Anatomical loci of HIV-associated immune activation and association with viraemia

Lancet. 2003 Sep 20;362(9388):945-50. doi: 10.1016/S0140-6736(03)14363-2.


Background: Lymphocyte activation, associated with vaccination or infection, can be measured by positron emission tomography (PET). We investigated the ability of PET to detect and measure magnitude of lymph-node activation among asymptomatic HIV-1-infected individuals.

Methods: Initially we assessed PET response in eight HIV-1-uninfected individuals who had received licensed killed influenza vaccine. In an urban teaching hospital, we recruited 12 patients recently infected with HIV-1 (<18 months since seroconversion) and 11 chronic long-term HIV-1 patients who had stable viraemia by RT-PCR (non-progressors). After injection with fluorine-18-labelled fluorodeoxyglucose, patients underwent PET. We correlated summed PET signal from nodes with viral load by linear regression on log-transformed values.

Findings: Node activation was more localised after vaccination than after HIV-1 infection. In early and chronic HIV-1 disease, node activation was greater in cervical and axillary than in inguinal and iliac chains (p<0.0001), and summed PET signal correlated with viraemia across a 4 log range (r2=0.98, p<0.0001). Non-progressors had small numbers of persistently active nodes, most of which were surgically accessible.

Interpretation: The anatomical restriction we noted may reflect microenvironmental niche selection, and tight correlation of PET signal with viraemia suggests target-cell activation determines steady-state viral replication.

Publication types

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

MeSH terms

  • Adolescent
  • Adult
  • Female
  • Fluorodeoxyglucose F18
  • HIV Infections / diagnostic imaging
  • HIV Infections / immunology*
  • HIV Infections / virology*
  • HIV Seropositivity / immunology
  • HIV-1* / immunology
  • HIV-1* / isolation & purification
  • Humans
  • Influenza Vaccines / immunology
  • Lymph Nodes / diagnostic imaging
  • Lymph Nodes / immunology*
  • Lymphocyte Activation / immunology*
  • Male
  • Middle Aged
  • Reverse Transcriptase Polymerase Chain Reaction
  • Tomography, Emission-Computed*
  • Viremia / diagnostic imaging
  • Viremia / immunology
  • Virus Replication / immunology


  • Influenza Vaccines
  • Fluorodeoxyglucose F18