Evaluation of clinical outcomes of efficacy in food allergen immunotherapy trials, COFAITH EAACI task force.

Food allergy is a global public health problem that until recent years lacked any aetiological treatment supported by academy, industry and regulators. Food immunotherapy (AIT) is an evolving treatment option, supported by clinical practice and industry trial data. Recent AIT meta-analyses have highlighted the difficulty in pooling safety and efficacy data from AIT trials, due to secondary heterogeneity in the study. An EAACI task force (CO-FAITH) initiated by the Paediatric Section was created to focus on AIT efficacy outcomes for milk, egg and peanut allergy rather than in trial results. A systematic search and a narrative review of AIT controlled clinical trials and large case series was conducted. A total of 63 manuscripts met inclusion criteria, corresponding to 23, 21 and 22 studies of milk, egg and peanut AIT, respectively. The most common AIT efficacy outcome was desensitization, mostly defined as tolerating a maintenance phase dose, or reaching a particular dose upon successful exit oral food challenge (OFC). However, a large degree of heterogeneity was identified regarding the dose quantity defining this outcome. Sustained unresponsiveness and patient-reported outcomes (e.g. quality of life) were explored less frequently, and to date have been most rigorously described for peanut AIT versus other allergens. Change in allergen threshold assessed by OFC remains the most common efficacy measure, but OFC methods suffer from heterogeneity and methodological disparity. This review has identified multiple heterogeneous outcomes related to measuring the efficacy of AIT. Efforts to better standardize and harmonize which outcomes, and how to measure them must be carried out to help in the clinical development of safe and efficacious food allergy treatments.

Effect of the SARS-CoV-2 pandemic on the control and severity of pediatric asthma.

BACKGROUND: The novel disease caused by the new coronavirus SARS-CoV-2 has caused an unprecedented global pandemic. Care providers of asthmatic children are increasingly con-cerned; as viral infections are one of the primary triggers of asthma flare-up. However, the effect of SARS-CoV-2 as well as the generated worldwide lockdown on asthmatic children is unknown. OBJECTIVE: The aim of this study was to analyze the effects of pandemic SARS-CoV-2 in pediat-ric asthma control. MATERIAL AND METHODS: A retrospective, open, transversal study was performed at five ter-tiary hospitals. Recruited patients were aged <18 years and had physician-diagnosed asthma. Information regarding the 2019 and 2020 seasons were provided. RESULTS: Data were collected from 107 children (age range: 3-18 years, mean age: 12 years). Well-controlled asthma was observed in 58 (54.2%) patients in 2020 versus 30 (28%) in 2019, and 15 (14%) patients had poorly controlled asthma in 2020 versus 28 (26.2%) in 2019. In 2020, a decrease in exacerbations caused by allergies to pollen, dust mites, molds, and through other causes not related to SARS-CoV-2 infection was observed. An increase in exacerbations was observed due to animal dander, stress, physical exercise, and SARSCoV-2 infection. Children had a reduced need for asthma-controlling medication, made fewer visits to healthcare providers and had lesser need of treatment with oral corticosteroids if compared with the same season of 2019. CONCLUSION: Pediatric asthma control improved, the need for controller medication declined, and fewer visits to healthcare providers were made during the pandemic if compared with the 2019 season.

Oral immunotherapy in severe cow's milk allergic patients treated with omalizumab: Real life survey from a Spanish registry.

BACKGROUND: Oral immunotherapy is a frequent treatment for the management of food allergies, but adverse events (AE) are common. This study assessed the outcome of cow's milk oral immunotherapy (MOIT) in severe cow`s milk-allergic patients treated with omalizumab in a real-life setting. METHODS: OmaBASE was a national, multicenter, open, and observational registry that collected clinical, immunologic, and treatment from patients with food allergy receiving omalizumab. RESULTS: Data derived from 58 patients aged 10.3 years (IQR 6.3-13.2) and median milk-specific IgE 100 kUA /L at the start of omalizumab treatment. Most had experienced anaphylaxis by accidental exposures (70.7%) and had asthma (81.0%). Omalizumab in monotherapy induced tolerance to ≥6000 mg of cow's milk protein (CMP) to 34.8% of patients tested by oral food challenge. Omalizumab combined with MOIT conferred desensitization to ≥6000 mg of CMP to 83.0% of patients. Omalizumab withdrawal triggered more AE (P = .013) and anaphylaxis (P = .001) than no discontinuation. Anaphylaxis was observed in 36.4% of patients who discontinued omalizumab, and more in those with sudden (50.0%) rather than progressive (12.5%) discontinuation. At database closure, 40.5% of patients who had completed follow-up tolerated CMP without omalizumab (7.2% 1500-4500 mg; 33.3% ≥6000 mg). CONCLUSION: Milk oral immunotherapy initiated under omalizumab allows the desensitization of subjects with severe cow's milk allergy even after omalizumab discontinuation. However, discontinuation of omalizumab can lead to severe AE and should be carefully monitored.

Evaluating primary end points in peanut immunotherapy clinical trials.

Food immunotherapy has been the focus of several allergy research initiatives over the last decade. Although many questions remain unanswered, the evidence suggests that this treatment might be available in the near future outside clinical trials. Additionally, pharmaceutical companies, in light of promising early-stage results, have shown interest in developing commercially available products, thus increasing the likelihood that new immunotherapy treatments will be introduced, especially for peanut allergy. Given this optimistic scenario and given the prospect of rigorously developed products for peanut allergy treatment, each allergist will need to understand the specificities of these treatments and their expected efficacy and adverse event profiles. Thus it is imperative that allergists understand the differences in efficacy between the different management options, as well as how the end points are measured in the relevant literature. However, given the significant heterogeneity detected among food immunotherapy trials, this task might not be as straightforward as desired. This article aims to dissect how primary efficacy end points are defined and assessed to facilitate understanding of the design of these trials and the potential effect that this variation might have on the reported outcomes.

Prospective assessment of diagnostic tests for pediatric penicillin allergy: From clinical history to challenge tests.

BACKGROUND: Diagnostic guidelines for penicillin allergy in children recommend cumbersome protocols based partially on data from adults, which may be suboptimal for pediatric use. OBJECTIVE: To assess the accuracy of tools for diagnosis of penicillin allergy in children. METHODS: A prospective, multicenter study was conducted in children with reported adverse events related to penicillin, excluding severe reactions. All patients underwent a uniform diagnostic protocol that consisted of clinical history, skin tests, serum specific IgE (sIgE), and, regardless of these results, drug provocation tests (DPTs). RESULTS: A total of 732 children (mean age, 5.5 years; 51.2% males) completed the allergy workup, including DPTs. Amoxicillin triggered 96.9% of all reactions. None of the patients with an immediate index reaction (IR) developed a reaction on DPT. Penicillin allergy was confirmed in 35 children (4.8%): 6 immediate reactions (17%) and 29 nonimmediate reactions (83%) on the DPT. No severe reactions were recorded. The allergist diagnosis based on the clinical history was not associated with the DPT final outcome. In 30 of 33 allergic patients (91%), the results of all skin tests and sIgE tests were negative. A logistic regression model identified the following to be associated with penicillin allergy: a family history of drug allergy (odds ratio [OR], 3.03; 95% confidence interval [CI], 1.33-6.89; P = .008), an IR lasting more than 3 days vs 24 hours or less (OR, 8.96; 95% CI, 2.01-39.86; P = .004), and an IR treated with corticosteroids (OR, 2.68; 95% CI, 1.30-5.54; P = .007). CONCLUSION: Conventional predictors of allergy to penicillin performed weakly. The authors propose straightforward penicillin provocation testing in controlled, experienced centers for the diagnosis of nonsevere penicillin allergy in children.

Efficacy and safety of high-dose rush oral immunotherapy in persistent egg allergic children: A randomized clinical trial.

BACKGROUND: Egg oral immunotherapy is effective but time consuming. OBJECTIVE: To assess the efficacy and safety of egg rush oral immunotherapy (ROIT) with a targeted dose equivalent to a raw egg white. METHODS: Thirty-three persistent egg allergic children confirmed by double-blind, placebo-controlled food challenge (DBPCFC) were randomized to receive egg ROIT immediately after randomization (ROIT1 group), or to continue an egg avoidance diet for 5 months after randomization (control group [CG]). A 5-day build-up phase starting with the highest single tolerated dose at baseline DBPCFC was scheduled and several doses administered daily until achieving a dose of approximately 2,808 mg of egg white protein. In the maintenance phase, patients ate an undercooked egg every 48 hours for 5 months. The CG participants who failed the DBPCFC at 5 months began active treatment. Children from the ROIT1 group plus children from the CG who failed a second DBPCFC at 5 months and then received egg ROIT were randomized to the ROIT2 group. Adverse events (AEs) and immune marker evolution were recorded. RESULTS: A total of 17 (89%) of 19 children in the ROIT1 group and no CG patients were desensitized at 5 months (P < .001). A total of 31 (97%) of the 32 children in the ROIT2 group completed the build-up phase in a median of 3 days (range, 1-14 days), and 30 (94%) of 32 maintained desensitization at 5 months. From baseline to 5 months of treatment, skin prick test, specific IgE, and specific IgE/IgG4 ratio to egg fractions significantly decreased, whereas specific IgG4 increased. During the build-up phase, AEs occurred in 69% of patients (50% had ≤2 AEs) and 31% of doses (2% severe, 55% gastrointestinal). Lower threshold dose in the DBPCFC and higher egg white and ovalbumin specific IgE levels at baseline revealed an association with a higher rate of AEs. CONCLUSION: The proposed 5-day egg ROIT desensitized 94% of the allergic patients, with most AEs being mild or moderate.

Exercise-induced bronchospasm diagnosis in children. Utility of combined lung function tests.

BACKGROUND: The diagnosis of exercise-induced asthma or bronchospasm (EIB) is a complex dare in daily clinical practice. The consensus is that if bronchial hyper-responsiveness (BHR) is demonstrated in a patient with symptoms consistent with EIB, then that patient can be diagnosed with exercise-induced bronchospasm. The aim of this study was to determine which BHR test is the most efficient to diagnose EIB. METHODS: Children under 16, without previous asthma diagnosis, or with stable asthma, complaining of asthma-like symptoms triggered by exercise were included. Bronchodilator, methacholine, mannitol, and exercise tests were performed on all patients, following established protocols. The performance of single and combined tests was determined. RESULTS: Of 46 patients (median age: 12 yr, ranged 8-16 y.o.) were recruited, 30 (70%) previously diagnosed of asthma. BHR was detected in 93.47% of the children. The exercise challenge test detected BHR in 11 of 46 (23.90%) patients, bronchodilator test in 10 of 46 (21.70%), mannitol in 36 of 45 (80%) and methacholine in 41 of 45 (91.11%). The total number of patients with BHR was detected using a combination of the methacholine and mannitol tests. A combination of the methacholine test performed first, followed by the mannitol test, was able to diagnose BHR in 100% of children with lower number of tests (n = 45) than if the order was reversed (n = 50). CONCLUSIONS: Methacholine and mannitol tests detect BHR in most children with suspected EIB. Bronchodilator and exercise tests show a low positivity rate. A combination of the methacholine test, followed by the mannitol test, gives the highest return to identify BHR in children for the diagnosis of EIB.

Dehydrated egg white: an allergen source for improving efficacy and safety in the diagnosis and treatment for egg allergy.

BACKGROUND: Raw and cooked eggs are used as allergens in oral food challenge (OFC). Raw egg is the best option, as it keeps proteins intact and retains their allergenicity, albeit microbiologically safe manipulation is difficult. Therefore, the use of dehydrated egg white (DEW) could improve the efficacy and safety profile of OFC. The aim of the study was to compare the allergenicity of DEW, a product that undergoes a double heat treatment (pasteurization and drying), with that of raw egg white (REW) and determine the efficacy of DEW in the diagnosis of egg allergy. METHODS: We conducted a prospective study of 40 egg-allergic patients who visited our outpatient clinic. Each patient underwent OFC with DEW and REW to determine the correlation between the tests. DEW and REW extracts were analyzed using SDS-PAGE. We compared the allergenicity of both extracts using IgE immunoblotting with a serum pool from patients with positive OFC results. RESULTS: Ten patients (25%) had positive OFC results with both DEW and REW, and the doses that triggered an allergic reaction in each patient were similar (p > 0.05). All 30 patients (75%) with a negative OFC result with DEW also had negative OFC results with REW. SDS-PAGE and IgE immunoblotting revealed that the protein composition and IgE-binding capacity of both extracts were virtually identical. CONCLUSIONS: This is the first time that it is shown that the allergenicity of commercially available DEW is equivalent to raw egg whites. In vivo and in vitro tests showed that processing of DEW does not affect the allergenicity of egg proteins. DEW is an effective and microbiologically safer source of allergen for the diagnosis of egg allergy. Furthermore, DEW can be used in egg oral immunotherapy.

Allergy to goat's and sheep's milk in a population of cow's milk-allergic children treated with oral immunotherapy.

BACKGROUND: Cow's milk oral immunotherapy (CMOIT) is a recognized treatment for persistent cow's milk (CM) allergy. However, further data are necessary on tolerance to milk from other mammals. OBJECTIVE: To describe the clinical and immunologic features of goat's and sheep's milk (GSM) allergy in patients who tolerated CM after CMOIT. METHODS: Fifty-eight CM-allergic patients who successfully underwent CMOIT in our department were evaluated using skin prick test (SPT), specific immunoglobulin (Ig) E determination, enzyme-linked immunoassay (ELISA), and controlled oral challenge to assess allergy to GSM. Statistical analysis was carried out to identify markers of allergy to GSM. RESULTS: Fifteen of 58 (25.9%) patients were allergic to either goat's or sheep's milk or to both, as confirmed by a controlled positive oral challenge. Forty-seven percent of all positive oral challenges were classified as anaphylactic reactions. Specific IgE to CM casein, goat's whole milk, and sheep's whole milk was 13.2, 18.0, and 21.4 kU(A)/l in the group of GSM-allergic patients and 6.6, 6.5, and 6.5 kU(A) /l in the GSM-non-allergic patients (p < 0.05). Decision-making cut-off points based on sIgE for diagnosing symptomatic GSM allergy could not be determined. ELISA inhibition assays showed limited cross-reactivity (up to 77.2%) between CM casein and GSM casein in the group of GSM-allergic patients in contrast with almost 100% in GSM-not-allergic patients. CONCLUSION: We found a high prevalence (26%) of allergy to GSM in our population of CM-allergic children treated with oral immunotherapy. Therefore, tolerance to GSM should be assessed in order to provide accurate nutritional advice and minimize life-threatening accidental intake. Specific IgE to CM casein, goat's and sheep's whole milk is a good marker of this allergy. Although CM oral immunotherapy is a specific treatment for CM allergy, it may not be effective against allergy to the milk of other mammals.

Efficacy of oral immunotherapy protocol for specific oral tolerance induction in children with cow's milk allergy.

BACKGROUND: In the last two decades milkoralimmunotherapy has gained interest as an effective treatment option for milk-allergic patients. OBJECTIVES: To report on the efficacy of a milk oral immunotherapy. METHODS: Children with immunoglobulin E-mediated cow's milk allergy were included in the protocol. The treatment consisted of an induction phase in which milk doses were increased weekly in the hospital, while the tolerated dose was continued daily at home. The goal was to achieve a minimum milk intake of 200 ml a day. During the maintenance phase, patients ingested at least 200 ml of milk in a single dose every day. RESULTS: The protocol was applied to 105 milk-allergic children diagnosed by specific IgE to milk and controlled oral food challenge. The mean duration of the induction phase was 19 weeks. Of the 105 subjects, 86 (81.9%) successfully complied with the protocol and 19 (19.1%) failed. Causes of failure were moderate/severe reactions in 12 patients (12.44%) and personal reasons in 7 (6.66%). A total of 182 adverse reactions occurred during the induction phase, most of them mild. Baseline specific IgE to milk and casein was significantly lower (P < 0.05) in the successfully treated group compared to the group in which the treatment failed. CONCLUSIONS: Milk oral immunotherapy is a safe and effective treatment for milk-allergic children, although adverse reactions may occur. Baseline milk and casein-specific IgE may be useful to predict a good response to milk oral immunotherapy.

Adverse Reactions to Anti-Infective Vaccines: an Emerging Problem in the COVID-19 Era.

Purpose of review: Vaccines are an essential tool for preventing infectious diseases and reducing associated morbidity and mortality. Vaccination has a significant impact at both individual and community levels, and COVID-19 vaccination programs are a new example of the great value of this public health strategy. However, adverse reactions, especially severe reactions such as anaphylaxis, prevent these programs from progressing properly, thus limiting vaccination uptake in the population. Recent findings: The frequency of reactions and types of vaccine components, with special attention to COVID-19 vaccines studies, provides information on the magnitude and causes of adverse events. The understanding of mechanisms involved has made it possible to adequately guide diagnosis, especially to COVID-19 vaccine components, such as polyethylene glycol, trometamol, and polysorbate-80. Summary: This review focuses on adverse reactions to vaccines, with emphasis on allergic reactions. A diagnostic pathway is suggested that, on the one hand, enables to take the necessary precautions in persons with a history of allergy to vaccine components or allergic reactions to vaccines and, on the other, supports administration of subsequent doses. The overall objective is to ensure that people with allergy can be vaccinated in the same way as the rest of the population, and that they are offered alternatives where necessary.

LTT and HLA testing as diagnostic tools in Spanish vancomycin-induced DRESS cases: A case-control study.

Drug reaction with eosinophilia and systemic symptoms (DRESS) is a severe T-cell-mediated off-target adverse reaction. DRESS cases caused by vancomycin have often been reported. The HLA-A*32:01 allele has been associated with genetic susceptibility to vancomycin-induced DRESS in US citizens of European descent. We have analyzed the association of the HLA-A*32:01 allele in 14 Spanish DRESS cases in which vancomycin was suspected as the culprit drug, and the lymphocyte transformation test (LTT) as an in vitro assay to evaluate vancomycin sensitization. The results were compared to vancomycin-tolerant control donors. LTT was performed in 12 DRESS cases with PBMCs from resolution samples available and in a group of 12 tolerant donors. ROC curves determined that LTT is a suitable tool to identify patients sensitized to vancomycin (AUC = 0.9646; p < 0.0001). When a stimulation index >3 was regarded as a positive result, contingency tables determined 91% sensitivity, 91.67% specificity, 91% positive predictive value, and 91.67% negative predictive value (p = 0.0001, Fisher's exact test). The HLA A*32:01 allele was determined by an allele-specific PCR assay in 14 cases and 25 tolerant controls. Among the DRESS cases, five carriers were identified (35.7%), while it was detected in only one (4%) of the tolerant donors, [odds ratio (OR) = 13.33; 95% CI: 1.364-130.3; p = 0.016]. The strength of the association increased when only cases with positive LTT to vancomycin were considered (OR = 24.0; 95% CI: 2.28-252.6; p = 4.0 × 10-3). Our results confirm the association of the risk allele HLA-A*32:01 with vancomycin-induced DRESS in Spanish cases, and support LTT as a reliable tool to determine vancomycin sensitization.

Pediatric Asthma Management During the COVID-19 Pandemic: Results of a National Survey.

Background: During the COVID-19 pandemic specialists were concerned about how to achieve the best control of pediatric asthmatic patients. Methods: A national survey was performed. Analysis of the mean of follow-up, complementary tests, health system (public/private/both), availability of severe asthma units, and geographic location (cities with high COVID-19 prevalence vs. other cities with low prevalence). Differences were analyzed using contingency tables and Pearson's chi-squared test. Results: We obtained 95 responses, mostly from cities with a high disease prevalence (39; 52%). Only 29 (38.6%) of respondents provided care in a severe asthma unit. Severe asthmatic children were followed up mainly by telephone (68; 90.7%) and by in-person visits (32; 42.7%). Face-to-face care was less frequent in cities with a high prevalence of COVID-19 when compared with smaller cities (P = 0.044). Some of the surveyed physicians had discontinued patient follow-up as they were caring for patients with COVID-19 (7; 9.3%). Of all specialists surveyed, 45.3% did not evaluate severe asthmatic children with any means of testing. Pulmonary function tests were scarcely implemented. Blood tests were the most common test performed (45.3%). Specialists working in a severe asthma unit carried out more pulmonary function tests (P = 0.019). Peculiarly, moderate persistent asthmatics underwent more spirometries in cities with a high prevalence rate (P = 0.03). Follow-up of asthmatic children during the pandemic was perceived to be reduced or altogether inexistent by 42.7% of respondents when compared with a similar season outside of this emergency situation. Remarkably, the perception that better management of asthma was delivered during the pandemic by those working in cities with a high prevalence of COVID-19 versus other regions. Conclusions: Pediatric asthma control is crucial to decrease the future risk presented by the condition. New technologies and severe asthma units may become key tools in global health emergencies such as the COVID-19 pandemic.

Effectiveness and safety of a glutaraldehyde-modified, L-tyrosine-adsorbed and monophosphoryl lipid A-Adjuvanted allergen immunotherapy in patients with allergic asthma sensitized to olive pollen: A retrospective, controlled real-world study.

BACKGROUND: Allergy to olive pollen is one of the primary causes of allergic asthma in Spain. Even though allergen immunotherapy (AIT) has shown clinical benefits in patients sensitized to different allergens, studies in asthmatic patients sensitized to olive pollen are insufficient. OBJECTIVE: To assess the effectiveness and safety of an ultra-short course of AIT with an L-tyrosine-adsorbed and monophosphoryl lipid A-adjuvanted olive pollen and olive/grass pollen extract (Pollinex Quattro®) in patients with allergic asthma in the real-world setting. METHODS: Retrospective, controlled study including patients with asthma, with and without allergic rhinitis, caused by sensitization to olive pollen from 11 centers in Spain. Patients received out-of-season (October-March) treatment with AIT in addition to their pharmacological treatment (active group) or pharmacological treatment (control group). Effectiveness variables, including unscheduled visits to the healthcare center, emergency room admissions, symptoms of asthma and rhinitis (following GEMA and ARIA classifications, respectively), and use of medication to treat asthma and rhinitis during the subsequent pollen season were compared between treatment groups. RESULTS: Of 131 study patients, 42 were treated with their usual asthma medication (control group) and 89 were treated with AIT (active group), either Pollinex Quattro® 100% olive pollen (n = 43, 48.3%) or 50% olive pollen/50% grass pollen (n = 46, 51.7%). Patients' demographic and clinical characteristics were similar between groups. The mean (SD) number of unscheduled visits to a healthcare center and emergency room admissions due to allergy symptoms was 2.19 (1.40) and 0.43 (0.63) in the control group, and 1.09 (1.25) and 0.11 (0.51) in the active group (P = 0.001 and P = 0.006, respectively). Severity and control of asthma symptoms remained unchanged (P = 0.347 and P = 0.179, respectively), rhinitis type improved (P = 0.025), and severity remained unchanged in the active compared to the control group. The use of short-acting beta-agonists and inhaled corticosteroids to treat asthma symptoms decreased in the active vs. the control group (P = 0.001 and P = 0.031, respectively). Twelve (13.5%) and two (2.2%) patients in the active group experienced local adverse reactions (edema, swelling, erythema, hives, pruritus, and heat), and systemic adverse reactions (hypertensive crisis and low-grade fever) to AIT, respectively; none was serious. CONCLUSION: AIT with Pollinex Quattro® specific for olive pollen and olive/grass pollens resulted in reduced visits to the healthcare center and emergency room and the use of asthma medication during the pollen season, indicating that this treatment was safe and effective in treating asthma in patients sensitized to these pollens.

Effect of the SARS-CoV-2 pandemic on the control and severity of pediatric asthma

Background: The novel disease caused by the new coronavirus SARS-CoV-2 has caused an unprecedented global pandemic. Care providers of asthmatic children are increasingly con-cerned; as viral infections are one of the primary triggers of asthma flare-up. However, the effect of SARS-CoV-2 as well as the generated worldwide lockdown on asthmatic children is unknown.Objective: The aim of this study was to analyze the effects of pandemic SARS-CoV-2 in pediat-ric asthma control.Material and Methods: A retrospective, open, transversal study was performed at five ter-tiary hospitals. Recruited patients were aged <18 years and had physician-diagnosed asthma. Information regarding the 2019 and 2020 seasons were provided.Results: Data were collected from 107 children (age range: 3–18 years, mean age: 12 years). Well-controlled asthma was observed in 58 (54.2%) patients in 2020 versus 30 (28%) in 2019, and 15 (14%) patients had poorly controlled asthma in 2020 versus 28 (26.2%) in 2019. In 2020, a decrease in exacerbations caused by allergies to pollen, dust mites, molds, and through other causes not related to SARS-CoV-2 infection was observed. An increase in exacerbations was observed due to animal dander, stress, physical exercise, and SARSCoV-2 infection. Children had a reduced need for asthma-controlling medication, made fewer visits to healthcare providers and had lesser need of treatment with oral corticosteroids if compared with the same season of 2019 (AU)

Immunological cross-reactivity between olive and grass pollen: implication of major and minor allergens.

BACKGROUND: Grasses and olive trees are the most common sources of allergenic pollen worldwide. Although they share some allergens, there are few studies analyzing the in vitro cross-reactivity between them. The aim was to define the cross-reactivity between Olea europaea and Phleum pratense using well-characterized sera of allergic children from Madrid, Spain. METHODS: 66 patients (mean age 10.32+/-4.07 years) were included in the study. All suffered from rhinoconjuntivitis and/or asthma and had a positive skin test and/or specific IgE determination to olive and grass pollen. Serum sIgE to individual allergens was conducted and sIgE against different grass species and olive was also determined by ELISA. Inhibition assays were performed using two serum sources, containing, or not, sIgE to minor allergens. Mass spectrometry analysis was performed in both extracts. RESULTS: 59/66 (89.39%) children had a positive sIgE determination by ELISA to grasses and 57/66 (86.36%) to olive pollen. There was no significant correlation between sIgE levels to grass and olive. Inhibition assays demonstrated no cross-reactivity between P. pratense and olive pollen when using the pool containing mainly sIgE to major allergens, whereas minimal to moderate cross-reactivity was detected when the serum contained high sIgE titers to minor allergens. Proteomic analyses revealed the presence of 42 common proteins in grasses and olive pollens. CONCLUSION: No in vitro cross-reactivity was observed when sIgE was mainly directed to major allergens. In our population, sensitization to olive and grasses is not due to cross-reactivity. The contribution of the major allergens seems to be determinant.