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Toll-like receptor 2 expression is decreased on alveolar macrophages in cigarette smokers and COPD patients

Daniel Droemann1, Torsten Goldmann, Thorsten Tiedje

  • 1Medical Clinic, Research Center Borstel, 23845 Borstel, Germany. ddroemann@fz-borstel.de

Respiratory Research
|July 12, 2005
PubMed
Abstract

Insights

Cigarette smoke alters immune cells in the lungs, reducing their ability to detect pathogens. This may impair defenses in chronic obstructive pulmonary disease (COPD) patients and smokers.

Area of Science:

  • Immunology
  • Pulmonology
  • Cell Biology

Background:

  • Cigarette smoke, including lipopolysaccharide (LPS), activates lung cells, contributing to chronic obstructive pulmonary disease (COPD) pathogenesis.
  • Respiratory infections trigger exacerbations in COPD, involving pathogen recognition by host receptors.
  • Pattern recognition receptors (PRRs), such as Toll-like receptors (TLRs), mediate host-pathogen interactions.

Purpose of the Study:

  • To investigate the expression of Toll-like receptor (TLR) 2, TLR4, and CD14 on alveolar macrophages (AMs) and monocytes.
  • To compare these receptor expressions in patients with COPD, healthy smokers, and healthy non-smokers.

Main Methods:

  • Studied 14 COPD patients, 10 healthy smokers, and 17 non-smokers.
  • Assessed TLR2, TLR4, and CD14 surface molecule expression on AMs and monocytes using flow cytometry (FACS).
  • Utilized in situ hybridization with HOPE-fixative on bronchoalveolar lavage (BAL) cells.

Main Results:

  • Expression of TLR2, TLR4, and CD14 was lower on AMs from all groups compared to autologous monocytes.
  • COPD patients and smokers showed reduced TLR2 expression on AMs.
  • LPS stimulation increased TLR2 mRNA and protein in non-smokers' AMs, but not in smokers' or COPD patients' AMs.

Conclusions:

  • Smoking appears to alter the phenotype of alveolar macrophages.
  • These changes may lead to a diminished cellular response to microbial stimulation.
  • Impaired host defenses in the lower respiratory tract could be associated with these smoke-induced alterations.

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