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  • Open Access

Follow-up of HTLV-1 positive individuals in the GIPH cohort (1997-2013): Proviral load was not a prognostic marker for HAM/TSP

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  • 1, 2Email author,
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Retrovirology201411 (Suppl 1) :P23

  • Published:


  • Infectious Disease
  • Cancer Research
  • Clinical Status
  • Prognostic Marker
  • Load Level


HTLV-1 proviral load (PVL) is considered a risk marker for diseases.


Quantification of HTLV-1 PVL was performed in 151 samples of 38 asymptomatic carriers (AC) collected at different times during follow-up (6.1 to 14.8 years, mean 10) and in samples of five individuals who developed HAM/TSP during follow-up (2.6 to 11.3 years, mean 7.2). We used SYBR Green and number of proviral copies/10,000 cells. Fluctuation of proviral load level was defined at 0.5 log or more.


PVL was stable in 52.6% (20/38) and floated in 47.4% (18/38) subjects. In AC, the median of PVL in the 1st sample was 85 and in the last 59 (p = 0.59). Among those individuals with low PVL who showed fluctuation, it remained low (£1%) in 77.8%. In 60% with high PVL who showed fluctuation, it remained high during follow-up. 10 patients developed HAM/TSP during the follow-up, and PVL was quantified before and after in 5 cases. Median of PVL in the 1st sample was 445, and in the last sample 98 (p = 0.56). In all cases, PVL was higher in the asymptomatic period, declining after onset of HAM/TSP.


PVL reaches a plateau, characteristic of each individual; high PVL appears to be followed by decrease and stabilization in lower levels. Although PVL is supposedly a risk marker for HAM/TSP, it had modest prognostic value in our cohort; changes in clinical status and PVL did not coincide, besides occurrence of high stable PVL in AC. Hemominas/FAPEMIG/DECIT/MS.

Authors’ Affiliations

GIPH (Interdisciplinary HTLV Research Group); Hemominas, Belo Horizonte, Minas Gerais, Brazil
Faculdade da Saúde e Ecologia Humana (FASEH), Vespasiano, Minas Gerais, Brazil


© Gonçalves et al; licensee BioMed Central Ltd. 2014

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated.