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LTR point mutations in the Tax-responsive elements of HTLV-1 isolates from HIV/HTLV-1-coinfected patients

Mariana Cavalheiro Magri12, Emanuela Avelar Silva Costa1 and Adele Caterino-de-Araujo12*

Author Affiliations

1 Immunology Department, Instituto Adolfo Lutz, Av. Dr. Arnaldo, 355, 11° andar, São Paulo, SP, 01246-902, Brazil

2 Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, Av. Prof. Lineu Prestes 580, São Paulo, SP, CEP 05508-000, Brazil

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Virology Journal 2012, 9:184  doi:10.1186/1743-422X-9-184

Published: 4 September 2012



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.


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).


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.

HTLV-1; LTR region; Sequencing