Investigating problematic severe asthma in children : a translational approach

Children with problematic severe asthma (PA) have persistent symptoms and/or severe exacerbations despite treatment with high doses of currently available asthma medications. The term PA includes children who are difficult to treat due to unidentified exacerbating factors (e.g. allergens or environmental hazards, comorbidities, psychological and social issues, and/or poor adherence) and those lacking identifiable aggravating factors but, nonetheless, do not respond well to asthma therapy. Children with PA are a heterogeneous group of patients with varying clinical presentations, pulmonary function and patterns of inflammation. This thesis is based on the results of a Swedish nationwide cross-sectional study in which school aged children with PA (n=57) were compared to age matched peers with persistent, but controlled asthma (CA), (n=39). The major objectives were to identify distinguishing features of children suffering from PA, to differentiate between children who were difficult to treat and those who were severely resistant to therapy and to investigate novel and potentially clinical relevant biomarkers of PA. PA was defined by insufficient asthma control despite high doses of inhaled corticosteroids. The protocol included a detailed characterization of: history and clinical presentation; pulmonary function; bronchial hyperresponsiveness; inflammatory biomarkers in blood (including white blood cells, interleukin-5 and chitinases (chitotriosidase and the chitinase-like protein YKL-40)), urine (EPX) and exhaled air (FeNO); allergy (IgE antibodies, component resolved allergy diagnostics, basophil allergen threshold sensitivity (CD-sens)); morphology (computerized tomography of sinuses and lungs (in the PA group only)). The major distinguishing features of children with PA involve familial background (heredity, socioeconomic status), clinical presentation (comorbidities and triggering factors) and pathophysiological differences including degree of airway obstruction, bronchial hyperresponsiveness and inflammatory profile (IL-5, number of eosinophilic and neutrophilic cells in blood). Sixty percent of children with PA had therapy-resistant asthma, with the remainder being difficult to treat due to identified aggravating factors. Individual IgE-responses were similar between children with PA and CA. Children with PA were more often multi-sensitized to > 3 single lipocalin (nMus m 1, rEqu c 1, Fel d 4, rCan f 1, 2), kallikrein (rCan f 5) and secretoglobin (rFel d 1) allergens compared to children with CA. Cat-allergic children with PA had higher allergen sensitivity, as measured by CDsens, compared to cat-allergic peers with CA. Furthermore, CD-sens correlated with clinical markers of asthmatic disease, including asthma control and biomarkers of eosinophilic inflammation. YKL-40 levels and chitotriosidase activity were increased in the serum of children with PA, and YKL-40 specifically correlated with airway remodelling (as assessed by computerized tomography) and blood neutrophils in children severely resistant to asthma therapy. By employing a comprehensive and standardized clinical assessment we have discerned specific features of children with PA and identified children who are severely resistant to therapy. We have applied two novel methods of allergy diagnostics (Component resolved diagnostics and CD-sens) and found that these two methods provide relevant information when investigating children with PA. Finally, our findings confirm that YKL-40 is a potential biomarker of asthma severity and airway remodeling. A translational research approach is necessary when investigating associations between disease mechanisms and clinical presentation in complex diseases

Transcriptome analysis of controlled and therapy-resistant childhood asthma reveals distinct gene expression profiles

Background: Children with problematic severe asthma have poor disease control despite high doses of inhaled corticosteroids and additional therapy, leading to personal suffering, early deterioration of lung function, and significant consumption of health care resources. If no exacerbating factors, such as smoking or allergies, are found after extensive investigation, these children are given a diagnosis of therapy-resistant (or therapy-refractory) asthma (SA). Objective: We sought to deepen our understanding of childhood SA by analyzing gene expression and modeling the underlying regulatory transcription factor networks in peripheral blood leukocytes. Methods: Gene expression was analyzed by using Cap Analysis of Gene Expression in children with SA (n = 13), children with controlled persistent asthma (n = 15), and age-matched healthy control subjects (n = 9). Cap Analysis of Gene Expression sequencing detects the transcription start sites of known and novel mRNAs and noncoding RNAs. Results: Sample groups could be separated by hierarchical clustering on 1305 differentially expressed transcription start sites, including 816 known genes and several novel transcripts. Ten of 13 tested novel transcripts were validated by means of RT-PCR and Sanger sequencing. Expression of RAR-related orphan receptor A (RORA), which has been linked to asthma in genome-wide association studies, was significantly upregulated in patients with SA. Gene network modeling revealed decreased glucocorticoid receptor signaling and increased activity of the mitogen-activated protein kinase and Jun kinase cascades in patients with SA. Conclusion: Circulating leukocytes from children with controlled asthma and those with SA have distinct gene expression profiles, demonstrating the possible development of specific molecular biomarkers and supporting the need for novel therapeutic approaches.Peer reviewe

Urinary leukotriene E4 and prostaglandin D2 metabolites increase in adult and childhood severe asthma characterized by type 2 Inflammation : a clinical observational study

Rationale: New approaches are needed to guide personalized treatment of asthma.Objective: To test if urinary eicosanoid metabolites can direct asthma phenotyping.Methods: Urinary metabolites of prostaglandins (PG), cysteinyl-leukotrienes (LT) and isoprostanes were quantified in the Unbiased Biomarkers for the Prediction of Respiratory Diseases Outcomes (U-BIOPRED) study including 86 adults with mild-to-moderate asthma (MMA), 411 with severe asthma (SA), and 100 healthy controls (HC). Validation was performed in 302 SA subjects followed-up after 12-18 months, and externally in 95 adolescents with asthma.Measurement and Main Results: Metabolite levels in HC were unrelated to age, BMI and sex, except for the PGE2-pathway. Eicosanoid levels were generally greater in MMA relative to HC, with further elevations in SA, except for PGE2-metabolites in males, which were the same or lower in non-smoking asthmatics as in HC. Metabolite levels were unchanged in asthmatics adherent to oral corticosteroid treatment as documented by urinary prednisolone detection, whereas SA treated with omalizumab had lower levels of LTE4 and the PGD2 metabolite 2,3-dinor-11?-PGF2?. High levels of LTE4 and PGD2-metabolites were associated with lower lung-function, and increased levels of exhaled nitric oxide and eosinophil markers in blood, sputum and urine in U-BIOPRED and in adolescents with asthma. These type-2 (T2) asthma associations were reproduced in the follow-up visit of the U-BIOPRED study, and found to be as sensitive to detect T2 inflammation as the established biomarkers. Conclusions: Monitoring of urinary eicosanoids can identify T2 asthma and introduces a new non-invasive approach for molecular phenotyping of adult and adolescent asthma

Bronchiolitis needs a revisit: Distinguishing between virus entities and their treatments

Current data indicate that the “bronchiolitis” diagnosis comprises more than one condition. Clinically, pathophysiologically, and even genetically three main clusters of patients can be identified among children suffering from severe bronchiolitis (or first wheezing episode): (a) respiratory syncytial virus (RSV)-induced bronchiolitis, characterized by young age of the patient, mechanical obstruction of the airways due to mucus and cell debris, and increased risk of recurrent wheezing. For this illness, an effective prophylactic RSV-specific monoclonal antibody is available; (b) rhinovirus-induced wheezing, associated with atopic predisposition of the patient and high risk of subsequent asthma development, which may, however, be reversed with systemic corticosteroids in those with severe illness; and (c) wheeze due to other viruses, characteristically likely to be less frequent and severe. Clinically, it is important to distinguish between these partially overlapping patient groups as they are likely to respond to different treatments. It appears that the first episode of severe bronchiolitis in under 2-year-old children is a critical event and an important opportunity for designing secondary prevention strategies for asthma. As data have shown bronchiolitis cannot simply be diagnosed using a certain cutoff age, but instead, as we suggest, using the viral etiology as the differentiating factor.</p

Unusual and Unexpected Allergic Reactions Can Be Unraveled by Molecular Allergy Diagnostics

The fifth class of immunoglobulin, immunoglobulin E (IgE) was discovered in 1967 and has had immense importance for the understanding, diagnosis, and treatment of allergic disease. More than 50 years have passed and efforts to characterize, standardize, and refine allergens with the aim to improve clinical diagnosis and allergen-specific immunotherapy are still ongoing. Another important breakthrough was made in 1999 with the introduction of component-resolved diagnostics (CRD), making it possible to quantify IgE antibodies against individual allergen proteins for diagnostic purposes at a molecular level. The progress and developments made in allergy diagnosis often originate from clinical observations and case studies. Observant physicians and health-care personnel have reported their findings in the medical literature, which in turn has inspired researchers to become involved in clinical research. Allergists continuously encounter new allergies and are often asked by their patients how to prevent new reactions. In the current article, we focus on recent clinical observations that can now be explained by CRD. The examples taken concern allergic reactions toward peanuts, tree nuts, lemon kernels, health drinks, meat, insects, dog dander, cannabis, and semen. We now have an improved understanding of why patients may react in a serious or unexpected way, as illustrated by these examples, yet many other clinical observations remain unexplained. The aim of this review is to highlight the importance of clinical observations among allergic patients, focusing on systemic, or unusual and unexpected allergic reactions, where component-testing has further refined the diagnosis of IgE-mediated allergy

Uncontrolled asthma in school-aged children : a nationwide specialist care study

Background: Uncontrolled asthma (UCA) is different from severe asthma and can be identified in children across all ranges of prescribed treatment. Objective: Our aim was to characterize uncontrolled childhood asthma in pediatric specialist care. Methods: We performed a nationwide cross-sectional study of 5497 children (aged 6-17 years) with asthma who were treated by pediatricians at outpatient clinics during 2019 and registered in the Swedish National Airway Register. UCA was defined as an Asthma Control Test score of 19 or lower and/or 2 or more exacerbations in the past year and/or an FEV1 value less than 80% predicted. Treatment was categorized from step 1 to step 5 according to the Global Initiative for Asthma. Results: UCA was identified in 1690 children (31%), of whom 64% had an Asthma Control Test score of 19 or lower, 20% had recurrent exacerbations, and 31% had an FEV1 value less than 80% predicted. UCA was associated with female sex (odds ratio [OR] = 1.29 [95% CI = 1.15-1.45]), older age (OR = 1.02 [95% CI = 1.00-1.04]), obesity (OR = 1.43 [95% CI = 1.12-1.83]), and more treatment using steps 1 and 2 as a reference (step 3, OR = 1.28 [95% CI = 1.12-1.46]); steps 4-5, OR = 1.32 [95% CI = 1.10-1.57]). UCA in children prescribed treatment steps 1 and 2 (group UCA1-2) occurred in 28% of all children at this treatment step (n = 887). Children in group UCA1-2 had exacerbations more frequently than did those children with UCA who were prescribed steps 4 and 5 treatment (24% vs 15% [P =.001]). Conclusion: UCA was common and associated with female sex, increasing age, obesity, and higher Global Initiative for Asthma treatment step. Surprisingly, UCA was also common in children prescribed less than the maximum treatment, and those children could be considered undertreated patients

Severe COVID-19 among patients with asthma and COPD : a report from the Swedish National Airway Register

Background: Patients with obstructive lung diseases may be at risk of hospitalization and/or death due to COVID-19. Aim: To estimate the frequency of severe COVID-19, and COVID-19-related mortality in a well-defined large population of patients with asthma and chronic inflammatory lung disease (COPD). Further to assess the frequency of asthma and COPD as registered comorbidities at discharge from hospital, and in death certificates. Methods: At the start of the pandemic, the Swedish National Airway Register (SNAR) included 271,404 patients with a physician diagnosis of asthma and/or COPD. In September 2020, after the first COVID-19 wave in Sweden, the database was linked with the National Patient Register (NPR), the Swedish Intensive Care Register and the Swedish Cause of Death Register, which all provide data about COVID-19 based on International Classification of Diseases (ICD-10) codes. Severe COVID-19 was defined as hospitalization and/or intensive care or death due to COVID-19. Results: Among patients in SNAR, 0.5% with asthma, and 1.2% with COPD were identified with severe COVID-19. Among patients  &lt; 18 years with asthma, only 0.02% were severely infected. Of hospitalized adults, 14% with asthma and 29% with COPD died. Further, of patients in SNAR, 56% with asthma and 81% with COPD were also registered in the NPR, while on death certificates the agreement was lower (asthma 24% and COPD 71%). Conclusion: The frequency of severe COVID-19 in asthma and COPD was relative low. Mortality for those hospitalized was double as high in COPD compared to asthma. Comorbid asthma and COPD were not always identified among patients with severe COVID-19

Multiple manifestations of uncontrolled asthma increase the risk of severe COVID-19

Objective: Asthma control is of importance when assessing the risk of severe outcomes of COVID-19. The aim of this study was to explore associations of clinical characteristics and the effect of multiple manifestations of uncontrolled asthma with severe COVID-19. Methods: In 2014–2020, adult patients with uncontrolled asthma, defined as Asthma Control Test (ACT) ≤19 were identified in the Swedish National Airway Register (SNAR) (n = 24533). The SNAR database, including clinical data, was linked with national registers to identify patients with severe COVID-19 (n = 221). The effect of multiple manifestations of uncontrolled asthma was based on: 1) ACT ≤15, 2) frequent exacerbations and 3) previous asthma inpatient/secondary care and evaluated stepwise. Poisson regression analyses were conducted with severe COVID-19 as the dependent variable. Results: In this cohort with uncontrolled asthma, obesity was the strongest independent risk factor for severe COVID-19 in both sexes, but even greater in men. Multiple manifestations of uncontrolled asthma were more common among those with severe COVID-19 vs. without: one, 45.7 vs. 42.3%, two, 18.1 vs. 9.1% and three, 5.0 vs. 2.1%. The risk ratio (RR) of severe COVID-19 increased with an increasing number of manifestations of uncontrolled asthma: one, RR 1.49 (95% CI 1.09–2.02), two, RR 2.42 (95% CI 1.64–3.57) and three, RR 2.96 (95% CI 1.57–5.60), when adjusted for sex, age, and BMI. Conclusions: It is important to consider the effect of multiple manifestations of uncontrolled asthma and obesity when assessing patients with COVID-19, as this increases the risk of severe outcomes substantially