title: Serum KL-6 in pulmonary alveolar proteinosis: China compared historically with Germany and Japan.
abstract: BACKGROUND
  KL-6 is a biomarker of the severity of pulmonary alveolar proteinosis (PAP). We noticed a significant difference in the mean serum KL-6 level between Japanese and Caucasian patients. To assess the clinical value of serum KL-6 in Chinese PAP patients, and to compare the differences in serum KL-6 levels in Chinese patients and patients of other ethnicities.
  
  
  METHODS
  From 2014-2016, we prospectively examined 37 Chinese Han patients with PAP, measured their serum KL-6 levels, evaluated the correlation between initial KL-6 levels and clinical variables, and compared our results with studies from Japan and Germany (similar methods were used). We searched dbSNP for theMUC1568 (rs4072037) genotype or allele frequency distributions in China, Japan, and Germany.
  
  
  RESULTS
  Initial serum KL-6 levels were significantly correlated with baseline PaO2, A-aDO2, DLCO, FVC, and LDH levels (all P<0.001). Compared with Chinese PAP patients, the mean serum KL-6 level was significantly lower in German PAP patients (P<0.001) but not in Japanese PAP patients (P>0.4). In the rs4072037 allele frequency distributions, the frequency of the A/A genotype was significantly higher while that of the G/G genotype was significantly lower in Chinese and Japanese cohorts than in Caucasian cohorts (both P<0.001).
  
  
  CONCLUSIONS
  Serum KL-6 can be used as a biological indicator for disease monitoring in Chinese patients. The difference in serum KL-6 level among Chinese, German, and Japanese PAP patients may be associated with the distribution of the rs4072037 genotype.
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510175, China.
authors.forename: Wen-Liang
authors.initials: WL
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510175, China.
authors.forename: Zi-Qing
authors.initials: ZQ
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510175, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510175, China.
authors.forename: Zhu-Quan
authors.initials: ZQ
authors.lastname: Su
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510175, China.
authors.forename: Chang-Hao
authors.initials: CH
authors.lastname: Zhong
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510175, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510175, China.
authors.forename: Shi-Yue
authors.initials: SY
authors.lastname: Li
keywords: KL-6; MUC1; pulmonary alveolar proteinosis (PAP); whole lung lavage (WLL)