When compared to healthy controls, the patients with COPD had significantly higher levels of CAF22 (57.2% higher, p < 0.05) and lower levels of BDNF and GDNF (30.3 and 15.5% lower, respectively, p < 0.05) at the time of diagnosis (Figure 3a–c). This evidence concerns the gene BDNF and chronic obstructive pulmonary disease.