Use of the the ED046 Kit to Analyze Serum KL-6 in Patients with Pneumonitis

Abstract KL-6 is a mucinous glycoprotein expressed on Type 2 pneumonocytes, and serum levels of KL-6 are reported to be abnormally high in patients with interstitial pneumonia. A new assay kit for serum KL-6 (ED046) was used in the evaluation of patients with pneumonitis. To clarify whether KL-6 is a useful marker of pneumonitis activity, 649 subjects were studied, including 185 healthy controls, 187 patients with 3 types of interstitial lung diseases, and 277 patients with 4 types of non-interstitial lung diseases. The serum KL-6 level was significantly higher in the patients with pneumonitis (1285 +/- 1196 U/ml) than in the patients without pneumonitis (307 +/- 232 U/ml). The KL-6 level was also significantly higher in patients with clinically active pneumonitis (1708 +/- 1338 U/ml) than in those with inactive pneumonitis (820 +/- 796 U/ml) (p < 0.0001). Serum KL-6 levels correlated significantly with serum c-reactive protein, lactic dehydrogenase, and PaO2 values. These results suggest that the ED046 assay is useful for measuring KL-6 as a marker of pneumonitis activity.