Expression of CCR3 on sputum macrophages in asthma, COPD and healthy subjects

Abstract

Macrophages are important immune cells involved in airway inflammation in obstructive lung diseases. Depending on local milieu macrophages can undergo distinct polarization with different functional capacities. Expression of CCR3 receptor on macrophages is associated with Th2 response but its role in Th1 response remains unclear.

The aim was to evaluate the expression of CCR3 receptor on M1- and M2-like sputum macrophages in obstructive lung diseases and healthy controls.

Study involved 19 asthmatics, 21 COPD patients, 9 healthy non-smokers, and 9 healthy smokers who underwent sputum induction. In immunofluorescence staining, CCR3 expression was assessed on CD80/CD86 positive (M1) and CD163/CD206 positive (M2) macrophages in sputum smears. Non-smokers and smokers were comparators for asthma and COPD, respectively. We noted increased number of M1+CCR3+ and M2+CCR3+ sputum macrophages in asthma vs non-smoking controls, in smoking control vs non-smoking control and in smoking control vs COPD.

Conclusion: Our study demonstrated an enhanced expression of CCR3 on M1 and M2 macrophages in asthma, COPD patients and healthy smokers. It suggests that expression of CCR3 on macrophages may be associated not only with Th2 response but also with Th1 response and be influenced by cigarette smoke exposure.