title: Perforin and Fas pathways of cytotoxic T-cells in histiocytic necrotizing lymphadenitis.
abstract: OBJECTIVE
  Cell death can be divided into necrosis and apoptosis. In histiocytic necrotizing lymphadenitis (HNL), apoptosis is the main form of cell death. Two molecular mechanisms of T-cell-mediated cytotoxicity, one perforin-based and the other Fas-based, have been demonstrated, and both systems induce apoptosis of the target cells. This study was designed to investigate the Fas and perforin pathways in HNL.
  
  
  RESULTS
  Twelve cases of HNL were analysed using immunohistochemical staining. The Fas and/or FasL-positive cells, including lymphocytes and histiocytes, were frequently encountered in the necrotizing lesions, however, they were rare in the nonpathological regions. The perforin and/or granzyme-positive cells were also confined in the necrotizing lesions. In double staining, CD8-positive lymphocytes occasionally expressed Fas and/or FasL, and histiocytes also expressed FasL and/or Fas. However, CD4-positive lymphocytes rarely expressed FasL and/or Fas. In a flow cytometric analysis, most of the cytotoxic T-cells, which were recognized by cytolytic granules of TIA-1 and considered to be CD8-positive lymphocytes, expressed FasL and Fas. The perforin-positive lymphocytes also expressed FasL and Fas.
  
  
  CONCLUSIONS
  In our previous study, the apoptotic cells were T-cells, especially CD8-positive cells rather than CD4-positive cells. Based on these findings, in Fas and perforin pathways, the CD8-positive cells were considered to be effector and target cells, while histiocytes could possibly be enhancers. As a result, both pathways seemed to induce an abundance of apoptosis and thus induce necrotizing lesions.
authors.affiliation: Department of Pathology, School of Medicine, Fukuoka University, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Ohshima
authors.forename: K
authors.initials: K
authors.lastname: Shimazaki
authors.forename: T
authors.initials: T
authors.lastname: Kume
authors.forename: J
authors.initials: J
authors.lastname: Suzumiya
authors.forename: M
authors.initials: M
authors.lastname: Kanda
authors.forename: M
authors.initials: M
authors.lastname: Kikuchi
mesh_terms: D000293:Adolescent; D000328:Adult; D015703:Antigens, CD / Q000032:analysis; D017209:Apoptosis; D002648:Child; D053222:Fas Ligand Protein; D005260:Female; D005434:Flow Cytometry; D020042:Histiocytic Necrotizing Lymphadenitis / Q000276:immunology*; D006801:Humans; D007124:Immunoenzyme Techniques; D017403:In Situ Hybridization; D008297:Male; D008562:Membrane Glycoproteins / Q000032:analysis*; D054353:Perforin; D052899:Pore Forming Cytotoxic Proteins; D013602:T-Lymphocytes, Cytotoxic / Q000737:chemistry* / Q000166:cytology; D019014:fas Receptor / Q000032:analysis*
chemical_list: D015703:Antigens, CD; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D008562:Membrane Glycoproteins; D052899:Pore Forming Cytotoxic Proteins; D019014:fas Receptor; D054353:Perforin