title: Triggering receptor expressed on myeloid cells-1 in pleural effusions: a marker of inflammatory disease.
abstract: BACKGROUND
  Triggering receptor expressed on myeloid cells (TREM)-1 is a recently described molecule that plays an important role in myeloid cell-activated inflammatory responses. The aim of this study was to investigate the expression of TREM-1 in pleural effusions of various causes.
  
  
  METHODS
  For this cross-sectional, observational study conducted between February and August 2005 in Taiwan, 74 patients with pleural effusions of varying etiology were investigated. Soluble TREM-1 (sTREM-1) was measured in pleural fluid samples, and cells in the fluid were assessed for surface expression of TREM-1.
  
  
  RESULTS
  Concentrations of sTREM-1 were significantly higher in infectious and neoplastic pleural effusions (189.1+/-36.7 and 69.9+/-22.8ng/ml, mean+/-sem) than in transudates (10.1+/-5.3ng/ml; P<0.001). Among infectious effusions, the sTREM-1 levels were significantly higher in parapneumonic than in tuberculous effusions (301.8+/-49.8 vs. 38.9+/-17.3ng/ml; P<0.001). TREM-1 was expressed on a portion of the myeloid (CD11b positive) cells in each type of effusion, without significant differences among them (transudative, 34.7%; neoplastic, 36.0%; parapneumonic, 27.7%; tuberculous, 21.2%; P=0.861). Non-myeloid cells expressed very little TREM-1 (transudative, 6.3%; neoplastic, 0.5%; parapneumonic, 1.0%; tuberculous, 0.7%; P=0.192).
  
  
  CONCLUSIONS
  sTREM-1 expression in pleural fluids is highest in parapneumonic and neoplastic effusions but low in transudates. In infectious effusions, a high concentration of sTREM-1 may exclude tuberculous pleurisy.
authors.affiliation: Division of Chest Medicine, Department of Internal Medicine, Mackay Memorial Taitung Branch Hospital, Taitung, Taiwan.
authors.forename: Ching-Lung
authors.initials: CL
authors.lastname: Liu
authors.forename: Wen-Yeh
authors.initials: WY
authors.lastname: Hsieh
authors.forename: Chien-Liang
authors.initials: CL
authors.lastname: Wu
authors.forename: Hsu-Tah
authors.initials: HT
authors.lastname: Kuo
authors.forename: Yen-Ta
authors.initials: YT
authors.lastname: Lu
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000378:metabolism; D039481:CD11b Antigen / Q000378:metabolism; D003430:Cross-Sectional Studies; D003937:Diagnosis, Differential; D005122:Exudates and Transudates / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008875:Middle Aged; D022423:Myeloid Cells / Q000473:pathology; D010996:Pleural Effusion / Q000209:etiology* / Q000473:pathology; D016066:Pleural Effusion, Malignant / Q000175:diagnosis / Q000473:pathology; D018410:Pneumonia, Bacterial / Q000150:complications / Q000175:diagnosis; D011971:Receptors, Immunologic / Q000378:metabolism*; D012995:Solubility; D000073871:Triggering Receptor Expressed on Myeloid Cells-1; D014396:Tuberculosis, Pleural / Q000150:complications / Q000175:diagnosis / Q000473:pathology
chemical_list: D015415:Biomarkers; D039481:CD11b Antigen; D008562:Membrane Glycoproteins; D011971:Receptors, Immunologic; C408842:TREM1 protein, human; D000073871:Triggering Receptor Expressed on Myeloid Cells-1