Retinoic acid receptor alpha: One of plasma biomarkers associated with exacerbation of chronic obstructive pulmonary disease.

Background: Exacerbation of COPD is a major risk factor for bad prognosis of COPD. A few plasma proteins have been discovered to associate with hospital admission due to exacerbation up to date. We tried to find new plasma biomarkers to predict the exacerbation of COPD.