Association of Plasma Heat Shock Protein 70 with Disease Severity, Smoking and Lung Function of Patients with Chronic Obstructive Pulmonary Disease

Abstract

Background: Extracellular heat shock protein 70 (eHsp70) acts like a damage-associated molecular pattern (DAMP) and it might modulate immune responses in patients with chronic obstructive pulmonary disease (COPD). The aim of the study was to explore plasma eHsp70 concentration in patients with stable COPD, its association with disease severity and smoking status as well as its diagnostic performance in COPD assessment.Methods: Blood samples were collected from 137 COPD patients and 95 healthy individuals. COPD patients were subdivided into GOLD 2-4 stages based on airflow obstruction severity and GOLD A-D groups regarding symptoms and exacerbations. Concentration of eHsp70 was assessed in EDTA plasma by the commercially available ELISA kit. Statistic analysis was performed by MedCalc statistical software.Results: eHsp70 concentration was increased in COPD patients when compared to controls and was increasing with the severity of airflow limitation as well as symptoms burden and exacerbation history. There were no differences in eHsp70 concentrations among COPD patients based on smoking status, yet eHsp70 was increased in healthy smokers compared to healthy non-smokers. Interestingly, healthy smokers had similar eHsp70 level as COPD patients in GOLD 2 stage and those in GOLD A group. In addition, eHsp70 showed significant negative correlation with lung function parameters FEV1 and FEV1/FVC and positive correlation with COPD multicomponent indices BODCAT, BODEx, CODEx and DOSE. Finally, eHsp70 showed great predictive value (OR=7.63) and correctly classified 76% of cases.Conclusions: Plasma eHsp70 is associated with COPD prediction and disease severity and might have a potential of becoming an additional biomarker in COPD assessment.