Rationale: Chronic obstructive pulmonary disease (COPD) is a multicomponent disease. Autoimmunity can contribute to the pathogenesis of COPD.
Objectives: This study investigates the prevalence of circulating antinuclear antibodies (ANA) and anti-tissue (AT) antibodies, two common markers of autoimmunity, in COPD and their relationship with several components of the disease.
Methods: We determined lung function, the serum titers of ANA and AT by immunofluorescence, and the serum levels of C-reactive protein (CRP) by high sensitivity nephelometry in 328 patients with clinically stable COPD and in 67 healthy controls recruited in the PAC-COPD study. Multiple linear and logistic regression analysis was used to analyze results.
Measurements and main results: The prevalence of abnormal ANA and AT titers was 34% and 26% in patients and 3% and 6% in controls, respectively. Levels of AT greater than or equal to 1:320 were seen in 21% of patients with COPD and were independently associated with the severity of airflow limitation and gas transfer impairment (P < 0.05). Neither ANA or AT titers was related to body mass index, current smoking status, use of inhaled steroids, the Charlson index, or serum C-reactive protein values.
Conclusions: Between a quarter and a third of patients with clinically stable COPD present abnormal titers of circulating ANA and AT. The observed relationship between AT and lung function supports a role for autoimmunity in the pathogenesis of COPD.