title: Prevalence, incidence density, and genotype distribution of GB virus C infection in a cohort of recently HIV-1-infected subjects in Sao Paulo, Brazil.
abstract: BACKGROUND
  The results of previous studies elsewhere have indicated that GB virus C (GBV-C) infection is frequent in patients infected with the human immunodeficiency virus type 1 (HIV-1) due to similar transmission routes of both viruses. The aim of this study was to determine the prevalence, incidence density and genotypic characteristics of GBV-C in this population.
  
  
  RESULTS
  The study population included 233 patients from a cohort primarily comprised of homosexual men recently infected with HIV-1 in São Paulo, Brazil. The presence of GBV-C RNA was determined in plasma samples by reverse transcriptase-nested polymerase chain reaction and quantified by real-time PCR. GBV-C genotypes were determined by direct sequencing. HIV viral load, CD4+ T lymphocyte and CD8+ T lymphocyte count were also tested in all patients. The overall prevalence of GBV-C infection was 0.23 (95% CI: 0.18 to 0.29) in the study group. There was no significant difference between patients with and without GBV-C infection and Glycoprotein E2 antibody presence regarding age, sex, HIV-1 viral load, CD4+ and CD8+T cell counts and treatment with antiretroviral drugs. An inverse correlation was observed between GBV-C and HIV-1 loads at enrollment and after one year. Also, a positive but not significant correlation was observed between GBV-C load and CD4+ T lymphocyte. Phylogenetic analysis of the GBV-C isolates revealed the presence of genotype 1 and genotype 2, these sub classified into subtype 2a and 2b.
  
  
  CONCLUSIONS
  GBV-C infection is common in recently HIV -1 infected patients in Sao Paulo, Brazil and the predominant genotype is 2b. This study provides the first report of the GBV-C prevalence at the time of diagnosis of HIV-1 and the incidence density of GBV-C infection in one year.
authors.affiliation: Division of Clinical Immunology and Allergy, University of Sao Paulo, Sao Paulo, Brazil.
authors.forename: Maria Teresa M
authors.initials: MT
authors.lastname: Giret
authors.forename: João Luiz
authors.initials: JL
authors.lastname: Miraglia
authors.forename: Maria Cecília Araripe
authors.initials: MC
authors.lastname: Sucupira
authors.forename: Anna
authors.initials: A
authors.lastname: Nishiya
authors.forename: José Eduardo
authors.initials: JE
authors.lastname: Levi
authors.forename: Ricardo S
authors.initials: RS
authors.lastname: Diaz
authors.forename: Ester C
authors.initials: EC
authors.lastname: Sabino
authors.forename: Esper G
authors.initials: EG
authors.lastname: Kallas
mesh_terms: D000328:Adult; D017677:Age Distribution; D001938:Brazil / Q000453:epidemiology; D018791:CD4 Lymphocyte Count; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology; D015331:Cohort Studies; D005838:Genotype; D015658:HIV Infections / Q000150:complications* / Q000276:immunology; D015497:HIV-1 / Q000502:physiology*; D006526:Hepatitis C / Q000150:complications / Q000453:epidemiology* / Q000235:genetics* / Q000276:immunology; D006801:Humans; D008297:Male; D017422:Sequence Analysis, DNA; D019562:Viral Load; D055815:Young Adult