IgE to cross-reactive carbohydrate determinants (CCD) in childhood: Prevalence, risk factors, putative origins.

BACKGROUND: IgE antibodies to cross-reactive carbohydrate determinants (CCD) are usually clinically irrelevant but they can be a cause of false positive outcomes of allergen-specific IgE tests in vitro. Their prevalence and levels have been so far cross-sectionally examined among adult allergic patients and much less is known about their origins and relevance in childhood. METHODS: We examined CCD with a cross-sectional approach in 1263 Italian pollen allergic children (Panallergen in Paediatrics, PAN-PED), as well as with a longitudinal approach in 612 German children (Multicenter Allergy Study, MAS), whose cutaneous and IgE sensitization profile to a broad panel of allergen extracts and molecules was already known. The presence and levels of IgE to CCD were examined in the sera of both cohorts using bromelain (MUXF3) as reagent and a novel chemiluminescence detection system, operating in a solid phase of fluorescently labelled and streptavidin-coated paramagnetic microparticles (NOVEOS, HYCOR, USA). RESULTS: IgE to CCD was found in 22% of the Italian pollen allergic children, mainly in association with an IgE response to grass pollen. Children with IgE to CCD had higher total IgE levels and were sensitized to more allergenic molecules of Phleum pratense than those with no IgE to CCD. Among participants of the German MAS birth cohort study, IgE to CCD emerged early in life (even at pre-school age), with IgE sensitization to group 1 and 4 allergen molecules of grasses, and almost invariably persisted over the full observation period. CONCLUSIONS: Our results contribute to dissect the immunological origins, onset, evolution and risk factors of CCD-sIgE response in childhood, and raise the hypothesis that group 1 and/or 4 allergen molecules of grass pollen are major inducers of these antibodies through an antigen-specific, T-B cell cognate interaction.

Validation Parameters of Patient-Generated Data for Digitally Recorded Allergic Rhinitis Symptom and Medication Scores in the @IT.2020 Project: Exploratory Study.

BACKGROUND: Mobile health technologies enable allergists to monitor disease trends by collecting daily patient-reported outcomes of allergic rhinitis. To this end, patients with allergies are usually required to enter their symptoms and medication repetitively over long time periods, which may present a risk to data completeness and quality in the case of insufficient effort reporting. Completeness of patient's recording is easily measured. In contrast, the intrinsic quality and accuracy of the data entered by the patients are more elusive. OBJECTIVE: The aim of this study was to explore the association of adherence to digital symptom recording with a predefined set of parameters of the patient-generated symptom and medication scores and to identify parameters that may serve as proxy measure of the quality and reliability of the information recorded by the patient. METHODS: The @IT.2020 project investigates the diagnostic synergy of mobile health and molecular allergology in patients with seasonal allergic rhinitis. In its pilot phase, 101 children with seasonal allergic rhinitis were recruited in Rome and instructed to record their symptoms, medication intake, and general conditions daily via a mobile app (AllergyMonitor) during the relevant pollen season. We measured adherence to daily recording as the percentage of days with data recording in the observation period. We examined the patient's trajectories of 3 disease indices (Rhinoconjunctivitis Total Symptom Score [RTSS], Combined Symptom and Medication Score [CSMS], and Visual Analogue Scale [VAS]) as putative proxies of data quality with the following 4 parameters: (1) intravariation index, (2) percentage of zero values, (3) coefficient of variation, and (4) percentage of changes in trend. Lastly, we examined the relationship between adherence to recording and each of the 4 proxy measures. RESULTS: Adherence to recording ranged from 20% (11/56) to 100% (56/56), with 64.4% (65/101) and 35.6% (36/101) of the patients' values above (highly adherent patients) or below (low adherent patients) the threshold of 80%, respectively. The percentage of zero values, the coefficient of variation, and the intravariation index did not significantly change with the adherence to recording. By contrast, the proportion of changes in trend was significantly higher among highly adherent patients, independently from the analyzed score (RTSS, CSMS, and VAS). CONCLUSIONS: The percentage of changes in the trend of RTSS, CSMS, and VAS is a valuable candidate to validate the quality and accuracy of the data recorded by patients with allergic rhinitis during the pollen season. The performance of this parameter must be further investigated in real-life conditions before it can be recommended for routine use in apps and electronic diaries devoted to the management of patients with allergic rhinitis.

Heterogeneity of pollen food allergy syndrome in seven Southern European countries: The @IT.2020 multicenter study.

BACKGROUND: Pollen food allergy syndrome (PFAS) is a frequently underdiagnosed disease due to diverse triggers, clinical presentations, and test results. This is especially relevant in geographic areas with a broad spectrum of pollen sensitization, such as Southern Europe. OBJECTIVES: To elucidate similarities and differences of PFAS in nine Southern European centers and identify associated characteristics and unique markers of PFAS. METHODS: As part of the @IT.2020 Multicenter Study, 815 patients with seasonal allergic rhinitis (SAR), aged 10-60 years, were recruited in seven countries. They completed questionnaires regarding SAR, comorbidities, family history, and PFAS, and underwent skin prick testing (SPT) and serum IgE testing. RESULTS: Of the 815 patients, 167 (20.5%) reported PFAS reactions. Most commonly, eliciting foods were kiwi (58, 34.7%), peach (43, 25.7%), and melon (26, 15.6%). Reported reactions were mostly local (216/319, 67.7%), occurring within 5 min of contact with elicitors (209/319, 65.5%). Associated characteristics included positive IgE to at least one panallergen (profilin, PR-10, or nsLTP) (p = 0.007), maternal PFAS (OR: 3.716, p = 0.026), and asthma (OR: 1.752, p = 0.073). Between centers, heterogeneity in prevalence (Marseille: 7.5% vs. Rome: 41.4%, p < 0.001) and of clinical characteristics was apparent. Cypress played a limited role, with only 1/22 SPT mono-sensitized patients reporting a food reaction (p < 0.073). CONCLUSIONS: PFAS is a frequent comorbidity in Southern European SAR patients. Significant heterogeneity of clinical characteristics in PFAS patients among the centers was observed and may be related to the different pollen sensitization patterns in each geographic area. IgE to panallergen(s), maternal PFAS, and asthma could be PFAS-associated characteristics.

EAACI Allergen Immunotherapy User's Guide.

Allergen immunotherapy is a cornerstone in the treatment of allergic children. The clinical efficiency relies on a well-defined immunologic mechanism promoting regulatory T cells and downplaying the immune response induced by allergens. Clinical indications have been well documented for respiratory allergy in the presence of rhinitis and/or allergic asthma, to pollens and dust mites. Patients who have had an anaphylactic reaction to hymenoptera venom are also good candidates for allergen immunotherapy. Administration of allergen is currently mostly either by subcutaneous injections or by sublingual administration. Both methods have been extensively studied and have pros and cons. Specifically in children, the choice of the method of administration according to the patient's profile is important. Although allergen immunotherapy is widely used, there is a need for improvement. More particularly, biomarkers for prediction of the success of the treatments are needed. The strength and efficiency of the immune response may also be boosted by the use of better adjuvants. Finally, novel formulations might be more efficient and might improve the patient's adherence to the treatment. This user's guide reviews current knowledge and aims to provide clinical guidance to healthcare professionals taking care of children undergoing allergen immunotherapy.

"Whole" vs. "fragmented" approach to EAACI pollen season definitions: A multicenter study in six Southern European cities.

BACKGROUND: The adequate definition of pollen seasons is essential to facilitate a correct diagnosis, treatment choice, and outcome assessment in patients with seasonal allergic rhinitis. A position paper by the European Academy of Allergy and Clinical Immunology (EAACI) proposed season definitions for Northern and Middle Europe. OBJECTIVE: To test the pollen season definitions proposed by EAACI in six Mediterranean cities for seven pollen taxa. METHODS: As part of the @IT.2020 multi-center study, pollen counts for Poaceae, Oleaceae, Fagales, Cupressaceae, Urticaceae (Parietaria spp.), and Compositae (Ambrosia spp., Artemisia spp.) were collected from January 1 to December 31, 2018. Based on these data, pollen seasons were identified according to EAACI criteria. A unified monitoring period for patients in AIT trials was created and assessed for feasibility. RESULTS: The analysis revealed a great heterogeneity between the different locations in terms of pattern and length of the examined pollen seasons. Further, we found a fragmentation of pollen seasons in several segments (max. 8) separated by periods of low pollen counts (intercurrent periods). Potential monitoring periods included often many recording days with low pollen exposure (max. 341 days). CONCLUSION: The Mediterranean climate leads to challenging pollen exposure times. Monitoring periods for AIT trials based on existing definitions may include many intermittent days with low pollen concentrations. Therefore, it is necessary to find an adapted pollen season definition as individual solution for each pollen and geographical area.

IgE antibody repertoire in nasal secretions of children and adults with seasonal allergic rhinitis: A molecular analysis.

BACKGROUND: There is growing interest both in testing IgE in nasal secretions (NS) and in molecular diagnosis of seasonal allergic rhinitis (SAR). Yet, the reliability of nasal IgE detection with the newest molecular assays has never been assessed in a large cohort of pollen allergic patients. OBJECTIVE: To investigate with microarray technology and compare the repertoires of specific IgE (sIgE) antibodies in NS and sera of a large population of children and adults with SAR. METHODS: Nasal secretions were collected with an absorbent device (Merocel 2000® , Medtronic) and a minimal dilution procedure from 90 children and 71 adults with SAR. Total IgE (tIgE) (ImmunoCAP, Thermo Fisher Scientific (TFS)) and sIgE antibodies against 112 allergen molecules (ISAC-112, TFS) were measured in NS and serum. RESULTS: Nasal sIgE was detectable in 68.3% of the patients. The detected nasal sIgE antibodies recognized airborne (88%), vegetable (10%), and animal food or other (<1%) allergen molecules. The prevalence and average levels of sIgE in NS and serum were highly interrelated at population level. A positive nasal sIgE antibody to a given molecule predicted the detection of the same antibody in the patient's serum with a specificity of 99.7% and a sensitivity of 40%. CONCLUSIONS: The concentration of sIgE is much lower in nasal secretions than in the serum. sIgE assays with very high analytical sensitivity and sampling methods with minimal dilution will be therefore needed to validate nasal secretions as alternative to serum in testing the sIgE repertoire.

A new molecular multiplex IgE assay for the diagnosis of pollen allergy in Mediterranean countries: A validation study.

BACKGROUND: The identification of the primary sensitizing pollen is difficult in Southern European patients with Seasonal Allergic Rhinitis (SAR) if sensitized to various pollen sources with overlapping seasonality. A more precise diagnosis is obtained by IgE assays to allergen molecules, currently available as singleplex or microarrays. OBJECTIVES: To test the analytical performance of a multi-parameter immunoblot molecular "Pollen Test" specifically designed to test IgE antibodies to pollen extracts and molecules clinically relevant in Southern Europe. METHODS: Sera were obtained from 101 children and 98 adults with SAR and tested with a customized multiplex immunoblot assay (EUROLINE Southern European Pollen Profile [ESEP]; EUROIMMUN AG, Luebeck, Germany) containing a comprehensive panel of allergen extracts and molecules. ESEP's outcomes were then compared in selected sera (ESEP positive to negative = 2:1) with those of singleplex IgE assays (ImmunoCAP; ThermoFisher Scientific, Uppsala, Sweden). For each of the examined reagents, qualitative (sensitivity, specificity, accuracy), semi-quantitative (classes) and quantitative (Spearman's rank correlation, Bland-Altmann plots) comparisons were performed. RESULTS: Compared to ImmunoCAP, cumulative ESEP's sensitivity and specificity were 87% (95% CI 84%-90%) and 88% (83%-93%) for extracts and 99% (98%-100%) and 87% (83%-91%) for molecules. Cohen's kappa coefficients (κC ) ranged for extracts from 0.18 (Pellitory) to 0.50 (Cypress) and for molecules from 0.21 (Ole e 1) to 0.68 (Phl p 7). The quantitative outcomes of the two diagnostic tests were highly correlated, with Spearman's rank correlation coefficients always exceeding 0.80. Bland-Altmann plots showed a tendency of ESEP to overestimate serum specific IgE levels, when compared to ImmunoCAP. CONCLUSIONS AND CLINICAL RELEVANCE: Sensitivity and specificity of ESEP in testing serum IgE antibodies against pollen allergen extracts and molecules, in Italian patients with SAR, both exceeded 85%. The advantages and limitations of a multiplex customized immunoblot assay, in the routine clinical use of molecular diagnostics in Southern European pollen allergic patients, deserve to be tested.