ST6GAL1 and chronic obstructive pulmonary disease: In this study, our goal was to determine the effects of gain- and loss-of-function of ST6GAL1 on the response of human bronchial epithelial cells (HBECs) to inflammatory stimuli, and identify the clinical relevance for changes in circulating ST6GAL1 in smoking, COPD, and acute exacerbations of COPD (AECOPD).