title: Expression of interleukin-16 by tumor-associated macrophages/activated microglia in high-grade astrocytic brain tumors.
abstract: BACKGROUND
  Macrophages/microglial cells are considered as immune cells in the central nervous system. Interleukin (IL)-16 is a proinflammatory cytokine produced by activated monocytic cells.
  
  
  METHODS
  Expression of IL-16 was analyzed by immunohistochemistry in human astrocytic brain tumors and the rat C6 glioblastoma tumor model. IL-16 was detected in both human astrocytic brain tumors and rat C6 glioma.
  
  
  RESULTS
  Compared with human control brains, a significant increase in the percentages of parenchymal IL-16+ macrophages/microglia was observed already in grade II astrocytomas, indicating that IL-16+ immunostaining could be a descriptor of a macrophage/microglia subset in astrocytic brain tumors. A further increase was observed at the transition from grade II to III astrocytomas. This increase in IL-16 immunoreactivity correlated with WHO grades of human astrocytic brain tumors.
  
  
  CONCLUSIONS
  Therefore, IL-16 might be a so far unknown factor in the regulation of the local inflammatory milieu of human and experimental astrocytomas.
authors.affiliation: Institute of Brain Research, University of Tuebingen, Medical School, Tuebingen, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Liebrich
authors.forename: Liang-Hao
authors.initials: LH
authors.lastname: Guo
authors.forename: Hermann J
authors.initials: HJ
authors.lastname: Schluesener
authors.forename: Jan M
authors.initials: JM
authors.lastname: Schwab
authors.forename: Klaus
authors.initials: K
authors.lastname: Dietz
authors.forename: Bernd E
authors.initials: BE
authors.lastname: Will
authors.forename: Richard
authors.initials: R
authors.lastname: Meyermann
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D001254:Astrocytoma / Q000276:immunology* / Q000378:metabolism; D001932:Brain Neoplasms / Q000276:immunology* / Q000378:metabolism; D045744:Cell Line, Tumor; D005260:Female; D005909:Glioblastoma / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism; D019410:Interleukin-16 / Q000096:biosynthesis*; D008264:Macrophages / Q000276:immunology* / Q000473:pathology; D008297:Male; D017628:Microglia / Q000276:immunology* / Q000378:metabolism; D008875:Middle Aged; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D018836:Inflammation Mediators; D019410:Interleukin-16