Serum and bronchoalveolar fluid KL-6 levels in patients with pulmonary alveolar proteinosis

Am J Respir Crit Care Med. 1998 Oct;158(4):1294-8. doi: 10.1164/ajrccm.158.4.9712003.


Pulmonary alveolar proteinosis (PAP) is a disease characterized by the filling of alveolar spaces with periodic acid-Schiff-positive proteinaceous material and by the hypertrophy of type II pneumocytes in the alveolar interstitium. To examine if KL-6, a mucinlike glycoprotein, is useful for the diagnosis of PAP and the estimation of its activity, serum KL-6 levels in patients with PAP were measured by an enzyme-linked immunosorbent assay and compared with those of patients with other lung diseases. Furthermore, to estimate the origin of KL-6 in some patients, measurements of KL-6 levels in bronchoalveolar lavage (BAL) fluid and immunohistochemical staining of the lung tissues with a monoclonal antibody to KL-6 antigen were performed. Serum KL-6 levels in patients with PAP were extremely high and were significantly higher than those in patients with interstitial lung diseases in which elevation of serum KL-6 has been recognized. BAL-fluid KL-6 levels in patients with PAP were higher than serum levels. Both serum and BAL-fluid KL-6 levels in patients with PAP correlated well with the disease activity. Immunohistochemically, positive staining was observed in proliferating type II pneumocytes. These results suggest the usefulness of KL-6 measurement in the diagnosis and estimation of disease activity of PAP.

Publication types

  • Comparative Study

MeSH terms

  • Antibodies, Monoclonal
  • Antigens
  • Antigens, Neoplasm
  • Biomarkers / analysis
  • Biomarkers / blood
  • Bronchoalveolar Lavage Fluid / chemistry*
  • Coloring Agents
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Glycoproteins
  • Humans
  • Hypertrophy
  • Immunohistochemistry
  • Lung / pathology
  • Lung Diseases, Interstitial / blood
  • Lung Diseases, Interstitial / metabolism
  • Male
  • Middle Aged
  • Mucin-1
  • Mucins / analysis*
  • Mucins / blood
  • Peptide Fragments / analysis*
  • Peptide Fragments / blood
  • Periodic Acid-Schiff Reaction
  • Procollagen / analysis*
  • Procollagen / blood
  • Pulmonary Alveolar Proteinosis / blood
  • Pulmonary Alveolar Proteinosis / metabolism*
  • Pulmonary Alveolar Proteinosis / pathology
  • Pulmonary Alveoli / pathology


  • Antibodies, Monoclonal
  • Antigens
  • Antigens, Neoplasm
  • Biomarkers
  • Coloring Agents
  • Glycoproteins
  • MUC1 protein, human
  • Mucin-1
  • Mucins
  • Peptide Fragments
  • Procollagen
  • procollagen Type III-N-terminal peptide