YKL-40, a marker of simian immunodeficiency virus encephalitis, modulates the biological activity of basic fibroblast growth factor

Am J Pathol. 2008 Jul;173(1):130-43. doi: 10.2353/ajpath.2008.080045. Epub 2008 Jun 13.


Human immunodeficiency virus encephalitis causes dementia in acquired immune deficiency syndrome patients. Using proteomic analysis of postmortem cerebrospinal fluid (CSF) and brain tissue from the simian immunodeficiency virus primate model, we demonstrate here a specific increase in YKL-40 that was tightly associated with lentiviral encephalitis. Longitudinal analysis of CSF from simian immunodeficiency virus-infected pigtailed macaques showed an increase in YKL-40 concentration 2 to 8 weeks before death from encephalitis. This increase in YKL-40 correlated with an increase in CSF viral load; it may therefore represent a biomarker for the development of encephalitis. Analysis of banked human CSF from human immunodeficiency virus-infected patients also demonstrated a correlation between YKL-40 concentration and CSF viral load. In vitro studies demonstrated increased YKL-40 expression and secretion by macrophages and microglia but not by neurons or astrocytes. We found that YKL40 displaced extracellular matrix-bound basic fibroblast growth factor (bFGF) as well as inhibited the mitogenic activity of both fibroblast growth factor receptor 1-expressing BaF3 cells and bFGF-induced axonal branching in hippocampal cultures. Taken together, these findings demonstrate that during lentiviral encephalitis, YKL-40 may interfere with the biological activity of bFGF and potentially of other heparin-binding growth factors and chemokines that can affect neuronal function or survival.

Publication types

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

MeSH terms

  • Adipokines
  • Animals
  • Biomarkers / cerebrospinal fluid*
  • Blotting, Western
  • Chitinase-3-Like Protein 1
  • Encephalitis, Viral / cerebrospinal fluid*
  • Encephalitis, Viral / metabolism
  • Enzyme-Linked Immunosorbent Assay
  • Extracellular Matrix
  • Fibroblast Growth Factor 2 / metabolism*
  • Glycoproteins
  • HIV Infections / complications
  • HIV Infections / metabolism
  • Humans
  • Immunohistochemistry
  • In Situ Hybridization
  • Lectins
  • Macaca nemestrina
  • Mass Spectrometry
  • Microglia / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Simian Acquired Immunodeficiency Syndrome / cerebrospinal fluid*
  • Simian Acquired Immunodeficiency Syndrome / complications
  • Simian Acquired Immunodeficiency Syndrome / metabolism
  • Simian Immunodeficiency Virus
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization


  • Adipokines
  • Biomarkers
  • CHI3L1 protein, human
  • Chitinase-3-Like Protein 1
  • Glycoproteins
  • Lectins
  • Fibroblast Growth Factor 2