Comprehensive analysis of allergen-specific IgE in COPD: mite-specific IgE specifically related to the diagnosis of asthma-COPD overlap

BACKGROUND: Although the relationship between allergic sensitization and increased respiratory symptoms of chronic obstructive pulmonary disease (COPD) has been suggested, which allergen has a significant effect on COPD pathology is unclear. This study aimed to identify the specific IgE related to clinical features of COPD and the diagnosis of asthma-COPD overlap (ACO). METHODS: We recruited 76 patients with COPD and analyzed 39 IgE using panel IgE test (View Allergy 39(®)). ACO was diagnosed according to the Japanese Respiratory Society Guidelines. RESULTS: As for perennial aeroallergens, the positivity for moth (31.5%), Candida (23.7%), Dermatophagoides pteronyssinus (22.4%) and house dust (22.4%), and concerning pollen, Japanese cedar (35.5%) and Japanese cypress (22.2%) exceeded 20%. Only the positivity of IgE for Dermatophagoides pteronyssinus and house dust was significantly higher in ACO compared with that in non-ACO COPD. Moreover, it contributed to the diagnosis of ACO in an IgE class-dependent manner. Patients with cockroach IgE exhibited higher residual volume, whereas those with Japanese cedar IgE exhibited better diffusion capacity than negative patients. The contribution for ACO diagnosis by the receiver operating characteristic curve analysis was comparable among total IgE (cutoff value: 158 IU/mL), blood eosinophil count (234/μL), and fraction of exhaled nitric oxide (31.0 ppb). CONCLUSIONS: The prominent role of mite-specific IgE in the diagnosis and pathology of ACO and the potentially detrimental effect of cockroach sensitization on air trapping in COPD were suggested. The finding highlights the future development of a treatment targeting IgE as a treatable trait in COPD.