Sensitization to as a risk factor for bronchiectasis in COPD.

BACKGROUND

Bronchiectasis-chronic obstructive pulmonary disease (COPD) overlap presents a possible clinical phenotype of COPD, but it is unclear why it develops in a subset of patients. We hypothesized that sensitization to () is associated with bronchiectasis in COPD and occurs more frequently in vitamin D-deficient patients.

METHODS

This observational study investigated sensitization to in an outpatient clinical cohort of 300 COPD patients and 50 (ex-) smoking controls. Total IgE, -specific IgE against the crude extract and against the recombinant antigens and IgG were measured using ImmunoCAP fluoroenzyme immunoassay. Vitamin D was measured by radioimmunoassay, and computed tomography images of the lungs were scored using the modified Reiff score.

RESULTS

Sensitization to occurred in 18% of COPD patients compared to 4% of controls (=0.0110). In all, 31 COPD patients (10%) were sensitized to the crude extract and 24 patients (8%) had only IgE against recombinant antigens. IgG levels were significantly higher in the COPD group (=0.0473). Within COPD, -sensitized patients were more often male (=0.0293) and more often had bronchiectasis (=0.0297). and were more prevalent in historical sputum samples of -sensitized COPD patients compared to -non-sensitized COPD patients (=0.0436). Vitamin D levels were comparable (=0.2057). Multivariate analysis demonstrated that sensitization to recombinant f1 or f3 had a 2.8-fold increased risk for bronchiectasis (=0.0030).

CONCLUSION

These results highlight a potential role for sensitization to in COPD-related bronchiectasis.