Serum eosinophil cationic protein (ECP): reference values in healthy nonatopic children

Eosinophil-derived neurotoxin levels in early childhood and association with preschool asthma - A prospective observational study

INTRODUCTION

Eosinophil-derived neurotoxin (EDN) is related to childhood asthma, while normal values are lacking. We aimed to document serum EDN levels at 1 and 3 years in general and in non-atopic children, and explore if EDN levels differed by sex or were associated with preschool asthma at 3 years.

METHODS

From the PreventADALL birth cohort, we included 1233 children with EDN analysed using ImmunoCAP at 1 and/or 3 years. Non-atopic children had no history of wheeze, asthma, allergic sensitization or atopic dermatitis. Preschool asthma was defined as having ≥3 episodes of bronchial obstruction between 2 and 3 years, plus doctor diagnosed asthma and/or asthma medication use by 3 years. The upper limit of normal (ULN) of EDN was defined as the 95th percentile. With Youden Index we calculated EDN cut-off levels for risk of preschool asthma.

RESULTS

The overall median (ULN) EDN levels were 27.4 (121) μg/L at 1 year (n = 787), and 20.1 (87.8) μg/L at 3 years (n = 857). Non-atopic children had EDN levels of 24.0 (107) μg/L at 1 year (n = 147), and 17.3 (84.6) μg/L at 3 years (n = 173). EDN levels were higher in boys compared to girls; 32.0 (133) versus 24.5 (97.0) μg/L at 1 year, and 20.9 (96.3) versus 19.0 (72.4) μg/L at 3 years. Preschool asthma was observed in 109/892 (12.2%) children. Higher EDN levels at 1 (>26.7 μg/L) and 3 (≥20.5 μg/L) years were associated with preschool asthma; adjusted OR (95% CI) 2.20 (1.09, 4.41) and 4.68 (2.29, 9.55), respectively.

CONCLUSION AND CLINICAL RELEVANCE

We report EDN values in early childhood, demonstrating higher levels at 1 compared to 3 years and in boys compared to girls at both ages. Higher EDN levels at both ages were associated with preschool asthma. However, EDN cut-off levels for preschool asthma were overall lower than the ULN of non-atopic children, limiting translation into clinical practice.

Soluble immune receptor serum levels are associated with age, but not with clinical phenotype or disease severity in childhood atopic dermatitis

BACKGROUND

Soluble immune receptors (SIRs) have been proposed as biomarkers in patients with atopic dermatitis (AD). However, their clinical applicability in affected children has rarely been studied.

OBJECTIVE

To assess the diagnostic usefulness of serum SIRs in childhood AD by correlating the obtained receptor profiles with serological parameters and clinical features such as age, AD phenotype and disease severity.

METHODS

We investigated 100 children with AD. The sCD14, sCD23, sCD25, sCD30, total IgE (tIgE) and eosinophilic cationic protein (ECP) were determined using sera of all children. The clinical phenotype was classified as extrinsic AD (ADe) or intrinsic AD (ADi) by the presence of allergen-specific IgE antibodies.

RESULTS

A total of 55 male and 45 female children were recruited. The sCD23, sCD25 and sCD30 serum levels revealed significant age-dependency. At a mean SCORAD of 40 (range 8-98), none of the evaluated SIRs was correlated to disease severity. In all, 73% of patients suffered from ADe while 27% showed the ADi phenotype. None of the analysed SIRs differed significantly between ADe and ADi patients, while tIgE and ECP levels were elevated in the ADe subgroup.

CONCLUSION

The current study provides evidence that sCD23, sCD25 and sCD30 serum levels are highly age-dependent. Serum concentrations of all investigated SIRs did not significantly correlate with disease severity in children with AD and were not differentially expressed in patients of different AD phenotypes. Therefore, we believe that the studied SIRs cannot be regarded as clinically useful biomarkers for the assessment of childhood AD.

Nocturnal enuresis and allergy

OBJECTIVE

To investigate whether an interaction exists between nocturnal enuresis and allergy.

MATERIAL AND METHODS

Thirty-seven (20 boys, 17 girls) children with monosymptomatic nocturnal enuresis were recruited. We studied an allergy panel that included total IgE, 10 examples of inhalant-specific IgE, 10 examples of food-specific IgE, eosinophilic cationic protein (ECP) and Phadiotop. The same panel was studied in a control group of 18 children without monosymptomatic nocturnal enuresis.

RESULTS

We did not determine statistically significant differences between the enuretic group and the control group in terms of levels of total IgE, the 10 examples of inhalant-specific IgE and Phadiotop. However, two (soybean and hazelnut) of the 10 food-specific IgE and ECP levels did differ significantly between the two groups.

CONCLUSIONS

This first specific IgE study showed that there may be a relationship between nocturnal enuresis and soybean and hazelnut food allergens. Our findings may explain some cases of nocturnal enuresis. However, further studies are necessary to explain the underlying mechanisms and management of this disorder.

Relationships between cotinine, lower respiratory tract infection, and eosinophil cationic protein in children

INTRODUCTION

The aim of this study was to investigate the effect of passive smoking on urine eosinophil cationic protein (u-ECP) in children with lower respiratory tract infections (LRTI).

METHOD

This was a case-control study. The study cohort consisted of 150 children with LRTI (case group) and 150 healthy children (control), all from a urban setting. The statistical parameters were: a minimum of 139 children for a 95% confidence interval (95% CI), 80% power, and a possible exposure prevalence of 50%. The u-cotinine and u-ECP levels were measured by radioimmunoassay and fluoroimmunoassay methods, respectively. Data were analyzed by the McNemar chi-square test, t-test, and Pearson correlation.

RESULTS

When the generally accepted cut-off level of 30 ng/mg urinary cotinine/creatinine was applied, 87.3% of the children with LRTI and 84.7% of healthy children were passive smokers. Using a cut-off level of 60 ng/mg, passive smoking increased the prevalence of LRTI by 4.7-fold (p=0.000). The mean u-ECP values were significantly higher in the case group than in the healthy control group (p=0.018). A positive association was found between u-cotinine and u-ECP values in children with LRTI (p=0.034).

CONCLUSION

The results of this study indicate that passive smoking may play an important role in the development of respiratory infections and can cause airway inflammation in children with existing LRTI.

Serum eosinophil cationic protein in children with atopic dermatitis

BACKGROUND

Eosinophil cationic protein (ECP) is a cytotoxic agent secreted by activated eosinophils during allergic and inflammatory processes. The aim of the study was to determine the ECP level, absolute and relative eosinophil count and IgE antibodies in children with atopic dermatitis (AD) compared with those of nonatopic children, and to assess the correlation of these laboratory parameters with the clinical severity of AD.

METHODS

This prospective study comprised 70 children. There were 49 children with AD aged 3-36 months, and the control group comprised 21 children with a negative personal and family history for atopic diseases. Detailed history, serum ECP levels (UniCAP FEIA), relative and absolute eosinophil counts and total serum IgE antibodies were determined in both groups. In the children with AD, skin involvement was measured by the SCORAD index.

RESULTS

The calculated SCORAD index was between 16 and 83. IgE antibodies, relative and absolute eosinophil counts showed a significantly wider range of values and a statistically higher median (P < 0.001) in the patients with AD compared with the control group. These laboratory parameters did not correlate with the severity of AD. The serum ECP median level, in the children with AD, was 16.2 microg/L (range 3.01-65.30) compared with 5.92 microg/L (range 2.76-21.90) in the control group. Correlation of the total SCORAD index and the serum ECP levels was negative, weak (r = -0.065) and statistically not significant (P > 0.05). The same was found for the correlation of serum ECP and intensity of skin changes (r = -0.095) and serum ECP and subjective symptoms (r = -0.045). The correlation was positive, but weak and statistically not significant for the serum ECP and extent of the skin lesions (r = 0.079, P > 0.05).

CONCLUSION

Elevated levels of ECP, relative and absolute eosinophil counts, as well as IgE antibodies were determined in the patients with AD. As these laboratory findings did not correlate with the severity of AD, they can be considered only as additional methods in the evaluation of patients with AD.

Salbutamol prevents the increase of respiratory resistance caused by tracheal intubation during sevoflurane anesthesia in asthmatic children

Asthmatic children having their tracheas intubated with sevoflurane often have an increase in respiratory system resistance (Rrs). In this randomized, placebo-controlled, double-blinded study, we investigated the protective effect of an inhaled beta2-adrenergic agonist. Either salbutamol or placebo was administered 30 to 60 min before anesthesia to 30 mildly to moderately asthmatic children scheduled for elective surgery. Induction was performed with sevoflurane in a mixture of 50% nitrous oxide in oxygen and maintained at 3%, with children breathing spontaneously via a face mask and Jackson-Rees modification of the T-piece. Airway opening pressure and flow were measured before and after insertion of an oral endotracheal tube. Rrs and respiratory system compliance were calculated with multilinear regression analysis. The groups were comparable with respect to age, weight, asthma history, and breathing pattern. Intubation induced a different Rrs response in the two groups: children treated with salbutamol showed a 6.0% (-25.2% to +13.2%) decrease (mean, 95% confidence interval), whereas in the Placebo group there was a 17.7% (+4.4% to +30.9%) increase (P = 0.04). Neither asthma history nor the serum inflammation marker eosinophilic cationic protein was predictive for this response. We conclude that when using sevoflurane in mildly to moderately asthmatic children, a preanesthetic treatment with inhaled salbutamol is protective of an increase in Rrs.

IMPLICATIONS

Tracheal intubation with sevoflurane as the sole anesthetic is now often performed in children. It can induce an increase in respiratory system resistance in children with asthma. This study shows that in children with mild to moderate asthma, a preanesthetic treatment with inhaled salbutamol can prevent the increase of respiratory system resistance.

Higher serum eosinophil cationic protein levels in children with cow's milk allergy

BACKGROUND

In the pathogenesis of cow's milk allergy, abnormal immunologically mediated reactions play a basic role. Eosinophil activation also participates in the development of several allergies. The purpose of this study was to characterize the degree of this activation by measuring the serum level of eosinophil cationic protein (sECP) and establishing whether it is a useful parameter in monitoring oral cow's milk allergy.

METHODS

The sECP level of 35 patients with previously confirmed cow's milk allergy (mean age, 16 months) was evaluated using a fluoroimmunoassay before the cow's milk rechallenge test and at 2 hours and 24 hours after cow's milk challenge.

RESULTS

Of the 35 children with previously confirmed cow's milk allergy, 10 had positive clinical reactions after the milk rechallenge test, whereas 25 children had no reaction. The median sECP level of all the patients before the challenge test was significantly higher (12.4 microg/L) than that of the control group (4.3 microg/L) (P < 0.05). Two hours after the challenge, the median sECP of all patients (9.4 microg/L) was lower than the starting values. The median sECP levels were higher in children with positive challenge test results at all time points. However, this difference was not statistically significant.

CONCLUSIONS

The normalization of sECP level may indicate the cessation of the cow's milk allergy. Therefore, the measurement of sECP may be helpful in determining the optimal time in which to repeat the challenge test, when the result will more likely be negative. The significant decrease of the sECP level 2 hours after the beginning of milk challenge test may be explained by the fact that this protein is excreted into the intestinal lumen.

Diagnostic value of skin-prick and patch tests and serum eosinophil cationic protein and cow's milk-specific IgE in infants with cow's milk allergy

The diagnosis of cow's milk allergy is based on a clinical response to an elimination-challenge test with cow's milk. We studied the usefulness of the skin-prick and patch tests and measurement of cow's milk-specific IgE and eosinophil cationic protein in serum as diagnostic tools for cow's milk allergy in a cohort of 6209 unselected infants followed from birth for the development of cow's milk allergy. Of the 239 infants challenged with cow's milk, 118 showed a positive and 121 a negative response at a mean age of 6.9 months. A positive reaction to a skin-prick test with cow's milk (> or = 3 mm) was seen in 72 (61%) and 29 (24%) infants with positive and negative challenges, elevated serum cow's milk-specific IgE (> or = 0.7 kU/L) in 52 (45%) and 15 (13%) infants, a positive reaction to patch test with cow's milk protein fractions in 26 (26%) and eight (8%) infants, and elevated serum eosinophil cationic protein (> or = 20 microg/L) in 22 (21%) and seven (13%) infants, respectively. Parallel use of the four tests with the above-mentioned cut-off values correctly classified 73% of the infants with a sensitivity of 0.76 and a specificity of 0.67. An immediate reaction to cow's milk challenge correlated with skin prick test positivity and elevated serum milk-specific IgE, and tended to correlate with patch test positivity. No single test or parallel use of the four tests could predict the challenge outcome acceptably in this prospectively followed, unselected cohort of 6209 infants. A positive reaction to one or more tests needs to be confirmed by a challenge test and a negative response to all four tests does not rule out the possibility of cow's milk allergy.

Eosinophil cationic protein (ECP) in school children living in a mountainous area of Norway: a population-based study of ECP as a tool for diagnosing asthma in children with reference values

BACKGROUND

Most previous studies on eosinophil cationic protein (ECP) have been performed on carefully selected groups of asthmatic patients. Few studies based upon population cohorts have been reported. The primary objective of the present study was to assess the usefulness of serum eosinophil cationic protein (s-ECP) in the diagnosis of asthma in schoolchildren and determine reference values based on measurements in healthy children.

METHODS

The population consisted of 216 schoolchildren (aged 7-16 years) who in a previous questionnaire had reported asthma or asthma-like symptoms and a control group. The questionnaire study comprised the entire population of schoolchildren in Upper Hallingdal. After clinical assessment, blood samples, and skin prick tests, these subjects were then reclassified into four groups: atopic and nonatopic asthmatic and nonasthmatics. S-ECP was assessed in relation to atopy, asthma severity, allergen exposure, and sex.

RESULTS

The asthma group (n = 105) had significantly higher mean s-ECP level than the nonasthma group (n = 111) (13.3 vs 8.3 microg/l, P < 0.001), with no significant difference between atopic asthmatics and atopic nonasthmatics. Mean s-ECP levels in children with mild, moderate, or severe asthma were 12.1, 18.5, and 12.2 microg/l, respectively. The children with animal dander allergy demonstrated higher levels of s-ECP than children without this allergy (12.9 vs 9.1 microg/l, P = 0.001). The upper reference limit (determined as the 95th percentile in healthy children) of 19.1 microg/l, showed low sensitivity (24%) and high specificity (93%) for the diagnosis of asthma. The positive and negative likelihood ratios for the asthma diagnosis were found to be 3.2 and 0.83, respectively.

CONCLUSIONS

The highest s-ECP values were found among children with moderate asthma. Animal dander allergy resulted in elevated s-ECP. However, mean values were still below the reference value of 19.1 microg/l, and the sensitivity was low, suggesting that s-ECP is not a useful parameter for diagnosing asthma in population-based studies.

Inflammatory mediators in blood and urine

Inflammation plays a major role in the pathophysiology of asthma. Therefore, monitoring of the disease and its management preferably should include assessment of mediators of airways inflammation. Much interest has been focused on using eosinophil granule proteins in blood and urine as markers of asthma inflammation. The eosinophil granule proteins are important mediators in allergic inflammation. They often function well as inflammatory markers when used in controlled clinical studies, and are therefore useful research tools. With urinary eosinophil-derived protein X (EPX) venous blood sampling is avoided. Disadvantages which limit usefulness in clinical practice are overlap between values in patients and controls, a rather weak correlation to traditional lung function variables, elevation of levels by concurrent allergic disease, and the delay between sampling and test results. Urinary excretion of leukotriene E4 (LTE(4)) reflects the production of cysteinyl leukotrienes, which are major mediators in asthma. The excretion of LTE4 possibly reflects lung function better than serum ECP. In the future, monitoring of cytokines may be used in clinical asthma to monitor control and aid in the prognosis of the disease in the young child. Techniques for simple and rapid monitoring of key type 1 and type 2 cytokines are needed.