Sialoadhesin (CD169) expression in CD14+ cells is upregulated early after HIV-1 infection and increases during disease progression

PLoS One. 2007 Feb 28;2(2):e257. doi: 10.1371/journal.pone.0000257.


Background: Sialoadhesin (CD169, siglec-1 or Sn) is an activation marker seen on macrophages in chronic inflammatory diseases and in tumours, and on subsets of tissue macrophages. CD169 is highly expressed by macrophages present in AIDS-related Kaposi's sarcoma lesions. It is also increased on blood monocytes of HIV-1 infected patients with a high viral load despite antiretroviral treatment.

Methodology/principal findings: We investigated expression of sialoadhesin in untreated HIV-1 and HHV-8 infected patients, by real-time PCR and FACS analysis to establish its expression in relation to infection and disease progression. Patients analysed were either HIV-1 seroconverters (n = 7), in the chronic phase of HIV-1 infection (n = 21), or in the AIDS stage (n = 58). Controls were HHV-8 infected, but otherwise healthy individuals (n = 20), and uninfected men having sex with men (n = 24). Sialoadhesin mRNA was significantly elevated after HIV-1, but not HHV-8 infection, and a further increase was seen in AIDS patients. Samples obtained around HIV-1 seroconversion indicated that sialoadhesin levels go up early in infection. FACS analysis of PBMCs showed that sialoadhesin protein was expressed at high levels by approximately 90% of CD14(+) and CD14(+)CD16(+)cells of HIV-1(+) patients with a concomitant 10-fold increase in sialoadhesin protein/cell compared with uninfected controls.

Conclusions/significance: We have shown that sialoadhesin is induced to high levels on CD14(+) cells early after HIV-1 infection in vivo. The phenotype of the cells is maintained during disease progression, suggesting that it could serve as a marker for infection and probably contributes to the severe dysregulation of the immune system seen in AIDS.

MeSH terms

  • Acquired Immunodeficiency Syndrome / complications
  • Acquired Immunodeficiency Syndrome / drug therapy
  • Acquired Immunodeficiency Syndrome / genetics
  • Acquired Immunodeficiency Syndrome / immunology
  • Acquired Immunodeficiency Syndrome / metabolism
  • Anti-HIV Agents / therapeutic use
  • Biomarkers
  • Disease Progression
  • Female
  • Gene Expression Profiling
  • HIV Infections / drug therapy
  • HIV Infections / genetics
  • HIV Infections / immunology
  • HIV Infections / metabolism*
  • HIV-1
  • Herpesvirus 8, Human
  • Humans
  • Immunophenotyping
  • Leukocytes, Mononuclear / metabolism*
  • Lipopolysaccharide Receptors / analysis*
  • Macrophages / metabolism*
  • Male
  • Membrane Glycoproteins / biosynthesis*
  • Membrane Glycoproteins / genetics
  • RNA, Messenger / biosynthesis
  • RNA, Messenger / genetics
  • Receptors, Immunologic / biosynthesis*
  • Receptors, Immunologic / genetics
  • Sarcoma, Kaposi / etiology
  • Sarcoma, Kaposi / genetics
  • Sarcoma, Kaposi / immunology
  • Sarcoma, Kaposi / metabolism*
  • Sialic Acid Binding Ig-like Lectin 1
  • Up-Regulation
  • Viral Load


  • Anti-HIV Agents
  • Biomarkers
  • Lipopolysaccharide Receptors
  • Membrane Glycoproteins
  • RNA, Messenger
  • Receptors, Immunologic
  • SIGLEC1 protein, human
  • Sialic Acid Binding Ig-like Lectin 1