Assessment of airway neutrophils by sputum colour: correlation with airways inflammation.
BACKGROUND
Airway inflammation, with recruitment of neutrophils to the airway lumen, results in purulent secretions and a variety of potential adverse consequences for patients with chronic bronchitis and bronchiectasis. We hypothesised that gradations of sputum colour would correlate directly with the myeloperoxidase content of sputum and with various other indicators of the activity and consequences of bronchial diseases.


METHODS
To test this hypothesis, we quantified sputum colour by reference to a sensitive nine point colour chart and correlated this assessment with indices of a number of inflammatory mediators in sputum.


RESULTS
The results indicate that standardised visual measurements of sputum colour correlated strongly with myeloperoxidase, interleukin 8, leucocyte elastase (both activity and total quantity), sputum volume, protein leak, and secretory leucocyte proteinase inhibitor (p<0.001 for all). In addition, there was a strong direct correlation between leucocyte elastase and both myeloperoxidase (p<0.003) and sputum volume (p<0.001), but a strong negative correlation with secretory leucocyte proteinase inhibitor (p<0.001).


CONCLUSIONS
These results indicate that sputum colour graded visually relates to the activity of the underlying markers of bronchial inflammation. The results of this simple visual analysis of sputum provides guidance concerning underlying inflammation and its damaging potential. It also provides a useful scientific tool for improving the monitoring of chronic airways diseases and response to treatment.
Stockley
R A
RA
Department of Medicine, Queen Elizabeth Hospital, Edgbaston, Birmingham B15 2TH, UK. r.a.stockley@bham.ac.uk
Bayley
D
D
Hill
S L
SL
Hill
A T
AT
Crooks
S
S
Campbell
E J
EJ
D015415:Biomarkers / Q000032:analysis; D001987:Bronchiectasis / Q000175:diagnosis* / Q000378:metabolism; D001991:Bronchitis / Q000175:diagnosis* / Q000378:metabolism; D002401:Cathepsin B / Q000032:analysis; D003116:Color; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D016209:Interleukin-8 / Q000032:analysis; D019272:Leukocyte Elastase / Q000032:analysis; D007975:Leukotriene B4 / Q000032:analysis; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000737:chemistry*; D010196:Pancreatic Elastase / Q000032:analysis; D009195:Peroxidase / Q000032:analysis; D053491:Proteinase Inhibitory Proteins, Secretory; D011506:Proteins / Q000032:analysis; D013183:Sputum / Q000737:chemistry*; D000515:alpha 1-Antitrypsin / Q000032:analysis
D015415:Biomarkers; D016209:Interleukin-8; D053491:Proteinase Inhibitory Proteins, Secretory; D011506:Proteins; D000515:alpha 1-Antitrypsin; D007975:Leukotriene B4; D009195:Peroxidase; D010196:Pancreatic Elastase; D019272:Leukocyte Elastase; D002401:Cathepsin B