Clinical significance of BPI‐ANCA detecting in COPD patients with Pseudomonas aeruginosa colonization

Background Antineutrophil cytoplasmic autoantibodies against neutrophil granule bactericidal/permeability‐increasing protein (BPI‐ANCA) has been found in many inflammatory diseases, such as COPD, which can reduce the killing effect of BPI on Gram‐negative bacteria. This study was aimed to assess the clinical significance of BPI‐ANCA detecting in COPD patients with Pseudomonas aeruginosa (P aeruginosa) colonization. Methods A total of 216 COPD patients with lung P aeruginosa colonization, 244 patients with P aeruginosa infection from June 2015 to June 2018, and 100 healthy individuals were included. Serum BPI‐ANCA, tumor necrosis factor (TNF)‐α, and interleukin (IL)‐6 and IL‐1β levels were detected by ELISA, and the lung function of the patients was measured at stable clinical stages. Patients with COPD were grouped according to BPI‐ANCA detection and GOLD criteria, and serum TNF‐α, IL‐6, and IL‐1β levels and indices reflecting lung function were compared and analyzed between groups. Results Positive rate of BPI‐ANCA in COPD patients with P aeruginosa colonization was 48.15%; and compared with BPI‐ANCA(‐) group, FEV1%pred and FEV1/FVC(%) in BPI‐ANCA(+) patients were significantly decreased, while TNF‐α, IL‐6, and IL‐1β levels were elevated. There were 31.73% and 36.54% BPI‐ANCA(+) patients with severe and very severe airflow limitation, respectively, which was significantly higher than that in the BPI‐ANCA(‐) group. FEV1%pred and FEV1/FVC(%) were negatively correlated with TNF‐α, IL‐6, IL‐1β, and NEU%. C‐reactive protein (CRP) was negatively correlated with FEV1%pred, yet not significantly correlated with FEV1/FVC(%). Conclusion BPI‐ANCA positivity is associated with inflammatory status in COPD patients with pulmonary P aeruginosa colonization and can be used as a potential biomarker assessing disease severity.