Sensitization patterns to cat molecular allergens in subjects with allergic sensitization to cat dander

BACKGROUND

The use of molecular allergology has increasingly become common in the diagnosis and management of allergic diseases. However, there is still a lack of data on cat molecular allergens in adults. Therefore, we aimed to uncover the sensitization patterns to cat molecular allergens.

METHODS

Participants were recruited from the West Asthma Sweden Study, a population-based study enriched with asthma subjects aged 16-75 years. Of 1872, 361 individuals were positive for cat dander immunoglobulin E and were further analysed for cat molecular allergens (Fel d 1/2/4/7). Sensitization patterns were classified as monosensitization, polysensitization, and concomitant sensitization, and were related to demographic and clinical measurements.

RESULTS

Among cat-sensitized subjects, 84.2% were sensitized to secretoglobin, while 42.4% were sensitized to lipocalins. Nearly half of the subjects were monosensitized to Fel d 1. Polysensitization was observed in 20.2%, and concomitant sensitization to protein families was seen in 7.2%. Asthma prevalence, cat exposure, and rural living were associated with poly- and concomitant sensitization to protein families. Concomitant sensitization to single allergens was more common in those with asthma than in those without, while concomitant sensitization to both Fel d 1 and Fel d 4 was the most common pattern in individuals with asthma. Sensitization patterns also differed according to cat ownership and the degree of urbanization.

CONCLUSION

Sensitization to molecular allergens was observed in 90.9% of cat-sensitized subjects and showed variations across participants' background characteristics and the presence of asthma. Identification of sensitization patterns to cat allergens might provide better characterization of cat-allergic subjects.

Molecular Profile Sensitization to House Dust Mites as an Important Aspect for Predicting the Efficiency of Allergen Immunotherapy

House dust mite (HDM) allergens are considered to be one of the most common causes of asthma and allergic rhinitis in the world. Cysteine proteases Der p 1 and Der f 1 (group 1) and also NPC 2 family proteins Der p 2 and Der f 2 (group 2) of D. pteronyssinus and D. farinae respectively are considered the main allergens of HDMs. The difference in the sensitivity of the population to these and other allergy causing components of HDM determines the treatment strategy. Thus, the purpose of this work was to determine the pattern of sensitization of the Ukrainian population to individual allergy causing molecular components of HDM in order to improve treatment strategies for the HDM allergy in various regions of Ukraine. To determine the molecular profile of sensitization to HDM, the data of multiplex allergy test Alex2 have been obtained from 10,651 patients. The sample included 57.86% children under the age of 18 and 42.14% adults. A Python language-based statistical analysis was performed, in order to group patients by sensitization to individual molecules and their combinations, regarding the age and geographical location of the patients. Simultaneous sensitization to Der f 2 and Der p 2 allergens was the most common among the entire group Simultaneous sensitization to 5 molecules—of group 1 (Der p 1 and Der f 1), group 2 (Der f 2 and Der p 2), and Der p 23—was the second most common for entire dataset and for the children group. This pattern differed in adults, where monosensitization to Der p 23 occupied the second position, suggesting that this molecule is an important factor of HDM allergy in Ukraine. Of the 16 analyzed regions, sensitization to Der p 23 prevailed in 2 Western regions of Ukraine. In the rest of the regions combination of Der p 2 and Der f 2 was the most prevalent. The established character of population sensitization to HDM in Ukraine is a good prognostic marker of allergen immunotherapy (AIT) efficacy.

Precision medicine in the allergy clinic: the application of component resolved diagnosis

INTRODUCTION

A precise diagnosis is key for the optimal management of allergic diseases and asthma. In vivo or in vitro diagnostic methods that use allergen extracts often fail to identify the molecules eliciting the allergic reactions.

AREAS COVERED

Component-resolved diagnosis (CRD) has solved most of the limitations of extract-based diagnostic procedures and is currently valuable tool for the precision diagnosis in the allergy clinic, for venom and food allergy, asthma, allergic rhinitis, and atopic dermatitis. Its implementation in daily practice facilitates: a) the distinction between genuine multiple sensitizations and cross-reactive sensitization in polysensitized patients; b) the prediction of a severe, systemic reaction in food or insect venom allergy; c) the optimal selection of allergen immunotherapy based on the patient sensitization profile. This paper describes its main advantages and disadvantages, cost-effectiveness and future perspectives.

EXPERT OPINION

The diagnostic strategy based on CRD is part of the new concept of precision immunology, which aims to improve the management of allergic diseases.

Specific IgG4 antibodies to cow's milk proteins in pediatric patients with eosinophilic esophagitis

BACKGROUND

Allergen-specific IgG₄ (sIgG₄) antibodies are often associated with tolerance, but sIgG₄ antibodies to causally relevant foods have been reported recently in adults with eosinophilic esophagitis (EoE). Prevalence and levels of food sIgG₄ are not well established in the general pediatric population.

OBJECTIVE

We sought to investigate serum food sIgG₄ with component diagnostics in children with EoE and children from an unselected birth cohort and to explore the effects of sex, age, and milk consumption on sIgG₄ levels.

METHODS

Sera from 71 pediatric patients with EoE and 210 early adolescent children from an unselected birth cohort (Project Viva) were assayed for sIgG₄ and specific IgE (sIgE) to major cow's milk (CM) proteins (α-lactalbumin, β-lactoglobulin, and caseins) and to wheat, soy, egg, and peanut proteins.

RESULTS

In the EoE cohort high-titer sIgG₄ (≥10 μg/mL) to CM proteins was more common than in control sera and achieved odds ratios for EoE ranging from 5.5 to 8.4. sIgE levels to CM proteins were mostly 4 IU/mL or less in patients with EoE, such that sIgG₄/sIgE ratios were often 10,000 or greater. When adjusted for age and milk consumption, high-titer sIgG₄ to CM proteins was strongly associated with EoE, with an odds ratio of greater than 20 to all 3 CM proteins in boys.

CONCLUSIONS

sIgG₄ to CM proteins are common and high titer in children with EoE. Although it is not clear that this response is pathogenic, sIgG₄ levels imply that these antibodies are an important feature of the local immune response that gives rise to EoE.

Aspergillus fumigatus in cystic fibrosis: An update on immune interactions and molecular diagnostics in allergic bronchopulmonary aspergillosis

A wide spectrum of pathological conditions may result from the interaction of Aspergillus fumigatus and the immune system of its human host. Allergic bronchopulmonary aspergillosis is one of the most severe A. fumigatus-related diseases due to possible evolution toward pleuropulmonary fibrosis and respiratory failure. Allergic bronchopulmonary aspergillosis occurs almost exclusively in cystic fibrosis or asthmatic patients. An estimated 8%-10% of patients with cystic fibrosis experience this condition. The diagnosis of allergic bronchopulmonary aspergillosis relies on criteria first established in 1977. Progress in the understanding of host-pathogen interactions in A. fumigatus and patients with cystic fibrosis and the ongoing validation of novel laboratory tools concur to update and improve the diagnosis of allergic bronchopulmonary aspergillosis.

Comparing immediate-type food allergy in humans and companion animals-revealing unmet needs

Adverse food reactions occur in human as well as veterinary patients. Systematic comparison may lead to improved recommendations for prevention and treatment in both. In this position paper, we summarize the current knowledge on immediate-type food allergy vs other food adverse reactions in companion animals, and compare this to the human situation. While the prevalence of food allergy in humans has been well studied for some allergens, this remains to be investigated for animal patients, where owner-reported as well as veterinarian-diagnosed food adverse reactions are on the increase. The characteristics of the disease in humans vs dogs, cats, and horses are most often caused by similar, but sometimes species-dependent different pathophysiological mechanisms, prompting the specific clinical symptoms, diagnoses, and treatments. Furthermore, little is known about the allergen molecules causative for type I food allergy in animals, which, like in human patients, could represent predictive biomarkers for risk evaluation. The definite diagnosis of food allergy relies-as in humans-on elimination diet and provocation tests. Besides allergen avoidance in daily practice, novel treatment options and tolerization strategies are underway. Taken together, numerous knowledge gaps were identified in veterinary food allergy, which need to be filled by systematic comparative studies.

Multivariate Analysis As a Support for Diagnostic Flowcharts in Allergic Bronchopulmonary Aspergillosis: A Proof-of-Concept Study

Molecular-based allergy diagnosis yields multiple biomarker datasets. The classical diagnostic score for allergic bronchopulmonary aspergillosis (ABPA), a severe disease usually occurring in asthmatic patients and people with cystic fibrosis, comprises succinct immunological criteria formulated in 1977: total IgE, anti-Aspergillus fumigatus (Af) IgE, anti-Af “precipitins,” and anti-Af IgG. Progress achieved over the last four decades led to multiple IgE and IgG(4) Af biomarkers available with quantitative, standardized, molecular-level reports. These newly available biomarkers have not been included in the current diagnostic criteria, either individually or in algorithms, despite persistent underdiagnosis of ABPA. Large numbers of individual biomarkers may hinder their use in clinical practice. Conversely, multivariate analysis using new tools may bring about a better chance of less diagnostic mistakes. We report here a proof-of-concept work consisting of a three-step multivariate analysis of Af IgE, IgG, and IgG4 biomarkers through a combination of principal component analysis, hierarchical ascendant classification, and classification and regression tree multivariate analysis. The resulting diagnostic algorithms might show the way for novel criteria and improved diagnostic efficiency in Af-sensitized patients at risk for ABPA.

Management of polysensitized patient: from molecular diagnostics to biomolecular immunotherapy

A panel of Italian allergists gathered to discuss the issue concerning the management of polysensitized patients. The main conclusions were as follows: polysensitization is a relevant clinical characteristic as it affects about 70-80% of the global allergic population; the diagnostic pathway needs the use of an adequate and thorough methodology, based on the demonstration of consistency between history and documented sensitization; polysensitization and polyallergy are not synonymous: true allergy should always be demonstrated; polysensitization does not constitute a limitation to allergen immunotherapy prescription, as 1-2 allergen extracts could be effective in polysensitized patients; the allergen immunotherapy product characteristics should include the following: high efficacy and optimal safety profile, standardized production, and documented presence and titration of the major allergen.

Allergen component specific ige measurement with the Immulite™ 2000 system: diagnostic accuracy and intermethod comparison

BACKGROUND

The identification of the allergenic molecules, associated to the advances in the field of recombinant allergens, led to the development of a new concept in allergy diagnosis called component-resolved diagnosis. The aim of our study was to evaluate the diagnostic accuracy of different allergen components using the full automatic singleplex quantitative platform Immulite™ 2000.

METHODS

One hundred ninety-five allergic outpatients (35 to olive pollen, 35 to birch pollen, 35 to profilin, 35 to house dust mites, 35 to peach, and 20 to shrimp) and 20 negative controls were enrolled for the study. Bet v 1, Bet v 2, Ole e 1, Der p 1, Der p 2, Der f 1, Der f 2, Pru p 3, tropomyosin were tested both with Immulite™ 2000 and ImmunoCAP™ (Thermo Fisher Scientific, Uppsala, Sweden).

RESULTS

Sensitivity of allergen-specific Immunoglobulin E (sIgE) to Ole e 1, Bet v 1, Der p 1, Der p 2, Der f 1, Der f 2, Pen m 1, and Pru p 3 with Immulite™ 2000 was 100%, 100%, 77.1%, 94.3%, 71.4%, 94%, 75%, and 97.1%, respectively, and the specificity was 100% for all the allergens. The overall agreement between Immulite™ 2000 and ImmunoCAP™ (Thermo Fisher Scientific) platforms was 98.6% (Cohen's kappa = 0.979; confidence interval [CI] 95%: 0.960-0.997). From moderate to strong, positive linear correlations between the assays (r(2) from 0.322 to 0.860, and Spearman's rho from 0.824 to 0.971) were showed.

CONCLUSIONS

A high diagnostic accuracy of the sIgE to allergen components measurement with Immulite™ 2000 and a high agreement with ImmunoCAP™ platforms were shown in this study.