A Preliminary Study On The Correlation Between Serum IL-21 And CXCL13 Levels And Chronic Obstructive Pulmonary Disease

BackgroundChronic obstructive pulmonary disease（COPD）is a common disease characterized by progressive airflow obstruction,chronic lung inflammation,and persistent symptoms and acute exacerbations.At present,chronic obstructive pulmonary disease is highly prevalent,the morbidity and the mortality are quite at the high level.Therefore,to discovery the inner characteristics of the disease,as well as the disease phenotype in the acute exacerbations,contribute to predict the disease changes and direct the clinical treatment at different stages of the disease.These efforts are expected to reduce the morbidity of chronic obstructive pulmonary disease,improve patient quality of life.Current studies have shown that although the pathogenesis of chronic obstructive pulmonary disease is complex,but the inflammatory response is still act as the important position.Because of its important immune-mediated function,it is speculated that IL-21 and CXCL13 may play a very important role in the duration of chronic obstructive pulmonary disease.It is suggested that IL-21 can be combined with some Inhibition of inflammation-related factors such as TGF-β1,IL-10,etc.through their own immune regulation to increase the anti-inflammatory factors to protect the organization to avoid injury,resulting in anti-inflammatory effect.However,the research of the acute exacerbations in COPD and its inflammatory factors were not yet reported.In this study,the stable period of COPD is evaluated through the lung function and symptoms,medical history,after further refinement,the level of inflammatory factors was evaluated,and to evaluate the level of inflammation in the acute exacerbation of COPD.So that we can explore the role of IL-21 and CXCL13 in the inflammatory process of COPD,and provide some reference for the anti-inflammatory treatment strategy of COPD.ObjectiveTo explore whether the specific cytokines IL-21 and CXCL13 are involved in acute exacerbation of chronic obstructive pulmonary disease.And to investigate whether the expression levels of IL-21 and CXCL13 can act as the biomarkers to predict the degree of obstruction in lung function.Methods1.Experimental design:The experimental study is divided into the following two parts:1.1.To include the research object,AECOPD patients admitted to Department of Respiratory Medicine in Xinqiao Hospital of third military medical university were recruited,the COPD patients admitted to respiratory department outpatient diagnosis were recruited in the same period,and the crowd were recruited at the hospital physical examination center of the physical examination.The levels of IL-21 and CXCL13 in the serum of the population were detected by ELISA,to investigate the inflammatory characteristics of the population in different status.1.2.The patients with chronic obstructive pulmonary disease（COPD）were selected as the study population.The lung function of patients with chronic obstructive pulmonary disease（COPD）was measured and the GOLD grade was evaluated.To explore the values of the levels of IL-21 and CXCL13 in the prediction of lung function damage.2.Peripheral blood collection:The Peripheral blood was collected in the morning on fasting conditions（Hospitalized patient on the day before admission treatment）,collecting elbow venous blood about 4ml,room temperature for 30min,3000r/min centrifugal 10min separation,take the supernatant placed in-80℃refrigerator,to be tested standby.3.Serum levels of IL-21 and CXCL13 were measured by ELISA.Remove the sample from the-80℃refrigerator,place it in a 4℃refrigerator and follow the instructions in the ELISA kit.4.Collect the general clinical pathology data of the study subjects:including the name,sex,age,occupation,smoking history,family history,improved British medical research council（mMRC）,acute exacerbation,Imaging,previous lung function and other related information.5.Statistical methods:Statistical software is based on SPSS 21.0.We use the x^<sub>±s form of expression to represent metrological data in this experiment and use the single factor analysis of variance method for statistical analysis.The count data were analyzed by x² test.The correlation between the observed indexes was Pearson correlation analysis:α=0.05.Research result1.The first part of the results:the total number of subjects included in the study involves101 cases,of which 31 cases of COPD stable patients from December 2015 to 2016 in May Third Military Medical University,Xinqiao Hospital,Department of Respiratory Medicine clinic diagnosis,30 patients with AECOPD who were hospitalized in the Department of Respiratory Medicine,and 20 healthy non-smokers and 20 healthy smokers in the hospital’s physical examination center were selected as subjects.In the general conditions of the study,the factor of age,sex and mMRC scores compared with other subjects in healthy non-smoking group,healthy smoking group,COPD stable group and AECOPD group were not statistically significant different.In the healthy smoking group,COPD stable group and AECOPD group,there was no statistically significant difference between the three groups in terms of smoking history,but compared with the healthy nonsmoking group,it was statistically significant different.The proportion of the study group,family history,imaging performance（bucket chest or emphysema）was higher than that of in healthy non-smoking group,moreover,the difference was statistically significant.2.The second part of the results:The expression of IL-21 and CXCL13 in the serum of non-smokers,healthy smoking group,COPD stable group and AECOPD group were significantly different.The levels of IL-21 and CXCL13 in serum of AECOPD group were higher than those in COPD group,healthy smoking group and healthy non-smoking group.The levels of IL-21 and CXCL13 in the serum of COPD and healthy smoking group were significantly higher than those in healthy non-smoking group,moreover,the difference was statistically significant significance.3.The third part of the results:In the COPD stable group,serum IL-21 expression levels and CXCL13 expression showed a positive correlation.The levels of IL-21 and CXCL13 in serum were negatively correlated with the FEV₁%of pulmonary function,and the expression levels of IL-21 and CXCL13 were positively correlated with GOLD grade.In conclusionThe levels of IL-21 and CXCL13 in serum were significantly correlated with the acute exacerbation of chronic obstructive pulmonary disease,and the levels of IL-21 and CXCL13in serum of COPD patients were correlated with the severity of lung function and disease.IL-21,CXCL13 may play a pro-inflammatory role in the COPD process.The level of IL-21 and CXCL13 cytokines in serum is positively correlated with the pulmonary function impairment in chronic obstructive pulmonary disease.Combined use of cytokines IL-21 and CXCL13 may be act as a certain predictive factor in the development of chronic obstructive pulmonary disease.