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a National Heart and
Lung Institute (NHLI), Royal Brompton Clinical Studies Unit, Royal
Brompton Hospital, London SW3 6HP, UK, b Electron Microscopy Unit,
Royal Brompton Hospital, London SW3 6HP, UK, c Bayer Diagnostics, Tarrytown, New York
10591-5097, USA, d Department
of Haematology, Royal Brompton Hospital, London SW3 6HP, UK, e Department of Thoracic
Medicine, NHLI, Imperial College School of Medicine, London SW3 6LY,
UK
Correspondence to: Dr M J Leckie email: m.leckie{at}ic.ac.uk
Received 5 July 1999; Returned to authors 27 October 1999; Revised version received 14 January 2000; Accepted for publication 10 February 2000
BACKGROUND
Asthma has
been associated with eosinophil activation, measured in serum, sputum,
bronchoalveolar lavage (BAL) fluid, and urine. A whole blood automated
method was developed to assess eosinophil and neutrophil activity in
terms of peroxidase content and cell morphology using the Bayer
haematology analyser. The method was applied to an in vitro stimulation
model when fMLP was added to whole blood and the samples were then
analysed for changes in granularity and shape. In addition, cells
stimulated with interleukin (IL)-8 were examined by electron microscopy.
METHODS
A cross
sectional analysis was performed on venous blood from non-atopic,
non-asthmatic normal subjects (n = 37), mild (n = 46) and symptomatic
(n = 22) asthmatic patients on inhaled
2 agonist only,
and more severe asthmatic patients (n = 17) on inhaled and oral
corticosteroid therapy. Samples were analysed by the haematology
analyser and peroxidase leucograms gated using the WinMDI software program.
RESULTS
There were
significant differences in the amount of light scatter by the
neutrophil populations in the symptomatic (p = 0.007) and severe
asthmatic (p = 0.0001) groups compared with the control group. However,
abnormalities in eosinophil populations were not observed. In vitro
activation of whole blood with fMLP caused similar changes in
neutrophil light scatter, suggesting that neutrophil activation is
present in peripheral blood of symptomatic asthmatic patients. IL-8
caused a change in shape of the neutrophils seen using transmission
electron microscopy.
CONCLUSIONS
Evidence
of neutrophil activation can be seen in whole blood from patients with
asthma using a novel automated method. This may potentially be applied
to other inflammatory diseases.
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