Biological or Clinical Significance:
Kerbs von Lungren 6 antigen (KL-6) is a mucinous high-molecular-weight glycoprotein, classified as cluster 9 (MUC1) of lung tumour and differentiation antigens. KL-6 splits off at the cystine bond near the epithelial membrane surface and becomes distributed in pulmonary epithelial lining fluid. This glycoprotein is predominantly expressed on alveolar type II cells in the lung, with expression increasing in proliferating, regenerating or injured type II cells more than normal type II cells. Serum levels of KL-6 are elevated in a variety of interstitial lung diseases that are characterized by alveolar epithelial cell damage. Serum KL-6 concentrations are associated with alveolar epithelial barrier dysfunction, as they have been shown to correlate with indices of alveolar capillary permeability.
Principle of Test Method:
The KL-6 immunoassay is a solid-phase ELISA designed to measure human KL-6.. This assay employs the quantitative sandwich enzyme immunoassay technique.
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Hisata S, Kimura Y, Shibata N, Ono S, Kobayashi T, Chiba S, Ohta H, Nukiwa T, Ebina M. A normal range of KL-6/MUC1 independent of elevated SP-D indicates a better prognosis in the patients with honeycombing on high-resolution computed tomography. Pulmonary Med. 2011; 2011:806014.