KL-6, a mucin-like glycoprotein, in bronchoalveolar lavage fluid from patients with interstitial lung disease.
KL-6, a mucin-like high-molecular-weight glycoprotein, is a serum marker indicating the disease activity of pneumonitis, such as idiopathic pulmonary fibrosis (IPF), hypersensitivity pneumonitis, and sarcoidosis. Immunohistochemical studies have shown that KL-6 is strongly expressed on Type 2 pneumocytes and also exists on epithelial cells in other organs. It has not been clarified whether the increased levels of KL-6 in sera from patients with pneumonitis are derived from the lower respiratory tract. In this study, KL-6 levels were evaluated in bronchoalveolar lavage fluid (BALF) samples from 9 healthy control subjects and 32 patients with interstitial pneumonitis. An abnormally high level of KL-6 in BALF was observed in 70% (7 of 10) of patients with IPF, 64% (9 of 14) of patients with sarcoidosis, and 100% (8 of 8) of patients with hypersensitivity pneumonitis but in none of the healthy control subjects. KL-6 levels in BALF were significantly correlated with numbers of total cells (p < 0.001), lymphocytes (p < 0.001), and neutrophils (p < 0.05) and with concentrations of albumin (p < 0.001) and total protein (p < 0.001) in BALF and, further, with serum KL-6 levels (p < 0.01). These results indicate that increased levels of serum KL-6 in patients with pneumonitis reflect the production levels of KL-6 derived from damaged or regenerating Type 2 pneumocytes in the lower respiratory tract.
Kohno
N
N
Second Department of Internal Medicine, Ehime University School of Medicine, Japan.
Awaya
Y
Y
Oyama
T
T
Yamakido
M
M
Akiyama
M
M
Inoue
Y
Y
Yokoyama
A
A
Hamada
H
H
Fujioka
S
S
Hiwada
K
K
D000542:Alveolitis, Extrinsic Allergic / Q000453:epidemiology / Q000378:metabolism; D000941:Antigens / Q000032:analysis*; D000951:Antigens, Neoplasm; D015415:Biomarkers / Q000032:analysis; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry* / Q000166:cytology; D002452:Cell Count; D016009:Chi-Square Distribution; D006023:Glycoproteins / Q000032:analysis*; D006801:Humans; D008171:Lung Diseases / Q000453:epidemiology / Q000378:metabolism; D018396:Mucin-1; D009077:Mucins; D011336:Probability; D011658:Pulmonary Fibrosis / Q000453:epidemiology / Q000378:metabolism*; D012507:Sarcoidosis / Q000453:epidemiology / Q000378:metabolism
D000941:Antigens; D000951:Antigens, Neoplasm; D015415:Biomarkers; D006023:Glycoproteins; C060192:MUC1 protein, human; D018396:Mucin-1; D009077:Mucins