title: HIV-1 superinfection in the antiretroviral therapy era: are seroconcordant sexual partners at risk?
abstract: BACKGROUND
  Acquisition of more than one strain of human immunodeficiency virus type 1 (HIV-1) has been reported to occur both during and after primary infection, but the risks and repercussions of dual and superinfection are incompletely understood. In this study, we evaluated a longitudinal cohort of chronically HIV-infected men who were sexual partners to determine if individuals acquired their partners' viral strains.
  
  
  METHODS
  Our cohort of HIV-positive men consisted of 8 couples that identified themselves as long-term sexual partners. Viral sequences were isolated from each subject and analyzed using phylogenetic methods. In addition, strain-specific PCR allowed us to search for partners' viruses present at low levels. Finally, we used computational algorithms to evaluate for recombination between partners' viral strains.
  
  
  CONCLUSIONS
  All couples had at least one factor associated with increased risk for acquisition of new HIV strains during the study, including detectable plasma viral load, sexually transmitted infections, and unprotected sex. One subject was dually HIV-1 infected, but neither strain corresponded to that of his partner. Three couples' sequences formed monophyletic clusters at the entry visit, with phylogenetic analysis suggesting that one member of the couple had acquired an HIV strain from his identified partner or that both had acquired it from the same source outside their partnership. The 5 remaining couples initially displayed no evidence of dual infection, using phylogenetic analysis and strain-specific PCR. However, in 1 of these couples, further analysis revealed recombinant viral strains with segments of viral genomes in one subject that may have derived from the enrolled partner. Thus, chronically HIV-1 infected individuals may become superinfected with additional HIV strains from their seroconcordant sexual partners. In some cases, HIV-1 superinfection may become apparent when recombinant viral strains are detected.
authors.affiliation: Department of Medicine, School of Medicine, University of Washington, Seattle, Washington, United States of America. msc6@u.washington.edu
authors.forename: Mary S
authors.initials: MS
authors.lastname: Campbell
authors.forename: Geoffrey S
authors.initials: GS
authors.lastname: Gottlieb
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Hawes
authors.forename: David C
authors.initials: DC
authors.lastname: Nickle
authors.forename: Kim G
authors.initials: KG
authors.lastname: Wong
authors.forename: Wenjie
authors.initials: W
authors.lastname: Deng
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Lampinen
authors.forename: Nancy B
authors.initials: NB
authors.lastname: Kiviat
authors.forename: James I
authors.initials: JI
authors.lastname: Mullins
mesh_terms: D023241:Antiretroviral Therapy, Highly Active; D003710:Demography; D015658:HIV Infections / Q000097:blood* / Q000188:drug therapy / Q000635:transmission*; D015497:HIV-1 / Q000502:physiology*; D018451:Homosexuality, Male; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000821:virology; D008297:Male; D009092:Mucous Membrane / Q000821:virology; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D011995:Recombination, Genetic / Q000235:genetics; D012307:Risk Factors; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D012725:Sexual Behavior; D012747:Sexual Partners; D013045:Species Specificity; D015163:Superinfection / Q000635:transmission* / Q000821:virology*