The utility of specific immunoglobulin E measurements in primary care

Identifying Region-Specific Allergy Sensitization Clusters to Optimize Diagnosis and Reduce Costs

OBJECTIVE

To delineate quantitatively the allergen sensitization patterns in a large pediatric cohort and inform the selection of a region-specific panel of allergen tests for timely and cost-effective in vitro atopy screening.

STUDY DESIGN

IgE levels for specific allergens from patients in the Texas Children's Health System were analyzed retrospectively. Statistical and network analyses were conducted to reveal sensitization patterns.

RESULTS

Network analysis of 114 distinct allergens among 12 065 patients identified 2 main groups of allergens: environmental and food. Approximately 67.5% of patients were sensitized to environmental allergens, 47.2% to food allergens, and 7.3% to at least 1 allergen from both groups. We identified a novel panel of 13 allergens that could detect sensitization in 95% of patients, whereas panels of 7 allergens within each category effectively identified sensitization in 95% of patients with specific sensitivities. This data-driven approach is estimated to reduce overall testing costs by 52%. In agreement with literature, we observed correlations among allergens within specific categories, such as pollen, shellfish, nuts, and dairy allergens.

CONCLUSIONS

This study provides insights into allergen sensitization patterns informing an algorithmic testing approach tailored for primary care settings. The use of a region and population-specific test panel can efficiently identify atopy, leading to more targeted testing. This strategy has the potential to refine laboratory testing, reduce costs, and improve the appropriateness of referrals to allergy specialists, ultimately enhancing diagnostic accuracy and resource allocation.

Laboratory Strategies to Improve Allergy First-Line Screening in Primary Care

BACKGROUND

There are nonestablished protocols in use for first-line allergy screening based on IgE testing. These protocols attempt to address an unmet need for sustainability of clinical laboratories, at a time when demand is increasing.

OBJECTIVE

To present a novel protocol for first-line allergy screening and to evaluate the implementation benefits for patients, the health care system, and payers.

METHODS

We carried out an observational retrospective study analyzing 4359 interventions on primary care testing requests. Interventions included overriding redundant serum IgE (sIgE) testing for allergen mixes, extracts included in mixes, low-prevalence extracts, and milk and egg molecular components without previous positive results when exposed to extracts. We also added prevalent allergen testing.

RESULTS

The strategy saved 683 tests from being performed unnecessarily. Test volume decline was primarily driven by the cancelation of 2186 egg and milk components tests; 561 tests were added for mixes, together with 942 allergen extracts tests.

DISCUSSION

The results of this study show how the allergy laboratory plays a key role in actively managing demand for sIgE testing, leading to optimized diagnosis.

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.

Sensitisation to airborne allergens as a risk factor for allergic rhinitis and asthma in the Polish population

Introduction

The patterns of sensitisation to airborne allergens and their association with allergic diseases have been analysed in different geographical regions.

Aim

To analyse the impact of sensitisation to airborne allergens on allergic rhinitis (AR) and asthma in different age groups of the Polish population.

Material and methods

Completed questionnaires of 18,617 subjects (53.8% females), collected within the ECAP, a cross-sectional multicentre study, were analysed. Three groups of respondents were included: 6-7-year-olds (24.2%), 13-14-year-olds (25.4%), 20-44-year-olds (50.4%). The clinical part (an anamnesis, physical examination, spirometry, skin prick tests and an assay of major airborne allergen-specific IgE) was attended by 25.7% of the respondents.

Results

The AR was most strongly related to sensitisation to Dermatophagoides pteronyssinus, with the highest odds ratios of 10 in two younger groups and of 16 for persistent AR in children. It was also the most important risk factor for allergic asthma, with odd ratios from 8.34 in children to 6.40 in adolescents. Sensitisation to grass pollen allergens was a major risk factor for both AR, with odds ratios from 9.16 in adults to 7.87 in adolescents, and asthma, with odds ratios from 6.16 in adolescents to 5.67 in adults.

Conclusions

AR and asthma shared common risk factors, independently of age. Sensitisation to airborne allergens was significantly associated with asthma and, even more strongly, with AR, across all age groups. The AR was the strongest risk factor for allergic asthma in the youngest group. Persistent AR increased asthma risk more than intermittent AR in all age groups.

Challenges in the implementation of the EAACI AIT guidelines: A situational analysis of current provision of allergen immunotherapy

PURPOSE

The European Academy of Allergy and Clinical Immunology (EAACI) has produced Guidelines on Allergen Immunotherapy (AIT). We sought to gauge the preparedness of primary care to participate in the delivery of AIT in Europe.

METHODS

We undertook a mixed-methods, situational analysis. This involved a purposeful literature search and two surveys: one to primary care clinicians and the other to a wider group of stakeholders across Europe.

RESULTS

The 10 papers identified all pointed out gaps or deficiencies in allergy care provision in primary care. The surveys also highlighted similar concerns, particularly in relation to concerns about lack of knowledge, skills, infrastructural weaknesses, reimbursement policies and communication with specialists as barriers to evidence-based care. Almost all countries (92%) reported the availability of AIT. In spite of that, only 28% and 44% of the countries reported the availability of guidelines for primary care physicians and specialists, respectively. Agreed pathways between specialists and primary care physicians were reported as existing in 32%-48% of countries. Reimbursement appeared to be an important barrier as AIT was only fully reimbursed in 32% of countries. Additionally, 44% of respondents considered accessibility to AIT and 36% stating patient costs were barriers.

CONCLUSIONS

Successful working with primary care providers is essential to scaling-up AIT provision in Europe, but to achieve this, the identified barriers must be overcome. Development of primary care interpretation of guidelines to aid patient selection, establishment of disease management pathways and collaboration with specialist groups are required as a matter of urgency.

Diagnostic Utility of Total IgE in Foods, Inhalant, and Multiple Allergies in Saudi Arabia

Objective. To assess the diagnostic significance of total IgE in foods, inhalant, and multiple allergies. Methods. Retrospective review of the laboratory records of patients who presented with clinical suspicion of food or inhalant allergy between January 2013 and December 2014. Total IgE level was defined as positive for a value >195 kU/L; and diagnosis was confirmed by the detection of specific IgE (golden standard) for at least one food or inhalant allergen and at least two allergens in multiple allergies. Results. A total of 1893 (male ratio = 0.68, mean age = 39.0 ± 19.2 years) patients were included. Total IgE had comparable sensitivity (55.8% versus 59.6%) and specificity (83.9% versus 84.4%) in food versus inhalant allergy, respectively, but a superior PPV in inhalant allergy (79.1% versus 54.4%). ROC curve analysis showed a better diagnostic value in inhalant allergies (AUC = 0.817 (95% CI = 0.796-0.837) versus 0.770 (95% CI = 0.707-0.833)). In multiple allergies, total IgE had a relatively good sensitivity (78.6%), while negative IgE testing (<195 kU/L) predicted the absence of multiple allergies with 91.5% certitude. Conclusion. Total IgE assay is not efficient as a diagnostic test for foods, inhalant, or multiple allergies. The best strategy should refer to specific IgE testing guided by a comprehensive atopic history.

Sensitization pattern to inhalant and food allergens in symptomatic children at first evaluation

Background

Data on specific IgE sensitization prevalence in children with allergy-like symptoms seen in the primary care setting are rare. Early diagnosis of allergic diseases is important to prevent clinical manifestations, exacerbations or expansion of allergic diseases to other organ systems. The present study aims to assess the usefulness of early serological diagnosis in children with common allergic symptoms.

Methods

532 children (<15 years of age), with at least one of ten allergy-like symptoms, from 21 primary care centers in two geographic areas of Italy and Spain were included in the study. Patients were tested with, either Phadiatop® Infant (0–5 years of age) or Phadiatop® and food mix (fx5e) (>5 years of age) to discriminate atopic from non-atopic subjects. A blood sample of atopic subjects was taken for additional 6–26 specific IgE antibody determinations from a predefined panel using the ImmunoCAP^® System.

Results

267 children (50.2 %) were positive in the initial test and were classified as atopic. 14 % were mono-sensitized, 37 % were sensitized to 2–3 allergens and 49 % to more than 3 allergens. The average number of symptoms in the atopic group was 3.3 vs 2.8 in the non-atopic group. The prevalence of sensitization to single allergens was highest for grass and ragweed pollen and house-dust mites (19–28 %). Sensitization to tree allergens was highest for olive tree (16.5 %). Cow’s milk and egg white were the most sensitizing foods (~15 %). Food allergen sensitization predominated in younger children (OR = 2.8) whereas the inverse occurred with inhalant allergens (OR = 2.5 to 5.6). A significant positive correlation between patient age and the number of sensitizations was found.

Conclusions

Specific IgE sensitization in children with allergy-like symptoms is common. Multiple sensitization is predominating. Number of clinical symptoms was higher in the atopic group compared to the non-atopic without a correlation with the number of positive allergens. Age seems to play a crucial role in the development of sensitization with a significant positive correlation between patient age and the number of sensitizations.

Allergy Diagnosis in Children and Adults: Performance of a New Point-of-Care Device, ImmunoCAP Rapid

BACKGROUND

: Allergy is a serious problem affecting approximately 1 of 4 individuals. The symptoms with and without allergy etiology are often difficult to distinguish from each other without using an IgE antibody test. The aim of this study was to investigate the performance of a new point-of-care (POC) test for IgE antibodies to relevant allergens in Europe.

METHODS

: IgE antibodies from children and adults with allergies recruited from allergy clinics in Sweden and Spain were analyzed for 10 allergens, suitable for the age groups, using the new POC test and ImmunoCAP laboratory test. The IgE antibody level best discriminating between positive and negative results (the cutoff point) for the different allergens of the POC test and the efficacy of the POC and the ImmunoCAP laboratory tests for diagnosing allergy compared with that of clinical diagnosis were investigated.

RESULTS

: The estimated cutoffs for the different allergens in the POC test ranged from 0.70 to 2.56 kUA/L. Taking into account all positive allergen results in a given patient, the POC test could identify 95% of the patients with allergies. Seventy-eight percent of the allergen-specific physicians' diagnoses were identified and 97% of the negative ones. Most allergens exhibited good performance, identifying about 80% of clinically relevant cases. However, dog, mugwort, and wall pellitory would benefit from improvement.

CONCLUSIONS

: The POC test will be a valuable adjunct in the identification or exclusion of patients with allergies and their most likely offending allergens, both in specialist and general care settings.

Health-care cost reduction resulting from primary-care allergy testing in children in Italy

Background

Allergy places a considerable cost burden on society. Specific immunoglobulin E (spIgE) testing may improve the management of allergy patients. There is therefore a reason to quantify the economic consequences of the use of spIgE testing in the diagnosis of allergic conditions.

Methods

The expected costs of spIgE testing versus no-testing were calculated using a clinical decision model based on a prospective clinical trial performed in primary care.

Results

The expected costs per patient over 2 years decreased from 802 euros in the "no-test strategy" to 560 euros in the spIgE "test strategy". Cost savings persisted even after assumptions about the prevalence of allergy and the prices of medications were changed. The "test strategy" increased the percentage of patients correctly diagnosed from 54 to 87%.

Conclusions

spIgE testing of children with respiratory and/or skin problems in primary care in Italy reduces overall costs to society. These cost savings mostly result from a reduction in the use of medications, particularly corticosteroids. The study indicates that spIgE testing of all children with respiratory and/or skin symptoms would be a cost-effective strategy.

Determination of multiple allergen-specific IgE by microfluidic immunoassay cartridge in clinical settings

Our aims were to evaluate the performance of an automated microfluidic immunoassay system for measuring allergen-specific IgE (sIgE) in sera against an established in vitro assay and to assess the system's diagnostic accuracy against objective clinical criteria for identifying sensitization to specific allergens in daily practice of allergy clinics. Using both the automated microfluidic-based immunoassay system (BioIC and ImmunoCAP, we measured sIgE in serum samples from 212 children who visited allergic clinics in two medical centers. Outcomes of skin prick tests (SPT) served as the clinical comparison method. The assay results of targeted allergen of BioIC have a good correlation with ImmunoCAP in the diagnosis of allergen sensitivity by patients' clinical history. When comparing the test results of the sIgE against overall allergens, in either two tests among the three assays performed showed high percentage of agreement between BioIC and ImmunoCAP (77.8%, 95% CI: 72-83.3%) but not with SPT (BioIC 64.9%, 95% CI: 58-72%; ImmunoCAP 67.5%, 95% CI: 61-74%). Using ROC analysis and SPT as quasi-standard, BioIC and ImmunoCAP have nearly the same performance of sensitivity and specificity in the confirmation of SPT results. The total and within one-class agreements of each allergen test result between BioIC and ImmunoCAP ranged between 55.2% and 99.5% with an overall average of 80.9%. Laboratory testing for sIgE can be performed on a fully automated, microfluidic cartridge system with advantages of low sample volume, simultaneously tested allergens, and with diagnostic accuracy for representative allergens equivalent to the semi-automated CAP technology.

Paediatric allergy diagnosis in primary care is improved by in vitro allergen-specific IgE testing

Allergy testing is an important pre-requisite for both early identification of infants at increased risk for later development of allergic diseases and for specific allergy treatment including specific allergen avoidance measures, pharmacotherapy and specific immunotherapy. The aim of this study was to investigate the influence of in vitro allergen-specific immunoglobulin E (IgE) testing on the primary care physician's diagnosis and clinical management of children with symptoms of eczema, wheezing/asthma and rhinitis. The trial was a prospective study performed at 14 paediatric primary care practices in Germany, covering 380 children below 6 yr of age. For one group of children the physician received the IgE test results as soon as possible and used them as an additional tool when diagnosing and giving clinical management advice. For the other group of children the IgE test results were not made available to the physician until the children were brought to a second visit, about 7 wk later. When diagnosis was made without access to allergen-specific IgE results, 8% of the children were diagnosed as allergic, 6% as non-allergic and in 86% of the cases the physician was uncertain. With access to allergen-specific IgE results the figures were 13%, 65% and 22%, respectively. Concerning clinical management advice no statistically significant differences between the two study groups were observed. When comparing the first and second visits of the patients coming for a second visit advice to reduce aeroallergen exposure was given to 27% of the patients at visit 1 and to 36% of the patients at visit 2 (p = 0.002). The difference between the first and second visits of the other clinical management advice studied did not reach statistical significance. In this study the availability of IgE test results to the primary care physician had an impact on the decision-making process of the diagnosis but not on the pharmaceutical or avoidance advice given. The reason why IgE test results were not fully exploited needs to be further scrutinized.

Phadiatop compared to skin-prick test as a tool for diagnosing atopy in epidemiological studies in schoolchildren

The validity of the Phadiatop test as compared to the skin-prick test (SPT) for diagnosing atopy in the epidemiological field has not been studied in schoolchildren. The aim of the present study was to evaluate its validity for classifying schoolchildren 9-12 yr old into atopics and non-atopics. A total of 621 children whose parents authorized both a SPT and a blood extraction from all children participating in the phase II of the International Study of Allergies in Children (ISAAC) in Cartagena (Spain) were included in the analysis. A positive SPT was that with at least a wheal having a maximum diameter of 3 mm, once the negative value had been subtracted. Phadiatop was performed according to the manufacturer instructions. Diagnostic tests using SPT as the gold standard were calculated for the whole group of children and also for those with asthma or rhinoconjunctivitis and for children without any of them. The results of the tests were: sensitivity 85.0% (95% CI 82.2-87.8%), specificity 85.5% (95%CI 82.7-88.3%), positive predictive value 72.7% (95%CI 69.0-76.1%), negative predictive value 92.7% (95%CI 90.6-94.7%) and accuracy 85.3% (95%CI 82.3-88.0%). The results improved among the symptomatic groups. Phadiatop can be used as a valid alternative to SPT in the epidemiological setting to diagnose atopy.

Oxidative stress in nonallergic nasal polyps associated with bronchial hyperresponsiveness

BACKGROUND

Nasal polyposis (NP) is a chronic inflammatory disease of upper airway with unknown etiology. NP is frequently associated with asthma; the interaction between these comorbidities remains interesting. Oxidative stress has been implicated in the pathophysiology of NP and asthma. The aim of this study is to investigate the significance of oxidative stress in sinonasal microenvironments by evaluating its association with clinopathological parameters and its impacts on the pathogenesis of bronchial hyperresponsiveness (BHR) in NP.

METHODS

Polyp biopsy specimens were obtained from 20 nonallergic patients; control mucosas were obtained from 20 volunteers. The levels of free radicals in the tissues and in blood were determined by a sensitive chemiluminescence (CL) method. NP patients were substratified into three subgroups, NP without BHR, NP with asymptomatic BHR, and NP with BHR and asthma by the results of provocative testing. Four histological characteristics of NP, inflammatory cells, eosinophil infiltration, edema and fibrosis were estimated and applied to correlate with the tissue-CL.

RESULTS

The mean CL level in polyp-tissues, but not in blood, was higher than in the control specimens. In NP patients, tissue-CL was associated with endoscopy score; high tissue-CL levels were positively correlated with the abundance of inflammatory cells and eosinophils. Tissue-CL and endoscopy score were associated with BHR/asthma phenotype.

CONCLUSION

These results suggest an important role for oxidative stress in the pathophysiology of NP and a causal relation between oxidative stress and inflammatory cells, especially the eosinophils. Free radical levels in polyp-tissues associated with NP severity and with BHR/asthma phenotype in nonallergic NP patients.

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

BACKGROUND

Correct diagnosis of immunoglobulin E (IgE)-mediated disease is the prerequisite for secondary allergy prevention during early childhood.

OBJECTIVE

To evaluate the diagnostic efficacy of a new blood test, Phadiatop Infant, in detecting IgE sensitisation to food and inhalant allergens among children at 2 years of age.

METHODS

Children (n = 239) were followed prospectively from birth to 2 years of age for the presence of IgE sensitisation and the development of atopic manifestations. Immunoglobulin E sensitisation was evaluated by skin prick test (SPT) and analysis of allergen-specific IgE antibodies in plasma to food and inhalant allergens. The children were classified into three groups: IgE-sensitised, non-IgE sensitised and inconclusive, depending on SPT and allergen-specific IgE results.

RESULTS

Twenty-six (11%) of the children were classified as IgE-sensitised, 182 (76%) as non-IgE sensitised and 31 (13%) as inconclusive. Phadiatop Infant was positive in 50 (21%) of the children. Ten children (4%) with identified IgE antibodies against the selected food and inhalant allergens showed negative Phadiatop Infant. Three children showed positive Phadiatop Infant but were negative in the other tests performed. These results correspond to positive and negative predictive values for Phadiatop Infant of 89 and 99%, respectively. Children with clinical symptoms of atopic diseases had significantly increased levels for Phadiatop Infant (P < 0.01).

CONCLUSION

Phadiatop Infant appears to be a reliable alternative to SPT and the measurement of allergen-specific IgE antibodies in plasma for detecting clinically important IgE sensitisation among children at 2 years of age.

Improving the management of atopic disease

Asthma, wheeze, eczema, and, to a certain extent, rhinitis are very common conditions among children. The prevalence of allergic disease in the general population has increased alarmingly over the past 25 years, particularly in Western industrialised countries. However, it is important to remember that the symptoms often associated with allergy can have other aetiologies. Evidence suggests that in most circumstances, only 30-40% of chronic allergic-type symptoms are due to allergy. Accurate diagnosis of the presence of allergy is therefore an important issue, particularly given the interventions that such a diagnosis may initiate. In this review, we examine management options for allergy, provide the evidence as to what proportions of patients with common allergic-type symptoms are actually allergic, and list other causes of such symptoms. The importance of allergy testing and the options available are described, particularly with reference to the role of the non-allergist.

Utility of the ratio of food-specific IgE/total IgE in predicting symptomatic food allergy in children

BACKGROUND

Double-blind, placebo-controlled food challenges are time-consuming, expensive and not without risk to patients. Therefore, an in vitro test that could accurately diagnose food allergy would be of great value.

OBJECTIVE

To evaluate the utility of the ratio of specific immunoglobulin E (IgE)/total IgE compared with specific IgE (sIgE) alone in predicting symptomatic food allergy.

METHODS

We retrospectively analysed 992 controlled oral food challenges performed in 501 children (median age 13 months). The ratio of sIgE/total IgE was calculated and tested for correlation with the outcome of food challenges. Receiver operator characteristics (ROC)-curves were performed; predicted probabilities and predictive decision points were calculated.

RESULTS

A significant correlation was found between the ratio and the outcome of food challenges for cow's milk (CM), hen's egg (HE), and wheat, but not for soy. The ROC and predicted probability curves as well as sensitivity and specificity of the decision points of the ratio were similar to those of sIgE levels for CM, HE and wheat.

CONCLUSION

In view of the greater effort needed to determine the ratio, without benefit compared with the sIgE alone, the calculation of the ratio of sIgE/total IgE for diagnosing symptomatic food allergy offers no advantage for CM, HE, wheat or soy. For the majority of cases controlled oral food challenges still remain the method of choice.