Urinary leukotriene E4 levels in atopic and non-atopic preschool children with recurrent episodic (viral) wheezing: a potential marker?

Epidemiological characteristics, clinical characteristics, and prognostic factors of children with atopy hospitalised with adenovirus pneumonia

Background

Atopy may be associated with disease severity and a poor prognosis of human adenovirus (HAdV) pneumonia in children. Our aim was to observe the clinical characteristics and pulmonary radiological changes in children with atopy and HAdV pneumonia in China.

Methods

Children hospitalised with HAdV pneumonia from June 2018 to December 2019 were analysed. All children were divided into atopic with HAdV, non-atopic with HAdV, and atopic without HAdV infection group. Each group was further divided into the mild and severe pneumonia groups according to disease severity. Standard treatment was initiated after admission, and regular follow-up evaluations were conducted at 1 month after discharge. Baseline and clinical characteristics and pulmonary radiological changes in children with and without atopy were evaluated. Risk factors associated with small airway lesions in patients with HAdV pneumonia were analysed.

Results

The eosinophil count in the atopic group was significantly higher than that in the non-atopic group (P < 0.05). Severe coughing, wheezing, and small airway lesions on chest high-resolution computed tomography (HRCT) upon admission, after discharge and 1 month after discharge were significantly higher in the atopic group (with or without HAdV infection) than in the non-atopic group (P < 0.05). There were significant differences in the number of patients with wheezing and small airway lesions during hospitalisation and after discharge among the three groups (P < 0.05). The risks of small airway lesions in children with a family or personal history of asthma, severe infection, atopy, and HAdV infection were 2.1-, 2.7-, 1.9-, 2.1-, and 1.4-times higher than those in children without these characteristics, respectively.

Conclusions

Children with atopy and HAdV pneumonia may experience severe coughing in mild cases and wheezing in mild and severe cases. Children with atopy are more susceptible to the development of small airway lesions, recurrent wheezing after discharge and slower recovery of small airway lesions as observed on pulmonary imaging than non-atopic children after HAdV infection. A family or personal history of asthma, atopy, severe infection, and HAdV infection are independent risk factors associated with the development of small airway lesion as observed on chest HRCT.

Influence of Second-Hand Smoke and Prenatal Tobacco Smoke Exposure on Biomarkers, Genetics and Physiological Processes in Children-An Overview in Research Insights of the Last Few Years

Children are commonly exposed to second-hand smoke (SHS) in the domestic environment or inside vehicles of smokers. Unfortunately, prenatal tobacco smoke (PTS) exposure is still common, too. SHS is hazardous to the health of smokers and non-smokers, but especially to that of children. SHS and PTS increase the risk for children to develop cancers and can trigger or worsen asthma and allergies, modulate the immune status, and is harmful to lung, heart and blood vessels. Smoking during pregnancy can cause pregnancy complications and poor birth outcomes as well as changes in the development of the foetus. Lately, some of the molecular and genetic mechanisms that cause adverse health effects in children have been identified. In this review, some of the current insights are discussed. In this regard, it has been found in children that SHS and PTS exposure is associated with changes in levels of enzymes, hormones, and expression of genes, micro RNAs, and proteins. PTS and SHS exposure are major elicitors of mechanisms of oxidative stress. Genetic predisposition can compound the health effects of PTS and SHS exposure. Epigenetic effects might influence in utero gene expression and disease susceptibility. Hence, the limitation of domestic and public exposure to SHS as well as PTS exposure has to be in the focus of policymakers and the public in order to save the health of children at an early age. Global substantial smoke-free policies, health communication campaigns, and behavioural interventions are useful and should be mandatory.

Viruses and non-allergen environmental triggers in asthma

Asthma is a complex inflammatory disease with many triggers. The best understood asthma inflammatory pathways involve signals characterized by peripheral eosinophilia and elevated immunoglobulin E levels (called T2-high or allergic asthma), though other asthma phenotypes exist (eg, T2-low or non-allergic asthma, eosinophilic or neutrophilic-predominant). Common triggers that lead to poor asthma control and exacerbations include respiratory viruses, aeroallergens, house dust, molds, and other organic and inorganic substances. Increasingly recognized non-allergen triggers include tobacco smoke, small particulate matter (eg, PM2.5), and volatile organic compounds. The interaction between respiratory viruses and non-allergen asthma triggers is not well understood, though it is likely a connection exists which may lead to asthma development and/or exacerbations. In this paper we describe common respiratory viruses and non-allergen triggers associated with asthma. In addition, we aim to show the possible interactions, and potential synergy, between viruses and non-allergen triggers. Finally, we introduce a new clinical approach that collects exhaled breath condensates to identify metabolomics associated with viruses and non-allergen triggers that may promote the early management of asthma symptoms.

The Role of Leukotrienes as Potential Therapeutic Targets in Allergic Disorders

Leukotrienes (LTs) are lipid mediators that play pivotal roles in acute and chronic inflammation and allergic diseases. They exert their biological effects by binding to specific G-protein-coupled receptors. Each LT receptor subtype exhibits unique functions and expression patterns. LTs play roles in various allergic diseases, including asthma (neutrophilic asthma and aspirin-sensitive asthma), allergic rhinitis, atopic dermatitis, allergic conjunctivitis, and anaphylaxis. This review summarizes the biology of LTs and their receptors, recent developments in the area of anti-LT strategies (in settings such as ongoing clinical studies), and prospects for future therapeutic applications.

Urine concentrations changes of cysteinyl leukotrienes in non-obese children with obstructive sleep apnea undergoing adenotonsillectomy

OBJECTIVE

The main objective of the study was to compare preoperative to postoperative levels of urine-Cysteinyl leukotrienes (uCysLT) in children undergoing adenotonsillectomy (AT) for obstructive sleep apnea (OSA) in order to investigate whether exaggerated leukotriene activity is the cause or consequence of OSA.

METHODS AND MATERIALS

A prospective study was conducted on non-obese children (4-10 years old) referred for overnight PSG. Children with moderate/severe OSA treated with AT were included. A second PSG study performed 2 months postoperatively to confirm OSA resolution, and those with residual OSA were excluded. Morning urine specimens after both PSG studies were obtained and pre-operative uCysLT levels were compared to postoperative levels.

RESULTS

27 children fulfilled the criteria and underwent a post-operative PSG study with three exclusions for residual OSA (postop-AHI>2), so the study group consisted of 24 children (mean age: 5.7 ± 2.1 years). Mean preoperative and postoperative AHI was 10.96 ± 5.93 and 1.44 ± 0.56 respectively. Mean preop-uCysLT were 21.14 ± 4.65, while after AT they significantly reduced to 12.62 ± 2.67 (P < 0.01).

CONCLUSION

uCysLT levels are significantly reduced after AT in non-obese children with moderate/severe OSA, suggesting that exaggerated leukotriene activity is mainly a consequence of OSA.

Serum leukotriene B4 levels, tonsillar hypertrophy and sleep-disordered breathing in childhood

OBJECTIVES

In children with snoring, increased production of leukotriene B₄ (LTB₄) may promote tonsillar hypertrophy and sleep-disordered breathing (SDB) or conversely SDB may enhance LTB₄ synthesis. We explored whether: i) high LTB₄ serum levels predict tonsillar hypertrophy; and ii) SDB severity correlates with LTB₄ serum concentration.

METHODS

Normal-weight children with SDB or controls underwent polysomnography and measurement of LTB₄ serum concentration. Tonsillar hypertrophy was the main outcome measure and high LTB₄ serum level (>75 t h percentile value in controls) was the primary explanatory variable. Odds ratio (OR) and the corresponding 95% confidence intervals (CI) for tonsillar hypertrophy in children with versus without high LTB₄ level were calculated. The control subgroup and subgroups of subjects with increasing SDB severity were compared regarding LTB₄ concentration by Kruskal-Wallis test. Spearman's correlation co-efficient was applied to assess the association of LTB₄ concentration with SDB severity.

RESULTS

A total of 104 children with SDB and mean obstructive apnea-hypopnea index-AHI of 4.8 ± 5.3 episodes/h (primary snoring: n = 19; mild SDB: n = 49; moderate/severe SDB: n = 36) and 13 controls (no snoring; AHI: 0.4 ± 0.2 episodes/h) were recruited. The four study subgroups were similar regarding LTB₄ serum concentration (P = 0.64). High LTB₄ (>170.3 pg/mL) was a significant predictor of tonsillar hypertrophy after adjustment for age and gender (OR 3.0 [1.2-7.2]; P = 0.01). There was no association between AHI or desaturation index and LTB₄ serum concentration (r = -0.08; P = 0.37 and r = -0.1; P = 0.30, respectively).

CONCLUSION

No association was identified between SDB severity and LTB₄ levels, but high LTB₄ concentration predicted tonsillar hypertrophy.

Urinary Leukotriene E4 as a Biomarker of Exposure, Susceptibility, and Risk in Asthma: An Update

Measurement of urinary leukotriene E₄ (uLTE₄) is a sensitive and noninvasive method of assaying total body cysteinyl leukotriene (CysLT) production and changes in CysLT production. Recent studies have reported on novel LTE4 receptor interactions and genetic polymorphisms causing CysLT variability. The applications of uLTE₄ as a biomarker continue to expand, including evaluation of environmental exposures, asthma severity risk, aspirin sensitivity, predicting atopy in preschool age children, obstructive sleep apnea, and predicting susceptibility to leukotriene receptor antagonists.

Biomarkers in inflammometry pediatric asthma: utility in daily clinical practice

Asthma is a common disease in both high and lower income countries that starts early and persists often for life. A correct and accurate diagnosis, treatment and follow-up during childhood are essential for a better understanding of adult asthma and avoiding over- or under-treatment. Th2 inflammation in children with asthma symptoms is usually assessed by measuring with serum total IgE, blood eosinophilia and FeNO levels that may help to predict asthma, particularly in those infants and young children in whom lung function tests are difficult to perform. FeNO measurement, compared to intra-individual levels, may be useful also for ascertaining treatment adherence. Nevertheless, an isolated measurement may be insufficient and only the combination of these markers improves the diagnosis, phenotyping and follow-up of an asthmatic child.

Serum biomarkers for allergy in children

A large number of studies investigating various biomarkers for allergy have been published over the past decades. The aim of this review was to evaluate these biomarkers on their diagnostic and/or predictive value. To this date, no single or specific biomarker for allergy has been identified. As allergy is not one disease, but a collection of a number of allergic conditions, it is more plausible a combination of clinical history, clinical readouts, and diagnostic markers will be needed.

Patient stratification and the unmet need in asthma

Asthma is often described as an inflammatory disease of the lungs and in most patients symptomatic treatment with bronchodilators or inhaled corticosteroids is sufficient to control disease. Unfortunately there are a proportion of patients who fail to achieve control despite treatment with the best current treatment. These severe asthma patients have been considered a homogeneous group of patients that represent the unmet therapeutic need in asthma. Many novel therapies have been tested in unselected asthma patients and the effects have often been disappointing, particularly for the highly specific monoclonal antibody-based drugs such as anti-IL-13 and anti-IL-5. More recently, it has become clear that asthma is a syndrome with many different disease drivers. Clinical trials of anti-IL-13 and anti-IL-5 have focused on biomarker-defined patient groups and these trials have driven the clinical progression of these drugs. Work on asthma phenotyping indicates that there is a group of asthma patients where T helper cell type 2 (Th2) cytokines and inflammation predominate and these type 2 high (T2-high) patients can be defined by biomarkers and response to therapies targeting this type of immunity, including anti-IL-5 and anti-IL-13. However, there is still a subset of T2-low patients that do not respond to these new therapies. This T2-low group will represent the new unmet medical need now that the T2-high-targeting therapies have made it to the market. This review will examine the current thinking on patient stratification in asthma and the identification of the T2-high subset. It will also look at the T2-low patients and examine what may be the drivers of disease in these patients.