Clinical Application Of Serum KL-6 In Different Types Of Connective Tissue Disease-Associated Interstitial Pulmonary Disease

Objective:To investigate the expression of serum KL-6 in different types of CTD-ILD and its clinical correlation with different types of CTD-ILD.Methods:The clinical data of 197 patients with CTD-ILD who were hospitalized in first affiliated hospital of Xinjiang Medical University from October 2018-March 2019 were retrospectively collected and analyzed.Serum KL-6 levels in various types of CTD-ILD patients were detected by ELISA method,and the difference of serum KL-6 levels in various types of CTD-ILD and its correlation with ESR,CRP,IL-6,C3,C4,FVC,DLCO,FEV1,PaO₂ and other indicators indicating the severity of the disease in various types of CTD-ILD patients were analyzed.Results:The mean value of serum KL-6 in each CTD-ILD was higher than the normal reference value range of the index,and there was no significant difference in the expression of KL-6 between different CTD-ILD?P=0.26?;in RA-ILD group,the levels of serum KL-6 concentration were positively correlated with ESR,RF,anti-CCP,CRP and IL-6,were negatively correlated with C3,C4,PaO₂,PaCO₂,SO₂?%?,FVC%pred,FEV1,DLCO%pred,the more severe the lesion,the higher the serum KL-6 level;in PM/DM-ILD group,serum KL-6 levels were positively correlated with ESR,CRP,IL-6and PaCO₂ levels,serum KL-6 levels were negatively correlated with C3,C4,PaO₂,SO₂,FVC%pred,FEV1,DLCO%pred,the more severe the lesion,the higher the serum KL-6 level;in SSc-ILD group,serum KL-6 concentration were positively correlated with ESR,CRP,IL-6,serum KL-6 concentration were negatively correlated with PaO₂,PaCO₂,SO₂,FVC%pred,FEV1,DLCO%pred,the more severe the lesion,the higher the serum KL-6 level,there was no significant correlation between serum KL-6 concentration and PaCO₂ level?P=0.658?,the more severe the lesion,the higher the serum KL-6 level;in pSS-ILD group,serum KL-6 level were positively correlated with ESR,CRP,KL-6 level were negatively correlated with IL-6,C3,PaO₂,SO₂,FVC%pred,EFV1,DLCO%pred,there was no significant correlation between C4,PaCO₂ levels and serum KL-6 concentration?P=0.34 and P=0.202,respectively?,the more severe the lesion,the higher the serum KL-6 level;in SLE-ILD patients,serum KL-6concentration were positively correlated with ESR,CRP,IL-6,serum KL-6 concentration were negatively correlated with PaO₂,SO₂,FVC%pred,FEV1,DLCO%pred,there was no significant correlation between serum KL-6 level and levels of C3,C4 and PaCO₂ and?P=0.918,P=0.523 and P=0.273,respectively?,the more severe the lesion,the higher the serum KL-6 level.Conclusion:The levels of serum KL-6 in different types of CTD-ILD patients were significantly increased,and the level of KL-6 was related to the severity of the disease.The high concentration of serum KL-6 is warning the severity of the disease,later phase,and the poor prognosis.