[The clinical significance of the levels of serum KL-6 mucin and interleukin-13 in pulmonary alveolar proteinosis].

ABSTRACT

OBJECTIVE: To explore the serum levels of KL-6 mucin and interleukin 13 (IL-13) in patients with pulmonary alveolar proteinosis (PAP) and to investigate their clinical significance. METHODS: The serum levels of KL-6 and IL-13 were measured in 54 patients with PAP and in 50 healthy volunteers. The relationships among clinical features, chest high resolution computed tomography image scores, serum KL-6 levels and serum IL-13 levels were analyzed. RESULTS: The serum levels of IL-13 in PAP patients were significantly higher than those in healthy controls [(23 ± 14) ng/L vs. (13 ± 9) ng/L, t = 3.71, P < 0.05]. The serum levels of IL-13 did not associate with lung function and image scores. The serum levels of KL-6 [median (inter quartile range) U/ml] were higher in PAP patients than those in healthy controls [3 498.50 (1 160.50-9 337.75) U/ml vs. 177.00 (147.50-255.00) U/ml, U = 6.00, P < 0.05]. The value of KL-6 negatively correlated with FVC % predicted, FEV1 % predicted, DLCO% predicted, and PaO2 (r = -0.591, -0.563, -0.529, and -0.618, P < 0.05) ; however positively correlated with serum lactate dehydrogenase, the degree of lung opacification opacity, ground glass opacity extent, ground glass opacity severity and reticulation extent (r = 0.645, 0.733, 0.500, 0.751 and 0.753, respectively, P < 0.05). The serum levels of KL-6 were higher in patients with PAP who required whole lung lavage (WLL) or inhalation of granulocyte-macrophage colony-stimulating factor (GM-CSF) than those who did not [5 592.00 (1 738.00-9 982.00) U/ml vs.1 329.00 (1 017.75-3 543.75) U/ml, U = 101.00, P < 0.05]. CONCLUSION: PAP patients had significantly higher levels of serum IL-13 and KL-6. The serum levels of KL-6 may reflect the severity of the disease and be taken as a marker of the necessity of treatment in PAP patients.