Automated quantitation of circulating neutrophil and eosinophil activationin asthmatic patients

Background-Asthma has been associated with eosinophil activation, measured in serum, sputum, bronchoalveolar lavage (BAL) fluid, and urine. A whole bl ood automated method was developed to assess eosinophil and neutrophil acti vity in terms of peroxidase content and cell morphology using the Bayer hae matology 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 c hanges in granularity and shape. In addition, cells stimulated with interle ukin (IL)-8 were examined by electron microscopy. Methods-A cross sectional analysis was performed on venous blood from nonat opic, non-asthmatic normal subjects (n = 37), mild (n = 46) and symptomatic (n 22) asthmatic patients on inhaled beta(2) agonist only, and more severe asthmatic patients (n = 17) on inhaled and oral corticosteroid therapy. Sa mples were analysed by the haematology analyser and peroxidase leucograms g ated using the WinMDI software program. Results-There were significant differences in the amount of light scatter b y the neutrophil populations in the symptomatic (p = 0.007) and severe asth matic (p 0.0001) groups compared with the control group. However, abnormali ties in eosinophil populations were not observed. In vitro activation of wh ole blood with fMLP caused similar changes in neutrophil light scatter, sug gesting that neutrophil activation is present in peripheral blood of sympto matic 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 fr om patients with asthma using a novel automated method. This may potentiall y be applied to other inflammatory diseases.