Abstract
Introduction: Despite important differences in the pathogenesis, natural history and prognosis, asthma and COPD have similar features, especially when asthma and smoking co-exist. Smoking asthmatics have an increased cytotoxic immune response (Granzymes A & B, Perforin) and oxidative DNA damage (8-OHdG) when compared to non-smoking asthmatics.
Aim: To study the above mentioned molecules in COPD, in comparison with smoking asthma, in order to determine similarities/differences.
Methods: Perforin, Granzyme A, Granzyme B and 8-OHdG levels were detected by ELISA, in induced sputum specimens from 24 COPD patients and 31 smoking asthmatics. Ten healthy non-smokers served as controls.
Results: Perforin, Granzyme A and B protein levels between COPD patients and smoking asthmatics did not differ statistically (p=0.69, p=0.28, p=0.42, respectively). Stratification analysis showed that Perforin was increased in 48% of smoking asthmatics and in 58% of COPD patients, while the percentage of smoking asthmatics with increased Granzyme A and B levels was higher than of COPD patients (Granzyme A: 52% vs. 42%; Granzyme B: 61% vs. 46%). In contrast, 8-OHdG levels were increased in COPD patients versus smoking asthmatics (p<0.001). Statistical analysis revealed a negative correlation between 8-OHdG expression levels and the degree of airway obstruction (FEV1) in both diseases (p<0.001).
Conclusions: Smoking asthma exhibited a similar but not identical pattern of cytotoxic activity with COPD. Additionally, although oxidative DNA damage was also present in smoking asthmatics, it was not as severe as in COPD patients. These results may explain, in part, the similarities and differences among the two diseases.
- Copyright ©ERS 2015
