title: Evolution of HTLV-1 proviral load in patients from Salvador, Brazil.
abstract: BACKGROUND
  Variations in human T cell lymphotropic virus type 1 (HTLV-1) proviral load (PVL) in infected individuals over time are not well understood.
  
  
  OBJECTIVE
  To evaluate the evolution of proviral load in asymptomatic individuals and HAM/TSP patients in order to help determine periodicity for measuring proviral load.
  
  
  METHODS
  A group of 104 HTLV-1 infected patients, followed at the HTLV reference center in Salvador, Brazil, were included in the study (70 asymptomatic and 34 HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) patients). HTLV-1 PVL was measured using real-time polymerase chain reaction (PCR) at baseline and again at another point, either ≤ 12 months, between 12-24 months, or ≥ 24 months.
  
  
  RESULTS
  HAM/TSP patients had higher PVL (ranging from 11,041 to 317,009 copies/10(6) PBMC) when compared to asymptomatic individuals (ranging from 0 to 68,228 copies/10(6) PBMC). No statistically significant differences were observed in the medians of PVL in HAM/TSP patients or asymptomatic individuals over time. However, in asymptomatic individuals with a PVL below 50,000 copies/10(6) PBMC, a statistically significant two-fold increase was observed over time.
  
  
  CONCLUSIONS
  HTLV-1-PVL remained stable in both asymptomatic individuals and HAM/TSP patients over time. Frequent monitoring of asymptomatic individuals with low PVLs is recommended and further studies should be conducted to assess the course of PVL in these patients over extended periods of time.
authors: Advanced Laboratory of Public Health, Centro Gonçalo Moniz, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil.
authors: Viviana Nilla
authors: VN
authors: Olavarria
authors: Alline do Nascimento
authors: Ado N
authors: Gomes
authors: Ramon de Almeida
authors: Rde A
authors: Kruschewsky
authors: Bernardo
authors: B
authors: Galvão-Castro
authors: Maria Fernanda Rios
authors: MF
authors: Grassi
mesh_terms: D000328:Adult; D004279:DNA, Viral / Q000097:blood*; D018450:Disease Progression; D005260:Female; D015490:HTLV-I Infections / Q000821:virology*; D015368:Human T-lymphotropic virus 1 / Q000235:genetics / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015493:Paraparesis, Tropical Spastic / Q000821:virology; D011533:Proviruses / Q000235:genetics / Q000502:physiology*; D060888:Real-Time Polymerase Chain Reaction; D012189:Retrospective Studies; D019562:Viral Load / Q000502:physiology*; D055815:Young Adult
chemical_list: D004279:DNA, Viral