ABSTRACT
Objective To evaluate early diagnostic value of matrix metalloproteinase 7 (MMP-7) and interferon inducible protein (IP-10) for rheumatoid arthritis-associated interstitial lung disease (RA-ILD).Methods Clinical and laboratory data and serum samples of patients with RA between March 2015 and June 2016 in our hospital were collected.Patients were subclassified as RA-without ILD,RA-with ILD,or RA-advanced ILD based on high-resolution computed tomography scans of the chest.Enzyme linked immunosorbent assay (ELISA) was used to assess MMP-7 and IP-10 in the serum of each group.The correlation between the two biomarkers and pulmonary function,the occurrence of ILD and other laboratory indexes were analyzed.Comparison of measurement data between the 3 groups was performed by single factor variance analysis,while count data was compared by Chi square test;the risk factors were analyzed by Logistic regression,receiver operating characteristic curve (ROC curve) was used to evaluate the diagnostic efficiency,correlation analysis was performed by Spearman correlation analysis.All statistical analysis was performed by Statistical Product and Service Solutions (SPSS) 19.0 statistical software.Results Serum levels of MMP-7 and IP-10 in RA-advanced ILD group and RA-mild ILD group were significantly higher than that of RA-without ILD group,the level of MMP-7 was [(1.9±3.0) ng/ml,(1.7±2.4) ng/ml,(0.2±0.2) ng/ml in turn,P＜0.05],IP-10 level was [(245± 394) pg/ml,(270±384) pg/ml,(38±26) pg/ml in turn,P＜0.05].And IP-10 level was significantly correlated with RA-ILD in both unadjusted and adjusted Logistic regression analyses,the values of OR were 1.024 and 1.023 respectively (P＜0.05).The ROC curves were plotted with MMP-7 and IP-10 respectively.The area under the curve (AUC) was 0.69 and 0.78 respectively.The AUC of combined detection increased to 0.83.Conclusion Levels of MMP-7 and IP-10 are elevated in the serum of RA patients with ILD,whether mild or advanced,supporting their value as pathogenically relevant biomarkers that may contribute to noninvasive detection of RA-ILD,and the combined estimate of them helps to improve the effectiveness of early diagnosis.