Abnormal Expression Of Peripheral Blood NK Cell Surface Receptors In Patients With Chronic Obstructive Pulmonary Disease And Its Clinical Significance

Purpose Chronic Obstructive Pulmonary Disease(COPD)is a chronic disease with respiratory system as the main symptom.Infection can cause acute exacerbation of COPD,and in severe cases,it can cause respiratory failure and even death.According to the World Health Organization,COPD ranks third among the top ten causes of death in the world,after ischemic heart disease and stroke.As the number of smokers increases and the aging population intensifies,the prevalence of COPD and the rate of hospitalization increase,which brings a huge burden on social and economic public health resources.The diagnosis of COPD mainly depends on the patient’s clinical manifestations and the measurement of lung function,which may easily lead to missed diagnosis or over-diagnosis,missed opportunities for early intervention of the disease or over-treatment leading to drug reactions.Despite a large number of studies,there is still no breakthrough in the diagnosis and treatment of COPD.Natural killer cells(NK cells)are considered to be the first line of defense of the host against viral infection.Some studies have shown that immune cells play an important role in the progress of COPD,including NK cells.However,at present,the specific mechanism and biological changes of NK cells in the progression of COPD are not clear.Therefore,we have detected the activity of NK cells and the changes of their surface receptors in the peripheral blood of patients with COPD and healthy people,helping us further understand the role of NK cells in the development of COPD,and looking forward to the immunotherapy based on NK cells.Methods The peripheral blood of 18 patients with acute exacerbation of COPD and 45 healthy donors were collected to extract NK cells.Using the principle of homotypic control,NK cell surface receptors are labeled with fluorescent labeled antibodies.Then detect the ability of NK cells to secrete cytokines.Detect the ability of NK cells to secrete cytokines(IFN-γ and TNF-α).Collect experimental data with flow cytometry,classify cell subgroups with gating strategy,and analyze and plot data with Flow Jo software.Results The results showed that the number of NK cells in peripheral blood of patients with COPD was no different from that of healthy donors,while the proportion of NK cells was smaller than that of healthy donors.Decreased expression of NK cell surface receptors CD16 and Siglec-7 in peripheral blood of patients with COPD.Most receptors(including TIM3,CD39,Siglec-9,CD73,PD-1,NKP46,NKG2 D and CD96)are upregulated.There was no significant difference in the expression of receptor TIGIT between the two groups.Detect the secretion of cytokines in the two groups,the ability of NK cells to secrete cytokines decreased in COPD group.Conclusions The expression of peripheral NK cell surface receptors in patients with COPD is abnormal,and the function of NK cells is damaged.The abnormal expression of NK cell surface receptors may promote the progress of COPD.