Reduced breath condensate pH in asymptomatic children with prior wheezing as a risk factor for asthma

Remission of adult-onset asthma is rare: a 15-year follow-up study

Background

There are few long-term clinical follow-up studies of adult-onset asthma. The aim of this article was to study clinical characteristics of adult-onset asthma in relation to remission and persistence of the disease in a 15-year follow-up.

Methods

A cohort of 309 adults aged 20–60 years with asthma onset during the last 12 months verified by bronchial variability, was recruited between 1995 and 1999 from the general population in northern Sweden. The cohort was followed-up in 2003 (n=250) and between 2012 and 2014 (n=205). Structured interviews and spirometry were performed at recruitment and the follow-ups. Bronchial hyperreactivity (BHR) and skin-prick tests were performed at recruitment and blood samples were collected at the last follow-up. Remission of asthma was defined as no asthma symptoms and no use of asthma medication during the last 12 months.

Results

Of eight individuals in remission in 2003, five had relapsed between 2012 and 2014 and in total, 23 (11%) were in remission, while 182 had persistent asthma. Those in remission had higher mean forced expiratory volume in 1 s % predicted at recruitment than those with persistent asthma (94.6 versus 88.3, p=0.034), fewer had severe BHR (27.3% versus 50.9%, p=0.037) and they had less body mass index increase (+1.6 versus +3.0, p=0.054). Of those with persistent asthma, 13% had uncontrolled asthma and they had higher levels of blood neutrophils than those with partly controlled or controlled asthma.

Conclusion

Higher forced expiratory volume in 1 s % predicted and less-severe BHR was associated with remission of adult-onset asthma, but still, the proportion in remission in this 15-year follow-up was low.

In this 15-year follow-up of a cohort with adult-onset asthma, the remission rate was low, and predictors of remission were higher FEV₁ % predicted and less-severe bronchial hyperreactivity at asthma onsethttps://bit.ly/2FEgoFa

Reduced Exhaled Breath Condensate pH and Severity of Allergic Sensitization Predict School Age Asthma

BACKGROUND

We previously reported that deaerated breath condensate pH (dEBC pH) can identify preschool children with recurrent wheezing at high asthma risk.

OBJECTIVE

To assess the ability of preschool dEBC pH to predict asthma risk at school age.

METHODS

Children of the baseline cohort were recontacted for follow-up. Asthma diagnosis at school age was evaluated according to Global Initiative for Asthma recommendations in 135 children who at baseline had been classified into the following groups: (asymptomatic) atopic wheezers (n = 30), (asymptomatic) nonatopic wheezers (n = 57), allergic rhinitis only (n = 14), and healthy controls (n = 34).

RESULTS

All (100%) former atopic wheezers, 12 (21%) of nonatopic wheezers, 2 (14%) of allergic rhinitis group, and 1 (3%) of healthy controls had developed asthma at follow-up. Among all children with baseline wheezing, baseline dEBC pH predicted asthma at follow-up with an area under the receiver operating characteristic curve (AUC) of 0.72 (sensitivity, 0.67; specificity, 0.76; at pH 7.83). Combining pH and Capacity class (CAP) led to substantial gain in sensitivity (0.96) and negative predictive value (NPV, 0.94). Additional clinical information (Asthma Predictive Index, family atopy, family asthma, and inhaled corticosteroids) further increased the potential to predict asthma (AUC, 0.94) and raised sensitivity (0.98) and NPV (0.97) to nearly perfect values.

CONCLUSION

Our findings suggest (1) that dEBC pH combined with CAP class may serve as highly sensitive, noninvasive marker for the early detection of young asymptomatic preschool children with increased asthma risk, and (2) the need for additional biomarkers with high specificity to optimize early risk stratification in this clinically challenging scenario.

Predicting Asthma Using Clinical Indexes

Asthma is no longer considered a single disease, but a common label for a set of heterogeneous conditions with shared clinical symptoms but associated with different cellular and molecular mechanisms. Several wheezing phenotypes coexist at preschool age but not all preschoolers with recurrent wheezing develop asthma at school-age; and since at the present no accurate single screening test using genetic or biochemical markers has been developed to determine which preschooler with recurrent wheezing will have asthma at school age, the asthma diagnosis still needs to be based on clinical predicted models or scores. The purpose of this review is to summarize the existing and most frequently used asthma predicting models, to discuss their advantages/disadvantages, and their accomplishment on all the necessary consecutive steps for any predictive model. Seven most popular asthma predictive models were reviewed (original API, Isle of Wight, PIAMA, modified API, ucAPI, APT Leicestersher, and ademAPI). Among these, the original API has a good positive LR~7.4 (increases the probability of a prediction of asthma by 2-7 times), and it is also simple: it only requires four clinical parameters and a peripheral blood sample for eosinophil count. It is thus an easy model to use in any rural or urban health care system. However, because its negative LR is not good, it cannot be used to rule out the development of asthma.

Identification of infants and preschool children at risk for asthma: predictive scores and biomarkers

PURPOSE OF REVIEW

Predictive asthma scores and biomarkers are important tools that help many physicians in the identification of infants and preschool children at high risk for asthma. Our objective was to review recent data regarding this subject.

RECENT FINDINGS

Recently, two new predictive asthma scores were developed with some innovative features, such as the definition of scales of asthma risk. In a systematic review, 12 asthma-predictive models were identified with heterogeneous performance. Prospective studies have shown that elevated fractional concentration of nitric oxide (FeNO) is a strong risk factor for latter asthma among early wheezers, and a predictive asthma score with FeNO values has been proposed. Plasma cytokines and exhaled volatile organic compounds were also identified as potential asthma predictors.

SUMMARY

Predictive scores are simple, practical, and inexpensive tools to identify children at high risk for asthma at school age. Whereas some scores are better at identifying asthmatic children, others are better at excluding the diagnosis of asthma. Although promising, clear evidence for FeNO as a robust asthma predictor in comparison to clinical scores is still lacking. Specific IgE and eosinophil counts remain the most consistent biomarkers for the identification of children at risk for asthma, and further studies are necessary to clarify the role of other biomarkers.

Exhaled breath analysis in childhood rheumatic disorders--a longitudinal study

We aimed to evaluate the fraction of exhaled nitric oxide (FENO50) and deaerated exhaled breath condensate pH (dEBCpH) as non-invasive markers of subclinical airway inflammation in pediatric patients with rheumatologic disorders. We determined FENO50 and dEBCpH in a prospective study spanning at least 12 months, comprising 85 pediatric patients with rheumatologic disorders, including juvenile idiopathic arthritis (JIA, n  =  63), chronic recurrent multifocal osteomyelitis (CRMO, n  =  6), systemic lupus erythematosus (SLE, n  =  3), juvenile dermatomyositis (JDM, n  =  1) and other rheumatic disorders (n  =  12). dEBCpH was determined once in a group of children without evidence of rheumatologic or pulmonary disease (controls, n  =  90). Findings were correlated with results of pulmonary function tests. Atopic sensitization was assessed by RAST or skin prick test in 76 patients. Atopic sensitization was detected in 34% (26/76) of patients. Neither FENO50 nor dEBCpH correlated with disease activity, but intermediately (20-35 ppb) or highly elevated (>35 ppb) levels were observed at least once in 26 patients (31%), 19 of whom had atopic sensitization. Median dEBCpH did not differ between cases and controls (8.05 versus 8.02; p  =  0.48). Median dEBCpH decreased slightly over the study period (p  =  0.02), whereas FENO50 values did not change significantly (p  =  0.89). There were several patients with significantly abnormal dEBCpH values that could not be readily explained by diagnosis, higher disease activity, medications, or atopic sensitization. Thus, there were no consistent abnormalities in FENO50 or dEBCpH in this cohort of Caucasian patients with relatively stable rheumatologic disorders, but there were some patients with abnormal values of unknown significance.

The analysis of volatile organic compounds in exhaled breath and biomarkers in exhaled breath condensate in children - clinical tools or scientific toys?

Current monitoring strategies for respiratory diseases are mainly based on clinical features, lung function and imaging. As airway inflammation is the hallmark of many respiratory diseases in childhood, noninvasive methods to assess the presence and severity of airway inflammation might be helpful in both diagnosing and monitoring paediatric respiratory diseases. At present, the measurement of fractional exhaled nitric oxide is the only noninvasive method available to assess eosinophilic airway inflammation in clinical practice. We aimed to evaluate whether the analysis of volatile organic compounds (VOCs) in exhaled breath (EB) and biomarkers in exhaled breath condensate (EBC) is helpful in diagnosing and monitoring respiratory diseases in children. An extensive literature search was conducted in Medline, Embase and PubMed on the analysis and applications of VOCs in EB and EBC in children. We retrieved 1165 papers, of which nine contained original data on VOCs in EB and 84 on biomarkers in EBC. These were included in this review. We give an overview of the clinical applications in childhood and summarize the methodological issues. Several VOCs in EB and biomarkers in EBC have the potential to distinguish patients from healthy controls and to monitor treatment responses. Lack of standardization of collection methods and analysis techniques hampers the introduction in clinical practice. The measurement of metabolomic profiles may have important advantages over detecting single markers. There is a lack of longitudinal studies and external validation to reveal whether EB and EBC analysis have added value in the diagnostic process and follow-up of children with respiratory diseases. In conclusion, the use of VOCs in EB and biomarkers in EBC as markers of inflammatory airway diseases in children is still a research tool and not validated for clinical use.

Monitoring asthma in childhood: lung function, bronchial responsiveness and inflammation

This review focuses on the methods available for measuring reversible airways obstruction, bronchial hyperresponsiveness (BHR) and inflammation as hallmarks of asthma, and their role in monitoring children with asthma. Persistent bronchial obstruction may occur in asymptomatic children and is considered a risk factor for severe asthma episodes and is associated with poor asthma outcome. Annual measurement of forced expiratory volume in 1 s using office based spirometry is considered useful. Other lung function measurements including the assessment of BHR may be reserved for children with possible exercise limitations, poor symptom perception and those not responding to their current treatment or with atypical asthma symptoms, and performed on a higher specialty level. To date, for most methods of measuring lung function there are no proper randomised controlled or large longitudinal studies available to establish their role in asthma management in children. Noninvasive biomarkers for monitoring inflammation in children are available, for example the measurement of exhaled nitric oxide fraction, and the assessment of induced sputum cytology or inflammatory mediators in the exhaled breath condensate. However, their role and usefulness in routine clinical practice to monitor and guide therapy remains unclear, and therefore, their use should be reserved for selected cases.

Biomarkers to predict asthma in wheezing preschool children

Wheezing in preschool children is a very common symptom. An adequate prediction of asthma in these children is difficult and cannot be reliably assessed with conventional clinical tools. The study of potential predictive biomarkers in various media, ranging from invasive sampling (e.g. bronchoscopy) to non-invasive sampling (lung function testing and exhaled breath analysis), was comprehensively reviewed. The evolution in biomarker discovery has resulted in an 'omics' approach, in which hundreds of biomarkers in the field of genomics, proteomics, metabolomics, and 'breath-omics' can be simultaneously studied. First, results on gene expression and exhaled breath profiles in predicting an early asthma diagnosis are promising. However, many hurdles need to be overcome before clinical implementation is possible. To reliably predict asthma in a wheezing child, probably a holistic approach is needed, combining clinical information with blood sampling, lung function tests, and potentially exhaled breath analysis. The further development of predictive, non-invasive biomarkers may eventually improve an early asthma diagnosis in wheezing preschool children and assist clinicians in early treatment decision-making.

Exhaled biomarkers and gene expression at preschool age improve asthma prediction at 6 years of age

RATIONALE

A reliable asthma diagnosis is difficult in wheezing preschool children.

OBJECTIVES

To assess whether exhaled biomarkers, expression of inflammation genes, and early lung function measurements can improve a reliable asthma prediction in preschool wheezing children.

METHODS

Two hundred two preschool recurrent wheezers (aged 2-4 yr) were prospectively followed up until 6 years of age. At 6 years of age, a diagnosis (asthma or transient wheeze) was based on symptoms, lung function, and asthma medication use. The added predictive value (area under the receiver operating characteristic curve [AUC]) of biomarkers to clinical information (assessed with the Asthma Predictive Index [API]) assessed at preschool age in diagnosing asthma at 6 years of age was determined with a validation set. Biomarkers in exhaled breath condensate, exhaled volatile organic compounds (VOCs), gene expression, and airway resistance were measured.

MEASUREMENTS AND MAIN RESULTS

At 6 years of age, 198 children were diagnosed (76 with asthma, 122 with transient wheeze). Information on exhaled VOCs significantly improved asthma prediction (AUC, 89% [increase of 28%]; positive predictive value [PPV]/negative predictive value [NPV], 82/83%), which persisted in the validation set. Information on gene expression of toll-like receptor 4, catalase, and tumor necrosis factor-α significantly improved asthma prediction (AUC, 75% [increase of 17%]; PPV/NPV, 76/73%). This could not be confirmed after validation. Biomarkers in exhaled breath condensate and airway resistance (pre- and post- bronchodilator) did not improve an asthma prediction. The combined model with VOCs, gene expression, and API had an AUC of 95% (PPV/NPV, 90/89%).

CONCLUSIONS

Adding information on exhaled VOCs and possibly expression of inflammation genes to the API significantly improves an accurate asthma diagnosis in preschool children. Clinical trial registered with www.clinicaltrial.gov (NCT 00422747).

Exhaled nitric oxide and nasal tryptase are associated with wheeze, rhinitis and nasal allergy in primary school children

Rhinitis and asthma are the most common respiratory diseases in children. We assessed whether airway inflammation markers were associated with nasal allergies and self-reported symptoms of wheeze and rhinitis in 130 children 6-12 year old in an epidemiological context. Independent of sex and age, the fraction of exhaled nitric oxide (FeNO) and nasal mast cell (MC) activation (tryptase ≥ 5 ng/mL) were positively associated with wheeze, rhinitis and with nasal allergy. Nasal eosinophil cationic protein (ECP) and exhaled breath condensate (EBC) markers (pH, 8-isoprostane, interleukin-1β) were not associated with symptoms or with nasal allergy. In conclusion, FeNO and nasal tryptase reflect allergic inflammation in the respiratory system.

Exhaled breath condensate pH does not discriminate asymptomatic gastroesophageal reflux or the response to lansoprazole treatment in children with poorly controlled asthma

BACKGROUND

Although exhaled breath condensate (EBC) pH has been identified as an "emerging" biomarker of interest for asthma clinical trials, the clinical determinants of EBC pH remain poorly understood. Other studies have associated acid reflux-induced respiratory symptoms, for example, cough, with transient acidification of EBC.

OBJECTIVE

We sought to determine the clinical and physiologic correlates of EBC acidification in a highly characterized sample of children with poorly controlled asthma. We hypothesized that (1) children with asymptomatic gastroesophageal reflux determined by 24-hour esophageal pH monitoring would have a lower EBC pH than children without gastroesophageal reflux, (2) treatment with lansoprazole would alter EBC pH in those children, and (3) EBC acidification would be associated with increased asthma symptoms, poorer asthma control and quality of life, and increased formation of breath nitrogen oxides (NOx).

METHODS

A total of 110 children, age range 6 to 17 years, with poor asthma control and esophageal pH data enrolled in the Study of Acid Reflux in Children with Asthma (NCT00442013) were included. Children submitted EBC samples for pH and NOx measurement at randomization and at study weeks 8, 16, and 24.

RESULTS

Serial EBC pH measurements failed to distinguish asymptomatic gastroesophageal reflux and was not associated with breath NOx formation. EBC pH also did not discriminate asthma characteristics such as medication and health care utilization, pulmonary function, and asthma control and quality of life both at baseline and across the study period.

CONCLUSION

Despite the relative ease of EBC collection, EBC pH as a biomarker does not provide useful information of children with asthma who were enrolled in asthma clinical trials.

Mycoplasma pneumoniae in children with acute and refractory asthma

BACKGROUND

The presence of Mycoplasma pneumoniae has been associated with worsening asthma in children. Sensitive assays have been developed to detect M pneumoniae-derived community-acquired respiratory distress syndrome (CARDS) toxin.

OBJECTIVES

To identify the frequency and persistence of M pneumoniae detection in respiratory secretions of children with and without asthma and to evaluate antibody responses to M pneumoniae and the impact of M pneumoniae on biological markers, asthma control, and quality of life.

METHODS

We enrolled 143 pediatric patients (53 patients with acute asthma, 26 patients with refractory asthma, and 64 healthy controls; age range, 5-17 years) during a 20-month period with 2 to 5 follow-up visits. We detected M pneumoniae using CARDS toxin antigen capture and polymerase chain reaction and P1 adhesin polymerase chain reaction. Immune responses to M pneumoniae were determined by IgG and IgM levels directed against CARDS toxin and P1 adhesin. pH was measured in exhaled breath condensates, and asthma control and quality of life were assessed using the Asthma Control Test and Pediatric Asthma Quality of Life Questionnaire.

RESULTS

M pneumoniae was detected in 64% of patients with acute asthma, 65% with refractory asthma, and 56% of healthy controls. Children with asthma had lower antibody levels to M pneumoniae compared with healthy controls. Exhaled breath condensate pHs and asthma control and quality of life scores were lower in M pneumoniae-positive patients with asthma.

CONCLUSION

The results suggest that M pneumoniae detection is common in children, M pneumoniae detection is associated with worsening asthma, and children with asthma may have poor humoral immune responses to M pneumoniae.

Markers of oxidative stress are increased in exhaled breath condensates of children with atopic dermatitis

BACKGROUND

Airway inflammation may be present in subjects affected by atopic dermatitis (AD) but still without asthma symptoms. Exhaled breath condensate (EBC) reflects the composition of bronchoalveolar extracellular lining fluid that contains a large number of mediators of airway inflammation and oxidative damage.

OBJECTIVES

  We assessed inflammatory markers in the EBC of patients with AD. Fifty-six children (34 girls and 22 boys) were enrolled: 33 affected by AD and 23 healthy controls.

METHODS

  EBC was collected using a condenser device. We measured EBC pH and concentrations of leukotriene B4 (LTB4), 8-isoprostane, H(2) O(2) , malondialdehyde and 4-hydroxynoneal. Respiratory resistance was also evaluated.

RESULTS

  EBC pH in patients with AD was significantly lower than in healthy children, median (range) being 8·02 (7·94-8·12) in AD vs. 8·11 (8·05-8·16) (P = 0·02). The values of exhaled 8-isoprostane and LTB4 were significantly increased in subjects with AD compared with normal controls (P < 0·01 and P < 0·001, respectively). There was increased 4-hydroxynoneal in patients with AD but this did not reach statistical significance. Evaluating respiratory resistance, no bronchoreversibility was demonstrated in the children with AD.

CONCLUSIONS

pH, LTB4 and 8-isoprostane in EBC could be sensitive markers of airway inflammation in children with AD. Prospective studies would be of interest to evaluate if airway inflammation, not yet clinically evident, could predict the development of asthma later in life in children with AD.

Advances in pediatric asthma in 2011: moving forward

Last year's "Advances in pediatric asthma" concluded with the following statement: "Perhaps new directions in personalized medicine and improved health care access and communication will help maintain steady progress in alleviating the burden of this disease in children, especially young children." This year's summary will focus on recent advances in pediatric asthma that show significant accomplishments in reducing asthma morbidity and mortality over the last 10 years and discuss some pathways to further reduce asthma burden, as indicated in Journal of Allergy and Clinical Immunology publications in 2011. Some of the recent reports continue to shed light on methods to improve asthma management through steps to reduce asthma exacerbations, identify features of the disease in early childhood, alter asthma progression, intervene with nutrition, and more effectively implement the asthma guidelines. As new information evolves, it is also time to consider a revision of the asthma guidelines based on key studies that affect our management of the disease since the last revision in 2007. Now is also the time to use information recorded in electronic medical records to develop innovative disease management plans that will track asthma over time and enable timely decisions on interventions to maintain control that can lead to disease remission and prevention.

Residential proximity to a major roadway is associated with features of asthma control in children

Background

While several studies suggest that traffic-related air pollutants are detrimental for respiratory health, few studies have examined relationships between residential proximity to a major roadway and asthma control in children. Furthermore, a major limitation of existing research is reliance on self-reported outcomes. We therefore determined the spatial relationship between the distance from a major roadway and clinical, physiologic and inflammatory features of asthma in a highly characterized sample of asthmatic children 6–17 years of age across a wide range of severities. We hypothesized that a closer residential proximity to a major roadway would be associated with increased respiratory symptoms, altered pulmonary function and a greater magnitude of airway and systemic inflammation.

Methodology/Principal Findings

224 children 6–17 years with confirmed asthma completed questionnaires and underwent spirometry, plethysmography, exhaled nitric oxide determination, exhaled breath condensate collection and venipuncture. Residential distance from a major roadway was determined by mapping the geographic coordinates of the residential address in Geographic Information System software. The distance between the home address and the nearest major roadway was calculated according to the shortest distance between the two points (i.e., “as the crow flies”). Asthmatic children living in closer proximity to a major roadway had an increased frequency of wheezing associated with increased medication requirements and more hospitalizations even after controlling for potential confounders. These children also had increased airway resistance, increased airway inflammation reflected by a lower breath condensate pH, and higher plasma EGF concentrations.

Conclusions/Significance

These findings suggest that closer residential proximity to a major roadway is associated with poorer asthma control in school-age children. Assessment of residential proximity to major roadways may be useful in the clinical evaluation of asthma in children.