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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) crosssectionally (n = 97). In analysis 2, we evaluated the impact of circulating YKL-40 levels on forced expiratory volume in 1 second (FEV1) 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 FEV1 was -33.7 (+/- 23.3) mL/y, and the circulating YKL-40 level was a significant independent factor associated with annual FEV1 decline (beta = -0.24, P =.02), even after controlling for exponent D (beta = -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. (C) 2022 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Fractional exhaled nitric oxide (FeNO) may have a role both as a prognostic and predictive biomarker, in combination with eosinophils, for assessing responsiveness to some biological therapies.We evaluated the value of baseline FeNO, adjusted for baseline blood eosinophil levels and other clinical characteristics, as an independent predictor of treatment response to dupilumab in patients with uncontrolled, moderate-to-severe asthma.We performed a post-hoc analysis of LIBERTY ASTHMA QUEST (NCT02414854), a phase 3, double-blind study in patients aged ≥ 12 years with uncontrolled moderate-to-severe asthma who received dupilumab 200/300 mg, or placebo every 2 weeks up to 52 weeks. Annualized event rate (AER) of severe exacerbations and least squares mean change from baseline in pre-bronchodilator forced expiratory volume in 1 s (FEVAER increased with increasing baseline FeNO in placebo, and decreased in dupilumab groups. The relative risk of severe exacerbations was 22·7%, 58·3%, and 69·3% lower for dupilumab vs placebo for the FeNO25, 25 to50, and ≥ 50 ppb subgroups. The magnitude of FEVIncreased baseline FeNO was associated with greater clinical effects in dupilumab vs placebo, independent of eosinophil levels and other clinical characteristics.

Interleukin (IL)-24 is a member of the IL-20 family of cytokines and is produced by various types of cells, such as CD4+ T cells, NK cells, mast cells, keratinocytes, bronchial epithelial cells, and myofibroblasts. Previous studies suggest that IL-24 plays an essential role in the pathogenesis of pro-inflammatory autoimmune disorders such as psoriasis, arthritis, and inflammatory bowel diseases. However, the role of IL-24 in the pathogenesis of allergic diseases has been elusive. It has already been reported that IL-24 is involved in the pathogenesis of allergic lung and skin diseases. Moreover, we have recently revealed for the first time the pivotal functions of IL-24 in IL-13–mediated skin barrier dysfunction in atopic dermatitis (AD), which is known to be a characteristic of AD caused by Th2 cytokines such as IL-4 or IL-13. In this review, we show recent advances in the basic characteristics of IL-24 and its novel functions in the pathogenesis of allergic skin inflammation, focusing on AD. A better understanding of the role of IL-24 in allergic diseases can lead to the development of new therapeutic options.

Omalizumab is more effective in severe allergic patients with eosinophilic asthma than those with non-eosinophilic asthma. IL-18, a unique cytokine involved in allergic but non-eosinophilic inflammation, might be associated with the latter condition. We aimed to clarify the roles of IL-18 related pathways in insufficient response to omalizumab treatment.Patients with severe allergic asthma who completed 2-year omalizumab treatments at Kyoto University Hospital were included in this study (UMIN000002389). Associations between pretreatment levels of serum free IL-18 in addition to other mediators and asthma phenotypes including responses to omalizumab treatment were analyzed. Changes in serum free IL-18, periostin and total IgE levels during the treatment were also examined.Twenty-seven patients (19 females, average age of 55.7 years) were examined. Fifteen incomplete responders who experienced exacerbations in the second year, were significantly and more frequently obese and showed significantly earlier asthma onset, lower blood eosinophils and more exacerbations before omalizumab treatment than complete responders. Significantly more patients showed high baseline serum free IL-18 levels (≥141 pg/mL, a threshold for the highest tertile) among the incomplete responders than complete responders. Patients with high serum free IL-18 levels shared similar characteristics with incomplete responders, showing significant reductions in serum total IgE levels during omalizumab treatment. Finally, serum free IL-18 levels negatively correlated with serum periostin levels at baseline and in change ratios.High baseline serum free IL-18 levels may predict reduced omalizumab efficacy in severe allergic patients with type-2 low asthma, regarding reduction of exacerbations.

Interleukin (IL)-4 and IL-13, signature type 2 cytokines, exert their actions by binding to two types of receptors sharing the IL-4R α chain (IL-4Rα). Since IL-4 and IL-13 play important and redundant roles in the pathogenesis of allergic diseases, blocking both the IL-4 and IL-13 signals would be a powerful and effective strategy for treating allergic diseases. Dupilumab (Dupixent®) is a fully human monoclonal antibody recognizing IL-4Rα and blocking both the IL-4 and IL-13 signals. Dupilumab was first prescribed for atopic dermatitis (AD) patients and has been widely approved for adult patients with moderate to severe AD since 2018. Dupilumab has since been used for asthma, receiving approval for uncontrolled asthma in 2019. A phase 3 study using dupilumab for chronic rhinosinusitis with nasal polyps (CRSwNP) has been just completed, with positive results. Several clinical trials of dupilumab for other diseases in which type 2 inflammation is dominant are now underway. It is hoped that dupilumab will open the door to a new era for treating allergic patients with AD, asthma, and CRSwNP, and for more patients with type 2 inflammations. Keywords: Asthma, Atopic dermatitis, Chronic rhinosinusitis with nasal polyps, Interleukin-4, Interleukin-13

Background: Periostin is a matricellular protein belonging to the fasciclin family, playing a role for the pathogenesis of allergic diseases by binding to integrins on cell surfaces. Serum periostin is elevated in various allergic diseases reflecting type 2 inflammation and tissue remodeling so that for allergic diseases, periostin is expected to be a novel biomarker for diagnosis, assessing severity or prognosis, and predicting responsiveness to treatments. We have previously shown that most serum periostin exists in the oligomeric form by intermolecular disulfide bonds. Methods: In this study, we examined how periostin forms a complex in serum, whether the periostin complex in serum is functional, and whether the complex formation interferes with reactivity to anti-periostin Abs. Results: We found that periostin formed a complex with IgA1 at a 1:1 ratio. The periostin in the serum complex contained at least five different isoforms. However, IgA was not essential for the oligomeric formation of periostin in mouse serum or in IgA-lacking serum. The periostin-IgA complex in human serum was functional, sustaining the ability to bind to αVβ3 integrin on cell surfaces. Moreover, periostin formed the complex with IgA broadly, which interferes the binding of the Abs recognizing all of the domains except the R4 domain to periostin. Conclusions: Periostin is a novel member of the IgA-associated molecules. These results are of great potential use to understand the pathological roles of periostin in allergic diseases and, from a practical standpoint, to develop diagnostics or therapeutic agents against periostin. Keywords: Complex, IgA, Integrin, Periostin, Serum

Background We recently reported that squamous cell carcinoma antigen 2 (SCCA2) is a reliable biomarker for atopic dermatitis (AD). Objective To further clarify its utility, we investigated for effects of comorbid allergies and AD treatment on serum SCCA levels. Methods Volunteers

The Global Initiative for Asthma report recommends consideration of add-on biologics for patients with type 2 inflammation (blood eosinophils ≥150 cells/μL, fractional exhaled nitric oxide [Feno] ≥20 parts per billion or allergic asthma) whose asthma cannot be controlled by high-dose inhaled corticosteroids. In QUEST (NCT02414854), add-on dupilumab versus placebo was efficacious in patients with uncontrolled, moderate to severe asthma, including those with eosinophils greater than or equal to 150 cells/μL and/or Feno greater than or equal to 25 parts per billion.To assess dupilumab efficacy in patients with a type 2 phenotype in the presence or absence of allergic asthma phenotype.Patients aged 12 years or older received add-on dupilumab 200/300 mg versus matched placebo every 2 weeks for 52 weeks. Allergic asthma phenotype was defined as baseline serum total IgE greater than or equal to 30 IU/mL and 1 or more perennial aeroallergen-specific IgE level greater than or equal to 0.35 kU/L. Annualized rate of severe asthma exacerbations and changes from study baseline in prebronchodilator and postbronchodilator FEVOf 1902 patients in QUEST, 83.3% had eosinophils and/or Feno above Global Initiative for Asthma thresholds; 56.9% had evidence for allergic asthma. Dupilumab significantly reduced the rate of severe asthma exacerbations in patients with (48.8%) and without (64.0%) evidence of allergic asthma and improved prebronchodilator and postbronchodilator FEVIn patients with type 2 biomarkers over Global Initiative for Asthma thresholds, dupilumab significantly reduced exacerbations and improved lung function. Efficacy was not impacted by allergic status.

Background: Periostin is an established biomarker of Th2 immune response and fibrogenesis. Recent research has indicated that periostin plays an important role in the pathogenesis of idiopathic interstitial pneumonias. To clarify the relationship between periostin and pathogenesis in chronic bird-related hypersensitivity pneumonitis (HP) and to reveal the usefulness of serum periostin levels in diagnosing and managing chronic bird-related HP. Methods: We measured serum periostin in 63 patients with chronic bird-related HP, 13 patients with idiopathic pulmonary fibrosis, and 113 healthy volunteers. We investigated the relationship between serum periostin and clinical parameters, and evaluated if the baseline serum periostin could predict the prognosis. Results: Serum periostin was significantly higher in patients with chronic bird-related HP compared to the healthy volunteers. In chronic bird-related HP, serum periostin had significant positive correlations with serum KL-6 levels, the CD4/CD8 ratio in bronchoalveolar lavage fluid, and fibrosis score on HRCT, and a significant negative correlation with the diffusing capacity of the lungs for carbon monoxide. Chronic bird-related HP patients with serum periostin levels exceeding ≥92.5 ng/mL and ≥89.5 ng/mL had a significantly worse prognosis and significantly higher frequency of acute exacerbation, respectively. Higher serum periostin (92.5 ng/mL or higher; binary response for serum periostin) was an independent prognostic factor in multivariate analysis. Conclusions: Serum periostin may reflect the extent of lung fibrosis and play an important role in pathogenesis of chronic bird-related HP. Elevated serum periostin could be a predictor of prognosis in patients with chronic bird-related HP. Keywords: Biomarker, Chronic hypersensitivity pneumonitis, High-resolution computed tomography, Lung fibrosis, Periostin

Background: Previous studies have used serum periostin levels as a biomarker of Th2-driven inflammatory responses. However, no population-based study has yet examined the association of serum periostin levels with the allergic status of children. Objectives: The aim of this study was to determine the usefulness of periostin as a biomarker for allergy in a group of 7-year-old Korean children. Method: This prospective cross-sectional study examined 451 children (aged 7 years to 7 years and 11 months) from the general pediatric population who attended 6 different schools between June and July 2016. A total of 249 children, all of whom completed the questionnaire and skin prick test and provided blood samples, were included in the final analysis. Results: The geometric mean serum periostin level was 107.6 ng/mL (95% CI 104.5–110.7). After adjustment for confounding, serum periostin levels were significantly associated with sensitization to poly-allergens (adjusted odds ratio, aOR 1.032, 95% CI 1.006–1.059, p = 0.016) and pollen (aOR 1.020, 95% CI 1.002–1.039, p = 0.026). Serum periostin levels were also associated with eosinophil levels (adjusted β = 0.023, SE = 0.009, p = 0.010), but were unrelated to body mass index, sex, obesity, or presence of an allergic disease. Conclusions: Our results suggest thatserum periostin level may have limited usefulness as a biomarker of allergic disease in children.

Allergen immunotherapy (AIT) has been in use for the treatment of allergic disease for more than 100 years. Asthma treatment relies mainly on corticosteroids and other controllers recommended to achieve and maintain asthma control, prevent exacerbations, and improve quality of life. AIT is underused in asthma, both in children and in adults. Notably, patients with allergic asthma not adequately controlled on pharmacotherapy (including biologics) represent an unmet health need. The European Academy of Allergy and Clinical Immunology has developed a clinical practice guideline providing evidence-based recommendations for the use of house dust mites (HDM) AIT as add-on treatment for HDM-driven allergic asthma. This guideline was developed by a multi-disciplinary working group using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. HDM AIT was separately evaluated by route of administration and children and adults: subcutaneous (SCIT) and sublingual AIT (SLIT), drops, and tablets. Recommendations were formulated for each. The important prerequisites for successful treatment with HDM AIT are (a) selection of patients most likely to respond to AIT and (b) use of allergen extracts and desensitization protocols of proven efficacy. To date, only AIT with HDM SLIT-tablet has demonstrated a robust effect in adults for critical end points (exacerbations, asthma control, and safety). Thus, it is recommended as an add-on to regular asthma therapy for adults with controlled or partially controlled HDM-driven allergic asthma (conditional recommendation, moderate-quality evidence). HDM SCIT is recommended for adults and children, and SLIT drops are recommended for children with controlled HDM-driven allergic asthma as the add-on to regular asthma therapy to decrease symptoms and medication needs (conditional recommendation, low-quality evidence).

Asthma is a significant comorbidity of eosinophilic chronic rhinosinusitis (CRS). Type2-driven biomarkers such as sinus tissue eosinophilia and fractional nitric oxide (FeNO) may be utilized to detect high risk patients who develop asthma symptoms after endoscopic sinus surgery (ESS) in CRS patients.Thirty-six CRS patients without asthma who agreed to undergo ESS between October 2015 and December 2017 were prospectively observed for 12 months following ESS. They were monitored for the development of typical asthma symptoms including dyspnea, wheezes, and cough which responded to anti-asthma medication. Biomarkers were compared between patients who developed asthma symptoms after ESS (asthma symptoms group) and those who did not (non-asthma group). Biomarker changes following ESS intervention were also evaluated.Six patients were lost to follow after ESS. Thus, 30 CRS patients [16 with nasal polyps (NPs) proved by surgery] were followed. Seven (23%) newly complained of asthma symptoms during follow-up. Levels of FeNO and the prevalence of eosinophilic NPs (eosinophils ≥ 70/high power fields) were significantly higher in the asthma symptom group than in non-asthma group [50.7 ppbEosinophils in NPs (≥70/high power fields) and preoperative FeNO may be significant biomarkers for predicting the development of asthma symptoms after ESS.

Background We recently reported that squamous cell carcinoma antigen 2 (SCCA2) is a reliable biomarker for atopic dermatitis (AD) in children. To further clarify its utility, we investigated for possible effects of comorbid allergies and AD treatment on serum SCCA levels in children and adolescents.Methods Volunteers aged less than 18 years were recruited through our website. Their allergic status was elucidated using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. We also recruited pediatric patients who needed to be hospitalized because of severe AD. The serum levels of SCCA1 and SCCA2 were measured by ELISAs. In the severe AD patients, the levels of thymus and activation-regulated chemokine (TARC), SCCA1 and SCCA2 were measured before and after hospitalization. The severity of AD was assessed using the severity scoring of atopic dermatitis (SCORAD) index.Results A total of 576 participants (547 volunteers and 29 patients) were enrolled in the study. The levels of SCCA1 and SCCA2 were significantly higher in volunteers with mild AD and patients with severe AD than in healthy volunteers without allergic diseases. In contrast, the levels were not elevated in those who had mild bronchial asthma or mild allergic rhinitis without AD. TARC, SCCA1 and SCCA2 were decreased in patients with severe AD, reflecting clinical improvement in response to treatment. Linear regression analysis for predicting a decrease in the SCORAD index showed R2 values of 0.16, 0.38 and 0.48 for TARC, SCCA1 and SCCA2, respectively..Conclusions SCCAs, especially SCCA2, are sensitive biomarkers for detecting AD in children and adolescents, even in the mild stage, and for assessing the severity and response to treatment of severe AD.

Background In all chronic airway diseases, the dynamics of airway function are influenced by underlying airway inflammation and bronchial hyperresponsiveness along with limitations in reversibility owing to airway and lung remodeling as well as mucous plugging. The relative contribution of each component translates into specific clinical patterns of symptoms, quality of life, exacerbation risk, and treatment success. Objective We aimed to evaluate whether subgrouping of patients with obstructive airway diseases according to patterns of fluctuation in lung function allows identification of specific phenotypes with distinct clinical characteristics. Methods We applied the novel method of fluctuation-based clustering (FBC) to twice-daily FEV1 measurements recorded over a 1-year period in a mixed group of 134 adults with mild-to-moderate asthma, severe asthma, or chronic obstructive pulmonary disease from the European BIOAIR cohort. Results Independently of clinical diagnosis, FBC divided patients into 4 fluctuation-based clusters with progressively increasing alterations in lung function that corresponded to patterns of increasing clinical severity, risk of exacerbation, and lower quality of life. Clusters of patients with airway disease with significantly elevated levels of biomarkers relating to remodeling (osteonectin) and cellular senescence (plasminogen activator inhibitor-1), accompanied by a loss of airway reversibility, pulmonary hyperinflation, and loss of diffusion capacity, were identified. The 4 clusters generated were stable over time and revealed no differences in levels of markers of type 2 inflammation (blood eosinophils and periostin). Conclusion FBC-based phenotyping provides another level of information that is complementary to clinical diagnosis and unrelated to eosinophilic inflammation, which could identify patients who may benefit from specific treatment strategies or closer monitoring.

Background Atopic keratoconjunctivitis (AKC) is a chronic allergic conjunctival disease. However, a mouse model of AKC to investigate the underlying mechanism of the therapeutic agents and estimate their efficacy has not been established. We recently generated mice in which Ikk2 is specifically deleted in facial skin fibroblasts and found that these mice spontaneously develop atopic dermatitis (AD)-like facial skin inflammation and scratching behaviors; thus, we named them facial AD with scratching (FADS) mice. Objective We sought to evaluate whether the ocular lesions that FADS mice spontaneously develop are similar to those of patients with AKC and to estimate the efficacy of topical treatments with tacrolimus and betamethasone for FADS mice by using tear periostin, a novel biomarker for allergic conjunctival disease. Methods FADS mice, in which Ikk2 is deleted in dermal fibroblasts, were generated by crossing female Ikk2Flox/Flox mice to male Nestincre; Ikk2Flox/+ mice. We conducted histologic analysis of the ocular lesions in FADS mice. Furthermore, we measured periostin in the tears collected from FADS mice untreated or treated with tacrolimus or betamethasone. Results The FADS mice exhibited severe blepharitis and scratch behaviors for their faces. In these mice, corneal epithelium and stroma showed hyperplasia and infiltration of eosinophils, mast cells, and TH2/TC2 cells. Periostin was significantly expressed in the lesions and tear periostin was upregulated. Betamethasone showed more suppressive effects than did tacrolimus on severe corneal lesions and increased tear periostin level. Conclusions The FADS mouse is a novel mouse model of AKC and is useful to examine the therapeutic effects of anti-AKC agents.

Background: Eosinophilic nasal polyps (NPs) are associated with the presence of asthma in chronic rhinosinusitis (CRS) patients. Serum periostin has been considered a relevant biomarker for unified airway diseases. Objective: To determine the utility of biomarkers including serum periostin that reflects reduction of exacerbations of comorbid asthma in CRS patients. Methods: We prospectively recruited 56 CRS patients who were subjected to undergo endoscopic sinus surgery (ESS) (20 with asthma) between October 2015 and December 2017 and followed them for 1 year after ESS. Blood eosinophil count, serum periostin, and fractional nitric oxide (FeNO) were measured at enrollment. How these type 2-driven biomarkers reflect comorbid asthma was determined using receiver operating characteristic (ROC) analysis. The frequency of asthma exacerbations during 1 year was counted both before and after ESS. Associations between preoperative biomarkers including eosinophils in NPs and asthma exacerbations were evaluated. Results: Blood eosinophil count, FeNO, and serum periostin levels were significantly higher in CRS patients with asthma than in those without (p < 0.01 for all) and discriminated comorbid asthma among CRS patients (p < 0.05; AUC > 0.80 for all). The increased preoperative serum periostin correlated with lower absolute number of postoperative exacerbations (ρ = −0.49, p = 0.03) and its relative reduction after ESS (ρ = 0.53, p = 0.03) in asthmatic patients. Increased eosinophils in NPs were also associated with reduced asthma exacerbations. Conclusion: Preoperative increased serum periostin and eosinophils in NPs are associated with the preventive effect of ESS for asthma exacerbations in CRS patients comorbid with asthma.

Background: Type 2 chronic rhinosinusitis (CRS), especially eosinophilic CRS (ECRS), is an intractable upper airway inflammatory disease. Establishment of serum biomarkers reflecting the pathophysiology of CRS is desirable in a clinical setting. As IgG4 production is regulated by type 2 cytokines, we sought to determine whether serum IgG4 levels can be used as a biomarker for CRS. Methods: Association between the serum IgG4 levels and clinicopathological factors was analyzed in 336 CRS patients. Receiver operating characteristics (ROC) analysis was performed to determine the cut-off value of serum IgG4 levels that can be used to predict the post-operative recurrence. Results: Serum IgG4 levels were significantly higher in patients with moderate to severe ECRS versus those with non to mild ECRS. The levels were also significantly higher in asthmatic patients and patients exhibiting recurrence after surgery compared to controls. ROC analysis determined that the best cut-off value for the serum IgG4 level to predict the post-operative recurrence was 95 mg/dL. The corresponding sensitivity and specificity were 39.7% and 80.5%, respectively. When we combined the two cut-off values for the serum IgG4 and periostin, patients with high serum levels of either IgG4 or periostin exhibited a high post-operative recurrence (OR: 3.95) as compared to patients having low serum levels of both IgG4 and periostin. Conclusions: The present results demonstrate that the serum IgG4 level is associated with disease severity and post-operative course in CRS. In particular, the combination of serum IgG4 and periostin could be a novel biomarker that predicts post-operative recurrence.

Background Barrier dysfunction is an important feature of atopic dermatitis (AD) in which IL-4 and IL-13, signature type 2 cytokines, are involved. Periostin, a matricellular protein induced by IL-4 or IL-13, plays a crucial role in the onset of allergic skin inflammation, including barrier dysfunction. However, it remains elusive how periostin causes barrier dysfunction downstream of the IL-13 signal. Methods We systematically identified periostin-dependent expression profile using DNA microarrays. We then investigated whether IL-24 downregulates filaggrin expression downstream of the IL-13 signals and whether IL-13-induced IL-24 expression and IL-24-induced downregulation of filaggrin expression are dependent on the JAK/STAT pathway. To build on the significance of in vitro findings, we investigated expression of IL-24 and activation of STAT3 in mite-treated mice and in AD patients. Results We identified IL-24 as an IL-13-induced molecule in a periostin-dependent manner. Keratinocytes are the main IL-24-producing tissue-resident cells stimulated by IL-13 in a periostin-dependent manner via STAT6. IL-24 significantly downregulated filaggrin expression via STAT3, contributing to barrier dysfunction downstream of the IL-13/periostin pathway. Wild-type mite-treated mice showed significantly enhanced expression of IL-24 and activation of STAT3 in the epidermis, which disappeared in both STAT6-deficient and periostin-deficient mice, suggesting that these events are downstream of both STAT6 and periostin. Moreover, IL-24 expression was enhanced in the epidermis of skin tissues taken from AD patients. Conclusions The IL-13/periostin pathway induces IL-24 production in keratinocytes, playing an important role in barrier dysfunction in AD.

Background: Many studies have attempted to clarify the factors associated with serum periostin levels in asthmatic patients. However, these results were based on studies of subjects mainly characterized by high eosinophil counts, which may present as an obstacle for clarification in the identification of other factors associated with serum periostin levels. The aim of this study was to determine the factors associated with serum periostin levels in healthy subjects. We also assessed some factors in asthmatic subjects to confirm their extrapolation for management of asthma. Methods: Serum periostin levels were measured in 230 healthy subjects. Clinical factors of interest included body mass index (BMI) and allergic rhinitis (AR). Additionally, we confirmed whether these factors were associated with serum periostin in 206 asthmatic subjects. We further evaluated several obesity-related parameters, such as abdominal fat distribution and adipocytokine levels. Results: Smoking status, blood eosinophil count, total immunoglobulin E, and the presence of AR were associated with serum periostin in healthy subjects. There was a negative association between BMI and serum periostin in both healthy and asthmatic subjects, while there was a tendency of a positive association with AR in asthmatic subjects. There were no differential associations observed for subcutaneous and abdominal fat in relation to serum periostin in asthmatic subjects. Serum periostin was significantly associated with serum levels of adiponectin, but not with leptin. Conclusions: Our results provided clarity as to the factors associated with serum periostin levels, which could be helpful in the interpretation of serum periostin levels in clinical practice. Keywords: Asthma, Healthy subjects, Obesity, Periostin, Rhinitis

BACKGROUND A predisposition to exacerbations is being recognized as a distinct phenotype with "previous exacerbations" representing the strongest clinical factor associated with future exacerbation. Thus, to identify additional novel biomarkers associated with asthma exacerbations, "past exacerbation status" must be included as a confounding factor. OBJECTIVE This study aimed to characterize the clinical and biomarker features associated with asthma exacerbations in severe asthma. METHODS We evaluated clinical parameters from 105 severe asthmatics yearly for 3 years, as well as their exacerbation status. We classified the subjects into 3 groups: (i) consistent non-exacerbators (CNE, subjects who did not experience any exacerbation over the 3-year period); (ii) consistent frequent exacerbators (CFE, subjects with frequent exacerbation, defined as those who had 2 or more exacerbations within 1 year, throughout the 3-year period); and (iii) intermittent exacerbators (IE). We conducted multivariate analysis for comparisons among the groups for multiple factors, including several Th2-related biomarkers, in addition to the "past exacerbation status." RESULTS Thirty-nine subjects were classified as CNE, 15 as CFE, and 51 as IE. Frequent exacerbations in the previous year predicted exacerbations for the following year (P

Objective: Periostin, a matricellular protein, is produced from airway epithelial cells and lung fibroblasts by IL-13. It has been suggested that periostin is involved in allergic inflammation and fibrosis. However, the usefulness of serum periostin measurement in the assessment of airway inflammation and remodeling and management of asthmatic patients is still debated. We aimed to determine whether serum periostin levels reflect eosinophilic airway inflammation and airway remodeling in asthma. Methods: We examined the relationship of serum periostin levels with clinical features, biomarkers for eosinophilic airway inflammation, fraction of exhaled nitric oxide (FeNO) levels and blood eosinophil counts, and pulmonary functions in 235 well-controlled asthmatic patients on inhaled corticosteroids (ICS) treatment. Results: Serum periostin levels were positively correlated with blood eosinophil counts (%) and age (r = 0.36 and 0.23, respectively), and were negatively correlated with body weight and FEV1/FVC (%) (r = −0.24 and − 0.23, respectively) in well-controlled asthmatic patients on ICS treatment (daily dose of 453 µg equivalent to fluticasone propionate). Blood eosinophil counts and serum periostin levels were similarly associated with increased FeNO levels (≥40 ppb) in the asthmatics. Serum periostin levels were better associated with fixed airflow limitation (FEV1/FVC ratio Conclusions: Serum periostin levels serve as a biomarker for both eosinophilic airway inflammation and fixed airflow limitation in well-controlled asthmatics on ICS treatment.

Background: Periostin and squamous cell carcinoma antigen (SCCA) are involved in the pathogenesis of asthma. Acute bronchitis due to respiratory syncytial virus (RSV) infection during infancy exhibits an asthma-like pathogenesis, suggesting that it may be associated with the subsequent development of asthma. However, the mechanism by which RSV infection leads to development of asthma has not yet been fully elucidated. Methods: Infants younger than 36 months were enrolled and classified into three groups. Group I included patients hospitalized with RSV-induced bronchitis. These patients were further stratified into two sub-groups according to whether the criteria for the modified Asthma Predictive Index (mAPI) had been met: Group I consisted of mAPI (+) and mAPI (−) patients; Group II included patients with food allergy as a positive control group; and Group III included children with no allergy as a negative control group. Serum periostin and SCCA levels were measured in the groups. This study was registered as a clinical trial (UMIN000012339). Results: We enrolled 14 subjects in Group I mAPI (+), 22 in Group I mAPI (−), 18 in Group II, and 18 in Group III. In Group I, the serum periostin and SCCA levels were significantly higher during the acute phase compared with the recovery phase. However, no significant differences were found between Group I mAPI (+) and mAPI (−). Conclusions: The serum periostin and SCCA levels increased during acute RSV bronchitis. Both periostin and SCCA may play a role in the pathogenesis of acute bronchitis due to RSV. Keywords: Infants, Periostin, Respiratory syncytial virus, Squamous cell carcinoma antigen, T-helper 2 cell cytokines

Background Recent studies have indicated that serum levels of squamous cell carcinoma antigen (SCCA) 1 and 2 induced by type 2 cytokines such as IL-4 and IL-13, are increased in patients with atopic dermatitis (AD). However, no clinical studies have analyzed serum levels of SCCA2 in larger series of AD patients or their association with various clinical characteristics. This study was performed to clarify whether serum levels of SCCA2 are associated with disease severity and clinical phenotypes of adult AD patients. Methods An enzyme-linked immunosorbent assay was performed to examine serum SCCA2 levels in 240 adult patients with AD and 25 healthy controls in this study. Serum SCCA2 levels were analyzed with clinical characteristics and laboratory parameters including thymus and activation-regulated chemokine (TARC), lactate dehydrogenase (LDH), blood eosinophils, total IgE, and specific IgE (Japanese cedar pollen, Dermatophagoides farina, Candida, malassezia, Staphylococcal enterotoxin B). Expression of SCCA2 in AD eruption was examined by immunohistochemistry. The effect of treatment on serum SCCA2 was also assessed. Results Serum SCCA2 level showed a positive correlation with disease severity, levels of TARC, LDH, eosinophil counts, and IgE levels. Robust expression of SCCA2 was detected in the supra basal keratinocytes in the epidermis of AD patients. Serial measurements of serum SCCA2 revealed decreased levels of SCCA2 after treatment for AD. Conclusions Serum SCCA2 levels reflected disease severity and clinical type of AD. Serum SCCA2 may thus be a relevant biomarker for AD.

Some patients with severe asthma also have fungal sensitization and are considered to have severe asthma with fungal sensitization. However, there is limited information on the clinical features of SAFS.To investigate the clinical characteristics of severe asthma with fungal sensitization.The present study enrolled 124 patients with severe asthma. We evaluated clinical aspects, such as various serum cytokines, fractional exhaled nitric oxide, pulmonary function, and serum immunoglobulin E (IgE). Fungal sensitization was assessed by determining serum levels of IgE specific to fungal allergens (Aspergillus, Alternaria, Candida, Cladosporium, Penicillium, and Trichophyton species and Schizophyllum commune). The protocol was registered at a clinical trial registry (www.umin.ac.jp/ctr/index-j.htm; UMIN 000002980).Thirty-six patients (29%) showed sensitization to at least 1 fungal allergen. The most common species were Candida (16%), Aspergillus (11%), and Trichophyton (11%). The rate of early-onset asthma (16 years of age) was higher in patients with fungal sensitization than in those without fungal sensitization (45% vs 25%; P = .02). Interleukin-33 levels were higher in patients with fungal sensitization than in those without fungal sensitization. Of patients with atopic asthma, Asthma Control Test scores were worse in patients with multiple fungal sensitizations than in patients with a single fungal sensitization or those without fungal sensitization.Severe asthma with fungal sensitization is characterized by early onset of disease and high serum levels of interleukin-33. Multiple fungal sensitizations are associated with poor asthma control.UMIN Clinical Trials Registry (UMIN-CTR; www.umin.ac.jp/ctr/index-j.htm): UMIN 000002980.

Periostin has been suggested as a novel, phenotype-specific biomarker for asthma driven by type 2 inflammation. However, large studies examining relationships between circulating periostin and patient characteristics are lacking and the suitability of periostin as a biomarker in asthma remains unclear.To examine circulating periostin in healthy controls and subjects with asthma from the general population with different severity and treatment profiles, both with and without chronic rhinosinusitis (CRS), in relation to other biomarkers and clinical characteristics.Serum periostin was examined by ELISA in 1100 subjects aged 17-76 from the Swedish Global Allergy and Asthma European Network (GA(2)LEN) study, which included 463 asthmatics with/without chronic rhinosinusitis (CRS), 98 individuals with CRS only, and 206 healthy controls. Clinical tests included measurement of lung function, Fraction of exhaled NO (FeNO), IgE, urinary eosinophil-derived neurotoxin (U-EDN), and serum eosinophil cationic protein (S-ECP), as well as completion of questionnaires regarding respiratory symptoms, medication, and quality of life.Although median periostin values showed no differences when comparing disease groups with healthy controls, multiple regression analyses revealed that periostin was positively associated with higher FeNO, U-EDN, and total IgE. In patients with asthma, an inverse relationship with lung function was also observed. Current smoking was associated with decreased periostin levels, whereas increased age and lower body mass index (BMI) related to higher periostin levels in subjects both with and without asthma.We confirm associations between periostin and markers of type 2 inflammation, as well as lung function, and identify novel constitutional factors of importance to the use of periostin as a phenotype-specific biomarker in asthma.

Background A variety of innate subsets of lymphoid cells such as natural killer (NK) cells, several populations of innate lymphoid cells (ILCs), and mucosal-associated invariant T (MAIT) cells as innate-like T lymphocytes are involved in asthma and may have important effector functions in asthmatic immune responses. In the present study, we investigated whether NK cells, ILCs, and MAIT cells in the peripheral blood of patients with asthma would be associated with clinical asthma parameters. Methods We recruited 75 adult patients with mild to severe asthma. The peripheral blood mononuclear cells in peripheral venous blood samples from the patients were purified and stained with different combinations of appropriate antibodies. The cells were analyzed by flow cytometry. Results The percentage of activated (i.e., CD69 + ) NK cells in the total NK cell population was negatively correlated with FEV 1 % which is calculated by the forced expiratory volume in 1 s (FEV 1 )/the forced vital capacity (FVC). The percentages of CD69 + ILC1s and ILC2s were negatively correlated with FEV 1 % and %FEV 1 . The percentage of CD69 + ILC3s was positively correlated with BMI, and the percentage of CD69 + MAIT cells was negatively correlated with FEV 1 %. Moreover, the percentage of CD69 + NK cells, ILC1s, ILC2s, ILC3s, and MAIT cells were positively correlated with each other. Conclusions For the first time, our data showed that activated NK cells, ILC1s, ILC2s, ILC3s, and MAIT cells were positively correlated with each other and may be associated with airflow limitation in patients with asthma.

Background Sensitization to Staphylococcus aureus enterotoxin (SE) is a known risk factor for asthma susceptibility and severity. However, how SE sensitization is involved in asthma, particularly nonatopic asthma and/or late-onset asthma, remains uncertain. Objective To clarify the involvement of SE sensitization in nonatopic and/or late-onset asthma and its association with a polymorphism of the cysteinyl leukotriene receptor 1 gene ( CysLTR1 ), which was examined because CysLT signaling is closely associated with late-onset eosinophilic asthma. Methods We assessed associations between sensitization to SE (A and/or B) and clinical indexes in 224 patients with asthma (mean age, 62.3 years; 171 women) from a cohort of the Kinki Hokuriku Airway Disease Conference, particularly those with nonatopic asthma (not sensitized to common aeroallergens) and/or late-onset asthma. Associations between SE sensitization and CysLTR1 polymorphism (rs2806489), a potential regulatory variant for atopic predisposition in women, were also assessed in a sex-stratified manner. Results A total of 105 patients (47%) with asthma were sensitized to SE. Among patients with nonatopic asthma (n = 67) or with late-onset asthma (n = 124), those sensitized to SE had significantly higher serum total IgE and periostin levels than those not sensitized. In nonatopic patients, a rapid decrease in forced expiratory volume in 1 second was associated with SE sensitization. In women with asthma, rs2806489 was associated with sensitization to SEB and age at asthma onset. Conclusion SE sensitization contributes to T H 2 inflammation in nonatopic and/or late-onset asthma. In women with asthma, the CysLTR1 variant might be associated with sensitization to SEB and age at asthma onset.

Background Multiple phenotypes exist within the classification of severe asthma. However, characteristics of patients with not well-controlled severe asthma have not been well identified. Methods Japanese patients with asthma (age ≥ 20 years) were enrolled at the Keio University Hospital and its affiliated hospitals in this observational study (Keio Severe Asthma Research Program). Among them, patients with severe asthma (those undergoing Global Initiative for Asthma [GINA] 2018 step 4 or 5 treatment) were included in this analysis and investigated clinical characteristics based on asthma control status. Results Of the 154 patients (men, 46.8%; age, 60.1 ± 14.9 years), 87 (56.5%) had not well-controlled (partly controlled and uncontrolled) asthma (GINA step 4, 42 patients; step 5, 45 patients). Overall, there were no significant differences in clinical characteristics between patients with well-controlled and not well-controlled asthma. However, cluster analysis revealed that distinct 5 clusters (cluster 1, well-controlled; cluster 2, eosinophilic; cluster 3, non–type 2 inflammation; cluster 4, high periostin; and cluster 5, late-onset type 2 inflammation), and clusters 2–5 were not well-controlled. Among them, cluster 3 was characterized by low eosinophil counts, low periostin levels, and less frequent olfactory disturbance, and this cluster had the worst asthma control. Conclusions Japanese patients with severe asthma were divided into well-controlled and not-well controlled asthma, and we confirmed heterogeneity of not well-controlled severe asthma. These patients, especially non-type 2 phenotype, require a further therapeutic approach. (University Hospital Medical Information Network Clinical Trials Registry, UMIN000002980)

Periostin is a matricellular protein as well as an extracellular matrix (ECM) protein belonging to the fasciclin family. Periostin plays important roles as a matricellular protein in the setting of allergic diseases by binding to several integrins on various cells. Since periostin is induced mainly by IL-4 and IL-13, signature type 2 cytokines, and it is highly expressed in the subepithelial regions of many chronic allergic diseases, periostin has emerged as a novel biomarker reflecting type 2 inflammation in allergic diseases. It has, moreover, been revealed that periostin has characteristics different from other type 2 biomarkers such as eosinophil count and fractional exhaled nitric oxide (FeNO), reflecting fibrosis or tissue remodeling. From this, we may say that serum periostin is a "chronic" type 2 biomarker, whereas FeNO and possibly the eosinophil count are "acute" type 2 biomarkers. In contrast, it is still uncertain how we can apply periostin measurement to the use of biologics for allergic diseases. By examining the roles of periostin in allergy and the utility and potential of periostin in developing diagnostics against allergic diseases, it is hoped that in the near future, we can develop a new strategy to treat allergic patients.

Background: Chronic rhinosinusitis (CRS) and asthma are collectively called unified airway diseases. Periostin has been implicated in the pathophysiologic link of these conditions but only by serum measurements. We sought to investigate sputum levels of periostin and their association with upper airway inflammation and olfactory function in CRS patients. Methods: We prospectively recruited 56 CRS patients who underwent endoscopic sinus surgery (20 with and 36 without comorbid asthma), and 28 healthy controls between October 2015 and December 2017. Lower and upper airway indices such as sputum periostin levels and eosinophil and neutrophil counts, exhaled fractional nitric oxide (FeNO) levels, and olfactory function were evaluated in the three groups. Radiological severity of CT images and tissue eosinophilia of surgical specimens were also assessed in the CRS patients. Results: Sputum periostin levels were highest, and olfactory function was most impaired, in the CRS patients with comorbid asthma, followed by those without asthma and controls in this order. CRS with asthma group showed higher sputum eosinophils and FeNO levels than the other two groups, while CRS patients without asthma showed significantly higher neutrophils in sputum than the other two groups. When confined to CRS patients, olfactory dysfunction was correlated with sputum eosinophil counts. Eosinophil counts of nasal polyps showed a significant positive correlation with sputum periostin and FeNO levels. Radiological severity of CRS was correlated with sputum eosinophil counts and FeNO levels. Conclusions: Periostin levels and inflammatory cells such as eosinophils and neutrophils in the lower airways are increased in patients with CRS, suggesting the presence of mutual interactions between upper and lower airways even if asthma does not coexist. Olfactory dysfunction and eosinophilic nasal polyps may be potential indicators of Th2-driven inflammation in the lower airways. Trial registration: This study was registered on the UMIN Clinical Trials Registry (Registry ID UMIN000018672). Keywords: Asthma, Chronic rhinosinusitis, Olfactory dysfunction, Eosinophils, Periostin, Fractional exhaled nitric oxides

Background: Periostin is induced by IL-13 and has been studied as a biomarker of asthma. The present study explored the relationship between serum levels of periostin and exercise-induced bronchoconstriction (EIB) in asthmatic children. Methods: The study population consisted of 86 children 6–15 years old divided into an asthmatic group (n = 56) and healthy controls (n = 30). We measured the levels of periostin in serum and performed pulmonary function tests including baseline measurements, post-bronchodilator inhalation tests, exercise bronchial provocation tests (BPTs), and mannitol BPTs. Results: The 56 asthmatic children were divided into four groups: asthmatics with positive exercise BPT and positive mannitol BPT (n = 30), asthmatics with positive exercise BPT but negative mannitol BPT (n = 7), asthmatics with negative exercise BPT but positive mannitol BPT (n = 10), and asthmatics with negative exercise BPT and negative mannitol BPT (n = 9). Serum levels of periostin in asthmatic children with both positive exercise and mannitol BPT were significantly greater than those in asthmatic children with both negative exercise and mannitol BPT (95.0 [75.0–104.0] vs. 79.0 [68.0–82.5] ng/mL, P = 0.008) and controls (74.0 [69.75–80.0] ng/mL, P

Background: Eosinophilic pneumonia (EP) is characterized by massive pulmonary infiltration by eosinophils. Although serum periostin is a novel marker for eosinophil-dominant asthma, the upregulation of periostin in the airway of asthmatics is controversial. In this study, we examined whether periostin concentrations are elevated in the bronchoalveolar lavage fluid (BALF) of patients with EP. Methods: BAL was performed in healthy volunteers and in patients with acute eosinophilic pneumonia (AEP), chronic eosinophilic pneumonia (CEP), and sarcoidosis. The periostin concentrations in the BALF were measured. Results: The periostin concentration in the BALF increased significantly with pulmonary eosinophil ia and was higher in AEP and CEP patients than in healthy volunteers and sarcoidosis patients, even after adjusting the albumin concentration. In pulmonary eosinophilia, the periostin concentration correlated with the eosinophil and lymphocyte counts, the concentration of albumin, and the concentration of cytokines such as IL-5, IL-13, and transforming growth factor β1. Conclusions: Although some blood leakage may be involved in the elevation of periostin in the BALF of EP, periostin can be induced locally, at least in part. Therefore, periostin may play a role in the development of EP.