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

BACKGROUND: Although serum ECP concentrations have been reported in normal children, there are currently no published upper cutoff reference limits for serum ECP in normal, nonatopic, nonasthmatic children aged 1-15 years. METHODS: We recruited 123 nonatopic, nonasthmatic normal children attending the Royal Belfast Hospital for Sick Children for elective surgery and measured serum ECP concentrations. The effects of age and exposure to environmental tobacco smoke (ETS) on the upper reference limits were studied by multiple regression and fractional polynomials. RESULTS: The median serum ECP concentration was 6.5 microg/l and the 95th and 97.5 th percentiles were 18.8 and 19.9 microg/l. The median and 95th percentile did not vary with age. Exposure to ETS was not associated with altered serum ECP concentrations (P = 0.14). CONCLUSIONS: The 95th and 97.5 th percentiles for serum ECP for normal, nonatopic, nonasthmatic children (aged 1-15 years) were 19 and 20 microg/l, respectively. Age and exposure to parental ETS did not significantly alter serum ECP concentrations or the normal upper reference limits. Our data provide cutoff upper reference limits for normal children for use of serum ECP in a clinical or research setting.     

Serum eosinophil cationic protein in the evaluation of asthma severity in children

To assess the sensitivity and specificity of serum eosinophil cationic protein (ECP) in the diagnosis of asthma and evaluation of asthma severity, we conducted a prospective study to compare parameters of asthma severity, peripheral blood eosinophilia, and serum ECP concentrations in 88 children presenting to a university hospital outpatient clinic with suspected ( n =59) or recently diagnosed asthma ( n =29). Serum ECP correlated significantly (r²=0.676. P=0.0001) with peripheral eosinophil counts, but only weakly with asthma severity (r,=0.21, P=0.046). Serum ECP was significantly higher in atopic children (25±11 μg/l) than in nonatopic children (16±15 μg/l) iP=0.01). Bronchial hyperresponsiveness had no significant correlation (r_s=-0.21, P=0.30) with serum ECP Lung function test results had no (peak flow) or only a weak (FEV) correlation with serum ECP. In distinguishing between children with and without asthma or in assessing asthma severity, serum ECP is not superior to the peripheral blood eosinophil count. The diagnostic sensitivity and specificity of ECP in serum for detecting symptomatically active asthma, evaluated against the cutoff level of ECP in serum of 16 mg/1, were 54% and 71%, respectively.     

Serum eosinophil cationic protein (ECP) as a marker of disease activity and treatment efficacy in seasonal asthma

This study was carried out to determine whether serum eosinophil cationic protein (ECP) represents a sensitive marker for disease activity in atopic asthmatic patients during the pollen season. The study, in double-blind fashion, was performed between February and June 1994. Two groups of 10 seasonal asthmatic patients randomly received two different treatments. The first group was treated with inhaled beclomethasone dipropionate (BDP) 500 μg bid; the second received a matched placebo (P). At the beginning and every month, blood samples for determination of ECP and eosinophil count were collected and lung function (FEV₁) and methacholine responsiveness (PD₂₀) were performed. Subjects recorded daily symptoms of asthma, salbutamol consumption, and peak expiratory flow (PEF) values. In the P group, all indices, except FEV₁, showed significant changes during the pollen season ( P < 0.001). In the BDP group, significant changes were detected for symptom score ( P < 0.01), salbutamol consumption ( P < 0.01), and eosinophil number ( P < 0.05). Between the two groups, significant differences for symptom score ( P < 0.001), salbutamol consumption ( P < 0.001), ECP levels ( P < 0.05), eosinophil count ( P < 0.02), PD₂₀ methacholine ( P < 0.02), and PEF values ( P < 0.01) were detected. Changes in serum ECP significantly correlated with changes in other parameters ( P < 0.001), except FEV₁. Our results provide evidence that serum ECP is a sensitive marker for monitoring of the disease activity in seasonal asthma. Furthermore, it may offer a useful tool for estimating treatment efficacy.     

支气管哮喘患者血清嗜酸细胞阳离子蛋白的变化

探讨检测血清嗜酸细胞阳离子蛋白在支气管哮喘的诊断１病情监测及疗效判断中的价值。方法采用荧光酶免疫法测定了发作期和缓解哮喘患者各２０例,慢性阻塞性肺疾病患者１６例和正常人２０例的血清ＥＣＰ,同时进行了肺功能测定,并对发作期哮喘患者在给予吸入皮质激素治疗３ｍｏ后复测其ＥＣＰ及肺。     

Eosinophil cationic protein(ECP) and eosinophil protein X (EXP) concentrations in serum and bronchial lavage fluid in asthma. effect of prednisolone treatment.

Background Eoswinophil granule proteins may contribute to hyperresponsiveness in asthma.
Objective To measure eosinophil cationic protein (ECP) and eosinophil protein X (EPX) in sereum and bronchial lavage fluid from 20 asthmatics and 16 control subjects. To asses the effect on these eosinophil proteins of corticosteroid treatment of asthma. To determine ehether serum ECP and EPX measured weekly in a longitudina study for 10 weeks reflected changes in lung function.
Methods Eosinophil granule proteins were measured by radiommunoassy of bronchial wash (BW), bronchoalveolar lavage (BAL) serum.
Results Eosinophils were elevated in BAL (P<0.01) , BW (P<0.01) and blood (P<0.01) from asthmatic compared with control subjects. Eosinophil cationic protein concentration was significantly elevated in BAL (P<0.05) and BW from asthmatics (P<0.01) and EPX was increased in BAL (P<0.05) and BW (P<0.01) . These changes were also reflected in elevated serum ECP (P<0.01) and EPX (P<0.01) concentrations is asthmatic subjects. There was no significant difference between sujects receiving prednisolone and the placebo group, but there was a fall in ECP in BW (P<0.05) and serum (P<0.01) and in EPX in BW (P<0.01) and serum (P<0.01) within the group receiving prednisolone. In the longitudinal study there was only significant difference between ECP values associated with highest and lowest peak expiratory flow rate (PEFR) (P<0.05).
Conclusion These data confirm a role for cosinophil activation in the airway in asthma pathogenesis, and add some support to the hypothesis that corticosteroids may inhibit cosinophil activation in asthma.     

Intracellular expression and serum levels of eosinophil peroxidase (EPO) and eosinophil cationic protein in asthmatic children

BACKGROUND: Eosinophils are involved in the chronic inflammatory response in asthma and their basic proteins are thought to play a major pathophysiological role in this process. While serum levels of basic proteins have been used to monitor the ongoing allergic disease, little is known about the intracellular expression of these proteins in clinical situations. OBJECTIVE: The aim of the study was to determine the intracellular expression of eosinophil cationic protein (ECP) and eosinophil peroxidase (EPO) in asthmatic children and control subjects and relate it to serum levels of both proteins, lung function tests and immunoglobulin (Ig)E levels. METHODS: Serum ECP and EPO concentrations were determined by immunoassays in 13 asthmatic children (mean age: 9 +/- 1 years, mean FEV1: 92 +/- 10% predicted, geometric mean PC20 histamine 0.5 mg/mL) and 10 age-matched, healthy control subjects. A flow cytometric single cell assay was employed to detect intracellular ECP and EPO in peripheral blood eosinophils. RESULTS: While serum concentrations of both ECP (asthma: median 15.0 microg/L [range 3.6-57.7] vs control: 5.9 microg/L [2.7-9.1]; P = 0.02) and EPO (22.9 microg/L [5.2-82.5] vs 7. 2 microg/L [2.5-12.7]; P = 0.008) were significantly elevated in asthmatics, the intracellular expression of ECP and EPO (measured as mean fluorescence intensity) was decreased (EG1: 55.3 [17.7-120.8] vs 100.3 [46.5-264.4]; P = 0.01; EG2: 80.2 [24.1-135.3] vs 133.7 [32. 1-244.9]; P = 0.04 and EPO: 49.7 [23.1-155.8] vs 94.9 [28.8-115.2]; P = 0.03). In asthmatics there was a significant correlation of FEV1 with intracellular ECP and of bronchial hyperresponsiveness with serum EPO and ECP. Furthermore, total IgE levels were positively correlated with serum EPO only. CONCLUSION: We conclude that in asthmatics the intracellular content of ECP and EPO in peripheral eosinophils is reduced possibly due to degranulation. Epitope masking in activated eosinophils or a shift to early bone marrow-derived progenitors with less granule proteins are further possible explanations.     

Measurements of ECP in serum and the impact of plasma coagulation

Serum measurement of ECP (eosinophil cationic protein) is used as an indication of eosinophil activation in diseases such as asthma. The levels are dependent on sample handling, since a certain amount of ECP is released during storage. The mechanisms that induce this in vitro release are not known, but are supposed to be related to the coagulation process. The aim of this study was to investigate this further. ECP was measured in EDTA plasma and serum at 22 and 37 degrees C from healthy individuals and patients with asthma and allergy. The serum levels of ECP increased with temperature. Recalcification of citrated plasma in the presence of granulocytes with increasing concentrations of Ca(2+) showed a dissociation between the levels of ECP and the occurrence of coagulation. Further experiments indicated that plasma coagulation is not of any importance for the degranulation of eosinophils, nor did the addition of platelets or mononuclear cells affect the ECP levels. Incubations of granulocytes with fresh or frozen plasma and Ca(2+) suggested the existence of a freezing labile factor in plasma, necessary for the degranulation of healthy eosinophils, but not for allergic/asthmatic eosinophils. Further experiments with pure eosinophils indicated the existence of factors in serum and plasma which facilitate ECP secretion of an active, temperature-dependent nature. We conclude that the raised ECP levels in serum, as compared to EDTA plasma, are unrelated to the coagulation process, but are due to the continuous secretion ex vivo of ECP from active eosinophils. This process is time and temperature dependent and may be facilitated by eosinophil-activating components in the extracellular environment.     

Twenty-four-hour time course of eosinophil granule proteins ECP and EPX during bronchial allergen challenges in serum of asthmatic children

To study in vivo monitoring variables for bronchial allergen challenges, we investigated the time course of the eosinophil granule proteins, eosinophil cationic protein (ECP) and eosinophil protein × (EPX) after allergen provocation in serum. Thirty-two asthmatic children sensitive to house-dust mites and six healthy young adult controls were challenged by bronchial allergen provocations with Dermatophagoides pteronyssinus and D. farinae. Blood samples were taken at regular intervals up to 24 h. Base-line concentrations of ECP ( P <0.004), EPX ( P <0.002), and eosinophils ( P <0.001) were found to be increased in asthmatic children, as compared with healthy controls. ECP and EPX concentrations showed a uniform pattern with two characteristic features: 1) a rapid increase for both mediators up to 30 min after provocation over base-line values ( P <0.0001 and P <0.001), followed by a rapid decrease nearly to base-line values in the next 30 min; and 2) a steady increase for ECP and EPX up to 10 h ( P <0.02 and P <0.01), and even higher levels at 24 h, after challenge ( P <0.002 and P <0.003). We conclude that although eosinophils are activated in asthmatic children after bronchial allergen challenge, ECP and EPX concentrations are not suitable monitoring variables. Base-line eosinophils seem to predict the occurrence of a late-phase asthmatic reaction after allergen provocation.     

Evaluation of serum eosinophil cationic protein as a predictive marker for asthma exacerbation in patients with persistent disease

BACKGROUND: Eosinophilic inflammation is a feature of asthma. However, serological markers to indicate eosinophil activation in this process are not fully defined. OBJECTIVE: To evaluate the relationship of serum eosinophil cationic protein (ECP) to asthma worsening and a marker for treatment effectiveness, 26 adult patients with an asthma exacerbation were identified. METHODS: Identified asthma subjects were treated with oral corticosteroids (prednisone) for 14 days. The lung function variables, forced expiratory volume in one second (FEV1) and peak expiratory flow (PEF), were determined as percentage of predicted and the blood total eosinophil count and serum ECP levels were measured. Patients were re-evaluated after 14 days of corticosteroid treatment and then every 3 months thereafter during a 12-month period. RESULTS: Eighteen patients responded to prednisone treatment, whereas eight did not, assessed as improvement of their lung function parameters. Different serum ECP patterns could be seen in the responders compared with the non-responders. All 18 responders had considerably increased serum ECP at the time of exacerbation, whereas the non-responders had lower serum ECP levels. The serum ECP levels decreased to a greater extent in the responder patient group than in the non-responder patients following prednisone treatment. This difference in patterns was not seen with total blood eosinophil counts. CONCLUSION: Our findings suggest that serum ECP may be used to predict a response to corticosteroid therapy in adult patients with asthma.     

Variations of serum eosinophil cationic protein and tryptase, measured in serum and saliva, during the course of immediate allergic reactions to foods

BACKGROUND: Subjective complaints and reactions after placebo administration during food challenges (FC) may make their outcome difficult to interpret. We determined serum ECP and tryptase as tryptase in saliva during FC, looking for markers to support challenge outcomes. METHODS: Twelve patients with systemic reactions after food intake and nine presenting oral allergy syndrome (OAS) underwent skin tests; total and specific IgE determination; double-blind, placebo-controlled FC (DBPCFC); and open challenges. Blood samples were collected before and 1, 2, and 5 h after challenge and saliva before and 5, 30, and 60 min after challenge. ECP and tryptase were quantified by ImmunoCAP (Pharmacia-Upjohn, Sweden). Serum tryptase of > 10 microg/l was considered positive. RESULTS: After positive DBPCFC (n = 8), ECP rose significantly (P < 0.05) at 1-h - 16.03 (12.8) microg/l (mean [standard deviation]) - and 2-h intervals - 17.56 (10.7) microg/l - compared to basal level of 9 (6.4) microg/l. After negative DBPCFC (n = 6), ECP increased from basal 9.63 (3.9) microg/l to 24.84 (14.17) microg/l at the 2-h time point. There were nonsignificant differences in ECP between patients with positive and negative FC. Two patients with positive challenge showed a tryptase level of >10 microg/l and only one patient with OAS showed 5.6 microg/l of tryptase 5 min after FC. CONCLUSIONS: ECP and tryptase in serum and saliva were not useful markers for FC outcomes.     

The use of serum eosinophil cationic protein (ECP) in the management of steroid therapy in chronic asthma

Background Corticosteroid therapy has become the mainstay in the treatment of asthma. However, the risk-benefit balance in the patient calls for assessment of the state of inflammation in the airways. In this respect serum eosinophil cationic protein (ECP) might be a marker, which can easily be measured in a clinical setting. Studies have indicated a relation between level of serum ECP and activity and severity in asthma. Objective To investigate the feasibility to guide steroid therapy on the basis of the level of serum ECP in patients with chronic asthma. Methods Twenty adult patients on maintenance inhaled steroid therapy visited the chest clinic once every 2 months over a 12-month period. At each visit a short history, blood sample for ECP and number of eosinophils, baseline spirometry, and histamine inhalation provocation test (PC₂₀) were obtained. On the basis of level of ECP, adjustments in daily dose of steroids were considered. Data were compared with those of a previous 6-month ECP evaluation study in these same patients. Results In 10 patients mean dose of inhaled steroids was decreased 25%. ECP rose slightly (antilogged mean from 9.06 to 11.8μg/L) and lung function decreased slightly (mean FEV₁%predicted from 85.5 to 81.6). In seven patients mean dose of inhaled or oral (n= 2) steroids was increased 25%. In this group ECP decreased but remained elevated at 20μg/L (antilogged mean from 30.5 to 25.6μg/L) and lung function improved (mean FEV₁%predicted from 67.2 to 74.5). In both groups patients' scores of asthmatic well-being increased significantly, and PC₂₀ did not show a trend. Exacerbation rate remained the same in the decreased and the no change group (n= 3, in which no substantial change in steroid dose occurred), but was reduced by about 50% in the increased group. Conclusion From this observational study it is concluded that adjusting steroid therapy guided by serum ECP-level may be helpful in tailoring asthma treatment.     

Lack of relationship between eosinophil cationic protein and eosinophil protein X in nasal lavage and urine and the severity of childhood asthma in a 6-month follow-up study.

BACKGROUND: Recent studies suggest that eosinophil cationic protein (ECP) and eosinophil protein X (EPX) may be valuable markers of airway inflammation in various body fluids of asthmatic children. Most of these studies have relied on a single measure of inflammatory markers. OBJECTIVE: We measured ECP and EPX in nasal lavage fluids (NALF) and urine samples in children with asthma over a 6-month period to study the relationship between inflammatory markers and clinical severity. METHODS: Fourteen children with mild persisting asthma (mean age 11.7 years, SD 2.2) were recruited. All patients were on therapy including inhaled steroids. For a 6-month period asthma severity was monitored by at least monthly physical examination and pulmonary function tests. Daily morning and evening PEF, asthma symptoms and medication were recorded in diaries for the whole study period. Telephone interviews were performed between visits and additional visits were done in case of an increase in asthmatic symptoms or drop of PEF values under 80% of best value. An exacerbation was defined by a fall of FEV1 > 10% and an increase in asthma symptoms and additional need of beta2-agonist. NALF and urine samples were obtained at each visit and analysed for ECP (NALF only) and EPX. RESULTS: Mean observation time was 186.4 days (SD 19.8). Thirteen patients completed the study. During the study period 11 exacerbations were observed in six patients. No significant associations between PEF, PEF variability (amplitude % of mean), daily symptoms, additional beta2-agonist, FEV1 and MEF50 and nasal ECP, nasal EPX and urinary EPX were found. However, at exacerbations an average increase of nasal ECP (9.3 vs 50.3 microg/L) and EPX (nasal EPX 36.4 vs 141.7 microg/L, urinary EPX 46.4 vs 74.1 microg/mmol creatinine) was observed. CONCLUSION: Serial measurements of ECP and EPX in NALF and urine samples do not provide additional information for the practical management in monitoring childhood asthma.     

Bronchoalveolar lavage eosinophil cationic protein and interleukin-8 levels in acute asthma and acute bronchiolitis

OBJECTIVE: In this study, we measured the levels of eosinophil cationic protein (ECP) and interleukin (IL)-8 in bronchoalveolar lavage (BAL) fluid from patients with acute asthma and acute bronchiolitis, to determine any similarities or dissimilarities in the profiles of these biochemical markers in the two diseases. METHODS: BAL fluids were obtained from children with acute asthma (n=16), infants with acute bronchiolitis caused by respiratory syncytial virus (n=18), and control subjects (n=14). Children with asthma were selected to be free of viral infection. BAL cell counts and differentials were determined, and ECP and IL-8 levels were measured by radioimmunoassay and ELISA, respectively. RESULTS: ECP levels in BAL fluids were significantly higher in the asthma group than in the bronchiolitis (P<0.01) or control (P<0.0001) groups. However, IL-8 levels were significantly higher in the bronchiolitis group than in the asthma (P<0.01) or control (P<0.001) groups. IL-8 levels in the asthma group and ECP levels in the bronchiolitis group were similar to those of the control group. CONCLUSION: This difference in profiles of ECP and IL-8 in acute asthma and acute bronchiolitis, together with a different inflammatory cell pattern, suggests that the nature of the inflammatory process within the lower respiratory tract may be distinctive in these two diseases.     

Serum eosinophil cationic protein in relation to bronchial asthma in a young Swedish population

How are the serum concentration of eosinophil cationic protein (S-ECP) and the blood eosinophil count (B-Eos) related to symptoms of asthma, allergy, and bronchial hyperresponsiveness (BHR)? We measured S-ECP, B-Eos, and total and specific IgE in serum in blood samples from 699 randomly selected persons 20–44 years old. They also underwent a structured interview, spirometry, a methacholine provocation test, and skin prick tests as part of the European Community Respiratory Health Survey. B-Eos and S-ECP were found to be closely related to asthma symptom score (P < 0.001), total IgE (P < 0.001), and BHR (P < 0.001). On the basis of the results, the subjects were divided into four groups: healthy controls, patients with allergic rhinitis, patients with nonallergic asthma, and patients with allergic asthma. There were significant differences in both B-Eos and S-ECP among the groups (P < 0.001), the highest values being found in the allergic asthma group. B-Eos and S-ECP each had an additive value in predicting the occurrence of asthma. Among persons with high concentrations of both variables, asthma was eight times more common than in those with low concentrations. Allergy and BHR were also found to be independently related to B-Eos and S-ECP levels. Furthermore, both B-Eos and S-ECP showed good correlation to subjective and objective measures of asthma activity. We conclude that both B-Eos and S-ECP and their interrelationship may be of value in assessing the activity of asthma. However, their role in disease management was not established in this cross-sectional study.     

Changes in serum ECP levels after storage at room temperature

Wantke F, Demmer CM, Götz M, Jarisch R. Changes in serum ECP levels after storage at room temperature.