Genotypic analysis of HIV-1 drug resistance at the limit of detection: virus production without evolution in treated adults with undetectable HIV loads

J Infect Dis. 2004 Apr 15;189(8):1452-65. doi: 10.1086/382488. Epub 2004 Apr 5.


Human immunodeficiency virus (HIV) production continues in patients receiving highly active antiretroviral therapy (HAART) with undetectable (<50 copies/mL) virus loads. Our initial cross-sectional study showed that this viremia is composed of viruses that lack new resistance mutations to the HAART regimen. Here we describe a longitudinal, clonal genotypic analysis of plasma virus loads in treated adults who had undetectable virus loads. We document a continuous production of virus in 8 HIV-1-infected adults who maintained suppression of viremia for up to 15 months. Using analytical approaches for distinguishing selected resistance mutations from nonselected mutations and polymerase chain reaction errors, we detected no evolution of resistance in the reverse-transcriptase and protease genes. Sporadic resistance mutations were detected in some viral clones that were not selected for subsequently. Thus, in some patients, HAART suppresses replication to a level that does not allow the evolution of drug resistance over a time frame of years.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Antiretroviral Therapy, Highly Active*
  • Base Sequence
  • Drug Resistance, Viral / genetics*
  • Evolution, Molecular
  • Gene Products, pol / genetics
  • HIV Infections / drug therapy*
  • HIV Infections / virology*
  • HIV Protease / genetics
  • HIV Reverse Transcriptase / genetics
  • HIV-1 / enzymology
  • HIV-1 / genetics*
  • Humans
  • Longitudinal Studies
  • Male
  • Middle Aged
  • Molecular Sequence Data
  • Phylogeny
  • Point Mutation
  • RNA, Viral / blood
  • RNA, Viral / chemistry
  • RNA, Viral / genetics
  • Reverse Transcriptase Polymerase Chain Reaction
  • Viremia / drug therapy
  • Viremia / virology


  • Gene Products, pol
  • RNA, Viral
  • HIV Reverse Transcriptase
  • HIV Protease