title: Characterization of human immunodeficiency virus type-1 from HIV-1 seropositive cases with undetectable viremia.
abstract: BACKGROUND
  Human immunodeficiency virus type 1 (HIV-1) viral load has become a standard of care among HIV-1-infected patients; however, a small number of patients have undetectable viral load even though they have never been treated.
  
  
  METHODS
  By using RT-PCR and DNA-PCR, and followed by sequencing and phylogenetic analyses, a detailed molecular characterization was carried out from five HIV-1-seropositive patients who had undetectable viral load by commercially available ultrasensitive viral load assays.
  
  
  RESULTS
  Of the four patients whose plasmas were available, viral RNAs were detected in three of them by using an in-house RT-PCR in at least one of the three regions (integrase, protease or envgp41). The fourth patient had positive RT-PCR signals in these regions only when RNA isolated from the supernatant of cocultivated patient PBLs with PHA-stimulated HIV-1 negative donor PBLs was used. Further analysis of DNA extracted from the PBMCs revealed that four of the five patients had detectable proviral sequences in at least two of the three regions. The fifth patient had only positive PCR results in all three regions when DNA isolated from PHA-stimulated patient's PBLs was used. Phylogenetic analysis of protease and envgp41 regions revealed that three patients were infected with subtype B viruses while the remaining two patients were infected with subtype C and CRF02_AG viruses. These subtypes coincided with geographic origin and known molecular epidemiology of HIV-1 infection.
  
  
  CONCLUSIONS
  These data provide evidence that both subtype B and non-B HIV-1 infection can result in undetectable viral load in HIV-1-infected patients and that efforts should continue to further characterize these viruses.
authors.affiliation: National Center for HIV, STD and TB Prevention, Centers for Disease Control and Prevention, Mail Stop D-12, 1600 Clifton Road, Atlanta, GA 30333, USA. cyang1@cdc.gov
authors.forename: Chunfu
authors.initials: C
authors.lastname: Yang
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.forename: Faye
authors.initials: F
authors.lastname: Cowart
authors.forename: Donna
authors.initials: D
authors.lastname: Rudolph
authors.forename: Bharat
authors.initials: B
authors.lastname: Parekh
authors.forename: J Steve
authors.initials: JS
authors.lastname: McDougal
authors.forename: Renu B
authors.initials: RB
authors.lastname: Lal
mesh_terms: D000328:Adult; D000368:Aged; D004279:DNA, Viral / Q000032:analysis; D005260:Female; D015483:HIV Antibodies / Q000097:blood*; D015658:HIV Infections / Q000175:diagnosis* / Q000821:virology; D006679:HIV Seropositivity / Q000821:virology*; D015497:HIV-1 / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010802:Phylogeny; D012367:RNA, Viral / Q000032:analysis; D017422:Sequence Analysis, DNA; D019562:Viral Load; D014766:Viremia / Q000821:virology
chemical_list: D004279:DNA, Viral; D015483:HIV Antibodies; D012367:RNA, Viral