title: The influence of HIV-1 subtypes C, CRF31_BC and B on disease progression and initial virologic response to HAART in a Southern Brazilian cohort.
abstract: BACKGROUND
  Although most HIV-1 infections in Brazil are due to subtype B, Southern Brazil has a high prevalence of subtype C and recombinant forms, such as CRF31_BC. This study assessed the impact of viral diversity on clinical progression in a cohort of newly diagnosed HIV-positive patients.
  
  
  METHODS
  From July/2004 to December/2005, 135 HIV-infected patients were recruited. The partial pol region was subtyped by phylogeny. A generalized estimating equation (GEE) model was used to examine the relationship between viral subtype, CD4+ T cell count and viral load levels before antiretroviral therapy. Hazard ratio (Cox regression) was used to evaluate factors associated with viral suppression (viral load < 50 copies/mL at six months).
  
  
  RESULTS
  Main HIV-1 subtypes included B (29.4%), C (28.2%), and CRF31_BC (23.5%). Subtypes B and C showed a similar trend in CD4+ T cell decline. Comparison of non-B (C and CRF31_BC) and B subtypes revealed no significant difference in the proportion of patients with viral suppression at six months (week 24). Higher CD4+ T cell count and lower viral load were independently associated with viral suppression.
  
  
  CONCLUSIONS
  No significant differences were found between subtypes; however, lower viral load and higher CD4+ T cell count before therapy were associated with better response.
authors.affiliation: Santa Marta Health Center, Municipal Health Department, Porto Alegre, RS, Brazil.
authors.forename: Cynara Carvalho
authors.initials: CC
authors.lastname: Nunes
authors.affiliation: State Foundation for Health Research and Production, Center for Scientific and Technological Development, Porto Alegre, RS, Brazil.
authors.forename: Maria Cristina Cotta
authors.initials: MC
authors.lastname: Matte
authors.affiliation: Municipal Health Department, STD/AIDS Specialized Care Center, Porto Alegre, RS, Brazil.
authors.forename: Claudia Fontoura
authors.initials: CF
authors.lastname: Dias
authors.affiliation: State Foundation for Health Research and Production, Center for Scientific and Technological Development, Porto Alegre, RS, Brazil.
authors.forename: Leonardo Augusto Luvison
authors.initials: LA
authors.lastname: Araújo
authors.affiliation: Department of Epidemiology and Biostatistics, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil.
authors.forename: Luciano Santos Pinto
authors.initials: LS
authors.lastname: Guimarães
authors.affiliation: State Foundation for Health Research and Production, Center for Scientific and Technological Development, Porto Alegre, RS, Brazil.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Almeida
authors.affiliation: Adolfo Lutz Institute, São Paulo, SP, Brazil.
authors.forename: Luis Fernando Macedo
authors.initials: LF
authors.lastname: Brígido
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D023241:Antiretroviral Therapy, Highly Active; D018791:CD4 Lymphocyte Count; D018450:Disease Progression; D005260:Female; D005838:Genotype; D015658:HIV Infections / Q000188:drug therapy* / Q000821:virology*; D015497:HIV-1 / Q000145:classification / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D008297:Male; D010802:Phylogeny; D011446:Prospective Studies; D019562:Viral Load
chemical_list: D019380:Anti-HIV Agents