ImmunoCAP Phadiatop Infant--a new blood test for detecting IgE sensitisation in children at 2 years of age

T-cell receptor diversity and allergen sensitivity in childhood asthma and atopic dermatitis

BACKGROUND

Childhood allergies of asthma and atopic dermatitis (AD) involve an overactive T-cell immune response triggered by allergens. However, the impact of T-cell receptor (TCR) repertoires on allergen sensitization and their role in mediating different phenotypes of asthma and AD in early childhood remains unclear.

METHODS

A total of 78 children, comprising 26 with asthma alone, 26 with AD alone, and 26 healthy controls (HC), were enrolled. TCR repertoire profiles were determined using a unique molecular identifier system for next-generation sequencing. Integrative analyses of their associations with allergen-specific IgE levels and allergies were performed.

RESULTS

The diversity in TCR alpha variable region (TRAV) genes of TCR repertoires and complementarity determining region 3 (CDR3) clonality in TRAV/TRBV (beta) genes were significantly higher in children with AD compared with those with asthma and HC (p < .05). Compared with HC, the expression of TRAV13-1 and TRAV4 genes was significantly higher in both asthma and AD (p < .05), with a significant positive correlation with mite-specific IgE levels (p < .01). In contrast, TRBV7-9 gene expression was significantly lower in both asthma and AD (p < .01), with this gene showing a significant negative correlation with mite-specific IgE levels (p < .01). Furthermore, significantly higher TRAV8-3 gene expression, positively correlated with food-specific IgE levels, was found in children with AD compared with those with asthma (p < .05).

CONCLUSION

Integrated TCR repertoires analysis provides clinical insights into the diverse TCR genes linked to antigen specificity, offering potential for precision immunotherapy in childhood allergies.

Cord blood IgE predicts allergic sensitization, elevation of exhaled nitric oxide, and asthma in schoolchildren

BACKGROUND

Few data are available in Asian children regarding the validity of cord blood immunoglobulin E (IgE) in predicting allergic sensitization and pulmonary function. The relationship between cord blood IgE and fraction of exhaled nitric oxide (FeNO) remains unknown. This study investigated the associations of cord blood IgE with allergic sensitization, FeNO, pulmonary function, and allergic diseases in Asian children.

METHODS

Five hundred and sixty-six Asian children with valid cord blood IgE measurements at birth participated a 6-year follow-up visit including a questionnaire, serum total and allergen-specific IgE, FeNO measurement, and spirometry. Regression-based analyses with covariates adjustment were applied.

RESULTS

Cord blood IgE levels were significantly associated with FeNO levels (β = 0.131, p < .001) and serum total IgE levels (β = 0.325, p < .001). Cord blood IgE levels were positively associated with allergic sensitization (adjusted odds ratio [AOR] = 2.22, p < .001), and sensitization to mites (p = .002), animals (p = .023), and foods (p = .048). Subjects with cord blood IgE ≥0.24 kU/L (the optimal cutoff) were significantly associated with an increased risk of allergic sensitization (AOR = 2.63, p < .001) and asthma (AOR = 2.35, p = .024) than those with cord blood IgE <0.24 kU/L. Subjects with cord blood IgE ≥0.24 kU/L had significantly higher FeNO levels than those with cord blood IgE <0.24 kU/L (p = .028). There were no significant associations between cord blood IgE levels and pulmonary function parameters.

CONCLUSION

Cord blood IgE ≥0.24 kU/L predicts allergic sensitization, FeNO elevation, and asthma among Asian schoolchildren, suggesting cord blood IgE would be useful for identifying newborns at risk of subsequent allergic sensitization and allergic airway inflammation.

Early-life weight gain is associated with non-atopic asthma in childhood

Background

Previous studies suggest the association between early-life weight gain and asthma. It remains unclear whether early-life weight gain is associated with atopic or non-atopic asthma. This study aimed to investigate whether early-life weight gain is associated with atopic or non-atopic asthma.

Methods

Included in this study were 1343 singleton-birth children (761 boys, 57%) born between January 2010 and December 2011 participating in the Longitudinal Investigation of Global Health in Taiwanese Schoolchildren (LIGHTS) cohort were evaluated by a modified International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire and interviewed by pediatricians between July 1, 2016 and May 31, 2018 at the mean age of 6.4 years. Weight gain z-scores during the first 6, 12, and 18 months of life were classified into 4 groups: slow (below −0.67), on track (−0.67 to 0.67), rapid (0.67 to 1.28), and extremely rapid (above 1.28). The main outcomes were atopic and non-atopic asthma. Asthma was defined as having physician-diagnosed asthma and the presence of wheeze or asthma exacerbations in the last 12 months. Atopy was determined by Phadiatop Infant.

Results

The extremely rapid weight gain group of children during the first 6, 12, and 18 months of life was significantly associated with an increased risk of non-atopic asthma (adjusted odd ratio [AOR], 2.14, 95% confidence interval [CI], 1.01–4.53 for the first 6 months; AOR, 2.86, 95% CI, 1.34–6.14 for the first 12 months; AOR, 3.26, 95% CI 1.49–7.15 for the first 18 months) compared with the on track group. No significant association was found in atopic asthma. A sex-stratified analysis revealed the association of early-life weight gain with non-atopic asthma was statistically significant only in boys (AOR, 4.24, 95% CI, 1.44–12.50).

Conclusion

Extremely rapid weight gain during the first 6–18 months of life was significantly associated with 2.1- to 3.3-fold increased risk of non-atopic asthma, with a more pronounced risk found in boys.

Metabolomics analysis reveals molecular linkages for the impact of vitamin D on childhood allergic airway diseases

BACKGROUND

Several studies have reported the relevance between serum vitamin D and allergic immunoglobulin E (IgE) responses and atopic diseases. However, a metabolomics-based approach to the impacts of vitamin D on allergic reactions remains unclear.

METHODS

A total of 111 children completed a 3-year follow-up were enrolled and classified based on longitudinal vitamin D status (≥ 30 ng/ml, n = 54; 20-29.9 ng/ml, n = 41; <20 ng/ml, n = 16). Urinary metabolomic profiling was performed using ¹ H-Nuclear magnetic resonance (NMR) spectroscopy at age 3. Integrative analyses of their associations related to vitamin D levels, atopic indices, and allergies were performed, and their roles in functional metabolic pathways were also assessed.

RESULTS

Six and five metabolites were identified to be significantly associated with vitamin D status and atopic diseases, respectively (FDR-adjusted p-value <.05). A further correlation analysis revealed that vitamin D-associated 3-hydroxyisobutyric acid and glutamine were positively correlated with atopic disease-associated succinic acid and alanine, respectively. Furthermore, hippuric acid was negatively correlated with atopic disease-associated formic acid, which was positively correlated with vitamin D level (p < .01). Absolute eosinophil count (AEC) was positively correlated with serum D. pteronyssinus- and D. farinae-specific IgE level (p < .01) but negatively correlated with vitamin D level (p < .05). Amino acid metabolisms were significantly associated with vitamin D related to childhood allergies.

CONCLUSION

Integrative metabolomic analysis provides the link of vitamin D-associated metabolites with the gut microbiome and immunoallergic reactions related to childhood allergies.

Longitudinal Metabolomic Analysis Reveals Gut Microbial-Derived Metabolites Related to Formula Feeding and Milk Sensitization Development in Infancy

Early exposure to formula milk increases the likelihood of cow’s milk sensitization and food allergies in the later childhood. However, the underlying mechanisms are multifactorial and unclear. Fifty-five children from a follow-up birth cohort study were grouped into exclusive breastfeeding (EBF, n = 33) and formula feeding (EFF, n = 22) in the first six months of life. Urinary metabolites were longitudinally assessed and analyzed at 6 months, 1, and 2 years of age using 1H-nuclear magnetic resonance (NMR) spectroscopy. Integrated analysis of metabolic profiling associated with formula feeding and milk sensitization related to IgE reactions was also investigated. Twenty-two metabolites were significantly obtained in the EFF set at age 0.5, whereas nine metabolites were predominantly obtained in the milk sensitization set at age 1. A subsequent analysis of metabolic change from 6 months to age 1 identified eight metabolites, including 3-methyl-2-oxovaleric acid, glutarate, lysine, N-phenylacetylglycine, N,N-dimethylglycine, 3-indoxysulfate, 2-oxoglutaric acid, and pantothenate associated with formula feeding and milk sensitization with same trend variation. Among them, 3-indoxysulfate, N-phenylacetylglycine, and N,N-dimethylglycine were gut microbial-derived without IgE association. By contrast, 3-methyl-2-oxovaleric acid, glutarate, and lysine were IgE related associated with formula feeding contributing to milk sensitization (p < 0.05). Longitudinal urinary metabolomic analysis provides molecular insight into the mechanism of formula feeding associated with milk sensitization. Gut microbial-derived metabolites associated with formula feeding and IgE associated metabolites related to branched-chain amino acid metabolism play roles in developing sensitization and allergic symptoms in response to formula feeding.

Allergic diseases attributable to atopy in a population sample of Asian children

The proportion of allergic diseases attributable to atopy remains a subject of controversy. This study aimed to estimate the population risk of physician-diagnosed asthma, rhinitis and eczema attributed to atopy among a population sample of Asian school-age children. Asian children aged 5–18 years (n = 1321) in the Prediction of Allergies in Taiwanese CHildren (PATCH) study were tested for serum allergen-specific immunoglobulin E. Physician-diagnosed asthma, rhinitis and eczema were assessed by a modified International Study of Asthma and Allergies in Childhood questionnaire. Atopy was defined as the presence of serum allergen-specific immunoglobulin E. In this population-based study, 50.4% of the subjects with asthma, 46.3% with rhinitis, and 46.7% with eczema were attributable to atopy. The population attributable risk (PAR) of atopy for three allergic diseases was higher in adolescents (asthma, 54.4%; rhinitis, 59.6%; eczema, 49.5%) than younger children aged less than 10 years (asthma, 46.9%; rhinitis, 39.5%; eczema, 41.9%). Among the seven allergen categories, sensitization to mites had the highest PARs for all three allergic diseases (51.3 to 64.1%), followed by sensitization to foods (asthma, 7.1%; rhinitis, 10.4%; eczema 27.7%). In conclusion, approximately half (46.3 to 50.4%) of Asian children in Taiwan with allergic diseases are attributable to atopy.

Longitudinal analysis of total serum IgE levels with allergen sensitization and atopic diseases in early childhood

There are few studies addressing the longitudinal analysis of serum IgE levels and its impact to the development of atopic diseases in early childhood. We investigated 170 children who regularly followed up at our clinic for 4 years in a birth cohort study with at least 3 time-points of serum samples. The pattern of total serum IgE levels from 6 months to 4 years of age was clustered using K-means method in R software. Specific immunoglobulin E antibodies against food (egg white and milk) and inhalant allergens (D. pteronyssinus and D. farinae) were measured at 0.5, 1, 1.5, 2, 3 and 4 years of age. By using K-means clustering, the dynamic changes in serum IgE levels was significantly stratified into 3 clusters (cluster A, < 100 kU/L, n = 106; cluster B, 100–200 kU/L, n = 35; cluster C, ≥ 200 kU/L, n = 29). A persistent total IgE levels higher than 100 kU/L appeared to be associated with higher prevalence of sensitization to food but not mite. However, a persistent IgE levels higher than 200 kU/L was not only remarkably related to increased prevalence of mite sensitization, but also risk of eczema at age 1 and allergic rhinitis and asthma at age 2, 3 and 4. In conclusion, a persistent total serum IgE level ≥ 200 kU/L since infancy is strongly associated with the presence of food and mite sensitization, as well as the development of eczema in infants, and rhinitis and asthma later in early childhood.

Association between maternal age at delivery and allergic rhinitis in schoolchildren: A population-based study

Background

Some studies have shown associations of maternal age at delivery with asthma and food allergy in offspring. However, the relationship between maternal age at delivery and allergic rhinitis is largely unclear. This study aimed to investigate the association between maternal age at delivery and allergic rhinitis in a population sample of Asian children, and to explore potential effect modifiers.

Methods

A total of 1344 singleton-birth children (763 boys, 56.8%; mean age, 6.4 years) participating in the Longitudinal Investigation of Global Health in Taiwanese Schoolchildren (LIGHTS) cohort were evaluated by a modified International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire and interviewed by pediatricians. Allergic sensitization was determined by using Phadiatop Infant. Multiple logistic regression models with covariates adjustment were performed to investigate the association of maternal age at delivery with allergic rhinitis and allergic sensitization in offspring.

Results

Among 1344 study children, 793 (59%) had physician-diagnosed allergic rhinitis. Advanced maternal age at delivery (≥40 years) was significantly associated with increased odds of allergic rhinitis (adjusted odds ratio [AOR] = 4.58, 95% confidence interval [CI]: 1.90–11.03) and allergic sensitization (AOR = 2.86, 95% CI: 1.13–7.22) in offspring. A sex-stratified analysis revealed that the association of advanced maternal age with allergic rhinitis was statistically significant only in female offspring (AOR = 7.02, 95% CI: 1.89–26.14). Stratified analyses by birth order or environmental tobacco smoke exposure during pregnancy did not reveal any significant differences.

Conclusion

Advanced maternal age at delivery was associated with increased risk of allergic rhinitis in Asian children, probably more pronounced among girls.

Phadiatop, Phadiatop Infant and total IgE evaluated in allergic Brazilian children and adolescents

The clinical history is of importance in the investigation of allergic diseases but does have limitations. Many allergic conditions will be over-diagnosed if anamnesis alone is used for diagnostic criteria. Serum total immunoglobulin E (TIgE) quantification, as well as panels containing allergens prevalent in the studied population, may serve as screening tests and facilitate the diagnosis of allergic disease or its exclusion. We assessed the positivity of two versions of these tests, Phadiatop Europe® (PhEU) and Phadiatop Infant® (PhInf), as well as total IgE (TigE) values in patients with a medical diagnosis of allergic disease and non-allergic individuals.

METHODS

A cross-sectional study performed in eleven Brazilian pediatric allergy centers with patients divided into groups according to the primary condition and a group of assessed control subjects. They were submitted to TIgE measurement and screening tests (PhEu and PhInf).

RESULTS

TIgE mean serum levels were significantly higher among allergic patients, especially those with asthma/rhinitis or atopic dermatitis. The positivity of the screening tests, considering the total population, was 63.8% for PhEU and 72.6% for PhInf. These increased when we evaluated only the allergic subjects. The concordance index of the two tests was Kappa=0.7 and higher among those of greater age.

CONCLUSIONS

In the assessed population, there were significantly higher levels among those with positive screening tests and PhInf showed better performance in the identification of sensitized individuals, regardless of age. This is the first study to evaluate Phadiatop and Phadiatop Infant in the same population.

Metabolomic Analysis Reveals Distinct Profiles in the Plasma and Urine Associated with IgE Reactions in Childhood Asthma

Several metabolomics studies have identified altered metabolic pathways that are related to asthma. However, an integrative analysis of the metabolic responses across blood and urine for a comprehensive framework of asthma in early childhood remains lacking. Fifty-four age-matched children with asthma (n = 28) and healthy controls (n = 26) were enrolled. Metabolome analysis of the plasma and urine samples was performed using ¹H-nuclear magnetic resonance (NMR) spectroscopy coupled with partial least-squares discriminant analysis (PLS-DA). Integrated analysis of blood and urine metabolic profiling related to IgE reactions for childhood asthma was investigated. A significantly higher plasma histidine level was found, in parallel with lower urinary 1-methylnicotinamide and trimethylamine N-oxide (TMAO) levels, in children with asthma compared to healthy controls. Compared to children without allergic sensitization, 11 (92%) plasma metabolites and 8 (80%) urinary metabolites were found to be significantly different in children with IgE and food sensitization respectively. There were significant correlations between the plasma 3-hydroxybutyric acid and excreted volumes of the hydroxy acids, which were strongly correlated to plasma leucine and valine levels. Urine N-phenylacetylglycine, a microbial-host co-metabolite, was strongly correlated with total serum and food allergen-specific IgE levels. Plasma pyruvate and urine valine, leucine, and isoleucine degradation metabolisms were significantly associated with allergic sensitization for childhood asthma. In conclusion, blood and urine metabolome reflect different metabolic pathways in allergic reactions. Plasma pyruvate metabolism to acetic acid appears to be associated with serum IgE production, whereas urine branched-chain amino acid metabolism primarily reflects food allergic reactions against allergies.

Children Monosensitized to Can f 5 Show Different Reactions to Male and Female Dog Allergen Extract Provocation: A Randomized Controlled Trial

BACKGROUND

Dog dander consists of several allergenic molecules including Can f 5, which is a protein expressed in the prostate of male dogs.

OBJECTIVE

To investigate whether children monosensitized to Can f 5 show different reactions to provocation tests with male versus female dog dander in a double-blind randomized clinical trial.

METHODS

Twenty-two children (15-18 years) with a history of dog sensitization were enrolled from the COpenhagen Prospective Studies on Asthma in Childhood₂₀₀₀ mother-child cohort. Skin prick test, specific IgE levels to dog dander (e5), and dog components Can f 1, 2, 3, and 5 were first assessed. We subsequently performed skin prick test and conjunctival allergen provocation test using dog dander collected separately from male and female dogs.

RESULTS

Seven of the 22 children were monosensitized to Can f 5. Eight were sensitized to a mix of the dog components, and 7 were no longer sensitized to dog. Of the children monosensitized to Can f 5, all had a positive skin prick test result to male dog extract and 1 of 7 was also positive to female dog extract (P = .01). Furthermore, 5 of 7 had a positive conjunctival allergen provocation test result to male dog extract and 1 of 7 also reacted to the female dog extract (P = .03). There was no difference between reactions to male and female dog extract provocation in children sensitized to a mix of the dog components.

CONCLUSIONS

Children monosensitized to Can f 5 show different reactions to male and female dog extract provocation using both skin prick test and conjunctival allergen provocation test, suggesting tolerance to female dogs.

Early-onset eczema is associated with increased milk sensitization and risk of rhinitis and asthma in early childhood

BACKGROUND

Atopic eczema and food allergy most commonly occur in the early childhood. However, the relationships between eczema onset and their relevance to the occurrence of atopic diseases relating to allergen sensitization remain unclear.

METHODS

We investigated 186 children who were followed up regularly at the clinic for 4 years in a birth cohort study. The children were classified into three groups: early-onset eczema (<2 years old, n = 55), late-onset eczema (≥2 years old, n = 40), and never eczema groups (n = 91). The associations between the different onsets of eczema and total immunoglobulin E levels, absolute eosinophil count, sensitization to food and inhalant allergens, and allergic outcomes were assessed.

RESULTS

A significantly higher prevalence of sensitization to food, especially milk was observed in children with early-onset eczema compared with those without eczema at age 1, 1.5, 2, 3, and 4 years. Furthermore, a significantly higher number of eosinophils was detected in children with early or late-onset eczema at the age of 1.5 years. Both the early- and late-onset eczema were significantly associated with a higher prevalence of allergic rhinitis at age 2, 3, and 4 years, and asthma at age 2. Moreover, the early-onset eczema group showed a significantly increased risk of allergic rhinitis (P = 0.010) and asthma (P = 0.032) at age 4.

CONCLUSION

The children with early-onset eczema (<2 years old) appear to be associated with an increased prevalence of milk sensitization and risk of rhinitis and asthma in early childhood.

Trajectories of childhood immune development and respiratory health relevant to asthma and allergy

Events in early life contribute to subsequent risk of asthma; however, the causes and trajectories of childhood wheeze are heterogeneous and do not always result in asthma. Similarly, not all atopic individuals develop wheeze, and vice versa. The reasons for these differences are unclear. Using unsupervised model-based cluster analysis, we identified latent clusters within a prospective birth cohort with deep immunological and respiratory phenotyping. We characterised each cluster in terms of immunological profile and disease risk, and replicated our results in external cohorts from the UK and USA. We discovered three distinct trajectories, one of which is a high-risk ‘atopic’ cluster with increased propensity for allergic diseases throughout childhood. Atopy contributes varyingly to later wheeze depending on cluster membership. Our findings demonstrate the utility of unsupervised analysis in elucidating heterogeneity in asthma pathogenesis and provide a foundation for improving management and prevention of childhood asthma.

Asthma causes wheezy and troubled breathing, and can be life-threatening. Scientists and doctors understand that asthma begins in early childhood. Chest infections, exposure to bacteria, viruses, and allergies may cause or trigger asthma. One person with asthma may not have the same origins as another. But it is not yet clear how various triggers may interact to trigger or exacerbate asthma.

To disentangle how these factors contribute to asthma, experts have tried to group people with asthma into subgroups. Unfortunately, the groups often vary from expert to expert. Now, some scientists are using computers to sort patients with asthma. The scientists let the computers decide the best criteria for sorting patients. This way the machines may identify patterns that are not obvious to humans.

Using this computer-based approach, Tang et al. sorted Australian children with asthma into 3 groups based on their early life allergies and respiratory health. One group has high-risk asthma with frequent chest infections and strong allergic responses. The other two groups are low-risk, but they respond differently to allergy and infection. Common tests used by doctors to diagnose patients with allergy or asthma may not work the same with all three groups. The bacteria found in the nose influence the risk of asthma, even in patients who are well, and the way this occurs varies by group. Similar groups were also found among children with asthma in the United States and the United Kingdom.

Learning more about subgroups of patients with asthma may help other scientists and doctors design better ways to diagnose, treat, or prevent asthma. Working together with scientists around the world to determine how to best describe subgroups of people according to asthma type and risk is a critical step in the process. Tang et al. hope other scientist will test whether these three groups are also found in people from other parts of the world.

Longitudinal urinary metabolomic profiling reveals metabolites for asthma development in early childhood

BACKGROUND

Several metabolites and altered metabolic pathways have been reported to be associated with asthma. However, longitudinal analysis of the dynamics of metabolites contributing to the development of asthma has not yet been fully clarified.

METHODS

We sought to identify the metabolic mechanisms underlying asthma development in early childhood. Thirty children with asthma and paired healthy controls from a prospective birth cohort were enrolled. Time series analysis of urinary metabolites collected at ages 1, 2, 3, and 4 years was assessed using ¹ H nuclear magnetic resonance (NMR) spectroscopy coupled with partial least squares discriminant analysis (PLS-DA). Metabolites identified were studied in relation to changes over time in a linear mixed model for repeated measures.

RESULTS

A total of 172 urine samples collected from the enrolled children were analyzed. Urinary metabolomics identified four metabolites significantly associated with childhood asthma development, with longitudinal analysis. Among them, dimethylamine, a metabolite produced by intestinal bacteria, appeared to shift from higher to lower level during asthma development. A persistent lower level of 1-methylnicotinamide and allantoin was found in children with asthma, with a peak difference at age 3 years (P = .032 and P = .021, respectively). Furthermore, a significant inverse correlation was found between allantoin and house dust mite sensitization (Spearman's r = -.297 P = .035).

CONCLUSIONS

Longitudinal urinary metabolomic profiling provides a link of microbe-environment interactions in the development of childhood asthma. 1-Methylnicotinamide and allantoin may participate in allergic reactions in response to allergen exposure, potentially serving as specific biomarkers for asthma.

Longitudinal vitamin D deficiency is inversely related to mite sensitization in early childhood

BACKGROUND

There are few studies addressing the longitudinal analysis of vitamin D deficiency and its impact on the development of atopic diseases in early childhood.

METHODS

We investigated 155 children who regularly followed up at our clinic for 5 years as subjects enrolled in a birth cohort study. The pattern of vitamin D levels from birth to 5 years of age was clustered using K-means method in R software. Absolute eosinophil count (AEC), and total serum and specific immunoglobulin E antibodies against food (egg white, milk, and wheat) and inhalant allergens (Dermatophagoides pteronyssinus, Dermatophagoides farina, and Cladosporium herbarum) were measured at 1.5, 3, 4 and 5 years of age.

RESULTS

A total of 137 children with serum samples obtained over at least 3 time points during the follow-up period were recruited. Using K-means clustering, the dynamic changes in vitamin D levels were significantly stratified into 3 clusters (cluster A, ≥30 ng/mL, n = 61; cluster B, 20-29.9 ng/mL, n = 53; cluster C, <20 ng/mL, n = 23). Despite no statistical association with atopic diseases, a persistent vitamin D deficiency appeared to be associated with eosinophilia at age 3, and total serum and mite-specific immunoglobulin E (IgE) levels at age 4. Furthermore, an associated higher prevalence of mite sensitization at age 4 was significantly associated with the risk of allergic rhinitis and asthma.

CONCLUSIONS

Vitamin D deficiency is inversely associated with AEC and mite-specific IgE levels, which may potentially increase susceptibility to develop allergies including rhinitis and asthma in early childhood.

Low Mother-to-Child CCL22 Chemokine Levels Are Inversely Related to Mite Sensitization and Asthma in Early Childhood

Few studies have addressed the mother-to-child transmission of Th2 immunity and the impact on the development of atopic diseases in early childhood. We investigated 186 children who were followed-up regularly for 4 years in a birth cohort study. The levels of Th2 related chemokine (C-C motif) ligand 17 (CCL17) and CCL22 were quantified in cord blood and at 1.5 years-of-age using multiplex Luminex kits. The levels of 125 pairs of CCL17 and CCL22 chemokines from birth to 1.5 years were recorded in this study. Using K-means clustering, only the declining trend of CCL22 levels was separately clustered (cluster A, n = 51; cluster B, n = 46; cluster C, n = 28). Mothers of children with higher CCL22 chemokine levels at birth were significantly more likely to display Dermatophagoides pteronyssinus sensitization. A lower CCL22 level at birth with a slight rise during infancy was associated with higher prevalence of mite sensitization and a higher risk of asthma at 3 years-of-age (P = 0.014). In conclusion, low mother-to-child Th2-associated chemokine CCL22 levels appear to be inversely related to mite sensitization and the risk of asthma development in early childhood.

High cord blood CCL22/CXCL10 chemokine ratios precede allergic sensitization in early childhood

Atopic diseases are known to be characterized by a T helper (Th) 2-skewed immunity; however, there are few studies addressing the Th1/Th2 immunity at birth related to the development of atopic diseases in early childhood. We investigated 186 children followed up regularly at the clinic for 4 years in a birth cohort study. The Th1-associated CXC chemokine ligand (CXCL)-10, CXCL11, and the Th2-associated CC chemokine ligand (CCL)-17 and CCL22 were quantified in cord blood by multiplex Luminex kits. Specific immunoglobulin E antibodies against food and inhalant allergens were measured at 6 months as well as 1, 1.5, 2, 3, and 4 years of age. Cord blood CCL22 levels were positively associated with IgE sensitization at age 2, whereas cord blood CXCL10 levels were negatively associated with mite sensitization at age 3. Furthermore, a high cord blood CCL22/CXCL10 chemokine ratio was significantly associated with a higher risk of allergic sensitization at age 3 (OR, 1.02; 95% confidence interval [CI], 1.0051.039; P = 0.012). However, cord blood Th1- and Th2-associated chemokines and their ratios were not associated with atopic diseases at different age. Our study indicates that a Th2-skewed immunity at birth may increase risk of allergic sensitization but not of allergic outcomes later in life.

FeNO and Exercise Testing in Children at Risk of Asthma

BACKGROUND

Exercise testing is the gold standard for diagnosing exercise-induced bronchoconstriction in children, but requires considerable cooperation and medical resources. Therefore, fraction of exhaled nitric oxide (FeNO) has been proposed as a tool to predict the need for exercise testing.

OBJECTIVE

The objective of this study was to investigate the relationship between FeNO, exercise test results, and a history of respiratory symptoms during exercise in children at risk of asthma.

METHODS

FeNO measurement, exercise testing, and interview about respiratory symptoms during exercise were completed in 224 seven-year-old children from the at-risk Copenhagen Prospective Studies on Asthma in Childhood₂₀₀₀ birth cohort. The associations between FeNO, exercise test results, and reported respiratory symptoms during exercise were analyzed adjusting for gender, respiratory infections, and inhaled corticosteroid treatment. The associations were also analyzed stratified by asthma and atopic status.

RESULTS

Of the 224 children, 28 (13%) had an established asthma diagnosis and 58 (26%) had a positive exercise test (≥15% drop in forced expiratory volume in 1 second [FEV₁] from baseline). FeNO and bronchial obstruction after exercise were linearly associated with a doubling of FeNO corresponding to a 2.4% drop in FEV₁ (95% confidence interval, 0.8-4.1; P < .01). However, a receiver operating characteristic curve analysis showed that the best cutoff of FeNO for predicting exercise test outcome among children who reported respiratory symptoms during exercise was 17 ppb, which only had 74% negative predictive value. There was no association between FeNO and reported respiratory symptoms during exercise (odds ratio = 1.3 [0.8-1.9]; P = .29) or reported symptoms during exercise and exercise test results (odds ratio = 1.0 [1.0-1.1]; P = .12).

CONCLUSIONS

A history of respiratory symptoms during exercise was not associated with either elevated FeNO or a positive exercise test in children at risk of asthma. FeNO and exercise test results were linearly associated traits, but FeNO could not reliably be used dichotomized to predict the need of exercise testing.

Preeclampsia Associates with Asthma, Allergy, and Eczema in Childhood

RATIONALE

Preeclampsia reflects an unusual increase in systemic inflammation during pregnancy.

OBJECTIVES

We studied associations between preeclampsia and asthma, allergy, and eczema in Copenhagen Prospective Studies on Asthma in Childhood₂₀₀₀ (COPSAC₂₀₀₀) and in national registries.

METHODS

COPSAC₂₀₀₀ is a high-risk birth cohort of 411 Danish children. Asthma, allergy, and eczema were diagnosed prospectively, and lung function measured at age 1 month and 7 years. Sensitization was evaluated at age 6 months, 18 months, 4 years, and 6 years by skin prick tests and IgE measurements. The register-based cohort included 1.7 million children from Danish national registries in the 35-year period 1977-2012. Children born to mothers with preeclampsia were analyzed regarding risk of asthma, allergy, and eczema.

MEASUREMENTS AND MAIN RESULTS

In the COPSAC₂₀₀₀ cohort, 5.6% (n = 23) were diagnosed with preeclampsia. Preeclampsia was associated with increased risk of treatment with inhaled corticosteroids at age 7 years (adjusted odds ratio, 4.01 [95% confidence interval (CI), 1.11-14.43]; P = 0.0337), increased bronchial responsiveness to methacholine (adjusted β-coefficient log-μmol, -0.80 [95% CI, -1.55 to -0.06]; P = 0.0348), and allergic rhinitis (adjusted odds ratio, 4.83 [95% CI, 1.58-14.78]; P = 0.0057) in the 7-year-old children. Furthermore, the children had an increased risk of sensitization to both aeroallergens and food allergens, and increased amount of total IgE during childhood. In the registry-based cohort, 3.7% (n = 62,728) were born to mothers with preeclampsia. Preeclampsia was associated with increased risk of asthma, eczema, and aeroallergen and food allergy, especially pronounced after a duration of preeclampsia of 14 days or more. Maternal asthma increased the risk of preeclampsia.

CONCLUSIONS

Preeclampsia is a shared prenatal risk factor for asthma, eczema, and allergy in childhood pointing toward in utero immune programming of the child.

Allergic sensitization at school age is a systemic low-grade inflammatory disorder

BACKGROUND

Systemic low-grade inflammation has been demonstrated in a range of the frequent noncommunicable diseases (NCDs) proposing a shared mechanism, but is largely unexplored in relation to allergic sensitization. We therefore aimed to investigate the possible association with childhood allergic sensitization.

METHODS

High-sensitivity C-reactive protein (hs-CRP), interleukin-1β (IL-1β), IL-6, tumor necrosis factor-α (TNF-α), and chemokine (C-X-C motif) ligand 8 (CXCL8) were measured in plasma at age 6 months (N = 214) and 7 years (N = 277) in children from the Copenhagen Prospective Studies on Asthma in Childhood₂₀₀₀ (COPSAC₂₀₀₀ ) birth cohort. Allergic sensitization against common inhalant and food allergens was determined longitudinally at ages ½, 1½, 4 and 6 years by specific IgE assessments and skin prick tests. Associations between inflammatory biomarkers and sensitization phenotypes were tested with logistic regression and principal component analyses (PCAs).

RESULTS

Adjusted for gender, recent infections, and a CRP genetic risk score, hs-CRP at 7 years was associated with concurrent elevated specific IgE against any allergen [adjusted OR (aOR) = 1.40; 95% CI, 1.14-1.72; P = 0.001], aeroallergens (aOR, 1.43; 1.15-1.77; P = 0.001), food allergens (aOR, 1.31; 95% CI, 1.02-1.67; P = 0.04), sensitization without any clinical allergy symptoms (aOR = 1.40; 1.06-1.85; P = 0.02), and with similar findings for skin prick tests. The other inflammatory markers were not univariately associated with sensitization, but multiparametric PCA suggested a specific inflammatory response among sensitized children. Inflammatory markers at age 6 months were not associated with subsequent development of sensitization phenotypes.

CONCLUSIONS

Elevated hs-CRP is associated with allergic sensitization in school-aged children suggesting systemic low-grade inflammation as a phenotypic characteristic of this early-onset NCD.

Airway Microbial Diversity is Inversely Associated with Mite-Sensitized Rhinitis and Asthma in Early Childhood

Microbiota plays an important role in regulating immune responses associated with atopic diseases. We sought to evaluate relationships among airway microbiota, serum IgE levels, allergic sensitization and their relevance to rhinitis and asthma. Microbial characterization was performed using Illumina-based 16S rRNA gene sequencing of 87 throat swabs collected from children with asthma (n = 32) and rhinitis (n = 23), and from healthy controls (n = 32). Data analysis was performed using QIIME (Quantitative Insights Into Microbial Ecology) v1.8. Significantly higher abundance of Proteobacteria was found in children with rhinitis than in the healthy controls (20.1% vs. 16.1%, P = 0.009). Bacterial species richness (Chao1 index) and diversity (Shannon index) were significantly reduced in children with mite sensitization but not in those with food or IgE sensitization. Compared with healthy children without mite sensitization, the mite-sensitized children with rhinitis and asthma showed significantly lower Chao1 and Shannon indices. Moraxella and Leptotrichia species were significantly found in the interaction of mite sensitization with rhinitis and asthma respectively. Airway microbial diversity appears to be inversely associated with sensitization to house dust mites. A modulation between airway dysbiosis and responses to allergens may potentially cause susceptibility to rhinitis and asthma in early childhood.

Obesity disproportionately impacts lung volumes, airflow and exhaled nitric oxide in children

Background

The current literature focusing on the effect of obesity and overweight on lung function and fraction of exhaled nitric oxide (FeNO) in children, particularly among healthy children of non-European descent, remains controversial. Furthermore, whether the relationship of obesity and overweight with lung function and FeNO in children is modified by atopy is unclear. The objective of this study was to examine the effect of excess weight on lung function parameters and FeNO among Asian children, with a particular focus on exploring the potential effect modification by atopy.

Methods

We investigated the effect of excess weight on lung function and FeNO in a population sample of 1,717 children aged 5 to 18 years and explored the potential modifying effect of atopy.

Results

There were positive associations of body mass index (BMI) z-score with forced vital capacity (FVC), forced expiratory volume in 1 second (FEV₁), peak expiratory flow (PEF), and forced expiratory flow at 25–75% (FEF_25-75) (all P<0.001), after controlling for confounders. The beta coefficient for FEV₁ (0.084) was smaller than that for FVC (0.111). In contrast, a negative association was found between BMI z-score and FEV₁/FVC ratio (P<0.001) and FeNO (P = 0.03). A consistent pattern of association for lung function variables was observed when stratifying by atopy. There was a negative association of BMI z-score with FeNO in atopic subjects (P = 0.006), but not in non-atopic subjects (P = 0.46).

Conclusions

Excess weight disproportionately impacts lung volumes and airflow in children from the general population, independent of atopic status. Excess weight inversely affects FeNO in atopic but not in non-atopic children.

Sensitization trajectories in childhood revealed by using a cluster analysis

BACKGROUND

Assessment of sensitization at a single time point during childhood provides limited clinical information. We hypothesized that sensitization develops as specific patterns with respect to age at debut, development over time, and involved allergens and that such patterns might be more biologically and clinically relevant.

OBJECTIVE

We sought to explore latent patterns of sensitization during the first 6 years of life and investigate whether such patterns associate with the development of asthma, rhinitis, and eczema.

METHODS

We investigated 398 children from the at-risk Copenhagen Prospective Studies on Asthma in Childhood 2000 (COPSAC₂₀₀₀) birth cohort with specific IgE against 13 common food and inhalant allergens at the ages of ½, 1½, 4, and 6 years. An unsupervised cluster analysis for 3-dimensional data (nonnegative sparse parallel factor analysis) was used to extract latent patterns explicitly characterizing temporal development of sensitization while clustering allergens and children. Subsequently, these patterns were investigated in relation to asthma, rhinitis, and eczema. Verification was sought in an independent unselected birth cohort (BAMSE) constituting 3051 children with specific IgE against the same allergens at 4 and 8 years of age.

RESULTS

The nonnegative sparse parallel factor analysis indicated a complex latent structure involving 7 age- and allergen-specific patterns in the COPSAC₂₀₀₀ birth cohort data: (1) dog/cat/horse, (2) timothy grass/birch, (3) molds, (4) house dust mites, (5) peanut/wheat flour/mugwort, (6) peanut/soybean, and (7) egg/milk/wheat flour. Asthma was solely associated with pattern 1 (odds ratio [OR], 3.3; 95% CI, 1.5-7.2), rhinitis with patterns 1 to 4 and 6 (OR, 2.2-4.3), and eczema with patterns 1 to 3 and 5 to 7 (OR, 1.6-2.5). All 7 patterns were verified in the independent BAMSE cohort (R² > 0.89).

CONCLUSION

This study suggests the presence of specific sensitization patterns in early childhood differentially associated with development of clinical outcomes. Using such patterns in future research might provide more robust and clinically relevant results.

Exposure to tobacco smoke and childhood rhinitis: a population-based study

Exposure to tobacco smoke has been associated with harmful effects on child health. The association between tobacco smoke exposure and childhood rhinitis has not been established in developed or developing countries. We investigated the association between serum cotinine levels and rhinitis in a population sample of 1,315 Asian children. Serum cotinine levels were positively associated with rhinitis ever (adjusted odds ratio [AOR] = 2.95; 95% confidence interval [CI]: 1.15–7.60) and current rhinitis (AOR = 2.71; 95% CI: 1.07–6.89), while the association for physician-diagnosed rhinitis approaching borderline significance (AOR = 2.26; 95% CI: 0.88–5.83). Stratified analyses demonstrated significant association of serum cotinine levels with current rhinitis among children without allergic sensitization (AOR = 6.76; 95% CI: 1.21–37.74), but not among those with allergic sensitization. Serum cotinine levels were positively associated with rhinitis ever (AOR = 3.34; 95% CI: 1.05–10.61) and current rhinitis (AOR = 4.23; 95% CI: 1.28–13.97) among adolescents but not in children aged less than 10 years. This population-based study demonstrates supportive evidence for positive association of tobacco smoke exposure with rhinitis, while the effect is mainly confined to non-allergic rhinitis and more pronounced in adolescents than in young children, highlighting the need for raising public health awareness about the detrimental effects of tobacco smoke exposure on children’s respiratory health.

Faecal eosinophil cationic protein and serum immunoglobulin E in relation to infant feeding practices

Background To date, the effects of exclusive breastfeeding duration and timing of solid food introduction on allergy prevention are unclear. The aim of this study was to determine the effect of variable feeding practices on intestinal inflammation in infants using faecal eosinophil cationic protein as a surrogate marker and to assess whether faecal eosinophil cationic protein is associated with serum immunoglobulin E. Methods Subjects ( n = 206) were enrolled from the Prediction of Allergies in Taiwanese CHildren (PATCH) birth cohort study. Stool samples were collected at 6 and 12 months for determining eosinophil cationic protein, and blood was collected for determining total and allergen-specific immunoglobulin E at 12 months. We compared these biomarkers between infants with variable exclusive breastfeeding duration and infants introduced to solid foods at various periods. The association between faecal eosinophil cationic protein, total serum immunoglobulin E and specific immunoglobulin E was also analysed. Results Faecal eosinophil cationic protein was significantly higher in exclusively breastfed infants compared with formula-fed infants and infants who were not exclusively breastfed at 6 months of age ( P < 0.05). At 12 months, infants who were introduced to solid foods at 5-6 months had the lowest faecal eosinophil cationic protein compared with those who were introduced at earlier and later periods. There was no significant association between faecal eosinophil cationic protein and serum immunoglobulin E. Conclusion We found that breastfeeding exclusively for >6 months did not reduce serum immunoglobulin E, but rather increased intestinal inflammation. Faecal eosinophil cationic protein was not associated with total serum immunoglobulin E and specific immunoglobulin E and might not be a useful indictor of immunoglobulin E sensitization in infancy.

Early indoor aeroallergen exposure is not associated with development of sensitization or allergic rhinitis in high-risk children

RATIONALE

Allergen exposure is associated with the development of allergic sensitization in childhood as reflected by global variations in sensitization patterns. However, there is little evidence to support a direct association.

OBJECTIVES

To investigate the association between perinatal aeroallergen exposure and sensitization and rhinitis to such allergens later in childhood.

METHODS

Allergic sensitization to cat, dog, and house dust mites was diagnosed longitudinally using skin prick tests and specific IgE measurements at ½, 1½, 4, 6, and 13 years in 399 children from the Copenhagen Prospective Study on Asthma in Childhood2000 birth cohort. Rhinitis was diagnosed at 7 and 13 years. Allergen exposure was defined as dog or cat in the home during the 3rd trimester of pregnancy or the first year of life and as allergen levels of dog, cat, and house dust mite in bed dust samples at 1 year. Associations between exposure and outcomes were analyzed by logistic regression and stratified for eczema status and test method (skin prick test and specific IgE).

RESULTS

We found no association between dog or cat exposure in perinatal life and sensitization or rhinitis during childhood. Similarly, there was no association between levels of allergens in bed dust samples and sensitization or rhinitis during childhood.

CONCLUSION

Perinatal indoor aeroallergen exposure does not seem to affect development of allergic sensitization or rhinitis during childhood questioning the relevance of allergen avoidance as a preventive measure. Other factors such as timing of allergen exposure or other environmental adjuvants may contribute in a more complex pathway to sensitization.

Atopic endotype in childhood

BACKGROUND

The term atopic disorder is an early attempt to define specific endotypes of children with asthma, eczema, or both and increased IgE levels.

OBJECTIVE

We performed a longitudinal analysis of the relevance of the atopic endotype from birth to age 13 years.

METHODS

Allergic sensitization against 28 inhalant and food allergens was assessed at ½, 1½, 4, 6, and 13 years of age in 399 children from the Copenhagen Prospective Study on Asthma in Childhood2000 birth cohort by using both skin prick test responses and specific IgE levels. Asthma and eczema were diagnosed longitudinally by strictly adhering to predefined algorithms. Associations between allergic sensitization, asthma, and eczema were estimated by means of logistic regression, and a machine learning approach was used to identify temporal phenotype clusters of these traits.

RESULTS

Allergic sensitization showed no association with asthma through early childhood (0-6 years) when analyzed as any sensitization (odds ratio [OR] range, 0.78-1.29; P ≥ .48). However, at 13 years of age, any sensitization was associated with asthma (OR range, 4.02-5.94; all P < .001). In contrast, any sensitization was associated with eczema at ½, 1½, and 6 years of age (OR range, 2.06-6.02; P ≤ .01) and borderline associated at 4 years of age (OR, 1.61 [95% CI, 0.96-2.69]; P = .07) but not at 13 years of age (OR, 1.57 [95% CI, 0.78-3.16]; P = .21). We identified 4 latent patterns of disease development that were either dominated by sensitization (37%), eczema (26%), asthma (14%), or healthy status (24%).

CONCLUSION

We found very little interdependency between asthma, eczema, and allergic sensitization through childhood. The associations between those entities were strongly dependent on age, type of allergens, and method of testing for sensitization. Therefore, atopy in children is unlikely to represent a true endotype.

Disagreement between skin prick test and specific IgE in young children

BACKGROUND

Skin prick test (SPT) and measurement of serum-specific IgE (sIgE) level are important tools for the clinician to diagnose allergic sensitization. However, little is known about the agreement between the two methods in young children.

METHODS

SPT and sIgE levels were assessed simultaneously for 16 common inhalant and food allergens at age ½, 1½, 4, and 6 years in 389 children from the Copenhagen Prospective Study on Asthma in Childhood2000 (COPSAC2000 ) at-risk birth cohort. Agreement between the two methods for diagnosing inhalant and food allergic sensitization at the four age points was analyzed using kappa statistics.

RESULTS

The prevalence of inhalant allergen sensitization increased during childhood diagnosed by both sIgE levels (0.6% to 4.2% to 18.1% to 24.8%, P < 0.0001) and SPT results (1.5% to 3.8% to 8.4% to 15.4%, P < 0.0001). In contrast, the prevalence of food sensitization increased during childhood when diagnosed from sIgE (7.8% to 12.1% to 15.0% to 18.9%, P < 0.0001), but decreased when diagnosed from SPT (5.3% to 5.1% to 3.7% to 3.0%, P = 0.05). Overall, the agreement between SPT and sIgE levels was poor to moderate (all κ-coefficients ≤ 0.60) and decreased from moderate to slight for food allergens by increasing age (κ-coefficients: 0.46 to 0.31 to 0.16 to 0.14).

CONCLUSION

There is a substantial disagreement between SPT and sIgE for diagnosing allergic sensitization in young children, which increases with age for food sensitization. Choice of assessment method therefore has major impact on results with wide implications for both clinical practice and research.

Urinary LTE4 levels as a diagnostic marker for IgE-mediated asthma in preschool children: a birth cohort study

Objectives

Leukotrienes play a central pathophysiological role in allergic asthma. The aim of this study was to investigate the utility of measuring urinary leukotriene E₄ (LTE₄) levels in the diagnosis of atopic diseases in early childhood.

Methods

Children aged 0 through 4 years from a birth cohort in the Prediction of Allergies in Taiwanese Children (PATCH) study were enrolled. Urinary LTE₄ levels were measured and its association between total serum IgE levels, allergen-specific IgE sensitization and atopic diseases were assessed.

Results

A total of 182 children were regular followed up at clinics for a four-year follow-up period. Urinary LTE₄ levels appeared to be elevated in children with total serum IgE levels exceeding 100 kU/L, allergen-specific IgE sensitization after 2 years of age. Elevation of urinary LTE₄ levels (≥500 pg/mg of creatinine) significantly discriminated high serum total IgE levels (≥100 kU/L) at age 2 (P = 0.027). A higher level of total serum IgE or urinary LTE₄ was significantly associated with the risk of developing allergic rhinitis and asthma at age 3. A significantly higher urinary LTE₄ level was found in children with a combination of IgE sensitization and asthma at age 4.

Conclusions

Urinary LTE₄ levels appear to be highly associated with IgE sensitization and its related allergic airway diseases after age 2. The measurement of urinary LTE₄ (≥500 pg/mg of creatinine) could not only be a non-invasive method for atopic predisposition but also potentially provide a strategy for the diagnosis and management of asthma in preschool children.

Low cord blood vitamin D levels are associated with increased milk sensitization in early childhood

BACKGROUND

The association between vitamin D status at birth and allergen sensitizations is uncertain. The aim of this study was to investigate the relationship between cord blood vitamin D status with allergen sensitizations and the development of atopic diseases in early childhood.

METHODS

Children aged 0 through 4 yr from a birth cohort in the Prediction of Allergies in Taiwanese Children (PATCH) study were enrolled. Serum levels of 25-hydroxyvitamin D (25(OH)D) in cord blood were measured by a new automated electrochemiluminescence-based assay. Specific IgE antibodies against food and inhalant allergens were measured at 6 months, and 1, 1.5, 2, 3, and 4 yr of age.

RESULTS

A total of 186 children were regular followed up at clinics for a 4-yr follow-up period. The mean level of cord blood 25(OH)D was 23.8 ± 9.5 ng/ml with a high prevalence of low vitamin D status (<20 ng/ml) at birth (42%). There was a tendency of low cord blood 25(OH)D levels being associated with higher risk of food sensitization throughout childhood. Cord blood 25(OH)D levels were inversely associated with the risk of milk sensitization at age 2, at which age a higher prevalence of milk sensitization was significantly associated with the risk of allergic rhinitis, and asthma development at age 4.

CONCLUSIONS

Low cord blood vitamin D levels appear to be associated with increased milk sensitization but not with asthma, eczema, or allergic rhinitis in early childhood.

Sensitization to food and inhalant allergens in relation to atopic diseases in early childhood: a birth cohort study

Objectives

A correct interpretation of sensitization to common allergens is critical in determining susceptibility to allergic diseases. The aim of this study was to investigate the patterns of sensitization to food and inhalant allergens, and their relation to the development of atopic diseases in early childhood.

Methods

Children aged 0 through 4 years from a birth cohort in the Prediction of Allergies in Taiwanese Children (PATCH) study were enrolled. Specific IgE antibody against food and inhalant allergens were measured and their association between total serum IgE levels and atopic diseases were assessed.

Results

A total of 182 children were regular followed up at clinics for a four-year follow-up period. The prevalence of food allergen sensitization increased markedly after 6 months of age, reaching up to 47% at 1.5 years of age and then declined significantly to 10% in parallel with a considerable increase in the prevalence of sensitization to inhalant allergens up to 25% at age 4. Food allergen sensitization appeared to be mainly associated with the elevation of serum total IgE levels before age 2. A combined sensitization to food and inhalant allergens had an additive effect on serum IgE levels after age 2, and was significantly associated with the risk of developing atopic diseases at age 4.

Conclusions

Sensitization to food occurs early in life, in parallel with the rising prevalence of sensitization to inhalant allergens at older age. A combined sensitization to food and inhalant allergens not only has an additive increase in serum IgE antibody production but also increases the risk of developing allergic respiratory diseases in early childhood.

Cord blood 25(OH)-vitamin D deficiency and childhood asthma, allergy and eczema: the COPSAC2000 birth cohort study

Background

Epidemiological studies have suggested an association between maternal vitamin D dietary intake during pregnancy and risk of asthma and allergy in the offspring. However, prospective clinical studies on vitamin D measured in cord blood and development of clinical end-points are sparse.

Objective

To investigate the interdependence of cord blood 25-hydroxyvitamin D (25(OH)-Vitamin D) level and investigator-diagnosed asthma- and allergy-related conditions during preschool-age.

Methods

Cord blood 25(OH)-Vitamin D level was measured in 257 children from the Copenhagen Prospective Studies on Asthma in Childhood (COPSAC₂₀₀₀) at-risk mother-child cohort. Troublesome lung symptoms (TROLS), asthma, respiratory infections, allergic rhinitis, and eczema, at age 0–7 yrs were diagnosed exclusively by the COPSAC pediatricians strictly adhering to predefined algorithms. Objective assessments of lung function and sensitization were performed repeatedly from birth.

Results

After adjusting for season of birth, deficient cord blood 25(OH)-Vitamin D level (<50 nmol/L) was associated with a 2.7-fold increased risk of recurrent TROLS (HR = 2.65; 95% CI = 1.02–6.86), but showed no association with respiratory infections or asthma. We saw no association between cord blood 25(OH)-Vitamin D level and lung function, sensitization, rhinitis or eczema. The effects were unaffected from adjusting for multiple lifestyle factors.

Conclusion

Cord blood 25(OH)-Vitamin D deficiency associated with increased risk of recurrent TROLS till age 7 years. Randomized controlled trials of vitamin D supplementation during pregnancy are needed to prove causality.

Suboptimal vitamin D status in a population-based study of Asian children: prevalence and relation to allergic diseases and atopy

Background

New evidence shows high prevalence of vitamin D deficiency in many countries and some studies suggest a possible link between vitamin D status and allergic diseases. The objectives of this study were to determine the prevalence of suboptimal vitamin D status in a population sample of Asian children and to investigate the relationship of vitamin D status with allergic diseases and atopy.

Methods

Children aged 5–18 years (N = 1315) in the Prediction of Allergies in Taiwanese CHildren (PATCH) study were evaluated using questionnaires, anthropometric measurements, and serum levels of 25-hydroxyvitamin D [25(OH)D] and total and specific immunoglobulin E (IgE).

Results

The mean concentration of serum 25(OH)D was 20.4 ng/mL (SD: 7.1 ng/mL). Vitamin D deficiency (defined as serum 25(OH)D<20 ng/mL) was present in 670 subjects (51.0%), while vitamin D insufficiency (defined as serum 25(OH)D<30 ng/mL) was observed in 1187 subjects (90.3%). Older age (P<0.001), female gender (P<0.001), higher body mass index (P = 0.001), winter and spring seasons (compared to summer; P both<0.001), and passive smoking (P = 0.011) were independently associated with low serum 25(OH)D levels. After adjusting for potential confounders, serum 25(OH)D status had no association with asthma, rhinitis, eczema, atopy, or total serum IgE (all P>0.05).

Conclusions

Low serum 25(OH)D levels are remarkably common in this population sample of Asian children, suggesting that millions of children living in Taiwan may have suboptimal levels of vitamin D, which should be a matter of public health concern. Our results provides epidemiological evidence against the association of vitamin D status with various allergic diseases and atopy in Asian children.

Determinants of allergic rhinitis in young children with asthma

Background

In the preschool period, allergic rhinitis (AR) is infrequent and thus under-diagnosed. However, recent works have highlighted the occurrence of AR in toddlers although the causes of AR in this young population remain unknown. The objective of this study was to identify determinants of AR in young children with asthma.

Methods

We carried out a case-control study of 227 children with active asthma and enrolled in the Trousseau Asthma Program. AR and other allergic diseases (asthma, food allergy and eczema) were diagnosed by medical doctors using standardized questionnaires. Parental history of AR and asthma, biological markers of atopy (total IgE, blood eosinophilia, allergic sensitization towards food and aeroallergens) and environmental parameters were also collected.

Results

Forty one of the children (18.1%) had AR. By univariate logistic regression analysis, AR was mainly associated with peanut sensitization (OR = 6.75; p = 0.002); food allergy (OR = 4.31; p = 0.026); mold exposure (OR = 3.81 p<0.01) and parental history of AR (OR = 1.42; p = 0.046). Due to the strong link between food allergy and peanut sensitization three models of multivariate logistic regression were performed and confirmed that AR is associated with peanut sensitization but also food allergy and mold exposure. A random forest analysis was also performed to explain AR. The results reinforced the logistic analysis that peanut sensitization and mold exposure were the principal determinants of AR.

Conclusions & Clinical Relevance

These results stress the importance of investigating AR in young children with asthma to potentially diagnose a particularly severe allergic asthmatic phenotype. Moreover, these data evoke the hypothesis that peanut could be an aeroallergen.

Total serum IgE in a population-based study of Asian children in Taiwan: reference value and significance in the diagnosis of allergy

Background

Total serum immunoglobulin (IgE) test is usually performed to aid in the diagnosis of allergic diseases, but its reference values may vary among people of different ethnic backgrounds.

Objectives

To establish reference values of total IgE in Asian children and to assess their significance in the diagnosis of atopy and allergic diseases.

Study design

1321 Asian children aged 5-18 years in the Prediction of Allergies in Taiwanese CHildren (PATCH) study, a population-based cohort, were evaluated for total and specific IgE by ImmunoCAP and Phadiatop Infant, respectively.

Results

Male, atopy, allergic diseases, recent symptoms of upper respiratory infection, and lower FEV₁/FVC, were associated with higher total IgE levels in univariate analyses. Multivariate analysis revealed that atopy was the single most important determinant explaining 66.1% of the variability of total IgE levels in this population. The area under the receiver-operator characteristic (ROC) curve of total IgE for diagnosing atopy, asthma, rhinitis, and eczema were 0.92, 0.72, 0.70, and 0.70, respectively. The sensitivity, specificity, and positive and negative predictive values of total IgE at the optimal cutoff of 77.7 kU/L on the ROC curve for diagnosing atopy were 82.3%, 87.1%, 89.5%, and 78.6%, respectively. The corresponding values using the upper 95% CI of total IgE (164.3 kU/L) in non-atopic children were 61.2%, 95.0%, 94.3%, and 64.6%, respectively; whereas a customary cutoff (100 kU/L) provided accuracy between that of the aforementioned two cutoffs. Total IgE at the cutoff of 77.7 kU/L provided modest sensitivity and specificity (49.0%-78.3%) for diagnosing allergic diseases, but had high negative predictive values (84.2%-97.9%).

Conclusions

Total serum IgE discriminates Asian children with and without atopy independent of allergic symptoms, with an optimal cutoff of 77.7 kU/L. The study confirms the insufficient diagnostic accuracy of total IgE alone to detect allergic diseases, but low total IgE levels may help exclude allergic diseases.

Cord blood Th2-related chemokine CCL22 levels associate with elevated total-IgE during preschool age

BACKGROUND

Early-life immune deviation is suspected in the inception of atopic disease.

OBJECTIVE

To investigate the association between cord blood chemokines and the subsequent development of atopic biomarkers and clinical end-points during the first 6 years of life.

METHODS

The Th1-associated chemokines CXCL10 and CXCL11 and the Th2-associated chemokines CCL17 and CCL22 were assessed in cord blood of asymptomatic at-risk newborn children from the Copenhagen Prospective Study on Asthma in Childhood (COPSAC(2000) ) birth cohort and associated with the longitudinal development of biomarkers and clinical end-points of asthma, eczema, and allergic rhinitis during the first 6 years of life.

RESULTS

Cord blood CCL22 levels were significantly associated to total-IgE levels measured at four time-points during the first 6 years of life; overall odds ratio, 1.54 [CI, 1.25-1.89; P < 0.0001]. CXCL10 and CXCL11 were not associated with development of any atopic disorders or biomarkers.

CONCLUSION AND CLINICAL RELEVANCE

High cord blood levels of the Th2 related chemokine CCL22 were significantly associated with high total- IgE levels during the first 6 years of life, but not with specific sensitization, asthma, eczema or allergic rhinitis. This suggests an inborn skewing of the immune system in healthy newborns developing elevated total- IgE later in life.

Comparison of three multiple allergen simultaneous tests: RIDA allergy screen, MAST optigen, and polycheck allergy

We compared the performances of 3 Multiple Allergen Simultaneous Test (MAST) assays: RIDA Allergy Screen (R-Biopharm, Darmstadt, Germany), MAST Optigen allergy system (Hitachi Chemical Diagnostics, Mountain View, CA), and Polycheck Allergy (Biocheck GmbH, Munster, Germany). Forty sera that tested positive with the RIDA Allergy Screen (20 for food and 20 for inhalant panel) were subjected to MAST Optigen and Polycheck Allergy. For 26 available sera with discrepant results, 62 ImmunoCAP allergen-specific IgE tests (Pharmacia Diagnostics, Uppsala, Sweden) were performed. Percent agreements (kappa value) were 87.6% (0.59) and 91.3% (0.60) between RIDA and MAST; 89.9% (0.55) and 88.3% (0.46) between RIDA and Polycheck; and 86.8% (0.51) and 90.6% (0.61) between MAST and Polycheck. Compared with ImmunoCAP, agreements (kappa value) of inhalant and food panels were 51.7% (0.04) and 33.3% (−0.38) for RIDA; 60.7% (0.27) and 81.8% (0.59) for MAST; and 65.5% (0.26) and 45.5% (0.07) for Polycheck. The agreements between RIDA, MAST, and Polycheck and ImmunoCAP-positivity were 45.7%, 88.2%, and 28.6%, respectively, and the agreements for ImmunoCAP-negativity were 37.0%, 51.9%, and 88.9%. MAST Optigen showed better agreement with ImmunoCAP than other assays in the food panel. Better sensitivity of MAST Optigen and better specificity of Polycheck Allergy were suspected.

Neonatal bronchial hyperresponsiveness precedes acute severe viral bronchiolitis in infants

BACKGROUND

Respiratory syncytial virus and other respiratory tract viruses lead to common colds in most infants, whereas a minority develop acute severe bronchiolitis often requiring hospitalization. We hypothesized that such an excessive response to respiratory tract viral infection is caused by host factors reflected in pre-existing increased bronchial responsiveness.

OBJECTIVE

We sought to compare bronchial responsiveness and lung function in 1-month-old neonates who later develop acute severe bronchiolitis with those who do not.

METHODS

We measured infant lung function (n=402) and bronchial responsiveness to methacholine (n=363) using the raised-volume rapid thoracoabdominal compression technique before any respiratory symptoms in 1-month-old neonates from the Copenhagen Prospective Study of Asthma in Childhood birth cohort born to mothers with asthma. The children were prospectively monitored for respiratory symptoms and given a diagnosis of acute severe bronchiolitis according to a fixed algorithm.

RESULTS

Thirty-four (8.5%) infants had acute severe bronchiolitis before 2 years of age, 21 (62%) were hospitalized, and 23 (67%) of the cases were associated with respiratory syncytial virus. Children who later had acute severe bronchiolitis irrespective of viral species had a 2.5-fold increased responsiveness to methacholine (provocative dose of methacholine producing a 15% decrease in transcutaneous oxygen pressure [PD(15)]) at age 1 month compared with control subjects (median PD(15) in cases vs control subjects, 0.13 vs 0.33 μmol; P=.01), whereas differences in baseline airflow were not significant for forced expiratory volume at 0.5 seconds (mean z score for cases vs control subjects, -0.18 vs -0.01; P=.36) and forced expiratory flow at 50% of forced vital capacity (mean z score for cases vs control subjects, -0.37 vs -0.09; P=.13).

CONCLUSION

Bronchial hyperresponsiveness in at-risk neonates precedes acute severe bronchiolitis in response to infections with respiratory tract virus.

Phadiatop Infant(®) detects IgE-mediated diseases among pre-school children: a prospective study

BACKGROUND

IgE-sensitization to food and inhalant allergens may precede and accompany the appearance of clinical symptoms of allergic diseases. The aim was to study the diagnostic capacity of Phadiatop(®) Infant (Phinf) for detecting IgE-sensitization at 5 yr of age and further to evaluate the predictive capacity of Phinf longitudinally with regard to sensitization and allergic symptoms in pre-school children.

METHODS

Two hundred and one children with complete data on sIgE testing for 10 individual allergens, Phinf analyses, and clinical evaluations at 2 and 5 yr of age were evaluated.

RESULTS

The diagnostic performance of Phinf, applied at the age of 5 and compared to specific IgE testing, gave a sensitivity of 84% and a specificity of 98%. The positive and negative predictive values were 97% and 92%, respectively. A positive Phinf test at 2 yr increased the odds 35.6-fold (95% CI 11.8-107) for IgE-sensitization and 14.7-fold (95% CI 4.4-49.7) for any allergic symptom at 5 yr of age. The association (OR) between Phinf and current symptoms was, at 2 and 5 yr of age, 3.6 (95% CI 1.6-7.9) and 18.4 (95% CI 7.4-45.8), respectively.

CONCLUSIONS

Phinf seems to be a reliable tool for predicting future sensitization as well as allergic symptoms in young children.

Overview of serological-specific IgE antibody testing in children

Allergic diseases are among the most common chronic conditions in the pediatric population. Allergy diagnostic testing is an important part of the evaluation/management of allergic patients because the history may not be precise enough to identify the specific allergen sensitivity. In addition to providing information about specific sensitivities, allergy diagnostic tests have some predictive value in terms of future risk of developing an allergic condition and the severity/persistence of the allergic disease. The two most commonly used methods of confirming allergen sensitization are skin testing and measurement of serum-specific IgE. Both methods have similar diagnostic value in terms of sensitivity and specificity, with both parameters varying with the clinical scenario and allergen tested. Currently, there are three US Food and Drug Administration-cleared, serum-specific IgE assays used in the United States. The three assays report comparable analytic sensitivity, with the coefficients of variation of the precision, reproducibility, and linearity being less than 15%. However, comparative studies have demonstrated significant inter-assay variability, suggesting that they detect different populations of IgE antibody in human sera or do not measure the same antibodies with the same efficiency. Current specific IgE assays utilize allergen extract reagents. Testing with these reagents may identify sensitivity to clinically irrelevant allergens. This diagnostic limitation has spurred the development of molecular diagnostic tests, also referred to as component-resolved diagnostics, which utilize purified native or recombinant allergens to detect IgE sensitivity to individual allergen molecules. These advancements in serum IgE testing may enhance the precision of allergy diagnostic testing, which may decrease the need for oral food challenges and improve the specificity of allergen immunotherapy.

Elevated eosinophil protein X in urine from healthy neonates precedes development of atopy in the first 6 years of life

RATIONALE

Biomarkers predicting development of atopic disease are needed for targeted preventive measures and to study if disease pathology may be active before onset of symptoms.

OBJECTIVES

To investigate whether eosinophil protein X, leukotriene-C4/D4/E4, and 11β-prostaglandin (PG) F2α (PGD2 metabolite) assessed in urine from healthy at-risk neonates precede development of atopic disease during the first 6 years of life.

METHODS

We measured eosinophil protein X (n = 369), leukotriene-C4/D4/E4 (n = 367), and 11β-PGF2α (n = 366) in urine from 1-month-old children participating in the Copenhagen Prospective Studies on Asthma in Childhood birth cohort. Clinical data on development of allergic sensitization, allergic rhinitis, nasal eosinophilia, blood eosinophilia, eczema, troublesome lung symptoms (significant cough or wheeze or dyspnea), and asthma were collected prospectively until age 6 years. Associations between urinary biomarkers and development of atopic traits were investigated using general estimating equations, logistic regression, and Cox regression.

MEASUREMENTS AND MAIN RESULTS

Eosinophil protein X in the urine of the asymptomatic 1-month-old neonates was significantly associated with development of allergic sensitization (odds ratio, 1.49; 95% confidence interval [CI], 1.08–1.89), nasal eosinophilia (odds ratio, 3.2; 95% CI, 1.2–8.8), and eczema (hazard ratio, 1.4; 95% CI, 1.0–2.0), but not with allergic rhinitis, asthma, or blood eosinophilia. Neither leukotriene-C4/D4/E4 nor 11β-PGF2α was associated with any of the atopic phenotypes.

CONCLUSIONS

Eosinophil protein X in urine from asymptomatic neonates is a biomarker significantly associated with later development of allergic sensitization, nasal eosinophilia, and eczema during the first 6 years of life. These findings suggest activation of eosinophil granulocytes early in life before development of atopy-related symptoms.

Allergy testing in childhood: using allergen-specific IgE tests

A variety of triggers can induce common pediatric allergic diseases which include asthma, allergic rhinitis, atopic dermatitis, food allergy, and anaphylaxis. Allergy testing serves to confirm an allergic trigger suspected on the basis of history. Tests for allergen-specific immunoglobulin E (IgE) are performed by in vitro assays or skin tests. The tests are excellent for identifying a sensitized state in which allergen-specific IgE is present, and may identify triggers to be eliminated and help guide immunotherapy treatment. However, a positive test result does not always equate with clinical allergy. Newer enzymatic assays based on anti-IgE antibodies have supplanted the radioallergosorbent test (RAST). This clinical report focuses on allergen-specific IgE testing, emphasizing that the medical history and knowledge of disease characteristics are crucial for rational test selection and interpretation.

Associations of age, gender, and BMI with prevalence of allergic diseases in children: PATCH study

BACKGROUND

Little is known about the prevalence of allergic diseases in children of different ages. This study aimed to investigate the prevalence of allergic diseases and allergic sensitization in children over a wide age range, with emphasis on the influence of age, gender, and body mass index (BMI).

METHODS

In a cross-sectional study, we assessed 5351 Taiwanese children aged 4-18 years using an International Study of Asthma and Allergies in Childhood questionnaire, BMI, and total and specific serum immunoglobulin E.

RESULTS

Forty-eight percent were currently symptomatic for at least one of three allergic diseases. Prevalence of wheeze ever, current wheeze, and diagnosed asthma were 17.0%, 7.5%, and 9.8%, respectively; analogous features for rhinitis were 47.8%, 44.2%, and 39.8%. Allergic sensitization was very common (57.3%). Half of the children (50.6%) with current wheeze had not been diagnosed with asthma by physicians, whereas undiagnosed rates were 32.3% for rhinitis and 25.3% for eczema. The male-to-female prevalence ratios of current wheeze increased with age from <1 at 4-5 years, peaked at 10-11 years (2.24), then reversed to 0.57 at 16-18 years. Childhood wheezing tended to remit with age, but rhinitis and eczema were more persistent. Total immunoglobulin E levels increased with age until 14-15 years, and declined thereafter. Elevated BMI was associated with greater prevalence of wheezing and eczema, with no evidence of significant effect modification by either gender or age. Multivariate analyses revealed that younger age, boys, and obesity were significantly and independently associated with current wheezing in children (all p < .01).

CONCLUSIONS

The burden and co-morbidity of childhood allergies are substantial. There are striking age-dependent gender differences in asthma prevalence, exhibiting an inverted U-shaped curve for male-to-female prevalence ratios by age. Obesity is associated with a greater prevalence of asthma in children with no evidence of a significant modulation by either gender or age.

[Diagnostic value of exhaled nitric oxide measurement in mild asthma]

OBJECTIVES

To assess the diagnostic value of fractional exhaled nitric oxide (FE(NO)) in mild asthma.

MATERIAL AND METHODS

Cross-sectional descriptive study in a group of patients with no history of respiratory or allergic illness (control group) and a group of patients with a history of mild asthma with no baseline treatment (asthma group), both aged 6 to 14 years. The following examinations were performed: measurement of FE(NO) using the portable NIOX MINO(®) device, allergy tests and spirometry. Repeatability of paired FE(NO) measurements was estimated with the intraclass correlation coefficient, the repeatability coefficient and the variation coefficient. The diagnostic value was assessed with the sensitivity, specificity, area under the ROC curve and positive likelihood ratio (LR+) for each cut-off point.

RESULTS

Eighty-seven patients were included in the control group and 57 in the asthma group. The mean FE(NO) value was 12.1 ppb (SD 13.5) in the control group and 42.9 ppb (SD 24.5) in asthmatics (P<.001). The intraclass correlation coefficient was 0.98 (95% CI: 0.96-0.99) and of 0.97 (95% CI: 0.92-0.99) in controls and asthmatics, respectively. The repeatability coefficient was 5.5 in controls and 9.2 in asthmatic children, and the median variation coefficient was 8.3% and 6.1%. The optimal cut-off value for FE(NO) was 19 ppb (sensitivity and specificity were 91.4% and 87.2%, respectively). The area under the ROC curve was 0.93 (95% CI: 0.88-0.97) (P<.001) and the LR+ was 7.1. Subclinical sensitisation to pneumoallergens accounted for most false positive cases.

CONCLUSIONS

The determination of FE(NO) with NIOX MINO(®) has an adequate repeatability, especially for healthy patients. For asthmatic patients we recommend determining the average of two measurements. The test has a high diagnostic value in mild asthma. Subclinical sensitisation to pneumoallergens can cause the FE(NO) value to rise to pathologic levels.