Chronic airflow limitation assessed by FEV1/FVC and % FEV1 predicted is positively associated with BMI and malnutrition in a large number of COPD patients [26], and plasma cathepsin S levels are reduced on surgery-related weight loss, linking to reduction of cathepsin S expression in subcutaneous adipose tissue mass [21]. Here, CTSS is linked to chronic obstructive pulmonary disease.