TBK1 and chronic obstructive pulmonary disease: To examine the baseline profile of the STING pathway in COPD human lung fibroblasts, the mRNA and protein expression levels of intermediates in the STING pathway, such as STING, TBK1 and interferon type I (IFN-β), were examined in fibroblasts from healthy non-smokers, healthy smokers, and smoker COPD patients.