title: HIV-1 outcompetes HIV-2 in dually infected Senegalese individuals with low CD4⁺ cell counts.
abstract: OBJECTIVE
  Dual infection with HIV-1 and HIV-2, which is not uncommon in West Africa, has implications for transmission, progression, and antiretroviral therapy (ART). Few studies have examined viral dynamics in this setting. Our objective was to directly compare HIV-1 and HIV-2 viral loads and to examine whether this relationship is associated with CD4⁺ cell count.
  
  
  METHODS
  This is a retrospective analysis of data from observational cohort studies.
  
  
  METHODS
  We compared HIV-1 and HIV-2 viral loads from 65 dually infected, ART-naive Senegalese individuals. Participants provided blood, oral fluid, and cervicovaginal lavage (CVL) or semen samples for virologic and immunologic testing. We assessed relationships between HIV-1 and HIV-2 levels using linear regression with generalized estimating equations to account for multiple study visits.
  
  
  RESULTS
  After adjusting for CD4⁺ cell count, age, sex, and commercial sex work, HIV-1 RNA levels were significantly higher than HIV-2 levels in semen, CVL, and oral fluids. Despite similar peripheral blood mononuclear cell DNA levels among individuals with CD4⁺ cell counts above 500 cells/μl, individuals with CD4⁺ cell counts below 500 cells/μl had higher HIV-1 and lower HIV-2 DNA levels. Individuals with high CD4⁺ cell counts had higher mean HIV-1 plasma RNA viral loads than HIV-2, with HIV-1 levels significantly higher and HIV-2 levels trending toward lower mean viral loads among individuals with low CD4⁺ cell counts.
  
  
  CONCLUSIONS
  Our data are consistent with the hypothesis that with disease progression, HIV-1 outcompetes HIV-2 in dually infected individuals. This finding helps explain differences in prevalence and outcomes between HIV-1, HIV-2, and HIV-dual infection.
authors.affiliation: aDepartment of Epidemiology, School of Public Health bDepartment of Medicine, Division of Allergy and Infectious Diseases, School of Medicine, University of Washington, Seattle, Washington, USA cClinique des Maladies Infectieuses Ibrahima DIOP Mar dDepartment of Dentistry, Centre Hospitalier Universitaire de Fann, Universite Cheikh Anta Diop de Dakar, Dakar, Senegal eInstitut d'Hygiene Sociale, Dakar, Senegal fDepartment of Pathology, School of Medicine, University of Washington, Seattle, Washington, USA.
authors.forename: Dana N
authors.initials: DN
authors.lastname: Raugi
authors.forename: Geoffrey S
authors.initials: GS
authors.lastname: Gottlieb
authors.forename: Papa S
authors.initials: PS
authors.lastname: Sow
authors.forename: Macoumba
authors.initials: M
authors.lastname: Toure
authors.forename: Fatima
authors.initials: F
authors.lastname: Sall
authors.forename: Awa
authors.initials: A
authors.lastname: Gaye
authors.forename: Ibra
authors.initials: I
authors.lastname: N'doye
authors.forename: Nancy B
authors.initials: NB
authors.lastname: Kiviat
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Hawes
mesh_terms: D000328:Adult; D018791:CD4 Lymphocyte Count; D005260:Female; D015658:HIV Infections / Q000097:blood / Q000821:virology*; D015497:HIV-1; D015498:HIV-2; D006801:Humans; D008297:Male; D008875:Middle Aged; D009061:Mouth Mucosa / Q000737:chemistry; D012367:RNA, Viral / Q000032:analysis* / Q000097:blood; D012189:Retrospective Studies; D012661:Semen / Q000737:chemistry; D012675:Senegal / Q000453:epidemiology; D014621:Vagina / Q000737:chemistry; D019562:Viral Load; D055815:Young Adult
chemical_list: D012367:RNA, Viral