Sung Do Moon, MD
,
Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University Hospital, Seoul, South Korea
Ha Kyung Won, MD
,
Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University Hospital, Seoul, South Korea
Kyonghee Sohn
,
Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, South Korea
Min-Koo Kang, MD
,
Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University Hospital, Seoul, South Korea
Byung-Keun Kim, MD
,
Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University Hospital, Seoul, South Korea
Ju-Young Kim, MD
,
Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University Hospital, Seoul, South Korea
Seoung-Eun Lee, MD
,
Internal Medicine, Yangsan Pusan National University Hospital, Yangsan, South Korea
Woo-Jung Song, MD
,
Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University Hospital, Seoul, South Korea
Kyung-Mook Kim, MD
,
Department of Internal Medicine, Pogunhan Mom Hospital, Seoul, South Korea
Hye-Ryun Kang, MD, PhD
,
Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University Hospital, Seoul, South Korea
Heung Woo Park, MD, PhD
,
Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University Hospital, Seoul, South Korea
Yoon-Seok Chang, MD, PhD
,
Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, South Korea
Kyung-up Min, MD, PhD
,
Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University Hospital, Seoul, South Korea
Claus Bachert, MD, PhD
,
Upper Airway Research Laboratory, University of Ghent, Ghent, Belgium
Sang-Heon Cho, MD, PhD
,
Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University Hospital, Seoul, South Korea
Background: The pathogenesis of asthma-chronic obstructive pulmonary disease overlap syndrome (ACOS) is supposed to be multifactorial but unclear. Recent evidence suggests staphylococcal enterotoxin IgE sensitization (SE-IgE) to be a risk factor for asthma and its severity in adults, including the elderly. We hypothesized SE sensitization contributes to the development of fixed airway obstruction in asthma, leading to an ACOS phenotype. The present study aimed to examine the associations of SE-IgE sensitization with fixed airway obstruction in elderly asthma patient.
Methods: We compared baseline characteristics between elderly controls, asthma and ACOS patients (≥65 years). Baseline assessment included demographics, lung functions, comorbidities, and serum total IgE and SE-IgE levels. SE-IgE sensitization was classified as negative (<0.10 kU/L), moderate (0.10-0.35 kU/L), and high (≥0.35 kU/L). SE-IgE sensitization was defined positive as ≥0.35 kU/L. Lung functions were serially checked every 3 month for two years in elderly asthma patients, and their best FEV1/FVC ratio was used to define fixed airway obstruction (persistently FEV1/FVC<0.7 during 2-year of asthma management). Exacerbation frequency was assessed during 1-year prospective follow-up.
Results: A total of 338 elderly subjects were analyzed (89 controls, 172 asthma, and 87 ACOS). Serum SE-IgE levels were higher among elderly ACOS and asthma patients, compared to controls (mean±SD; 0.74±1.34, 0.56±2.32, and 0.20±0.36, respectively). SE-IgE sensitization rates significantly differed between groups (high SE-IgE sensitization; 44.2% in ACOS, 27.9% in asthma, and 14.6% in control; P<0.001). The presence of fixed airway obstruction (FEV1/FVC<0.70) showed relationships with male sex, smoking history, chronic rhinosinusitis (CRS), and SE-IgE sensitization. In multivariate analyses, smoking history and high SE-IgE sensitization had independent relationships with fixed airway obstruction. In both of asthma and ACOS groups, SE-IgE levels showed significant correlations with exacerbation frequency.
Conclusions: Staphyloccocal enterotoxin could have a pathogenic role in the development of COPD overlap in late-onset elderly asthma. These findings warrant further investigation for mechanisms of SE in mediating airway remodeling.
