Prevalence of CXCR4 tropism among antiretroviral-treated HIV-1-infected patients with detectable viremia

J Infect Dis. 2006 Oct 1;194(7):926-30. doi: 10.1086/507312. Epub 2006 Aug 29.


Although CXCR4-tropic viruses are relatively uncommon among untreated human immunodeficiency virus (HIV)-infected individuals except during advanced immunodeficiency, the prevalence of CXCR4-tropic viruses among treated patients with detectable viremia is unknown. To address this issue, viral coreceptor usage was measured with a single-cycle recombinant-virus phenotypic entry assay in treatment-naive and treated HIV-infected participants with detectable viremia sampled from 2 clinic-based cohorts. Of 182 treated participants, 75 (41%) harbored dual/mixed or X4-tropic viruses, compared with 178 (18%) of the 976 treatment-naive participants (P<.001). This difference remained significant after adjustment for CD4+ T cell count and CCR5 Delta 32 genotype. Enrichment for dual/mixed/X4-tropic viruses among treated participants was largely but incompletely explained by lower pretreatment nadir CD4 + T cell counts. CCR5 inhibitors may thus be best strategically used before salvage therapy and before significant CD4 + T cell depletion.

Publication types

  • Clinical Trial
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Anti-HIV Agents / therapeutic use*
  • CD4 Lymphocyte Count
  • Drug Resistance, Viral
  • Drug Therapy, Combination
  • Female
  • HIV Infections / drug therapy*
  • HIV Infections / virology
  • HIV-1 / genetics
  • HIV-1 / metabolism*
  • HIV-1 / pathogenicity
  • Humans
  • Male
  • Middle Aged
  • Prevalence
  • RNA, Viral / blood
  • Receptors, CXCR4 / metabolism*
  • Reverse Transcriptase Inhibitors / therapeutic use*
  • Treatment Outcome
  • Viremia / drug therapy*
  • Viremia / virology


  • Anti-HIV Agents
  • RNA, Viral
  • Receptors, CXCR4
  • Reverse Transcriptase Inhibitors