KL-6 as a useful serum marker for interstitial lung disease in patients with idiopathic inflammatory myopathies / 中华风湿病学杂志

ABSTRACT

Objective To determine the serum level of KL-6 in patients with polymyositis(PM)and dermatomyositis(DM),and to investigate the possible diagnostic value for interstitial lung diseases(ILD)in pa- tients with PM/DM.Methods Serum KL-6 concentrations were measured by ELISA in 53 adult PM/DM pa- tients,the control groups of 22 patients with infectious lung disease,and 50 healthy subjects.The association with clinical features and serum KL-6 levels was analyzed.Results The serum levels of KL-6 were(1543?761)、(429?106)、(336?196)and(289?105)U/ml in PM/DM patients with ILD and without ILD,patients with infectious lung disease and healthy controls,respectively.Serum KL-6 levels in the PM/DM patients with ILD were significantly higher compared with PM/DM patients without ILD,patients with infectious lung disease and healthy controls(all P＜0.01 ).However,no significant differences of serum KL-6 levels was found among PM/ DM patients without ILD,patients with infectious lung disease and healthy controls(P＞0.05).Significant cor- relations were found between the elevated levels of serum KL-6 and the presence of ILD in patients with PM/ DM(P＜0.01).The sensitivity and specificity of serum abnormal KL-6 levels for ILD in patients with PM/DM were 90.9% and 80.6%.Additionally,follow-up study showed the mean serum levels of KL-6 in six patients who died were significantly higher than that in other PM/DM patients with ILD(P＜0.01).Conclusion Serum KL-6 level is a reliable serum marker for ILD in idiopathic inflammatory myopathies,which may contribute to early differentiate ILD from lung infectious disease.Increased serum level of KL-6 may predict a poor out- come.