Figure 2

A. The numbers of alveolar macrophages were increased in smokers and in stage I-II COPD compared to non-smokers and stage IV COPD (p = 0.009). The post-hoc comparison was significant at 0.05 level between non-smokers and stage I-II COPD (*). B. The mean percentage of GSTO1-1 positive macrophages was higher in severe stage IV COPD compared to smokers or COPD stage I-II (p = 0.004). The difference between non-smokers and other groups was not statistically significant. The post-hoc comparison was significant at 0.05 level between stage IV COPD and smokers and between stage IV and stage I-II COPD (*).