Transcription factor NF-κB, interleukin-1β, and interleukin-8 expression and its association with tobacco smoking and severity in chronic obstructive pulmonary disease

Background: Chronic obstructive pulmonary disease (COPD) prevalence increases with tobacco smoking, suggesting a relationship between disease severity and an increased rate of systemic symptoms with smoking. Aim: To evaluate IL-1 beta, IL-8 and NF-kappa B expression in COPD patients with smoking and non-smoking habits and determine their levels with disease severity compared to respective healthy controls. Methods: One hundred seventy-six subjects (88 COPD cases and 88 healthy controls) details demographic smoking, and disease severity enrolled in the study. Interleukin transcript and protein levels were measured by quantitative real-time PCR and enzyme-linked immunosorbent assay (ELISA). Statistical Package for the Social Sciences (SPSS) software version 21.0 was used to analyse the data. Statistical significance was set at p < 0.05. Results: IL-1 beta, IL-8 and NF-kappa B mRNA levels were significantly higher (p < 0.001) in COPD cases than in healthy controls. NF-kappa B increased (1.50-folds) in patients with COPD compared to that in controls. NF-kappa B, IL-1 beta and IL-8 mRNA expression were significantly higher in smokers with COPD than non-smokers (p < 0.0001). With pack-year NF-kappa B, IL-1 beta and IL-8 transcript levels increased and showed a significant positive correlation (p < 0.0001). Moreover, with increasing pack-years, COPD severity was also significantly elevated (p < 0.0001). The Pearson correlation showed a significant positive, strong correlation with the severity of the patients. The intercorrelation between IL-1 beta and IL-8 and NF-kappa B showed a significant weak positive correlation between IL-1 beta and IL-8 (r = 0.30, p = 0.001); however, NF-kappa B showed no association (0.22, p = 0.04) either with IL-1 beta or IL-8. Conclusion: IL-1 beta and IL-8 expression correlated with COPD severity, which worsened with pack-years tobacco smoking.