Triggering Receptor Expressed on Myeloid cells-1 in Pleural Effusions: A Marker of Inflammatory Disease

Respir Med. 2007 May;101(5):903-9. doi: 10.1016/j.rmed.2006.09.021. Epub 2006 Nov 13.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Biomarkers / metabolism
  • CD11b Antigen / metabolism
  • Cross-Sectional Studies
  • Diagnosis, Differential
  • Exudates and Transudates / metabolism
  • Female
  • Flow Cytometry
  • Humans
  • Male
  • Membrane Glycoproteins / metabolism*
  • Middle Aged
  • Myeloid Cells / pathology
  • Pleural Effusion / etiology*
  • Pleural Effusion / pathology
  • Pleural Effusion, Malignant / diagnosis
  • Pleural Effusion, Malignant / pathology
  • Pneumonia, Bacterial / complications
  • Pneumonia, Bacterial / diagnosis
  • Receptors, Immunologic / metabolism*
  • Solubility
  • Triggering Receptor Expressed on Myeloid Cells-1
  • Tuberculosis, Pleural / complications
  • Tuberculosis, Pleural / diagnosis
  • Tuberculosis, Pleural / pathology


  • Biomarkers
  • CD11b Antigen
  • Membrane Glycoproteins
  • Receptors, Immunologic
  • TREM1 protein, human
  • Triggering Receptor Expressed on Myeloid Cells-1