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This article is part of the supplement: 15th International Conference on Human Retroviruses: HTLV and Related Viruses

Open Access Open Badges Meeting abstract

Human leukocyte antigen (HLA) class I frequencies in human T-cell lymphotropic virus type 1 (HTLV-1)-infected patients from Salvador-Brazil

Viviana N Olavarria1, Maria F Grassi12, Ramon Kruschewsky1, Xiao-Jiang Gao3, Alline Nascimento1, David Watkins4, Mary Carrigton3 and Bernardo Galvao-Castro12*

Author Affiliations

1 Bahiana School of Medicine and Public Health (EBMSP) Salvador, Bahia, Brazil

2 Advanced Laboratory of Public Health, Gonçalo Moniz Center, Fundação Oswaldo Cruz, Salvador, Bahia, Brazil

3 Laboratory of Genomic Diversity, SAIC-Frederick, Inc., National Cancer Institute, Frederick, Maryland, 21702, USA

4 Wisconsin National Primate Center, University of Wisconsin–Madison, Madison, Wisconsin, USA

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Retrovirology 2011, 8(Suppl 1):A121  doi:10.1186/1742-4690-8-S1-A121

The electronic version of this article is the complete one and can be found online at:

Published:6 June 2011

© 2011 Olavarria et al; licensee 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 development of human T- cell lymphotropic virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) may be related to genetic factors related to the presentation of viral antigens by human leukocyte antigen (HLA).


To determine the HLA class I genotype of HTLV-1-infected patients.


420 HTLV-1-infected patients (280 healthy carriers (HC) and 140 HAM/TSP) from the HTLV Reference Center in Salvador, Brazil were evaluated. HLA genotype was performed using automated DNA sequencers and analyzed using the software program Assign-SBT TM 3.2.


The HLA types most frequently observed in all individuals combined were A*02 (26.1%), A*03 (10.5%); B*35 (13.1%), B*44 (10.4%), Cw*04 (21.9) and Cw* 07 (17.7%). The presence of HLA-A*02 reduced the odds of HAM-TSP (Odds Ratio: 0.4, p<0.0001 and IC95%: 0.28-0.59). The frequency of homozygosity of HLA-A was 8%, 4% for HLA-B and 9% for HLA-C overall. Proviral load was significantly lower in HC among those heterozygous at all three HLA class I loci group relative to HC who were homozygous at one or more HLA class I loci group (p = 0.029). However, no difference in homozygosity between proviral load in the HAM/TSP patients was observed (p = 0.57).


HLA-A*02 allele is more prevalent in the HC patients, which suggests a protective role of this allele against HAM/TSP. Furthermore, HC patients had a higher frequency of heterozygosity at all three HLA class than that in HAM/TSP patients.