Post mass spectrometry, the results were analysed, and two proteins, namely, reticulocalbin-1, and sideroflexin-4 with localized expression in the lungs and bronchus, previously unexplored in COPD, were found to show consistent differential upregulation in all the exacerbated COPD samples with respect to stable COPD and healthy control. This evidence concerns the gene RCN1 and chronic obstructive pulmonary disease.