Journal of Asthma and Allergy (Jan 2023)
A Multi-Center Study of the Prevalence and Characteristics of Eosinophilic Phenotype and High IgE Levels Among Chinese Patients with Severe Asthma
Abstract
Fanny Wai-San Ko,1 Julie KL Wang,2 David SC Hui,1 Johnny WM Chan,3 Pik-Shan Cheung,4 Yiu-Cheong Yeung,5 Kit Man Sin,6 Mary Sau-Man Ip7 1Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, People’s Republic of China; 2Department of Medicine, Queen Mary Hospital, Hong Kong, People’s Republic of China; 3Department of Medicine, Queen Elizabeth Hospital, Hong Kong, People’s Republic of China; 4Department of Medicine, United Christian Hospital, Hong Kong, People’s Republic of China; 5Department of Medicine and Geriatrics, Princess Margaret Hospital, Hong Kong, People’s Republic of China; 6Department of Medicine, Tuen Mun Hospital, Hong Kong, People’s Republic of China; 7Department of Medicine, School of Clinical Medicine, The University of Hong Kong, Hong Kong, People’s Republic of ChinaCorrespondence: Mary Sau-Man Ip, Division of Respiratory Medicine, Department of Medicine, School of Clinical Medicine, The University of Hong Kong, 4/F, Professorial Block, Queen Mary Hospital, Pokfulam, Hong Kong, People’s Republic of China, Email [email protected]: Patients with severe asthma have higher total- and asthma-related health burden than those whose disease is not severe. Recent medical advances in biologic therapies allow better control of asthma characterized by type 2 inflammation.Objective: To study the prevalence of eosinophilic phenotype and IgE levels in Chinese with severe asthma, and the relationship of these type 2 characteristics with asthma control, exacerbations and lung function.Methods: This was a multicenter cross-sectional observational study in Hong Kong, in Chinese adults with asthma on Step 4 or 5 of GINA treatment. Their blood eosinophil counts and total IgE levels were measured, and the relationship of these phenotypic parameters to the number of exacerbations in the past 12 months, and to symptom control in the past 4 weeks, were investigated.Results: A total of 232 subjects were recruited from 6 centers. The mean age was 53.9± 12.9 years, with 86 (37.1%) male, and the duration of diagnosed asthma was 26.2± 15.7 years. A T-helper 2 (Th2) phenotype indicated by elevated eosinophils and/or IgE was present in 169 (72.8%) of patients. Of 232 patients, 43% had an eosinophilic phenotype (blood eosinophil count ≥ 300 cell/mm3), while 59% had high total IgE levels of > 100 IU/mL (overlap with eosinophilic phenotype in 30%) and 44% had IgE levels of > 150 IU/mL (overlap with eosinophilic phenotype in 22%). Subjects with eosinophilic phenotype and IgE > 150 IU/mL had a higher rate (1.8 times) of uncontrolled asthma compared with those without such a combination.Conclusion: In Chinese adults with severe asthma defined by the use of conventional maintenance medication regimens, the prevalence of Th2 inflammation is comparable to that reported from other ethnic populations. Those with both eosinophil count ≥ 300 cell/mm3 and high IgE levels > 150 IU/mL had a higher rate of uncontrolled asthma compared with those without a combination of these features.Keywords: asthma, Chinese, cross-sectional, eosinophils, Hong Kong, immunoglobulin E
