Research On Clinical Significance Of The CCL21 Serum Level In Rheumatoid Arthritis Patients Involved With Interstitial Lung Disease

Objective: Rheumatoid arthritis(RA)is a chronic disabling disease characterized by joints and systemic organs involved,which requiring long-term systematic treatment.The disorder not only increases the economic burden of patients,but also causes a decline in quality of life.Infiltration of inflammatory cells such as T cell B cells,monocytes and macrophages were filled in synovial tissue around the joints of RA patients.Together with activation and proliferation of the synovial fibroblasts,these cells become the driving force for joint destruction in RA patients.Approximately30 % RA patients have pulmonary involvement.Interstitial lung disease(ILD)induced by RA is one of the main factors leading to poor prognosis even death in patients.Chemokines play a key role in the aggregation of inflammatory cells in inflammatory sites,so chemokines and chemokine receptors are considered to be important molecules in the pathogenesis of RA.It has been proved that the chemokine CCL21 regulates the homing of immune cells,such as T cells and dendritic cells,affects the activation and differentiation of T cells,and participates in the occurrences of angiogenesis,chronic inflammation,autoimmune diseases as well as the occurrence and metastasis of neoplasm,which may be the pathophysiology foundation of the extraarticular lesions in RA.The study was conducted to investigate the relationship between the expression level of chemokine CCL21 and pulmonary interstitial lesion in RA patients and explore the role of chemokine CCL21 in the pathogenesis and development of RA by determined the expression level of chemokine CCL21 in serum of RA patients as well as the correlation between the chemokine CCL21 and the clinical parameters.To help monitor the activity of RA and estimate prognosis,and to provide a new therapeutic target for RA related ILD.Methods: From May 2016 to March 2017,a total of 62 RA patients hospitalized in the Department of Rheumatology at the First Hospital of China Medical University were enrolled to this study.The patients were judged whether they were complicated with pulmonary interstitial changes according to the results of the HRCT tests,including 34 cases(RA-ILD)without pulmonary interstitial involvement and 28 cases(RA+ILD)with pulmonary interstitial changes.18 cases with idiopathic interstitial pneumonia(IIP)hospitalized in the Department of Respiratory and 20 healthy controls(HC)were admitted.The fasting peripheral blood samples were collected from the patients in the morning and were centrifuged into serum.Level of CCL21 in the serum was measured and calculated by the method of enzyme-linked immunosorbent assay(ELISA).The basic clinical data,laboratory and examination data of the patients were recorded while they're in hospital.T-test,One-way ANOVA,LSD-t test,Kruskal-Wallis test,Pearson and Spearman correlation analysis were used for the succedent statistical analysis,the difference was deemed statistically significant when(49)<0.05.Results: 1.The serum levels of CCL21 were higher in RA patients than the health controls,the difference is statistically significant.The concentrations of CCL21 in serums of the RA patients with interstitial lung disease were higher than those without ILD,the difference is statistically significant.Serum CCL21 levels in patients with IIP were higher than health controls,the difference is statistically significant.2.There exists gender differences in serum CCL21 levels in RA patients with a statistically significant difference.Whether the DAS28 score is high or not,or CCP,RF and ANCA is positive or not had nothing to do with the levels of CCL21 in serum of RA patients.Both albumin and BMI had a negative correlation with the serum CCL21 levels in RA patients,but there is no correlation with age,course of disease and so on.Conclusion: Chemokine CCL21 is highly expressed in serum of patients with RA than that of normal controls,indicating that CCL21 may be involved in the pathogenesis of RA.RA patients with interstitial pneumonia had a higher serum CCL21 levels than those without pulmonary interstitial lesion.Furthermore,CCL21 levels were higher in IIP patients and RA patients with interstitial pneumonia than in health controls.It suggests that CCL21 may has a correlation with the pathogenesis of interstitial lung disease associated with IIP and RA.