CR3 (CD11b/CD18) activation of nasal neutrophils: a measure of upper airway endotoxin exposure

Abstract

Inhaled endotoxin (lipopolysaccharide, LPS) initiates an inflammatory response and leads to the expression of CR3 (CD11b/CD18) receptors on polymorphonuclear leukocytes (PMNs). We determined if PMN activation in nasal lavage fluid (NLF) is a possible biomarker of occupational endotoxin exposure. Seven subjects exposed to endotoxin provided NLF samples that were split into three aliquots (negative control – 1 M nicotinamide; sham; positive control – 11 ηg of exogenous LPS) and PMN activation was measured using a chemiluminometer. Differences in mean PMN activation were apparent, negative control: 548 ± 15.65 RLU 100 μl⁻¹; sham: 11469 ± 2582 RLU 100 μl⁻¹; positive control: 42026 ± 16659 RLU 100 μl (n = 7; p <0.05). This technique shows promise as a diagnostic method for measuring upper airway LPS exposure.

Keywords::

• Chemiluminescence
• CR3
• endotoxin
• lipopolysaccharide
• polymorphonuclear leukocytes

Acknowledgments

The research was funded by a grant from the Ontario Thoracic Society. R. Seth would like to further acknowledge the Institute of Medical Sciences (University of Toronto), St. Michael’s Hospital and the Ontario Thoracic Society for summer research funding.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.