The Presence Of Inflammatory Biomarkers And Auto-antibodies In COPD And Their Relationship With COPD Exacerbations

BackgroundChronic obstructive pulmonary disease (COPD) is a complex disease with pulmonary and extra-pulmonary manifestations. Spirometry by itself could not adequately describe the complexity of the disease and it cannot be used in isolation for the optimal management of the disease. Recently, elevated levels of circulating inflammatory biomarkers which is associated with systemic inflammation has been reported in some patients with stable COPD, on the other hand, the presence of auto-antibodies which is associated with autoimmune has also been described in some other patients, both factors could contribute to disease progression of COPD and may be associated with clinical outcomes.ObjectiveTo investigate if inflammatory biomarkers and auto-antibodies are presented in COPD, and to explore if the presence of inflammatory biomarkers and auto-antibodies are associated with exacerbation frequency.MethodsPatients with stable COPD and healthy controls were included in this study. Four inflammatory biomarkers (CRP、IL-6、IL-8and TNF-a) were quantified in their serum by enzyme-linked immunosorbent assay. While two auto-antibodies (anti-elastin antibody and anti-nuclear antibody) were detected in their serum by indirect immunofluorescence. Patients were divided into several groups according to the results of blood test and they were followed-up for one year.Results75patients with stable COPD and20healthy controls were included in this study. Compared to healthy controls, circulating inflammatory biomarkers were increased in12(16.0%) patients, and serum auto-antibodies were positive for34(45.3%) patients, however, both abnormalities were found in9(12%) patients. In correlation analyses, there was a significant correlation between IL-8and anti-elastin antibodies (r=0.331, p=0.004). During the1year follow-up period, the annual rate of COPD exacerbations was higher in patients with elevated inflammatory biomarkers compared to those with normal inflammatory biomarkers [1.0(0.2) vs0.5(0.1), p=0.024], and the annual rate of COPD exacerbations was also higher in patients with positive auto-antibodies compared to those with negative auto-antibodies [0.8(0.1) vs0.3(0.1), p=0.001].ConclusionsThe elevation of circulating inflammatory biomarkers in some patients with stable COPD suggested that systemic inflammation is associated with COPD, while the presence of auto-antibodies in some other patients indicated that autoimmune is also associated with COPD. Furthermore, the correlation between inflammatory biomarkers and auto-antibodies implied that systemic inflammation may be associated with autoimmune, these two factors could interact with each other and contribute to disease progression of COPD. Most importantly, COPD patients with elevated inflammatory biomarkers or positive auto-antibodies may be associated with higher risk of exacerbations and worse clinical outcomes.