of Guaymi Indians in Panama
       document differences in patterns of seroprevalence (equal male to female
       ratio in each age group) and certain clinical syndromes which bear
       investigation as possible HTLV-II associated diseases. Human
       retroviruses are important candidates for diseases of unknown etiology,
       particularly involving lymphoproliferative and immunologic processes.
 DE    Adult  Biological Markers  Breast Feeding  Cell Division  Female  HTLV-I
       Infections/IMMUNOLOGY/*TRANSMISSION  HTLV-II
       Infections/IMMUNOLOGY/*TRANSMISSION  Human  Infant, Newborn  Leukemia,
       T-Cell/ETIOLOGY  Lymphocytes/PATHOLOGY  Male  Maternal-Fetal Exchange
       Milk, Human  Paraparesis, Tropical Spastic/COMPLICATIONS  Sexually
       Transmitted Diseases  MEETING ABSTRACT

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       protected by Copyright Law (Title 17, U.S.Code).