<b>Letter to the Editor</b>: Phylogenetic Analysis of HIV Type 2 Strains from Portugal

Heredia, Alonso; Vallejo, Alejandro; Soriano, Vincent; Silva, A.; Kamal, Mehnaz; Fevereiro, S.; Más, Antonio; Gutiérrez, M.; Epstein, Jay S.; Hewlett, I.K.

doi:10.1089/aid.1998.14.471

Cited by 5 publications

(5 citation statements)

References 6 publications

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“…2 Phylogenetic analysis of HIV-2 from infected individuals residing in Portugal showed that subtype A is responsible for the infections studied. 31 However, subtyping data are not available for HIV-1 strains. Because no prior work has documented the molecular epidemiology of the Portuguese HIV-1 epidemic, the present study was undertaken to survey circulating subtypes and transmission patterns of viruses from seropositive individuals, both persons of Portuguese origin and African immigrants, living in the urban area of Lisbon.…”

Section: Introduction Tmentioning

confidence: 99%

Molecular Epidemiology of HIV Type 1 Infection in Portugal: High Prevalence of Non-B Subtypes

Esteves

Parreira

Venenno

et al. 2002

AIDS Research and Human Retroviruses

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In this study, we have investigated the diversity of current HIV-1 strains circulating in the metropolitan area of Lisbon, Portugal. A total of 217 HIV-1-positive blood samples, collected between October 1998 and December 2000, was genetically characterized in the gp120 C2V3C3 region (n 5 205) or part of the gp41 N-terminal segment (n 5 12) by heteroduplex mobility assay (HMA) and/or DNA sequencing. The HMA subtyping efficiency (number of samples unambiguously subtyped by HMA divided by the total number of samples subtyped) was 65.9% (143 of 217), with indeterminate migration patterns of subtype A and G strains contributing significantly to this value. On the overall, subtype B was the most prevalent (50.2%), followed by subtypes G (21.7%), A (17.5%), and F (5.5%), whereas subtypes C, D, H, and J accounted altogether for 5.1% of the infections. Non-B subtypes were responsible for 77.4 and 33.1% of the infections among African immigrants and Portuguese subjects, respectively. Angolan individuals (n 5 25) were the only ones infected with all the HIV-1 subtypes documented, probably reflecting a high degree of viral genetic diversification in their country of origin. Phylogenetic analysis showed a predominance of IbNG-like viruses among subtype A sequences and two new major subclusters within subtype G (G P and G P 9). The majority of the Portuguese G sequences described formed a well-defined subcluster (G P ), supported by bootstrap values .90%, phylogenetically distant from clade G sequences in databases. gag (p24/p7) sequence analysis of these variants confirmed the maintenance of the subtype G subclusters. The multiple subclustering observed for the major clades A, B, D, and G, as well as the variety of subtypes found, indicate a high diversity of HIV-1 variants circulating in Portugal and suggest a need for continuous epidemiologic surveillance. 313

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Section: Introduction Tmentioning

confidence: 99%

Molecular Epidemiology of HIV Type 1 Infection in Portugal: High Prevalence of Non-B Subtypes

Esteves

Parreira

Venenno

et al. 2002

AIDS Research and Human Retroviruses

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“…HIV-2 has been found to be quite common in West African countries and, to a lesser extent, in other regions with historical socioeconomic ties, such as the former Portuguese colonies, including Angola, Mozambique, Guinea-Bissau, India, and Brazil [SantosFerreira et al, 1990;Kanki et al, 1994;Marlink et al, 1996;Heredia et al, 1998a;Kanki, 1999]. In Europe and North America, most reported HIV-2-infected subjects have been African immigrants or, less frequently, natives who had lived in West Africa for a while or who had had sex with people from that region [SmallmanRaynor and Cliff, 1991;O'Brien et al, 1992;Quinn, 1994;Van der Ende et al, 1996;Soriano et al, 1996].…”

Section: Introductionmentioning

confidence: 99%

Human immunodeficiency virus type 2 (HIV-2) in Portugal: Clinical spectrum, circulating subtypes, virus isolation, and plasma viral load

et al. 2000

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The human immunodeficiency virus type 2 (HIV-2) is responsible for 4. 5% of AIDS cases in Portugal. Six HIV-2 subtypes have been described so far, subtype A being proposed as more pathogenic than the rest. The relationship between the clinical status and levels of both cellular and plasma HIV-2 viraemia is not well known, nor their modifications under antiretroviral therapy. Thirty-two consecutive HIV-2 infected persons (17 men, 15 women) attending two different hospitals in Lisbon in 1997 were enrolled prospectively in the study. All but 4 individuals most likely acquired the infection through heterosexual contact. More than half of the study population was of African origin, mainly from Guinea-Bissau. Eleven (34.4%) patients had developed clinical manifestations included within the B or C groups of the CDC classification system for HIV infection, with the rest being asymptomatic. Half of the population was undergoing antiretroviral treatment at the time of the study. HIV-2 subtypes were investigated using a new Nef-based restriction fragment length polymorphism (RFLP) method that allows differentiation of the main two variants, A and B. Plasma viral load was quantified using a new quantitative competitive reverse transcriptase polymerase chain reaction (QcRT-PCR) procedure as well as the Amp-RT assay. Virus isolation was attempted from peripheral blood mononuclear cells. All but one person carried HIV-2 subtype A. Plasma viraemia examined by QcRT-PCR was measurable in 15 (50%) of 30 subjects, yielding in all instances values below 20,000 HIV-2 RNA copies per ml. Plasma RT activity could be detected in only 10 (33%) of 30 subjects, a rate much lower than that seen in HIV-1 infection. Virus was isolated from 16 (53.3%) of 30 patients. A significant correlation was found between CD4+ counts, clinical status, rate of virus isolation, and plasma viral load by both QcRT-PCR and Amp-RT. In conclusion, HIV-2 subtype A is the predominant variant circulating in Portugal among both natives and immigrants. A lower cellular and plasma viral load with respect to HIV-1 was seen in persons without immunosuppression, from whom the rate of virus recovery was extremely low.

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“…Unfortunately, no such improvement was observed for group B HIV-2 RNA quantification, and this is probably due to the high diversity of HIV-2 group B isolates and viral assay design directed at HIV-2 group A isolates in most labs. The level of HIV-2 viral diversity, as well as interlab assay heterogeneity, may make it difficult to compare results between the different HIV-2-infected cohorts of the ACHI E V 2E collaboration, especially in countries where HIV-2 group B circulates (4,6,14,18). Ultimately, further efforts to standardize, validate, and commercialize simple, lowcost HIV-2 viral load assays are needed.…”

Section: Discussionmentioning

confidence: 99%

An International Collaboration To Standardize HIV-2 Viral Load Assays: Results from the 2009 ACHI _E V _2E Quality Control Study

et al. 2011

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Accurate HIV-2 plasma viral load quantification is crucial for adequate HIV-2 patient management and for the proper conduct of clinical trials and international cohort collaborations. This study compared the homogeneity of HIV-2 RNA quantification when using HIV-2 assays from ACHI E V 2E study sites and either in-house PCR calibration standards or common viral load standards supplied to all collaborators. Each of the 12 participating laboratories quantified blinded HIV-2 samples, using its own HIV-2 viral load assay and standard as well as centrally validated and distributed common HIV-2 group A and B standards ( http://www.hiv.lanl.gov/content/sequence/HelpDocs/subtypes-more.html ). Aliquots of HIV-2 group A and B strains, each at 2 theoretical concentrations (2.7 and 3.7 log 10 copies/ml), were tested. Intralaboratory, interlaboratory, and overall variances of quantification results obtained with both standards were compared using F tests. For HIV-2 group A quantifications, overall and interlaboratory and/or intralaboratory variances were significantly lower when using the common standard than when using in-house standards at the concentration levels of 2.7 log 10 copies/ml and 3.7 log 10 copies/ml, respectively. For HIV-2 group B, a high heterogeneity was observed and the variances did not differ according to the type of standard used. In this international collaboration, the use of a common standard improved the homogeneity of HIV-2 group A RNA quantification only. The diversity of HIV-2 group B, particularly in PCR primer-binding regions, may explain the heterogeneity in quantification of this strain. Development of a validated HIV-2 viral load assay that accurately quantifies distinct circulating strains is needed.

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Letter to the Editor: Phylogenetic Analysis of HIV Type 2 Strains from Portugal

Cited by 5 publications

References 6 publications

Molecular Epidemiology of HIV Type 1 Infection in Portugal: High Prevalence of Non-B Subtypes

Molecular Epidemiology of HIV Type 1 Infection in Portugal: High Prevalence of Non-B Subtypes

Human immunodeficiency virus type 2 (HIV-2) in Portugal: Clinical spectrum, circulating subtypes, virus isolation, and plasma viral load

An International Collaboration To Standardize HIV-2 Viral Load Assays: Results from the 2009 ACHI _E V _2E Quality Control Study

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Letter to the Editor: Phylogenetic Analysis of HIV Type 2 Strains from Portugal

Cited by 5 publications

References 6 publications

Molecular Epidemiology of HIV Type 1 Infection in Portugal: High Prevalence of Non-B Subtypes

Molecular Epidemiology of HIV Type 1 Infection in Portugal: High Prevalence of Non-B Subtypes

Human immunodeficiency virus type 2 (HIV-2) in Portugal: Clinical spectrum, circulating subtypes, virus isolation, and plasma viral load

An International Collaboration To Standardize HIV-2 Viral Load Assays: Results from the 2009 ACHI E V 2E Quality Control Study

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An International Collaboration To Standardize HIV-2 Viral Load Assays: Results from the 2009 ACHI _E V _2E Quality Control Study