Eotaxin and CCR3 are up-regulated in exacerbations of chronic bronchitis

Background: Eosinophils and T lymphocytes represent constant features in the airways of subjects with exacerbated chronic bronchitis. Eotaxin is the most potent and selective eosinophil chemoattractant which can also attracts lymphocytes. The aim of the study was to evaluate the expression of eotaxin and its receptor, CCR3, in bronchial airways during exacerbation of chronic bronchitis. Methods: By immunohistochemistry we studied eotaxin and CCR3 expression in the lamina propria of 14 subjects with acute exacerbation of chronic bronchitis, 20 asthmatics, and 8 healthy subjects. We determined the cell types expressing the CCR3 receptor by colocalization experiments. We finally studied the relationship between eotaxin and CCR3 and eosinophils and T lymphocytes. Results: The number of eotaxin(+) and CCR3(+) cells was significantly higher in exacerbated chronic bronchitis (P<0.003 and P<0.002) and asthma (P<0.002 and P<0.0001) when compared to healthy subjects. CCR3 was mainly expressed by eosinophils and to a lesser extent by CD4(+) and CD8(+) lymphocytes. In exacerbated chronic bronchitis the number of CCR3(+) cells was strongly correlated to the number of eosinophils (P<0.0002, r=0.85) and to the number of CD4(+) lymphocytes (P<0.05, r=0.57). Conclusion: Our study suggests that eotaxin and CCR3 are up-regulated and could be involved in the eosinophil and CD4(+) lymphocyte recruitment into the airways Which occur during acute exacerbations of chronic bronchitis.