IL6 and chronic obstructive pulmonary disease: Similar to cytokine network analysis, the most developed network could be seen in COPD patients where nodes of IL-1β, IL-6, TNFα, CRP, Fbg, eATP and eHsp70 were significantly larger in comparison to both healthy non-smokers (p < 0.001 for all except for CRP whose p value is <0.01) and healthy smokers (p < 0.001 for all except for CRP whose p value is <0.05, and Fbg whose p value is <0.01).