IFIH1 and chronic obstructive pulmonary disease: Interestingly, the cytosolic receptor for viral RNAs MDA5 and the adaptor molecule STING mRNA levels measured in the bronchial biopsies were about 3-fold more abundant in severe/very severe COPD compared to control smokers, confirming a “primed” state of the bronchial mucosa for viral clearance in those patients.