The Role of PARC/CCL-18and IL-6in Assessment of Chronic Obstructive Pulmonary Disease Severity

Objective:Chronic Obstructive Pulmonary Disease（COPD）is amajor disease with high morbidity and mortality throughout theworld,which is characterized by persistent airflow limitation that isusually progressive.Exacerbations are important events in thehistoryof COPD,which cause the decline in lung function,enhance thehospital admission,health care costs and mortality.The diagnosismainly depends on the manifestions such as cough,sputumproduction and dyspnea, risk factors such somoking or air pollution,but its certainty depends on spirometry. Because thepathophysiological mechanisms of COPD are comlex,the diagnosisand prognosis value with lung function alone is not enough. It iswell recognized that COPD is characterized by chronic systemicinflammation.The aim of this study was to investigate serum levelsof pulmonary activation regulated chemokine（PARC）/chemokineligand-18（CCL-18）、hsCRP and IL-6in patients with COPD and healthy control subjects,to check their correlation with FEV1%pre and BODE index,to assess the value of PARC/CCL-18in confirmingexacerbation,predicting disease severity and prognosis.Materials and methods:Patients with COPD exacerbation,stable and healthy control subjects were recruited fromthe inpatient,outpatient department of respiratory medicine andhealthy center of Affiliated Hospital of Luzhou Medical college.Onthe day of visiting,a medical history was taken,spirometry and bloodsamples were performed. Data were analyzed using stasticalsoftware SPSS,version21.Results were represented as means±SD ofthe mean.PARC/CCL-18、IL-6were measured by ELISA;comparisons of groups of data were performed by Kruskal-Wallis test andMann-Whitney U test.Nonprarametric Spearman rank correlationcoeffient was used to test correlations between two parameters.AP value of＜0.05was considered statistically significant.Results:1.Serum levels of PARC/CCL-18，IL-6，and CRP in patientswith COPD exacerbation were significantly higher than those ofstable group or healthy control subjects（P＜0.001）, serum levelsof PARC/CCL-18and IL-6in stable group were significantly higherthan control group.2.In COPD exacerbation group:serum levels of PARC/CCL-18negatively correlated with FEV1%pred（r=-0.792，P＜0.001, levelsof IL-6negatively correlated with FEV1%pred（r=-0.619，P＜0.001;in the stable group: serum levels of PARC/CCL-18negativelycorrelated with FEV1%pred(r=-0.77，P＜0.001, levels of IL-6 negatively correlated with FEV1%pred(r=-0.705，P＜0.001.3.In COPD exacerbation group:serum levels of PARC/CCL-18positively correlated with BODE index(r=0.567，P=0.001, levels ofIL-6positively correlated with BODE index; In COPD stable group:serum levels of PARC/CCL-18positively correlated with BODEindex(r=0.553，P=0.002, levels of IL-6positively correlated with BODE index(r=0.589，P=0.001.4. Serum levels of PARC/CCL-18positively correlated with IL-6in COPD exacerbation group(r=0.671，P＜0.001and COPD stablegroup(r=0.727，P＜0.001.Conclusion:1.serum level of PARC/CCL-18in patients with COPD washigher than healthy subjects,and COPD exacerbation group washigher than COPD stable group.2.serum level of PARC/CCL-18negatively correlated with FEV1%pred,positively with BODE index,which means PRAC/CCL-18canbe a biomarker for disease severity and prognosis.3.The relationship between serum PARC/CCL-18and IL-6suggests that they both participate the pathophysiology of COPD,and the mechanisms are still unclear.