KL-6 and surfactant proteins A and D in serum and bronchoalveolar lavage fluid in patients with acute eosinophilic pneumonia

Intern Med. 2005 Aug;44(8):811-7. doi: 10.2169/internalmedicine.44.811.


Object: The serum levels of KL-6, surfactant protein A (SP-A), and SP-D are useful biomarkers and prognostic factors for the activity of interstitial pneumonias. The aim of this study was to determine the clinical roles of the levels of KL-6, SP-A, and SP-D in the serum and bronchoalveolar lavage fluid (BALF) of patients with acute eosinophilic pneumonia (AEP).

Materials and methods: We researched 5 cases of AEP. The levels of KL-6, SP-A, and SP-D in the sera and BALF of those patients were measured by enzyme-linked immunosorbent assay.

Results: KL-6 levels in BALF did not differ between AEP patients and the healthy control group, while SP-A and SP-D levels in BALF were significantly higher in the AEP patients than in the healthy control group. In sera, AEP patients had significantly higher than normal levels of SP-A and SP-D, but not of KL-6. Only in sera there was a positive correlation between SP-A and SP-D, but no apparent correlations in BALF and also between KL-6 and the others. Furthermore, the BALF levels of SP-D, but not of SP-A or KL-6, statistically correlated with the concentration of albumin in BALF. After clinical improvement, the elevated levels of serum SP-A or SP-D in AEP patients decreased until normal levels were reached within 2 months.

Conclusion: These results suggest that the serum or BALF levels of SP-D appear to be more sensitive than those of SP-A or KL-6 at reflecting the inflammatory response in AEP lungs.

MeSH terms

  • Acute Disease
  • Adolescent
  • Adult
  • Antigens / blood*
  • Antigens / metabolism*
  • Antigens, Neoplasm
  • Biomarkers / analysis
  • Biomarkers / blood
  • Bronchoalveolar Lavage Fluid / chemistry*
  • Case-Control Studies
  • Female
  • Glycoproteins / blood*
  • Glycoproteins / metabolism*
  • Humans
  • Male
  • Mucin-1
  • Mucins / blood*
  • Mucins / metabolism*
  • Prognosis
  • Pulmonary Eosinophilia / blood*
  • Pulmonary Eosinophilia / metabolism*
  • Pulmonary Surfactant-Associated Protein A / blood*
  • Pulmonary Surfactant-Associated Protein A / metabolism*
  • Pulmonary Surfactant-Associated Protein D / blood*
  • Pulmonary Surfactant-Associated Protein D / metabolism*
  • Retrospective Studies


  • Antigens
  • Antigens, Neoplasm
  • Biomarkers
  • Glycoproteins
  • MUC1 protein, human
  • Mucin-1
  • Mucins
  • Pulmonary Surfactant-Associated Protein A
  • Pulmonary Surfactant-Associated Protein D