| Objective : To evaluate the application value of serum biomarkers in patients with connective tissue disease interstitial lung disease(CTD-ILD)by comparing the levels of Krebs von den Lungen-6(KL-6)、Alveolar Surface Protein A(SP-A)、Alveolar Surface Protein D(SP-D)in patients with CTD-ILD、connective tissue disease without interstitial lung disease(CTD-non ILD)and healthy individuals.Methods: A total of 272 cases of CTD-ILD patients diagnosed and treated in inpatients and outpatients in the Department of rheumatology and immunology and respiratory medicine of a Class III hospital from June 2021 to November 2022 were retrospectively collected.At the same time,100 cases of newly diagnosed and treated patients with CTD-non ILD and 100 cases of healthy individuals in physical examination center were collected.The routine laboratory examination,lung function examination indexes and chest CT results of all patients were collected.The serum levels of KL-6,SP-A and SP-D in each group were detected and statistically analyzed and obtain the sensitivity,specificity and diagnostic value of CTD-ILD separately and in combination.Results: 1.The levels of serum lactate dehydrogenase and complement C3 were significantly different between the CTD-ILD group and the CTD-non ILD group(P <0.05),while the levels of red blood cells,hemoglobin,white blood cells,neutrophils,albumin,creatinine and uric acid were significantly different among the three groups(P< 0.05).There was no statistical difference in the remaining indicators between the groups(P > 0.05).2.KL-6 511.75(304.68,941.88)U/m L and SP-D 15.25(12.48,20.04)ng/L levels were significantly higher in patients in the CTD-ILD group than in the CTD-non ILD and HC groups,and the differences were statistically significant(P < 0.01),while the difference between the CTD-non ILD and HC groups was not statistically significant(P >0.05);while comparison of serum SP-A revealed that the difference between CTD-ILD group and CTD-non ILD group was not statistically significant(P > 0.05),but the differences between these two groups and HC group were both statistically significant(P< 0.05).3.Serum KL-6 level in patients with CTD-ILD was positively correlated with serum ESR,LDH,erythrocyte,hemoglobin,leukocyte and neutrophil(r=0.146,P < 0.05;r=0.333,P<0.01;r=0.117,P<0.05;r=0.225,P<0.01;r=0.176,P<0.01;r=0.224,P<0.01),was negatively correlated with white sphere ratio(r=-0.139,P<0.05),but had no significant correlation with other indicators(P > 0.05).Serum SP-A level was positively correlated with leukocytes,neutrophils and platelets(r=0.175,P<0.01;r=0.186,P<0.01;r=0.184,P<0.01),was negatively correlated with total protein(r=-0.120,P<0.05);Serum SP-D level was positively correlated with D-dimer,neutrophil and platelet formation(r=0.199,P <0.01;r=0.124,P <0.05;r=0.161,P <0.01),and the ratio of erythrocyte and albumin was negatively correlated(r=-0.123,P<0.05;r=-0.219,P<0.01).4.In studying the diagnostic value of the three serological markers,the area under the KL-6 curve was 0.903,95% CI: 0.873-0.933(P < 0.01),and the ROC curve analysis yielded the largest area under the curve when the serum KL-6 value was 226.20 U/m L,while yielding a sensitivity of 0.860,specificity of 0.760,positive predictive value of The area under the SP-A curve was 0.531,95% CI: 0.462-0.933(P > 0.05),which could not be used for the diagnosis of CTD-ILD;the area under the SP-D curve was 0.693,95% CI:0.625-0.760(P < 0.01),which was determined by ROC curve analysis yielded the maximum area under the curve when the serum SP-D value was 11.857 ng/L,and also yielded a sensitivity of 0.827,specificity of 0.540,positive predictive value of 0.643,negative predictive value of 0.747,and Yordon index of 0.367.The area under the curve of KL-6 and SP-D combined diagnosis was 0.910,95% CI: 0.881-0.939(P < 0.01),with a sensitivity of 0.783,specificity of 0.910,positive predictive value of 0.897,negative predictive value of 0.807,and Yorden index of 0.820.5.According to the chest CT findings of CTD-ILD patients,they were divided into87 cases(32.00%)in stage 1,102 cases(37.50%)in stage 2 and 83 cases(30.50%)in stage 3.By compairing KL-6 levels in each eases,we found that the level of 1193.20(950.80,1715.60)U/m L in stage 3 was higher than that of 515.65(411.43,617.65)U/m L in stage 2.The level of KL-6 in stage 2 was higher than that in stage 1(245.77±87.81)U/m L,and the difference was statistically significant(P < 0.01).There was no significant difference in the levels of SP-A and SP-D in the three stages(P > 0.05).6.Serum KL-6 levels in CTD-ILD patients were negatively correlated with DLCO and FVC(r=-0.339,P<0.01;r=-0.229,P<0.05),but had no significant correlation with FEV1 and TLC(r=-0.182,P=0.05;r=-0.212,P > 0.05);There was no correlation between serum SP-A and SP-D levels and lung function indexes(P > 0.05).Conclusion: Serum KL-6 and SP-D levels were significantly increased in CTD-ILD patients,which was of great value in the diagnosis of CTD-ILD.The combined detection of KL-6 and SP-D could significantly improve the diagnostic efficacy of CTD-ILD.Serum KL-6 level is closely related to the severity of CTD-ILD and can be used as an indicator to monitor the therapeutic effect of CTD-ILD. |
PDF Full Text Request