title: The CYP2B6 G516T polymorphism influences CD4+T-cell counts in HIV-positive patients receiving antiretroviral therapy in an ethnically diverse region of the Amazon.
abstract: OBJECTIVE
  Cytochrome P450 (CYP) enzyme polymorphisms seem to significantly influence the variability of the responses to certain antiretroviral drugs and their toxicity levels. The objective of this study was to evaluate the influence of the CYP2B6 G516T polymorphism on hepatic, renal, immunological, and viral marker changes in HIV-1-positive patients receiving treatment in an ethnically diverse region of the Amazon.
  
  
  METHODS
  CYP2B6 G516T genotyping was performed by real-time PCR (RT-PCR) in samples from 185 patients. Urea, creatinine, aspartate aminotransferase (AST), alanine aminotransferase (ALT), CD4+/CD8+T-cell counts, and HIV-1 plasma viral load were measured.
  
  
  RESULTS
  The polymorphic CYP2B6 G516T allele frequency was 0.36, which is different from the frequencies in other ethnic groups. The polymorphic genotype was associated with changes in the urea and ALT levels, although the median values were within the normal range. The TT genotype was also associated with significantly lower CD4+T-cell counts in patients using efavirenz.
  
  
  CONCLUSIONS
  The CYP2B6 G516T polymorphism seems to affect the response to efavirenz treatment by reducing CD4+T-cell counts in patients with a high degree of miscegenation who use this antiretroviral agent.
authors.affiliation: Laboratório de Virologia, Instituto de Ciências Biológicas, Universidade Federal do Pará, Rua Augusto Correa s/no., Guamá, CEP 66.075-110, Belém, Pará, Brazil.
authors.forename: Maria Alice Freitas
authors.initials: MAF
authors.lastname: Queiroz
authors.affiliation: Laboratório de Virologia, Instituto de Ciências Biológicas, Universidade Federal do Pará, Rua Augusto Correa s/no., Guamá, CEP 66.075-110, Belém, Pará, Brazil.
authors.forename: Rogério Valois
authors.initials: RV
authors.lastname: Laurentino
authors.affiliation: Laboratório de Virologia, Instituto de Ciências Biológicas, Universidade Federal do Pará, Rua Augusto Correa s/no., Guamá, CEP 66.075-110, Belém, Pará, Brazil.
authors.forename: Ednelza
authors.initials: E
authors.lastname: da Silva Graça Amoras
authors.affiliation: Hospital Universitário João de Barros Barreto, Universidade Federal do Pará, Belém, Pará, Brazil.
authors.forename: Mauro Sérgio Moura de
authors.initials: MSM
authors.lastname: Araújo
authors.affiliation: Laboratório de Virologia, Instituto de Ciências Biológicas, Universidade Federal do Pará, Rua Augusto Correa s/no., Guamá, CEP 66.075-110, Belém, Pará, Brazil.
authors.forename: Samara Tatielle Monteiro
authors.initials: STM
authors.lastname: Gomes
authors.affiliation: Laboratório de Virologia, Instituto de Ciências Biológicas, Universidade Federal do Pará, Rua Augusto Correa s/no., Guamá, CEP 66.075-110, Belém, Pará, Brazil.
authors.forename: Sandra Souza
authors.initials: SS
authors.lastname: Lima
authors.affiliation: Laboratório de Virologia, Instituto de Ciências Biológicas, Universidade Federal do Pará, Rua Augusto Correa s/no., Guamá, CEP 66.075-110, Belém, Pará, Brazil.
authors.forename: Antonio Carlos Rosário
authors.initials: ACR
authors.lastname: Vallinoto
authors.affiliation: Laboratório de Virologia, Instituto de Ciências Biológicas, Universidade Federal do Pará, Rua Augusto Correa s/no., Guamá, CEP 66.075-110, Belém, Pará, Brazil.
authors.forename: Marluísa
authors.initials: M
authors.lastname: de Oliveira Guimarães Ishak
authors.affiliation: Laboratório de Virologia, Instituto de Ciências Biológicas, Universidade Federal do Pará, Rua Augusto Correa s/no., Guamá, CEP 66.075-110, Belém, Pará, Brazil.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Ishak
authors.affiliation: Laboratório de Virologia, Instituto de Ciências Biológicas, Universidade Federal do Pará, Rua Augusto Correa s/no., Guamá, CEP 66.075-110, Belém, Pará, Brazil. Electronic address: lfam@ufpa.br.
authors.forename: Luiz Fernando Almeida
authors.initials: LFA
authors.lastname: Machado
mesh_terms: D000328:Adult; D000480:Alkynes; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D048588:Benzoxazines / Q000627:therapeutic use; D001938:Brazil; D018791:CD4 Lymphocyte Count; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000187:drug effects; D003521:Cyclopropanes; D065702:Cytochrome P-450 CYP2B6 / Q000235:genetics*; D005006:Ethnicity / Q000235:genetics*; D005260:Female; D005838:Genotype; D015658:HIV Infections / Q000188:drug therapy* / Q000235:genetics / Q000276:immunology* / Q000821:virology; D006801:Humans; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D055815:Young Adult
chemical_list: D000480:Alkynes; D019380:Anti-HIV Agents; D048588:Benzoxazines; D003521:Cyclopropanes; D065702:Cytochrome P-450 CYP2B6; C098320:efavirenz
keywords: Antiretroviral drugs; CYP2B6; HIV-1; Miscegenation; Treatment response