SFTPB and chronic obstructive pulmonary disease: The median concentrations of pro-SFTPB and CCSP-16 in BAL fluid were lower in subjects with COPD compared to those without COPD (271.86 ng/ml vs. 921.55 ng/ml, p = 0.059; 27.62 ng/ml vs. 75.87 ng/ml, p = 0.040).