Surfactant protein A predicts survival in idiopathic pulmonary fibrosis

Am J Respir Crit Care Med. 1995 Aug;152(2):751-9. doi: 10.1164/ajrccm.152.2.7633738.


The purpose of this study was to determine if the measurement of surfactant protein A (SP-A) in bronchoalveolar lavage (BAL) fluid predicts survival in patients with idiopathic pulmonary fibrosis (IPF). We performed BAL on 44 patients with IPF and 33 healthy volunteers. SP-A and total phospholipid (PL) were measured in the surfactant pelleted by centrifugation and expressed as a ratio to account for differences in the alveolar surface area sampled. The mean SP-A/PL was lower in patients with IPF than in healthy volunteers (31.8 +/- 2.8 versus 63.9 +/- 6.4 micrograms/mumol, p = 0.006) and in patients who died within 2 yr than in those who survived (23.4 +/- 2.6 versus 37.5 +/- 4.2 micrograms/mumol, p = 0.015). Using Cox's proportional hazard model, we found that SP-A/PL modeled continuously was associated with survival time (p = 0.002). The 5-yr survival of patients with SP-A/PL above the median level for all patients with IPF (29.7 micrograms/mumol) was more than twice that of patients below the median (68 versus 30%, p = 0.007). SP-A/PL improved upon prediction of survival modeled by most routine physiologic variables with the exception of percent predicted TLC or the multifarious clinical-radiographic-physiologic score (CRP). Cellular analysis of lavage did not predict survival in this cohort of patients. We conclude that SP-A/PL is a biochemical marker in lavage that predicts survival in patients with IPF.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Aged
  • Biomarkers / analysis
  • Bronchoalveolar Lavage Fluid / chemistry
  • Bronchoalveolar Lavage Fluid / cytology
  • Case-Control Studies
  • Cause of Death
  • Cohort Studies
  • Female
  • Follow-Up Studies
  • Forced Expiratory Volume
  • Forecasting
  • Glycoproteins / analysis*
  • Humans
  • Male
  • Middle Aged
  • Phospholipids / analysis
  • Proportional Hazards Models
  • Proteolipids / analysis*
  • Pulmonary Fibrosis / metabolism*
  • Pulmonary Fibrosis / physiopathology
  • Pulmonary Surfactant-Associated Protein A
  • Pulmonary Surfactant-Associated Proteins
  • Pulmonary Surfactants / analysis*
  • Smoking / metabolism
  • Survival Rate
  • Total Lung Capacity
  • Vital Capacity


  • Biomarkers
  • Glycoproteins
  • Phospholipids
  • Proteolipids
  • Pulmonary Surfactant-Associated Protein A
  • Pulmonary Surfactant-Associated Proteins
  • Pulmonary Surfactants