Interpreting epidemiologic distribution of total and specific IgE levels for food allergy in Southern China from 2004 to 2023: understanding the mechanisms and focusing on prevention.

BACKGROUND: The burgeoning prevalence of food allergy-related diseases is closely associated with geographical allergen distribution and societal lifestyle paradigms. This study aims to shed light on the distribution patterns of specific IgE (sIgE) and total IgE (tIgE) reactivity to common food allergens in the Southern Chinese populace. METHODS: Employing an analytical technique spanning two decades, we conducted specific IgE and total IgE on serum samples harvested from patients with food allergy-related pathologies at First Affiliated Hospital of Guangzhou Medical University from 2004 to 2023. This comprehensive examination of eight prototypical food allergens: egg white, milk, wheat, sesame, peanut, soybean, shrimp, and crab. RESULTS: Our analysis showed a 100% positivity rate for sIgE and an 86.54% positivity rate for tIgE. Milk had the highest positive response rate, followed by egg white and shrimp. Age-stratified data indicated that milk sensitization peaked in children aged 2 years or younger, while egg white sensitization peaked between 3 and 5 years of age. Sensitization rates for the remaining six allergens increased with age. Additionally, co-sensitization was observed between milk, egg white, crab, and shrimp with other allergens. CONCLUSION: In common allergens of Southern China, egg white, milk, and shrimp ascend as the dominant subjects, underlining their imperative role in food allergy pathogenesis. This landscape-wide allergenic profiling, segregated across age clusters and enhanced by co-sensitization data, augments our power for early diagnosis and strategic intervention in food allergy diseases.

A systematic review of total IgE reference intervals - A 2024 update.

BACKGROUND: Total IgE (tIgE) is a frequently requested analyte in patients presenting with symptoms of atopy. Although tIgE has limited clinical utility in the diagnosis of atopic diseases, it is still important that appropriate reference intervals are provided to the intepreting clinician. Concerns have recently been raised whether laboratories are using outdated tIgE reference intervals. The aim of this study was therefore to perform the first systematic literature review of tIgE reference intervals to aid laboratories in choosing appropriate sources of tIgE reference intervals. METHODS: A search was performed in MEDLINE, Embase and the Cochrane Library from time of inception to July 2024. Eligible studies had to provide an estimate of paediatric and/or adult tIgE reference intervals using current generation immunoassays. The methodology followed PRISMA guidelines, and the study protocol was registered in the PROSPERO database (CRD42023396441). RESULTS: A total of 1667 records were screened of which 20 studies remained after the full text review. The studies included 23 910 individuals and covered 18 countries. Upper reference limits varied significantly, with participant selection (inclusion or exclusion of in vitro confirmed specific IgE sensitised individuals) and statistical methods identified as the most important factors influencing the upper reference limit. CONCLUSION: This review emphasises the need for laboratories to carefully evaluate the participant selection criteria and employed statistical methods whilst determining which tIgE reference intervals are the most appropriate to report to clinicians. Further efforts should also be made to harmonise and improve the reporting of tIgE reference interval studies.

Allergen Sensitivity Patterns and Their Correlation With Total Serum IgE Levels and Absolute Eosinophil Counts Among Patients With Allergic Rhinitis and Asthma in North Karnataka.

Introduction Respiratory allergies are prevalent across all populations and age groups, with the specific types of allergens varying according to geographic area, climate, location, economic status, and ethnic identity. While skin prick testing is considered the gold standard for assessing specific IgE against particular allergens, several factors can make the test less preferred. Consequently, total serum IgE levels and eosinophil counts are often used instead. Objectives The study aimed to determine allergen sensitivity patterns among patients with allergic rhinitis and/or asthma and to correlate skin prick test (SPT) reactivity with total serum IgE levels and absolute eosinophil count (AECs). This was done to assess the potential use of these measures as screening tests. Materials and methods A cross-sectional study was conducted on 44 patients diagnosed with allergic rhinitis and/or asthma. Each patient underwent an allergen SPT, and measurements were taken for total serum IgE levels and eosinophil counts. The study identified the most common allergens resulting in positive SPTs. Pearson correlation test was used for continuous variables, and a p-value of <0.05 was considered statistically significant. Results The study found that the majority of patients had only allergic rhinitis (17, 38.6%), followed by those with only asthma (12, 27.3%), and those with both allergic rhinitis and asthma (15, 34.1%). The most common allergen was Blomia (house dust mite), affecting 22 (50%) patients, while the least common were honey bee and lemon, each affecting 1 (2.3%) patient. There was a significant correlation between total serum IgE levels and AECs (p < 0.05). Additionally, a statistically significant correlation was found between total serum IgE levels, eosinophil counts, and the number of allergens to which patients were sensitized. Conclusion Blomia (house dust mite) is the most common allergen among patients with respiratory allergies in North Karnataka. While total serum IgE levels and AECs may help identify the extent of allergen sensitivity, the SPT remains the gold standard.

Fish and shellfish allergy: Presentation and management differences in the UK and US-analysis of 945 patients.

Background: Seafood allergy (SA), including allergy to shellfish (crustacean and mollusks) and fish, is among the 4 most common food allergies causing anaphylaxis, but there are limited data showing SA clinical management in different countries. Objective: We sought to characterize a large cohort of patients with fish and shellfish allergy and to facilitate standardization of future care for this increasingly common allergic disease. Methods: We performed a retrospective, observational, noninterventional study from 945 patients from 2015 to 2019 in 7 hospitals in the United States and the United Kingdom to evaluate SA. A chi-square test was used to detect differences in family history, medical history, and current symptoms between patients in 2 countries. Results: Underdiagnosed anaphylaxis in patients with SA was associated with underuse of epinephrine (adrenaline) autoinjectors in both countries. Oral food challenge was used only when skin or serologic test results were negative. Asthma and allergic rhinitis were more common in the US patients with SA, but eczema was more common in UK patients with SA (P < .001). Respiratory, gastrointestinal, and neurological symptoms were higher in UK patients with SA than in US patients with SA (P < .001). Conclusions: In international multicenter cohorts of patients with fish and shellfish allergy, there are opportunities for improvement in management. Physician identification of anaphylaxis, use of diagnostic oral food challenges, and anaphylaxis treatment with epinephrine are areas with significant knowledge gaps in need of improvement in the United Kingdom and the United States. There is an opportunity for the development of unified, standardized diagnostic protocols for SA with distribution for allergists and trainees.

Total IgE Trends in Children with Allergic Diseases.

Background/Objectives: The importance of non-invasive biomarkers for the diagnosis and monitoring of allergic diseases in childhood is currently unknown. From this perspective, data on the role of the total (t) immunoglobulin E (IgE) in relation to different allergic diseases across different age groups until adulthood remain unclear. The potential association of tIgE levels with types of allergic diseases diagnosed in an specialized tertiary allergy center, in relation to sex and the age group spanning from birth to 20 years, are evaluated in the present study. Methods: In this retrospective study, the tIgE values were obtained from children assessed for allergy-associated symptoms in our department from January 2015 to December 2020. The tIgE values were analyzed in relation to age and diagnosis. Results: Data from 2127 patients (1321 boys (62.1%)), with a median age of 6.31 (3.01-9.95) years, were available. The tIgE median values for the studied population were 132 (37.7-367.5) kU/lt. The tIgE values showed a significant increase from 0-2 years to 2-5 and 5-12 years, but not from 5-12 to 12-20 years. Boys exhibited significantly higher tIgE values compared to girls. Furthermore, the tIgE levels were significantly increased in children with asthma, allergic rhinitis, food allergy, and atopic dermatitis in comparison to children without these diagnoses. Conclusions: The total IgE values exhibit a significant and progressive longitudinal increase in children with allergic diseases, particularly notable in the 0-2 and 5-12 age groups, in boys, and in children diagnosed with atopic conditions.

Next-generation reference interval for total IgE in the United States: A retrospective real-world analysis.

OBJECTIVE: To establish a next-generation reference interval (RI) for total IgE (tIgE) and evaluate its usefulness. METHODS: A new allergen-specific IgE (sIgE)-based tIgE RI, including a continuous RI in children, was established using the NHANES 2005-2006 project. The usefulness of the RI was evaluated by sensitivity (Sen), specificity (Spec), positive predictive value (PPV), negative predictive value (NPV), κ coefficient and consistency. RESULTS: The new tIgE RI showed better performance in identifying allergic sensitization (Sen 0.53, Spec 0.90, PPV 0.83, NPV 0.68, κ 0.44, consistency 0.72) than allergic diseases (Sen 0.37, Spec 0.75, PPV 0.55, NPV 0.60, κ 0.13, consistency 0.59). The 2014 U.S. tIgE RI was more effective in identifying allergic diseases (consistency 0.63 vs. 0.54, P<0.001) but less accurate in identifying allergic sensitization (consistency 0.59 vs. 0.67, P<0.001) in children than in adults. The new RI improved the accuracy of identifying allergic sensitization in children to a level similar to that in adults (consistency 0.72 vs 0.73, P=0.37) and maintained its advantage in identifying allergic diseases in children (consistency 0.64 vs 0.55, P<0.001). CONCLUSIONS: The established next-generation tIgE RI is useful for identifying allergic sensitization, especially in children.

JACQLQ subjective symptom questionnaire score and clinical test results for patients with allergic conjunctival disease.

We investigated the relationship between subjective symptoms and objective findings in patients with allergic conjunctival diseases (ACD) and test results for tear total IgE (t-tIgE), conjunctival eosinophils (c-Eo), serum total IgE (s-tIgE), serum-antigen specific IgE (s-sIgE), and serum eosinophils (s-Eo). Subjective symptoms and objective findings of patients with ACD were evaluated using Japanese Allergic Conjunctival Disease Quality of Life Questionnaire (JACQLQ), which described disability score and emotional score written by patient and clinical findings score written by ophthalmologist. We investigated the relationship between questionnaire scores and laboratory data for t-tIgE, c-Eo, s-tIgE, s-sIgE, and s-Eo. Scores of impediments to life and of moods were highest in vernal keratoconjunctivitis among ACD. Cases with positive pollen-sIgE showed significantly more nasal symptom score than those with negative pollen-sIgE (P < 0.05). Cases with positive t-tIgE or c-Eo showed significantly more objective symptoms' JACQLQ score than those with negative t-tIgE or c-Eo (P < 0.05), respectively. Cases positive for house dust/mite-sIgE, showed significantly more objective symptoms' JACQLQ score than those without for house dust/mite-sIgE (P < 0.05). These results indicate that ACD could be analyzed more accurately by the combination of JACQLQ and laboratory data.

Association of serum total IgE and allergen-specific IgE with insulin resistance in adolescents: an analysis of the NHANES database.

BACKGROUND: Recent studies have found that total immunoglobulin E (IgE) and allergen-specific IgE were associated with some metabolic diseases. However, the role of IgE in metabolism among adolescents is still unclear. Herein, this study aims to investigate the associations of serum total IgE and allergen-specific IgE with insulin resistance (IR) in adolescents, in order to provide some reference for the prevention and treatment of metabolic diseases in a young age. METHODS: Data of 870 adolescents were extracted from the National Health and Nutrition Examination Survey (NHANES) database in 2005-2006 in this cross-sectional study. Weighted univariate and multivariate logistic regression analyses were utilized to screen covariates and explore the relationships of serum total IgE and allergen-specific IgE with IR. The evaluation indexes were odds ratios (ORs) and 95% confidence intervals (CIs). In addition, these relationships were also assessed in subgroups of allergy history, asthma history, and number of allergens. RESULTS: Among eligible adolescents, 168 had IR. No significant association between serum total IgE level and IR was found. However, adolescents with higher level of allergen-specific IgE to rye grass [OR = 0.47, 95%CI: (0.25-0.91)], white oak [OR = 0.57, 95%CI: (0.37-0.88)], or peanut [OR = 0.38, 95%CI: (0.15-0.97)] seemed to have lower odds of IR, whereas those had higher level of shrimp-specific IgE [OR = 2.65, 95%CI: (1.21-5.84)] have increased odds of IR. In addition, these associations between allergen-specific IgE and IR were also discovered in adolescents who had allergy history or asthma history, or had different numbers of allergens. CONCLUSION: Paying attention to different allergens in adolescents may be important in the early identification of IR among this high-risk population. The study results relatively provided some reference for further exploration on IR prevention.

Predicting responses to omalizumab in antihistamine-refractory chronic urticaria: A real-world longitudinal study.

Background: Treating chronic urticaria (CU) that is unresponsive to H1-antihistamines (H1AHs) is challenging, and the real-world effectiveness of omalizumab remains unclear. Objective: Our aim was to evaluate the real-world effectiveness of omalizumab, optimal response assessment timing, and predictive factors. Methods: Initially, 5535 patients with CU who were receiving at least 20 mg of loratadine daily for at least 6 months (January 2007-August 2021) were screened. Ultimately, 386 patients who had been receiving omalizumab add-on treatment for >6 months were followed-up for more than 2 years. Predictors of treatment response to omalizumab add-on therapy for patients with antihistamine-refractory CU were identified by using a generalized linear model. Results: In our retrospective cohort, omalizumab treatment showed cumulative response rates of 55.2% at 3 months, 71.0% at 6 months, and 81.4% at 9 months for patients with H1AH-refractory CU. Analysis of longitudinal responses to omalizumab treatment revealed 3 distinct clusters: favorable (cluster 1 [n = 158]), intermediate (cluster 2 [n =1 43]), and poor responses (cluster 3 [n = 85]). Subjects were categorized on the basis of whether they had achieved a complete response within 3 months; 213 early responders, 117 late responders, and 56 nonresponders were identified. The initial dose of omalizumab differed significantly among the 3 clusters. Low total IgE level (<40 kU/L) predicted nonresponse (odds ratio [OR] = 3.10 [P = .018]). Early responders were associated with a higher initial omalizumab dose (≥300 mg) (OR = 2.07 [P = .016]), higher basophil counts (OR = 2.0 [P = .014]), total IgE levels exceeding 798 kU/L (OR = 0.37 [P = .047]), and lower platelet-to-lymphocyte ratio (OR = 0.50 [P = .050]). Conclusion: Real-world data reveal 3 distinct clusters for response to omalizumab treatment; confirm low serum total IgE level (<40 kU/L) as a predictor of nonresponse; and identify potential biomarkers, including IgE level, basophil count, and PLR, for early responders.

Predicting the Speed of Response to Omalizumab in Chronic Spontaneous Urticaria.

INTRODUCTION: Two distinct chronic spontaneous urticaria (CSU) endotypes, IgE-mediated autoallergic and IgG-mediated autoimmune, were defined based on the response patterns to omalizumab. However, the coexistence of IgE and IgG autoantibodies in a subset of patients might complicate the prediction of the treatment outcomes. This study aimed to evaluate the effectiveness and safety of omalizumab in CSU patients, focusing on the factors predicting the response patterns. METHODS: This was a retrospective cross-sectional single-center study investigating CSU patients treated with omalizumab for at least 6 months between September 2015 and February 2023. Patients were evaluated regarding demographics, clinical findings, baseline laboratory parameters, treatment outcomes, and side effects. Early and late responders were defined depending on the time for response, within or after 3 months, respectively. RESULTS: Among 82 patients, 75 (91.5%) responded to omalizumab during the first 6 months, classified as early (n = 51) and late responders (n = 24). The IgG anti-thyroid peroxidase (anti-TPO)/total IgE ratio was an independent predictor for determining the speed of response (p < 0.05). Of 29 patients who discontinued omalizumab, 19 (65.5%) experienced relapse with a good response to retreatment (n = 18/19, 94.7%). Early responders relapsed more frequently than late responders (77.3% vs. 28.6%) (p < 0.05). Only mild side effects were observed in a minority of patients (n = 8/82, 9.8%). CONCLUSION: Omalizumab is an effective and safe treatment in CSU. The IgG anti-TPO/total IgE ratio seems a valuable tool to predict the early and late responders, the former having a higher possibility of relapse upon drug withdrawal.

The Associations between Exposure to Multiple Heavy Metals and Total Immunoglobulin E in U.S. Adults.

Immunoglobulin E (IgE) is a type of immunoglobulin, and elevated serum total IgE is often present in allergic diseases. Exposure to environmental heavy metals has been markedly linked to allergic diseases, leading to elevated total IgE levels. However, studies concerning the effects of multiple metal exposures on total IgE levels are limited. Therefore, the current study seeks to explore the correlation between heavy-metal co-exposure and total IgE levels based on the National Health and Nutrition Examination Survey (NHANES, 2005-2006). Participants possessed complete data on total IgE levels, 11 urinary metal concentrations and other covariates. The correlations between 11 metals and total IgE levels were analyzed using multiple linear regression, and total IgE levels were a continuous variable. Total IgE levels exceeding 150 kU/L were considered sensitized. Binary logistic regression analyses were employed to assess the correlation between metal exposure and the occurrence of an allergic state. Then, the association between co-exposure to the 11 metals and total IgE levels or the occurrence of sensitization status was further analyzed by Bayesian kernel machine regression (BKMR), a multi-contaminant model. There were 1429 adults with complete data included. Based on the median concentration, molybdenum (Mo) had the highest concentration (46.60 µg/L), followed by cesium (Cs), barium (Ba), lead (Pb), and mercury (Hg). And the median (interquartile range) for total IgE levels was 43.7 (17.3, 126.0) kU/L. Multiple linear regression results showed that Pb was significantly and positively associated with total IgE levels (ß = 0.165; 95% CI: 0.046, 0.284). Binary logistic regression showed a significant positive correlation between urinary Pb (OR: 1.258; 95% CI: 1.052, 1.510) and tungsten (W) (OR: 1.251; 95% CI: 1.082, 1.447). Importantly, the BKMR model found a positive correlation between combined-metal exposure and total IgE levels and the occurrence of sensitization status. The mixed heavy-metal exposure was associated with increased total IgE levels, and this association may be driven primarily by the exposure of Pb and W. This study provides new insights into the relationship between heavy-metal exposure and allergic diseases. More research is needed to confirm these findings.

Nasal epithelial gene expression and total IgE in children and adolescents with asthma.

BACKGROUND: Little is known about nasal epithelial gene expression and total IgE in youth. OBJECTIVE: We aimed to identify genes whose nasal epithelial expression differs by total IgE in youth, and group them into modules that could be mapped to airway epithelial cell types. METHODS: We conducted a transcriptome-wide association study of total IgE in 469 Puerto Ricans aged 9 to 20 years who participated in the Epigenetic Variation and Childhood Asthma in Puerto Ricans study, separately in all subjects and in those with asthma. We then attempted to replicate top findings for each analysis using data from 3 cohorts. Genes with a Benjamini-Hochberg-adjusted P value of less than .05 in the Epigenetic Variation and Childhood Asthma in Puerto Ricans study and a P value of less than .05 in the same direction of association in 1 or more replication cohort were considered differentially expressed genes (DEGs). DEGs for total IgE in subjects with asthma were further dissected into gene modules using coexpression analysis, and such modules were mapped to specific cell types in airway epithelia using public single-cell RNA-sequencing data. RESULTS: A higher number of DEGs for total IgE were identified in subjects with asthma (n = 1179 DEGs) than in all subjects (n = 631 DEGs). In subjects with asthma, DEGs were mapped to 11 gene modules. The top module for positive correlation with total IgE was mapped to myoepithelial and mucus secretory cells in lower airway epithelia and was regulated by IL-4, IL5, IL-13, and IL-33. Within this module, hub genes included CDH26, FETUB, NTRK2, CCBL1, CST1, and CST2. Furthermore, an enrichment analysis showed overrepresentation of genes in signaling pathways for synaptogenesis, IL-13, and ferroptosis, supporting interactions between interleukin- and acetylcholine-induced responses. CONCLUSIONS: Our findings for nasal epithelial gene expression support neuroimmune coregulation of total IgE in youth with asthma.

Establishment of a homogeneous chemiluminescence immunoassay for cat dander sIgE antibody detection.

BACKGROUND: In vitro specific IgE (sIgE) testing has become an important tool for the diagnosis of IgE-mediated allergic diseases. Current methods used to detect allergen sIgE are time consuming and/or expensive. Therefore, a new method was developed for rapid quantitative detection of cat dander-sIgE antibody based on homogeneous chemiluminescence immunoassay. METHODS: Selection of chemibeads with different chemical groups, and the best Light-initiated chemiluminescence assay (LiCA) analytical mode for cat dander-sIgE detection. To validate and eliminate the interference of IgE on the detection of cat dander-sIgE, concentration of biotinylated anti-human IgE antibody was optimized. For quantification of cat dander-sIgE, a calibration curve was established, and the performance of the assay was evaluated according to clinical guidelines. RESULTS: Indirect LiCA is the best mode of analysis and biotinylated anti-human IgE antibody at a dilution ratio of 1:250 minimizes IgE interference. The coefficient of variation of the developed LiCA was 1.49% to 4.66%, with an intermediate precision of 6.90% to 8.21%. The LoB, LoD, and LoQ of the assay were 0.023 kUA/L, 0.056 kUA/L and 0.185 kUA/L. The coefficient of correlation (r) between LiCA and ImmounoCAP was 0.9478. CONCLUSIONS: A cat dander-sIgE quantitation assay based on homogeneous chemiluminescence immunoassay was established, which could be a new reliable analytical tool for the determination of cat dander-sIgE.

Gene-based association study of rare variants in children of diverse ancestries implicates TNFRSF21 in the development of allergic asthma.

BACKGROUND: Most genetic studies of asthma and allergy have focused on common variation in individuals primarily of European ancestry. Studying the role of rare variation in quantitative phenotypes and in asthma phenotypes in populations of diverse ancestries can provide additional, important insights into the development of these traits. OBJECTIVE: We sought to examine the contribution of rare variants to different asthma- or allergy-associated quantitative traits in children with diverse ancestries and explore their role in asthma phenotypes. METHODS: We examined whole-genome sequencing data from children participants in longitudinal studies of asthma (n = 1035; parent-identified as 67% Black and 25% Hispanic) to identify rare variants (minor allele frequency < 0.01). We assigned variants to genes and tested for associations using an omnibus variant-set test between each of 24,902 genes and 8 asthma-associated quantitative traits. On combining our results with external data on predicted gene expression in humans and mouse knockout studies, we identified 3 candidate genes. A burden of rare variants in each gene and in a combined 3-gene score was tested for its associations with clinical phenotypes of asthma. Finally, published single-cell gene expression data in lower airway mucosal cells after allergen challenge were used to assess transcriptional responses to allergen. RESULTS: Rare variants in USF1 were significantly associated with blood neutrophil count (P = 2.18 × 10-7); rare variants in TNFRSF21 with total IgE (P = 6.47 × 10-6) and PIK3R6 with eosinophil count (P = 4.10 × 10-5) reached suggestive significance. These 3 findings were supported by independent data from human and mouse studies. A burden of rare variants in TNFRSF21 and in a 3-gene score was associated with allergy-related phenotypes in cohorts of children with mild and severe asthma. Furthermore, TNFRSF21 was significantly upregulated in bronchial basal epithelial cells from adults with allergic asthma but not in adults with allergies (but not asthma) after allergen challenge. CONCLUSIONS: We report novel associations between rare variants in genes and allergic and inflammatory phenotypes in children with diverse ancestries, highlighting TNFRSF21 as contributing to the development of allergic asthma.

Biomarkers of Autoimmune Chronic Spontaneous Urticaria.

PURPOSEOF REVIEW: Chronic spontaneous urticaria and chronic inducible urticaria (CSU/CindU) are caused by mast cell and basophil activation leading to degranulation and the release of histamine and several other mediators. Three kinds of factors can trigger mast cells in CSU: (1) activation of stimulating receptor(s) on the mast cell membrane, (2) upregulation of certain receptor(s), and (3) intracellular dysregulation in signaling with overexpression of the spleen tyrosine kinase (SYK) or reduced activation of the inhibitory Src homology 2 (SH2)-containing inositol phosphatases (SHIP)-related pathways. In CSU, two major endotypes exist based on the primary receptor activating mechanism: type I hypersensitivity (IgE-mediated, directed against auto-allergens) and type IIb (autoimmune, via IgG autoantibodies directed against IgE or the IgE-receptor). Their treatment responses vary. We discuss in vitro and in vivo biomarkers. RECENT FINDINGS: Patients with auto-allergic CSU have clinical characteristics that can distinguish them partly from those with autoimmune CSU. Most importantly, their disease generally presents a less aggressive course, a better response to second generation (up-dosed) antihistamines and a good response to omalizumab, if necessary. Meanwhile, autoimmune CSU/CindU patients fare less well and often need immunosuppressive drugs. Biomarkers that might help endotype CSU/CindU patients and select the most appropriate treatment, dose, and duration, e.g., for autoallergic CSU, high total IgE and IgE against auto-allergens; for autoimmune CSU, low IgE, basopenia, and IgG against autoantigens like thyroid peroxidase and a positive autologous serum skin test (but sometimes also positive in autoallergy). Some biomarkers are easily accessible but of low specificity; others are highly specific but more futuristic.

Reference values of serum total IgE in Uppsala - comparison over four decades.

Background: Total immunoglobulin E (IgE) analysis is a common tool in allergy diagnosis. Suggested reference values for IgE are divergent and sometimes based on outdated assay methods. We aimed to validate the published reference values (geometric mean [GM]: 13.2 kU/L, upper limit of normal [ULN], 114 kU/L) shown in an Uppsala cohort from 1974 using Phadebas IgE PRIST, and the suggested clinical threshold of 100 kU/L (Zetterström and Johansson 1981). Methods: Immunoglobulin E was measured in two Uppsala cohorts from 1997 (Blood bank) and 2011 to 2013 (the European community respiratory health survey part III [ECRHS III]) using ImmunoCAP™ Total IgE. For the reference value calculations, exclusion criteria were atopy (both cohorts), doctor's diagnosis of asthma and self-reported allergy (hay fever, rhinitis, rash) (only ECRHS III). Upper limit of normal was defined as mean + 2 standard deviations (SD) calculated using log-transformed values and back-transformation of the ULN prior to presentation. Common imputation methods for results below the assay range were evaluated. Results: The average GM was 14.2 kU/L (Blood bank, n = 63; imputation method range: 16.9-17.4 kU/L; ECRHS III, n = 113: 10.7-11.6 kU/L) and the overall mean ULN was 118 kU/L (Blood bank: 113-130 kU/L; ECRHS III: 104-128 kU/L). The clinical sensitivity and specificity of the 100 kU/L IgE threshold were 37.8 and 94.3% for atopy, 34.9 and 89.5% for doctor's diagnosis of asthma, and 24.5 and 97.3% for any self-reported allergy (ECRHS III). Conclusion: The calculated ULN values were similar between the cohorts. We conclude that the total IgE reference values shown for Uppsala subjects from 1974 are still valid and suitable also for the ImmunoCAP Total IgE assay. The 100 kU/L threshold for total IgE had a low sensitivity but high specificity for atopy, asthma, and allergy.

Investigating Forkhead Box O Transcription Factor 1 Gene's Relation to Immunoglobulin E in House Dust Mite-Allergic Asthma Patients.

House dust mite (HDM)-allergic asthma is an abnormal immune response to extrinsic aeroallergens found in human vicinities. Studying the role of the associated immunity biomarkers and their interplay helps in discovering novel therapeutic strategies that can be used in adjunct with effective long-term immunotherapy. This study investigates the total serum IgE, FoxO1, and Sirtuin 1 (SIRT1) gene expressions in HDM-allergic asthma patients. We enrolled 40 patients for each of the following three groups: an HV group of healthy volunteers and HDM/AA and HDM/SCIT groups of HDM-allergic asthma patients who did not and who did receive immunotherapy before recruitment in this study, respectively. The results elucidated that total IgE was strikingly elevated in the HDM/AA group and showed little decline in the HDM/SCIT group. Both FoxO1 and SIRT1 gene expressions showed the highest levels in the HDM/SCIT group. There was a negative correlation between total IgE and both FoxO1 and SIRT1 in the HDM/AA group while there was a positive correlation with SIRT1 in the HDM/SCIT group. In conclusion, the interplay of the three immunity biomarkers related to HDM-allergic asthma after the course of immunotherapy treatment suggests further, broader studies on the feasibility of their role as immunity biomarkers in the control and remission of HDM-allergic asthma.

Exhaled nitric oxide is only an asthma-relevant biomarker among children with allergic sensitization.

BACKGROUND: Fraction of exhaled nitric oxide (FeNO) is used for diagnosing and monitoring asthma in children, but the influence of allergic sensitization is still poorly understood. Here, we investigate how asthma and allergic sensitization influence FeNO levels during childhood. METHODS: We investigated the associations between asthma, aeroallergen sensitization, and FeNO measured from age 5-18 years in the COPSAC2000 birth cohort of 411 children using repeated measurement mixed models adjusted for gestational age, sex, concurrent airway infection, inhaled corticosteroids, and tobacco exposure. Replication was sought in the similarly designed COPSAC2010 cohort of 700 children. RESULTS: In the COPSAC2000 cohort, 133 had asthma between age 5 and 18 years, and in the COPSAC2010 cohort, 112 had asthma between age 5 and 10 years. In the COPSAC2000 cohort, asthma and aeroallergen sensitization were both associated with higher FeNO from age 5 to 18 years: adjusted geometric mean ratio (aGMR), 1.22 (1.08-1.35), p < .01, and 1.41 (1.21-1.65), p < 0.001, respectively. However, asthma was associated with increased FeNO among children with aeroallergen sensitization: 1.44 (1.23-1.69), p < .0001, whereas asthma was associated with decreased FeNO among nonsensitized children: 0.80 (0.65-0.99), p = .05 (p-interaction<.0001 for asthma x sensitization). Replication in the COPSAC2010 cohort showed similar results (p-interaction <.01). Further, blood eosinophil count, total-IgE, bronchodilator response, and bronchial hyperreactivity were all associated with increased FeNO among children sensitized to aeroallergens, but not among nonsensitized children. CONCLUSION: Fraction of exhaled nitric oxide is elevated through childhood in children with asthma and is correlated with asthma-associated traits depending on the presence of aeroallergen sensitization. These findings indicate that FeNO is only a valid asthma biomarker in children with concurrent aeroallergen sensitization, which is important for guideline recommendations on the clinical use of FeNO.

Evaluation of the predictive value of total IgE and absolute eosinophil levels on allergy test positivity.

OBJECTIVE: Atopic diseases are the most common chronic conditions in childhood. The best treatment for allergic disease is possible with early diagnosis. The purpose of the study was to assess the predictive value of total immunoglobulin E (IgE) and eosinophil levels for allergy test positivity in patients diagnosed with asthma, allergic rhinitis (AR), atopic dermatitis (AD), and food allergy (FA). METHODS: Pediatric patients between 0 and 18 years old diagnosed with asthma, AR, AD, and FA were included in the study. Demographic characteristics of the patients, total IgE, eosinophil (absolute and %) values, specific igE (SPIGE), and skin prick test (SPT) results were recorded. RESULTS: The data of 2665 patients were evaluated in the study. Of the patients, 58.6% were male, whereas 41.4% were female. The median age of the children was significantly higher both in SPT-positive and SPIGE-positive patients (p<0.001). If the criteria positivity is accepted as total IgE value is ≥104.5 (for AD: 86.5, asthma: 116.5, AR: 120.5, FA: 42.5) and absolute eosinophil ≥500 and/or eosinophil (%) ≥5%; test positivity was higher for each disease and all patients (p<0.001). CONCLUSION: Total IgE and eosinophil levels can be used to identify atopy in patients with symptoms of AD, asthma, and AR. Total IgE and eosinophil values are suitable and easily obtainable parameters for better evaluation of health-care resources for the diagnosis and follow-up of atopic illnesses.

A survey of total IgE reference intervals reported by Scandinavian and British medical laboratories - a need for harmonisation.

OBJECTIVES: There appears to be marked discrepancies between total IgE reference intervals (RIs) in use by many laboratories and those recommended by published studies. The aim of this study was therefore to review total IgE RIs currently reported by Scandinavian and British laboratories and to compare these to published RIs identified by a literature review. METHODS: Relevant laboratories were identified by test directories provided by the national accreditation bodies in Norway, Sweden, Denmark and the UK. Total IgE RIs and their sources were acquired by accessing laboratory user handbooks or by an electronic survey. In addition a literature review of published total IgE RI studies was performed. RESULTS: From 172 accredited laboratories providing total IgE analysis, data was acquired from 122 laboratories. An adult upper reference limit between 81 to 150 kU/L was reported by 89% of these. Denmark and Sweden reported the most harmonised RIs whilst Norway and the UK exhibited the least degree of harmonisation. Published adult (n = 6) and paediatric (n = 6) RI studies reported markedly higher upper limits than those currently in use by the laboratories included in this study. There were also large variations in the number of age strata in use for paediatric RIs. CONCLUSION: This study demonstrates large variations in currently utilised IgE RIs by Scandinavian and British accredited laboratories and most report markedly lower RIs than those recommended by recent RI publications. Many laboratories likely utilise outdated RIs and should consider critically reviewing and updating their RIs.