title: LTR point mutations in the Tax-responsive elements of HTLV-1 isolates from HIV/HTLV-1-coinfected patients.
abstract: BACKGROUND
  In Virology Journal 2011, 8:535, Neto et al. described point mutations into Tax-responsive elements (TRE) of the LTR region of HTLV-1 isolates from asymptomatic carriers from Sao Paulo, Brazil, and hypothesized that the presence of the G232A mutation in the TRE-1 increase viral proliferation and consequently the proviral load (PvL), while the A184G mutation in the TRE-2 do not have such effect.
  
  
  RESULTS
  We performed the real-time PCR assay (pol) and sequenced LTR region of HTLV-1 isolates from 24 HIV/HTLV-1-coinfected patients without HTLV-1-associated diseases from the same geographic area. These sequences were classified as belonging to the transcontinental subgroup A of the Cosmopolitan subtype a. The frequency of G232A mutation (16/24, 66.7%) was high as much as 61.8% reported by Neto's in HTLV-1 asymptomatic carriers with high PvL. High frequency (13/24, 54.2%) of double mutations G232A and A184G was also detected in HIV/HTLV-1-coinfected patients. We did not quantify PvL, but comparative analyses of the cycle threshold (Ct) median values of the group of isolates presenting the mutated-types sequences (Ct 33.5, n = 16) versus the group of isolates with the wild-type sequences (Ct 32, n = 8) showed no statistical difference (p = 0.4220).
  
  
  CONCLUSIONS
  The frequencies of mutated-type sequences in the TRE-1 and TRE-2 motifs were high in HIV/HTLV-1-coinfected patients from Sao Paulo, Brazil. If these LTR point mutations have predictive value for the development of HTLV-1-associated diseases or they correspond to the subtype of virus that circulate in this geographic area has to be determined.
authors.affiliation: Immunology Department, Instituto Adolfo Lutz, Av, Dr, Arnaldo, 355, 11° andar, São Paulo, SP, 01246-902, Brazil.
authors.forename: Mariana Cavalheiro
authors.initials: MC
authors.lastname: Magri
authors.forename: Emanuela Avelar Silva
authors.initials: EA
authors.lastname: Costa
authors.forename: Adele
authors.initials: A
authors.lastname: Caterino-de-Araujo
mesh_terms: D000328:Adult; D001483:Base Sequence; D001938:Brazil; D060085:Coinfection; D005260:Female; D016356:Gene Products, tax / Q000494:pharmacology*; D015658:HIV Infections / Q000821:virology; D015497:HIV-1 / Q000235:genetics* / Q000302:isolation & purification; D015490:HTLV-I Infections / Q000821:virology; D015368:Human T-lymphotropic virus 1 / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D008297:Male; D008875:Middle Aged; D059372:Nucleotide Motifs; D017354:Point Mutation; D020218:Response Elements / Q000235:genetics*; D020079:Terminal Repeat Sequences / Q000235:genetics*
chemical_list: D016356:Gene Products, tax