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Background: Fraction of exhaled nitric oxide (FeNO) is used for diagnosing and monitoring asthma in children, but the influence of allergic sensitization is still poorly understood. Here, we investigate how asthma and allergic sensitization influence FeNO levels during childhood. Methods: We investigated the associations between asthma, aeroallergen sensitization, and FeNO measured from age 5–18 years in the COPSAC2000 birth cohort of 411 children using repeated measurement mixed models adjusted for gestational age, sex, concurrent airway infection, inhaled corticosteroids, and tobacco exposure. Replication was sought in the similarly designed COPSAC2010 cohort of 700 children. Results: In the COPSAC2000 cohort, 133 had asthma between age 5 and 18 years, and in the COPSAC2010 cohort, 112 had asthma between age 5 and 10 years. In the COPSAC2000 cohort, asthma and aeroallergen sensitization were both associated with higher FeNO from age 5 to 18 years: adjusted geometric mean ratio (aGMR), 1.22 (1.08–1.35), p <.01, and 1.41 (1.21–1.65), p < 0.001, respectively. However, asthma was associated with increased FeNO among children with aeroallergen sensitization: 1.44 (1.23–1.69), p <.0001, whereas asthma was associated with decreased FeNO among nonsensitized children: 0.80 (0.65–0.99), p =.05 (p‐interaction<.0001 for asthma x sensitization). Replication in the COPSAC2010 cohort showed similar results (p‐interaction <.01). Further, blood eosinophil count, total‐IgE, bronchodilator response, and bronchial hyperreactivity were all associated with increased FeNO among children sensitized to aeroallergens, but not among nonsensitized children. Conclusion: Fraction of exhaled nitric oxide is elevated through childhood in children with asthma and is correlated with asthma‐associated traits depending on the presence of aeroallergen sensitization. These findings indicate that FeNO is only a valid asthma biomarker in children with concurrent aeroallergen sensitization, which is important for guideline recommendations on the clinical use of FeNO. [ABSTRACT FROM AUTHOR]

Thus, using SEC, a very high proportion of patients with severe asthma of up to 76.8% would have severe eosinophilic asthma, which is higher than in other severe asthma cohorts7-9 of Caucasian populations. Keywords: blood eosinophil count; cigarette smoking; exacerbations; fractional exhaled nitric oxide; severe asthma EN blood eosinophil count cigarette smoking exacerbations fractional exhaled nitric oxide severe asthma 1 7 7 03/03/22 20220201 NES 220201 Dear Editor, In China, asthma affects 45.7 million adults with a prevalence of 4.2%,1 while that of severe asthma ranges from 3.4% to 8.3% among asthmatic patients.2-4 There is scarce information on the characteristics and biomarker expression, and the different phenotypes of severe asthma. Therefore, severe asthma patients have more symptoms, more exacerbations, more airflow obstruction, and more nasal polyps even if they are on high-dose asthma medication regimens, including oral corticosteroids. [Extracted from the article]

Background: Chronic rhinosinusitis with nasal polyps (CRSwNP) is a common heterogenous disease in the patients with chronic airway diseases. This study investigated the role of blood eosinophil count (BEC) in the classification of CRSwNP and its recurrence in eosinophilic CRSwNP. Methods: Sixty‐five patients who underwent nasal endoscopic resection of CRSwNP were recruited and divided into eosinophilic CRSwNP and non‐eosinophilic CRSwNP groups based on the levels (10% cutoff) of eosinophil infiltration as indicated by hematoxylin and eosin (H&E) staining. Results: We recruited 30 patients in the eosinophilic CRSwNP group and 35 patients in the non‐eosinophilic CRSwNP group. The outcome of preoperative visual analogue scale (VAS) score, preoperative Lund‐Mackay score, and preoperative Lund‐Kennedy score between the 2 groups were comparable. The level of BEC in the eosinophilic CRSwNP group was significantly higher than that of non‐eosinophilic CRSwNP group (0.79 ± 0.27 × 109/L vs 0.30 ± 0.22 × 109/L; p < 0.001). We observed a statistical significance in the number of H&E eosinophils (29.11 ± 2.93 vs 3.17 ± 0.51; p < 0.001) and CRSwNP phenotypes (eosinophilic/non‐eosinophilic, 28/3 vs 2/32; p < 0.001) when the cutoff value of BEC was set at 0.39 × 109/L. The disease‐free recurrence (DFR) was found to be statistically significant when the cutoff value of BEC was 0.73 × 109/L in eosinophilic CRSwNP (p = 0.009). Conclusion: Results indicate that BEC may be capable of distinguishing CRSwNP phenotypes as well as predicting polyp recurrence in eosinophilic CRSwNP. Given the relatively small sample size, further studies will be necessary to confirm a role for BEC as a systemic biomarker in CRSwNP. [ABSTRACT FROM AUTHOR]

Background The fractional exhaled nitric oxide ( FENO) and the blood eosinophil count (B-eos) are markers of eosinophilic inflammation used in the diagnosis and management of asthma. The relationships between smoking cigarette and both FENO and B-eos are complex and raise questions about the association between these markers and asthma in smokers. Objective To determine the relationships between both FENO and B-eos on one hand and asthma and atopy on the other, according to smoking status. Methods FENO and B-eos were measured in, respectively, 1579 and 1496 of the 1607 middle-aged adults randomly selected from the general population in the cross-sectional ELISABET survey. Allergic asthma was defined as asthma (a self-report of physician-diagnosed asthma, and wheezing in the previous 12 months or the use of asthma medications) with atopy (allergic rhinitis or hayfever in the previous 12 months, or a previous positive prick test or allergen desensitization therapy). Non-allergic asthma was defined as asthma without atopy. Results The analysis included 812 (51.4%) never, 473 (30%) former and 294 (18.6%) current smokers. A total of 490 (32%) participants were atopic, 80 (5.1%) had allergic asthma, and 31 (2%) had non-allergic asthma. Only 16.2% (18/111) of asthmatics were treated with glucocorticoid inhalants, suggesting that among them a majority of participants had mild asthma. A positive interaction between smoking status and allergic asthma was observed in multivariate models explaining FENO ( P = 0.003) and B-eos ( P = 0.001). Thus, compared to those without allergic asthma, participants with allergic asthma had higher FENO values (+ 63.4%, 95% CI = [39; 92]) and higher B-eos (+ 63.2% [38.2; 92.7]) in never and former smokers, but not in current smokers. Lastly, an analysis of receiver-operating characteristic curves showed that each of the two markers was able to discriminate moderately allergic asthma but only in non-smokers. Conclusions & Clinical Relevance FENO and B-eos were associated with the presence of mild allergic asthma only in non-smokers, not in current smokers. These findings raise questions about the clinical value of FENO and B-eos in smokers. [ABSTRACT FROM AUTHOR]