Objective: To explore non-invasive and specific markers for airway inflammation.
Methods: RT-PCR methods were used to measure GM-CSF mRNA expression in airway mucosa and induced sputum from asthmatic patients. The correlation was analyzed between expression of GM-CSF mRNA and eosinophils or other inflammatory cells.
Results: (1) The numbers of eosinophils and EG2 positive cells were (17.9 +/- 7.0) x 10(2) per mm2, and (8.9 +/- 3.0) x 10(2) per mm2 in the asthmatic group, significantly higher than those in the non-asthmatic control which were (1.9 +/- 1.0) x 10(2) per mm2, and (0.8 +/- 0.2) x 10(2) per mm2, respectively (P < 0.05). (2) The expression of GM-CSF mRNA was (1.4 +/- 0.6) in the asthmatic group, significantly higher than that in the control group (0.3 +/- 0.3) (P < 0.05), and GM-CSF mRNA expression was correlated with the numbers of EG2 positive cell (r = 0.73 and P < 0.05). (3) The percentage of eosinophils in induced sputum from asthmatic patients was (0.334 +/- 0.067), which was significantly higher than that from chronic bronchitis and control (0.021 +/- 0.004), (0.008 +/- 0.003) (P < 0.05). (4) The expression of GM-CSF mRNA in asthmatics was (0.320 +/- 0.054), significantly higher than that in chronic bronchitis and the control group (0.188 +/- 0.024 and 0.058 +/- 0.028) (P < 0.05). The expression of GM-CSF mRNA in patients with chronic bronchitis was also significantly higher than that in the control group (P < 0.05).
Conclusions: The expression of GM-CSF mRNA in induced sputum may be a relatively specific marker for airway inflammation.