title: Quantification of the virus-host interaction in human T lymphotropic virus I infection.
abstract: BACKGROUND
  HTLV-I causes the disabling inflammatory disease HAM/TSP: there is no vaccine, no satisfactory treatment and no means of assessing the risk of disease or prognosis in infected people. Like many immunopathological diseases with a viral etiology the outcome of infection is thought to depend on the virus-host immunology interaction. However the dynamic virus-host interaction is complex and current models of HAM/TSP pathogenesis are conflicting. The CD8+ cell response is thought to be a determinant of both HTLV-I proviral load and disease status but its effects can obscure other factors.
  
  
  RESULTS
  We show here that in the absence of CD8+ cells, CD4+ lymphocytes from HAM/TSP patients expressed HTLV-I protein significantly more readily than lymphocytes from asymptomatic carriers of similar proviral load (P = 0.017). A high rate of viral protein expression was significantly associated with a large increase in the prevalence of HAM/TSP (P = 0.031, 89% of cases correctly classified). Additionally, a high rate of Tax expression and a low CD8+ cell efficiency were independently significantly associated with a high proviral load (P = 0.005, P = 0.003 respectively).
  
  
  CONCLUSIONS
  These results disentangle the complex relationship between immune surveillance, proviral load, inflammatory disease and viral protein expression and indicate that increased protein expression may play an important role in HAM/TSP pathogenesis. This has important implications for therapy since it suggests that interventions should aim to reduce Tax expression rather than proviral load per se.
authors.affiliation: Department of Immunology, Imperial College, London W2 1PG, UK. b.asquith@imperial.ac.uk
authors.forename: Becca
authors.initials: B
authors.lastname: Asquith
authors.forename: Angelina J
authors.initials: AJ
authors.lastname: Mosley
authors.forename: Adrian
authors.initials: A
authors.lastname: Heaps
authors.forename: Yuetsu
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Graham P
authors.initials: GP
authors.lastname: Taylor
authors.forename: Angela R
authors.initials: AR
authors.lastname: McLean
authors.forename: Charles R M
authors.initials: CR
authors.lastname: Bangham
mesh_terms: D000328:Adult; D000368:Aged; D018791:CD4 Lymphocyte Count; D002353:Carrier State / Q000821:virology; D016356:Gene Products, tax / Q000032:analysis* / Q000235:genetics; D015490:HTLV-I Infections / Q000276:immunology / Q000821:virology*; D006801:Humans; D008875:Middle Aged; D011533:Proviruses / Q000302:isolation & purification; D012333:RNA, Messenger / Q000032:analysis; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D019562:Viral Load
chemical_list: D016356:Gene Products, tax; D012333:RNA, Messenger