title: Strong correlation between tax and HBZ mRNA expression in HAM/TSP patients: distinct markers for the neurologic disease.
abstract: BACKGROUND
  HTLV-1 proviral load is a risk marker for HAM/TSP, but it is insufficient to determine the disease outcome. HTLV-1 Tax and HBZ proteins have been implicated in HAM/TSP pathogenesis in inducing cell proliferation and cytotoxic T lymphocytes response.
  
  
  OBJECTIVE
  To quantify the expression of tax and HBZ mRNA in asymptomatic carriers (AC) and HAM patients, and to investigate their association with HAM/TSP.
  
  
  METHODS
  We quantified the expression of HTLV-1 tax and HBZ mRNA in 37 AC and 26 HAM patients classified according to proviral load as low (AC(L) and HAM(L): <1% infected cells) or high (AC(H) and HAM(H): >1%).
  
  
  RESULTS
  The AC(L) subgroup showed the lowest frequency of individuals expressing tax mRNA in comparison with AC(H), HAM(L) and HAM(H), and tax mRNA load normalized by proviral load was significantly lower in the AC(L). In turn, normalized HBZ mRNA expression was similar in all subgroups. Both tax and HBZ mRNA expression were moderately correlated with proviral load in AC (r=0.6, p<0.001) and were weaker in HAM (r=0.4, p<0.05). In contrast, the correlation between tax and HBZ mRNA load was moderate in AC (r=0.5, p=0.001) and was much stronger in HAM (r=0.8, p<0.001). In addition, HBZ mRNA load, but not tax, was significantly associated with motor disability in HAM patients (p=0.036).
  
  
  CONCLUSIONS
  The expression of tax mRNA seems to be best to estimate the risk of HAM/TSP, whereas HBZ mRNA appears to be a surrogate marker to disease progression, indicating that they have important but distinct roles in HAM/TSP pathogenesis.
authors.affiliation: Microbiology Department, Biology Science Institute, Federal University of Minas Gerais, Brazil. rafaela_biolog@yahoo.com.br
authors.forename: Rafaela Gomes
authors.initials: RG
authors.lastname: Andrade
authors.forename: Poliane de Cássia
authors.initials: Pde C
authors.lastname: Gonçalves
authors.forename: Maisa Aparecida
authors.initials: MA
authors.lastname: Ribeiro
authors.forename: Luiz Cláudio Ferreira
authors.initials: LC
authors.lastname: Romanelli
authors.forename: João Gabriel
authors.initials: JG
authors.lastname: Ribas
authors.forename: Elídio Barbosa
authors.initials: EB
authors.lastname: Torres
authors.forename: Anna Bárbara de Freitas
authors.initials: AB
authors.lastname: Carneiro-Proietti
authors.forename: Edel Figueiredo
authors.initials: EF
authors.lastname: Barbosa-Stancioli
authors.forename: Marina Lobato
authors.initials: ML
authors.lastname: Martins
mesh_terms: D050976:Basic-Leucine Zipper Transcription Factors / Q000096:biosynthesis*; D015415:Biomarkers; D002353:Carrier State / Q000821:virology; D015870:Gene Expression; D020869:Gene Expression Profiling; D016356:Gene Products, tax / Q000096:biosynthesis*; D015490:HTLV-I Infections / Q000473:pathology* / Q000821:virology*; D015368:Human T-lymphotropic virus 1 / Q000235:genetics / Q000472:pathogenicity*; D006801:Humans; D011379:Prognosis; D012333:RNA, Messenger / Q000096:biosynthesis*; D012191:Retroviridae Proteins; D014764:Viral Proteins / Q000096:biosynthesis*; D037521:Virulence Factors / Q000096:biosynthesis
chemical_list: D050976:Basic-Leucine Zipper Transcription Factors; D015415:Biomarkers; D016356:Gene Products, tax; C479751:HBZ protein, human T-cell leukemia virus type I; D012333:RNA, Messenger; D012191:Retroviridae Proteins; D014764:Viral Proteins; D037521:Virulence Factors; C514970:tax protein, Human T-lymphotrophic virus 1