Background: Clara cell 10-kDa protein (CC10) is one of the most abundant proteins in bronchoalveolar lavage fluis and has been described as a biomarker for airway obstructive diseases. CC10 possesses the properties of suppression Th2 cell differentiation and Th2 cytokine production. In this study, we aimed to determine whether CC10 can be a sensitive biomarker to identify Th2 phenotypes of asthma.Methods: Adults with asthma (n = 50) were categorized as Th2-high asthma or Th2-low asthma

more »

... to serum IgE, blood eosinophils and fractional exhaled nitric oxide (FeNO). Patients were classified as Th2-high asthma when two or more biomarkers (high IgE ≥ 100 IU/mL, high Eos ≥ 300/µL, or high FeNO ≥ 30 ppb) were elevated, and classified as Th2-low asthma when one or no biomarker was elevated. Enzyme-linked immunosorbent assay (ELISA) was used to assess the CC10 and periostin levels in plasma. All participants underwent sputum induction, and different types of inflammatory cells were counted.Results: The plasma CC10 levels from patients with Th2-low asthma were higher than patients with Th2-high asthma(P<0.001. The receiver-operating characteristic (ROC) analysis showed a sensitivity of 0.73 and specificity of 0.74 for plasma CC10 of 19.76 ng/ml to distinguish asthmatic patents with Th2-high phenotype or Th2-low phenotype. Correlation analysis indicated that the plasma CC10 levels were inversely correlated with plasma periostin, sputum eosinophil and negative logPD20 (p<0.05), however positively correlated with sputum neutrophil percentages and FEV1 % predictions (p<0.05). Conclusions: The plasma CC10 was potentially useful in predicting Th2-high and Th2-low phenotypes in patients with asthma. Lower plasma CC10 was associated with enhanced airway hyperresponsiveness, Th2-high inflammation and subsequent airflow limitation.