Despite large variability within each group (note the logarithmic scale on Figure 1) and relatively small absolute differences between groups (Table 1), on average the WBC count and levels of CRP, IL-6 and fibrinogen were significantly higher in COPD patients than in smokers with normal lung function and nonsmokers, whereas IL-8 and TNFα values were higher in smokers without COPD (Figure 1, Table 1). Here, CRP is linked to chronic obstructive pulmonary disease.