Role of systemic inflammation mediated by IL-6 and TNF-alpha cytokines in chronic obstructive pulmonary disease and its progression: A three year follow up study

Background: Many of the systemic manifestations of COPD are mediated through increased levels of inflammatory proteins. Past studies have shown that mean value of Interleukin-6 (IL-6) and TNF Alpha do not change significantly in COPD patients over a one-year period. However, longer period follow-up studies are still lacking. We assessed the long term repeatability of IL-6 and TNF-alpha in COPD patients to test the association between these inflammatory mediators, smoking status and disease progression. Methods: A cross sectional analysis comparing 250 COPD patients, 50 current smokers and 30 never smoker controls was performed. Assessments included medical history, BMI, spirometry, 6MWT, BODE index at baseline and after three years. Serum & plasma concentrations of IL-6 and plasma TNF Alpha was measured by high sensitivity ELISA. Results: Serum TNF Alpha and IL-6 were higher in COPD patients (4.2; 0.9 pg/ml) and in current smokers (3.8;0.3pg/ml) compared to non smoker controls (2.9; 0.27 pg/ml) at the baseline. TNF alpha showed moderate repeatability and increase over 3 year period and multiple regression analysis with or without adjustments models showed that TNF alpha levels were associated with smoking status (p Conclusions: Systemic inflammatory process mediated by IL-6 seems to be persistent, progressive and associated with worse physical performance in COPD Patients and smoking may influence TNF- Alpha mediated systemic inflammation.