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Background: Real-time asthma exacerbation prediction and acute asthma attack detection are essential for patients with severe asthma. Peak expiratory flow (PEF) exhibits a potential for use in long-term asthma self-monitoring. However, the method for processing PEF calculations remains to be clarified., Objective: To develop clinically applicable novel exacerbation predictors calculated using PEF records., Methods: Previously proposed exacerbation predictors, including the slope of PEF, percentage predicted PEF, percentage best PEF, the highest PEF over the lowest PEF within specific periods, and PEF coefficient of variation, in addition to a novel indicator delta PEF moving average (ΔMA), defined as the difference between 14-day and 3-day average PEF values, along with moving average (MA) adjusted for PEF reference (%ΔMA), were verified using the Hokkaido-based Investigative Cohort Analysis for Refractory Asthma data of 127 patients with severe asthma from whom 73,503 PEF observations were obtained. Receiver operating characteristic curves for all predictors were drawn, and the corresponding areas under the curve (AUCs) were computed. Regression analysis for MA and percentage MA were conducted., Results: The most outstanding performance was shown by ΔMA and %ΔMA, with AUC values of 0.659 and 0.665 in the univariate model, respectively. When multivariate models were incorporated with random intercepts for individual participants, the AUC for ΔMA and %ΔMA increased to 0.907 and 0.919, respectively., Conclusion: The MA and percentage MA are valuable indicators that should be considered when deriving predictors from the PEF trajectory for monitoring exacerbations in patients with severe asthma., Trial Registration: The Hokkaido-based Investigative Cohort Analysis for Refractory Asthma was registered in the University Hospital Medical Information Network Clinical Trials Registry (UMIN ID: 000003254). https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000003917., Competing Interests: Disclosures Dr Yokota received research funding from Nihon Medi-Physics and speaker fees from Chugai Pharmaceutical Co and AstraZeneca, outside the submitted work. Dr Nishimura received research funding from AstraZeneca KK, Kyorin Pharmaceutical Ltd, and MSD. The remaining authors have no conflicts of interest to report., (Copyright © 2023 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Background: Blood eosinophils are essential biomarkers that vary substantially over time in patients with COPD and asthma. However, no study has identified the changes and effects in the changes of the blood eosinophil counts over time in both diseases. This study aimed to demonstrate blood eosinophil variability in patients with COPD and severe asthma based on these backgrounds., Methods: A total of 172 patients with COPD from the Hokkaido COPD cohort study and 96 patients with severe asthma from the Hokkaido Severe Asthma Cohort Study, whose blood eosinophil counts were measured annually over a 3-year period, were analyzed. The factors contributing to consistently high or low blood eosinophil counts were examined in each cohort. The stability of the eosinophil classification (<150, 150-299, ≥300 cells/μL) was compared based on the number of asthma-like features in patients with COPD and the smoking status in patients with severe asthma., Results: Among all the patients, the most stable range of baseline blood eosinophil counts differed between the two diseases, with <150 cells/μL in COPD and ≥300 cells/μL in severe asthma. In COPD, the number of asthma-like features (bronchodilator reversibility, blood eosinophilia, and atopy) affects the blood eosinophil count variation patterns. In severe asthma, smoking status did not affect the blood eosinophil count variation patterns., Conclusions: We identified variations in the blood eosinophil counts and their contributing factors in patients with COPD and severe asthma., (Copyright © 2022 Japanese Society of Allergology. Published by Elsevier B.V. All rights reserved.)

Background: The physiological importance of mucus plugs in computed tomography (CT) imaging is being increasingly recognized. However, whether airway inflammation and smoking affect the association between mucus plugs and clinical-physiological outcomes in asthma remains to be elucidated. The objective of this study is to examine how airway inflammation and/or smoking affect the correlation of CT-based mucus plug scores with exacerbation frequency and airflow limitation indices in asthma., Methods: A total of 168 patients with asthma who underwent chest CT and sputum evaluation were enrolled and classified in eosinophilic asthma (EA; n = 103) and non-eosinophilic asthma (NEA; n = 65) groups based on sputum eosinophil percentage (cut-off: 3%). The mucus plug score was defined as the number of lung segments with mucus plugs seen on CT., Results: More mucus plugs were detected on CT scans in the EA group than in the NEA group, regardless of smoking status. Mucus plug score and exacerbation frequency during one year after enrollment were significantly associated in the EA group but not in the NEA group after adjusting for demographics, blood eosinophil count, and fractional exhaled nitric oxide. Mucus plug score was associated with percentage of predicted forced expiratory volume in 1 s in non-smoking individuals in the EA and NEA group and in smoking individuals in the EA group but not in the NEA group after adjusting for demographics., Conclusions: The association of mucus plug score with exacerbation frequency and reduced lung function may vary due to airway inflammatory profile and smoking status in asthma., (Copyright © 2022 Japanese Society of Allergology. Published by Elsevier B.V. All rights reserved.)

Background: The mechanism of high transfer coefficients of the lungs for carbon monoxide (Kco) in non-smokers with asthma is explained by the redistribution of blood flow to the area with preserved ventilation, to match the ventilation perfusion. Objectives: To examine whether ventilation heterogeneity, assessed by pulmonary function tests, is associated with computed tomography (CT)-based vascular indices and Kco in patients with asthma. Methods: Participants were enrolled from the Hokkaido-based Investigative Cohort Analysis for Refractory Asthma (Hi-CARAT) study that included a prospective asthmatic cohort. Pulmonary function tests including Kco, using single breath methods; total lung capacity (TLC), using multiple breath methods; and CT, were performed on the same day. The ratio of the lung volume assessed using single breath methods (alveolar volume; V A ) to that using multiple breath methods (TLC) was calculated as an index of ventilation heterogeneity. The volume of the pulmonary small vessels <5 mm 2 in the whole lung (BV5 volume), and number of BV5 at a theoretical surface area of the lungs from the plural surface (BV5 number) were evaluated using chest CT images. Results: The low V A /TLC group (the lowest quartile) had significantly lower BV5 number, BV5 volume, higher BV5 volume/BV5 number, and higher Kco compared to the high V A /TLC group (the highest quartile) in 117 non-smokers, but not in 67 smokers. Multivariable analysis showed that low V A /TLC was associated with low BV5 number, after adjusting for age, sex, weight, lung volume on CT, and CT emphysema index in non-smokers (not in smokers). Conclusion: Ventilation heterogeneity may be associated with low BV5 number and high Kco in non-smokers (not in smokers). Future studies need to determine the dynamic regional system in ventilation, perfusion, and diffusion in asthma., Competing Interests: MS received grants from GlaxoSmithKline, Novartis, and AstraZeneca outside the current work. NT, and SS, report a grant from Fujifilm Medical outside the current work. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Shimizu, Kimura, Tanabe, Chubachi, Sato, Suzuki, Tanimura, Iijima, Oguma, Ito, Wakazono, Takimoto-Sato, Matsumoto-Sasaki, Abe, Takei, Makita, Nishimura, Konno and Hi-CARAT investigators.)

Background: There are knowledge gaps in the potential role of Club cell 16-kDa secretory protein (CC16) in severe asthma phenotypes and type 2 inflammation, as well as the longitudinal effect of CC16 on pulmonary function tests and exacerbation risk in epidemiological studies., Objective and Methods: To assess whether serum CC16 is associated with eosinophilic inflammation in patients with severe asthma. We also examined the effect of this protein on the annual decline in forced expiratory volume in the first second (FEV 1 ) and the risk of exacerbation using a longitudinal approach. We recruited 127 patients with severe asthma from 30 hospitals/pulmonary clinics in Hokkaido, Japan. The least square means and standard error were calculated for T-helper 2 (Th2) biomarkers and pulmonary function test across CC16 tertiles at baseline. We did the same for asthma exacerbation and annual decline in FEV 1 with 3 and 5 years' follow-up, respectively., Results: We found that serum CC16 was inversely associated with sputum eosinophils and blood periostin in a dose-response manner. Baseline CC16 and FEV 1 /forced vital capacity ratio were positively associated in adjusted models (p for trend = 0.008). Patients with the lowest tertile of serum CC16 levels at baseline had a -14.3 mL decline in FEV 1 than those with the highest tertile over 5 years of follow-up (p for trend = 0.031, fully adjusted model). We did not find any association of CC16 with exacerbation risk., Conclusion: Patients with severe asthma with lower circulatory CC16 had enhanced eosinophilic inflammation with rapid FEV 1 decline over time., Competing Interests: Declaration of competing interest None to declare., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Background: Quality of life (QoL) assessment is important in the management of severe asthma, and comorbidities and/or exacerbations may affect longitudinal QoL. However, there are few reports on the longitudinal assessment of QoL in patients with asthma over multiple years and its related factors. This study aimed to clarify the relationship of longitudinal changes in QoL with comorbidities and/or exacerbations during a prolonged observation period in patients with severe asthma., Methods: A total of 105 subjects who participated in the Hokkaido-based Investigative Cohort Analysis for Refractory Asthma (Hi-CARAT) with a six-year follow-up were analyzed. QoL was assessed annually, using the Standardized Asthma Quality of Life Questionnaire, and the subjects were divided into three groups: (1) persistently good QoL, (2) persistently poor QoL, and (3) fluctuating QoL. Assessed comorbidities comprised depression, gastroesophageal reflux disease, and excessive daytime sleepiness (EDS), a key symptom of obstructive sleep apnea., Results: Of 105 subjects with severe asthma, 53 (50%) were classified in the persistently good QoL group, 10 (10%) in the persistently poor QoL group, and 42 (40%) in the fluctuating QoL group. The persistently poor QoL group was associated with shorter time to hospitalization due to exacerbation and the presence of multiple comorbidities. In addition, the presence of EDS was an independent contributor to the fluctuating QoL group compared to the persistently good QoL group., Conclusions: The presence of multiple comorbidities and hospitalization due to exacerbation contribute to longitudinal changes in QoL in patients with severe asthma., (Copyright © 2022 Japanese Society of Allergology. Production and hosting by Elsevier B.V. All rights reserved.)

Background: The chitinase-like protein YKL-40 is associated with airflow limitation on spirometry and airway remodeling in patients with asthma. It remains unclear whether YKL-40 is associated with morphologic changes in the airways and parenchyma or with future progression of airflow limitation in severe asthma., Objective: To evaluate the association of circulating YKL-40 levels with morphologic changes in the airways and parenchyma and with longitudinal progression of airflow limitation., Methods: The patients were participants in the Hokkaido Severe Asthma Cohort Study (n = 127), including smokers. This study consisted of 2 parts. In analysis 1, we analyzed associations between circulating YKL-40 levels and several asthma-related indices, including computed tomography-derived indices of proximal wall area percentage, the complexity of the airways (airway fractal dimension), and the parenchyma (exponent D) cross-sectionally (n = 97). In analysis 2, we evaluated the impact of circulating YKL-40 levels on forced expiratory volume in 1 second (FEV 1 ) decline longitudinally for a 5-year follow-up (n = 103)., Results: Circulating YKL-40 levels were significantly associated with proximal wall area percentage and airway fractal dimension (r = 0.25, P = .01; r = -0.22, P = .04, respectively), but not with exponent D. The mean annual change in FEV 1 was -33.7 (± 23.3) mL/y, and the circulating YKL-40 level was a significant independent factor associated with annual FEV 1 decline (β = -0.24, P = .02), even after controlling for exponent D (β = -0.26, P = .01)., Conclusion: These results provide further evidence for the association of YKL-40 with the pathogenesis of airway remodeling in severe asthma., (Copyright © 2022 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Purpose: Biologics have been used increasingly for the treatment of severe asthma. However, established guidelines for the selection, switching, or discontinuation of biologics do not exist. We aimed to identify the clinical characteristics of patients with asthma who required switching biologics and the factors associated with switching biologics., Patients and Methods: This was a retrospective study of 42 patients with severe asthma treated with biologics at the Hokkaido University Hospital between 23 rd June 2016 and 30 th April 2021, when two biologics were available in Japan. We compared the characteristics of subjects who continued and switched biologics. The time to switch the biologics was assessed by type 2 inflammatory biomarkers, pulmonary function indices, and the presence of comorbidities, including the Japanese Epidemiological Survey of Refractory Eosinophilic Chronic Rhinosinusitis (JESREC) score and aspirin exacerbated respiratory diseases (AERD), using the Kaplan-Meier method and a multivariate Cox proportional hazards model., Results: Eight and five patients were treated by mepolizumab and benralizumab at baseline, respectively among the 31% (13/42) who switched the biologics. Subjects who required switching biologics were characterized by high blood eosinophil counts, younger age, JESREC scores of 11 points or higher, and AERD. The time taken to switch biologics was significantly shorter in the subgroups with high JESREC scores (≥11) or AERD, compared with their counterparts with low JESREC scores or without AERD (both, P < 0.05). JESREC scores of ≥11, but not the presence of AERD, were associated with time to switch biologics., Conclusion: The presence of eosinophilic chronic rhinosinusitis based on JESREC scores of ≥11 and younger age were factors associated with switching biologics in asthma., Competing Interests: Masaru Suzuki reports Lecture fee from GlaxoSmithKline, Novartis, and AstraZeneca outside the current work. YI reports consulting fees from JAPAN TOBACCO INC., Kowa Company, Limited, Nipro Corporation, ONO PHARMACEUTICAL CO., LTD and payment for speaker from Novartis Japan and participation on a Data safety monitoring Board or Advisory Board from Janssen Pharmaceutical, K.K. outside the current work. SK received grants from AstraZeneca, Kyorin Pharmaceutical, Nippon Boehringer Ingelheim, Novartis and payment for speaker from Astra Zeneca and Nippon Boehringer Ingelheim. The rest of the authors declare that they have no relevant conflicts of interest. The above-mentioned companies or organizations has not been involved in the concept or analysis of the present work., (© 2022 Matsumoto-Sasaki et al.)

At the time of writing of this manuscript, four biologics were clinically available for the treatment of severe asthma, and there were no established recommendations for the period of administration or timing of discontinuation of each biologic. We present a case of severe asthma that was well controlled with long-term omalizumab treatment; however, prolongation of the dosing intervals resulted in disease exacerbation that was refractory to omalizumab treatment despite the restoration of the recommended interval of administration. We suspect that the prolonged dosing intervals might have reduced the efficacy of omalizumab. We report this case because dosing intervals should be considered in clinical practice in cases of long-term omalizumab treatment.

At the time of writing of this manuscript, four biologics were clinically available for treatment against severe asthma. The choice of four biologics has been taking into account of the results of several type 2 inflammationrelated biomarkers, and the comorbidities of asthma, such as eosinophilic chronic rhinosinusitis, allergic rhinitis, and atopic dermatitis.In this study, we have experienced a case of severe asthma complicated by eosinophilic chronic rhinosinusitis and eosinophilic otitis media, resulting in the use of four biologics, and we observed differential response of upper and lower airways. As a clear algorithm has not been established for the use of four biologics, our experience of this case would provide important lesson for considering the therapeutic strategies against severe asthma.

We report the case of a 66-year-old patient with severe asthma complicated by eosinophilic chronic rhinosinusitis (ECRS). The patient was initially treated with benralizumab, which resulted in marked improvement of asthma symptoms and reduced the peripheral blood eosinophil count to 0/μL. Additionally, oral steroids were discontinued. After 7 months of benralizumab administration, the asthma symptoms worsened and peripheral blood eosinophil count increased to 813/μL. The neutralizing antibodies to benralizumab may have resulted in the recurrence of symptoms due to eosinophilic inflammation. The nasal symptoms, on which benralizumab had an unremarkable effect, improved when treatment was switched to mepolizumab. However, the difference in effects of biologics on ECRS has not been elucidated and warrants further investigation. To the best of our knowledge, this is the first report of a case of severe asthma in which mepolizumab administration reversed the clinical deterioration of asthma, which was possibly caused by neutralizing antibodies to benralizumab.