IL6 and chronic obstructive pulmonary disease: The COPD pathogenesis is highly associated with the local appearances and distribution of IL-1 (IL-1α, IL-1β) and IL-33 signalling pathways [16], IL-6, IL-8 [17], IL-4, IL-7 [18,19,20], IL-10 [21], IL-12 [22], and TNF-α [23] that determine chronic, ongoing, and continuous inflammation [24].