title: Genotypic analysis of the gp41 HR1 region from HIV-1 isolates from enfuvirtide-treated and untreated patients.
abstract: OBJECTIVE
  To evaluate the polymorphisms and resistance mutations in gp41 HR1 region of HIV-1.
  
  
  METHODS
  The study included 28 HIV-positive patients undergoing enfuvirtide (ENF) treatment or not from Porto Alegre, Rio Grande do Sul state, and Rio de Janeiro, Rio de Janeiro state, between 2006 and 2009. Resistance mutations and polymorphisms of the gp41 HR1 region were detected using the genomic DNA of 12 ENF-untreated patients and 16 patients in ENF treatment, encompassing subtypes B, C, and F1. Sample subtypes were determined by neighbor-joining phylogenetic analysis with a Kimura's two-parameter correction.
  
  
  RESULTS
  A high prevalence of polymorphisms unrelated to resistance was observed. Among ENF-untreated patients, 16% showed mutations related with resistance. Among patients in ENF treatment, 50% had resistance-related mutations. Overall, 17% of all isolates showed the N42S polymorphism related to ENF hypersusceptibility. The presence of ENF resistance mutations in the group of treated patients reduced viral load. The V38A substitution was the most frequent among treatment-experienced patients followed by the G36D/E, N42D, and V38M substitutions.
  
  
  CONCLUSIONS
  The V38A substitution in the gp41 HR region was the most common resistance mutation among ENF-treated patients and was associated with increased viral load.
authors.affiliation: Departamento de Genética, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Luciana Santos
authors.initials: LS
authors.lastname: Pessoa
authors.forename: Ana Luiza Chaves
authors.initials: AL
authors.lastname: Valadão
authors.forename: Celina Monteiro
authors.initials: CM
authors.lastname: Abreu
authors.forename: Alexandre Rodrigues
authors.initials: AR
authors.lastname: Calazans
authors.forename: Angélica Nascimento
authors.initials: AN
authors.lastname: Martins
authors.forename: Suwellen S S D
authors.initials: SS
authors.lastname: Azevedo
authors.forename: José Carlos
authors.initials: JC
authors.lastname: Couto-Fernandez
authors.forename: Marcelo C M V
authors.initials: MC
authors.lastname: Azevedo
authors.forename: Amilcar
authors.initials: A
authors.lastname: Tanuri
mesh_terms: D019943:Amino Acid Substitution / Q000235:genetics; D019380:Anti-HIV Agents / Q000494:pharmacology* / Q000627:therapeutic use; D016000:Cluster Analysis; D024882:Drug Resistance, Viral; D000077560:Enfuvirtide; D005838:Genotype; D015700:HIV Envelope Protein gp41 / Q000235:genetics* / Q000494:pharmacology* / Q000627:therapeutic use; D015658:HIV Infections / Q000188:drug therapy / Q000821:virology*; D015497:HIV-1 / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D010446:Peptide Fragments / Q000494:pharmacology* / Q000627:therapeutic use; D010802:Phylogeny; D011110:Polymorphism, Genetic; D017422:Sequence Analysis, DNA
chemical_list: D019380:Anti-HIV Agents; D015700:HIV Envelope Protein gp41; D010446:Peptide Fragments; C514787:gp41 protein, Human immunodeficiency virus 1; D000077560:Enfuvirtide