Association Of Anti-CK18 And Anti-CK19 With Chronic Obstructive Pulmonary Disease

Objective: Recently,some studies report that autoimmune processes are involved in the progression of chronic obstructive pulmonary disease(COPD),and autoantibodies against cytokeratin18(CK18)and cytokeratin19(CK19)could be associated with lung injury.Therefore,the aim of present study was to explore the effect of the anti-CK18 and anti-CK19 autoantibodies in the development of COPD by detecting the circulating levels of anti-CK18 and anti-CK19 autoantibodies(Ig G,Ig A,Ig M)in the COPD patients and the effect of cigarette smoke in the generation of anti-CK18 and anti-CK19 autoantibodies.Methods: 1.The blood samples from 228 COPD patients or 136 healthy controls with gender and age matched were employed as experimental subjects to detect the plasma levels of anti-CK18 and anti-CK19 autoantibodies(Ig G,Ig A,Ig M)by enzyme-linked immunosorbent assay(ELISA),exploring the relationship between the autoantibodies of anti-CK18 and anti-CK19 and the different stages of lung function,meanwhile the clinical data of different stages of COPD could be analyzed.2.We constructed a mice model to develop COPD-like pathology with cigarette smoke exposure.Male C57BL/6J mice were exposed to cigarette smoke for six months or nine months,and the control group was made at the same time,collecting the blood sample and lung tissue.And the serum levels of anti-CK18 and anti-CK19 autoantibody(Ig G,Ig A,Ig M)in the mice exposed to cigarette smoke and control group were determined by ELISA.3.The left lung was fixed with 4% paraformaldehyde,and the pathological changes of lung tissues of mice exposed to cigarette smoke were observed by staining with hematoxylin and eosin,and the distribution of Ig G?Ig A?Ig M antibody in the lung tissues of mice exposed to cigarette smoke and control group was observed by the indirect immunofluorescence.4.The presence of anti-CK18 and anti-CK19 autoantibody in the lung tissues of mice exposed to cigarette smoke was further identified by western blot.Results: 1.Plasma levels of anti-CK18 and anti-CK19 autoantibodies(Ig G,Ig A,Ig M)were higher in the patients with COPD compared with control group especially in the patient with GOLD III and GOLD IV disease,which had statistical difference(p<0.05).The circulating levels of anti-CK18 Ig G,Ig M and anti-CK19 Ig A,Ig M were raised gradually as the severity of disease increase,however,the levels of anti-CK18 Ig A and anti-CK19 Ig G were not elevated with the increase of the severity of disease.The COPD patients had trend of smoking,and the lung function in the patients with COPD was markedly reduced compared with control group.Furthermore,the anti-CK18 Ig G,Ig A,Ig M and anti-CK19 Ig A,Ig M were negatively related with the FEV1(%)predicted of patients with COPD.2.The serum levels of anti-CK18 and anti-CK19 Ig G were increased significantly in the mice exposed to cigarette smoke for six months and nine months compared with control group,however,there was no obvious change in the serum levels of anti-CK18 and anti-CK19 Ig G in the mice exposed to cigarette smoke for six months and nine months,indicating the Ig G levels was associated with the environment smoke exposed,the difference had statistical significance(p<0.05).However,the serum levels of anti-CK18 and anti-CK19 Ig A were significantly raised in the mice exposed to cigarette smoke for nine months compared with those for six months.4.The apparent pathological changes were discovered in the lung tissues of mice exposed to cigarette smoke.The alveolar walls were weakly destructed and abundant of inflammatory cells were present in the lung tissues of mice exposed to cigarette smoke for six months,and the pulmonary alveoli was remarkably destroyed and few inflammatory cells were infiltrated in the lung tissues of mice exposed to cigarette smoke for nine months.The Ig G,Ig A and Ig M antibodies were mainly present at alveolar septa,small airway walls and vascular walls.The prevalence of Ig G,Ig A and Ig M was 57.1%,42.9% and 57.1% in the lung tissues of mice exposed to cigarette smoke for six months respectively,and 40%,33.3% and 46.7% respectively for those exposed to cigarette smoke for nine months.The proportion of subjects with Ig G,Ig A and Ig M antibodies were prominent increased in the lung tissues of mice exposed to cigarette smoke compared with control.5.The results identified the presence of the autoantibodies(Ig G)against CK18 and CK19 in the lung tissue where the distribution of Ig G,Ig A and Ig M antibodies is postive in mice exposed to cigarette smoke by western blot.Conclusions: Our results demonstrate that anti-CK18 and anti-CK19 autoantibodies(Ig G,Ig A,Ig M)are disease-related antibodies,the circulating levels are associated with the severity of disease,which may play an important role in monitoring the development of COPD.And the anti-CK18 and anti-CK19 autoantibodies are promising to serve as marker to monitor the lung injury in order to further guide the treatment and prognosis of COPD.