Increased chemokinetic and chemotactic responses of eosinophils in asthmatic patients

Abstract

The aim of the present study was to investigate the migratory responses of eosinophil and neutrophil granulocytes from asthmatic patients compared with granulocytes from healthy individuals. Twenty-three patients with unstable and severe asthma and blood eosinophilia (greater than 400 x 10(6) cells/l) were selected for the study. Eosinophil and neutrophil chemotactic and chemokinetic responses were tested twice, at the beginning and end of a 5 week treatment period. Lung function was followed by daily measurements of PEF. The eosinophils of the asthmatics demonstrated increased chemokinetic responses to albumin, autologous serum, and normal human serum (NHS), and an increased chemotactic response to NHS at the beginning of the treatment period compared with eosinophils from the references. At the end of the period the eosinophil chemokinetic responses to albumin, autologous serum and NHS were still increased and so was the chemotactic response to zymosan-activated serum (ZAS). The neutrophil migratory responses were not increased compared with those of the references, except for the chemokinetic response to autologous serum, which was increased both at the beginning and end of the treatment period. Patients in whom the eosinophil migratory responses, to most of the agents used, decreased over the treatment period, demonstrated a significantly greater improvement of their lung function at the end of the period compared with patients in whom the eosinophil migratory responses increased. However, no direct relationship between eosinophil migratory responses and lung function of the patients was found. In conclusion, the present investigation demonstrated increased migratory responses of eosinophils from asthmatic patients. This enhanced responsiveness is proposed to be due to priming of the eosinophils in vivo, and might be one mechanism behind the selective recruitment of eosinophils to the lungs of asthmatics.