Clinical management of plant food allergy in patients sensitized to lipid transfer proteins is heterogeneous: identifying the gaps

Background and objective: Patients sensitized to lipid transfer protein (LTP) present a wide clinical variability. The lack of practical diagnostic and therapeutic guidelines complicate their management. The aim of the study was to describe the clinical approach of Spanish allergists to this pathology using a survey designed by PICO method and subsequent Delphi approach validation. Methods: Designed survey was answered by 224 allergists (75% women; 57.1% with >20 years of professional experience). Homogeneity regarding clinical practice on the main points of LTP allergy diagnosis was observed, except for patients with suspected NSAID hypersensitivity (44.6% frequently include LTP skin testing). Oral food challenges were not frequently performed (63.6% occasionally to never), and they were generally (75.5%) used to confirm tolerance. It was common to recommend fruit skins avoidance (77.2%) and maintaining consumption of foods to which patients are sensitised but tolerant (99.1%). Results: There was heterogeneity on other dietary indications, modifications due to co-factors, or traces avoidance. Peach sublingual immunotherapy (SLIT) was considered very/quite effective by 55.9% of allergists. The majority (79.5%) consider SLIT indicated in <25% of LTP allergic patients, based on severity (95.2%), frequency of reactions (99.4%), allergy to multiple food families (97.4%), and the quality of life/nutrition impairment (91.5%). There was different practice on SLIT prescription based on co-factor involvement. Conclusion: These data suggest that there is a need to increase evidence to reduce the clinical practice heterogeneity in the management of LTP allergy

Validation of novel recipes for masking peanuts in double-blind, placebo-controlled food challenges

Background: Double-blind, placebo-controlled oral food challenges are the gold standard in food allergy diagnosis. Nevertheless, proper masking of peanuts is particularly complex owing to their intense flavor and odor. Thus, it is important to use validated recipes to ensure their adequate masking during oral food challenges. Objective: To design and validate recipes containing masked peanuts for double-blind, placebo-controlled oral food challenges. Methods: Two types of products (cookies and a custard‐type dessert) containing the masked peanuts and other ingredients with low allergenic potential were designed and validated. For this purpose, of the 24 initial cookie recipes and 12 initial custard recipes developed, those that did not exhibit significant differences in their texture were selected for sensory validation. Results: Similarity triangle tests were performed using a panel of 36 selected tasters, enabling the validation of 1 pair of cookie recipes and 1 pair of custard-type dessert recipe, both with low allergenic potential and suitable for those with celiac disease and for vegans. Conclusion: The validated recipes are of clinical and research interest because they allow to confirm a peanut allergy and detect a wide range of tolerated threshold doses, which makes it possible to provide specific indica- tions for each patient

Validation of a commercial allergen microarray platform for specific immunoglobulin E detection of respiratory and plant food allergens

Background As the use of multiplex-specific immunoglobulin E (sIgE) detection methods becomes increasingly widespread, proper comparative validation assessments of emerging new platforms are vital. Objective To evaluate the clinical and technical performance of a newly introduced microarray platform, Allergy Explorer (ALEX) (MacroArray Diagnostics), in the diagnosis of pollen (cypress, grass, olive), dust mite (Dermatophagoides pteronyssinus), mold (Alternaria alternata), fruit (apple, peach), and nut (walnut, hazelnut and peanut) allergies and to compare it with those of the ImmunoCAP Immuno Solid-phase Allergen Chip (ISAC) 112 microarray and the ImmunoCAP singleplex method (ThermoFisher Scientific). Methods We enrolled 153 patients with allergy and 16 controls without atopy. The sIgE assays were conducted using ISAC112, ALEX version 2 (ALEX2), and ImmunoCAP for whole extracts and major components. Technical validation of ALEX2 was performed by measuring repeatability and interassay, interbatch, and interlaboratory reproducibility. Results When measured globally (detection by 1 or more allergen components), ALEX2 had adequate sensitivity and specificity for most of the allergens studied, comparable in general with that of ISAC112 (except for olive pollen and walnut) and similar to that of ImmunoCAP whole extract measurements. Component-by-component analysis revealed comparable results for all techniques, except for Ole e 1 and Jug r 3, in both ISAC112 and ImmunoCAP comparisons, and Alt a 1, when compared with ISAC112. Continuous sIgE levels correlate with sIgE by ImmunoCAP. Good reproducibility and repeatability were observed for ALEX2. Conclusion ALEX2 has sound technical performance and adequate diagnostic capacity, comparable in general with that of ISAC112 and ImmunoCAP

Validation of a commercial allergen microarray platform for specific immunoglobulin E detection of respiratory and plant food allergens - Improvement of the Elevated Tryptase Criterion to Discriminate IgE- From Non–IgE-Mediated Allergic Reactions - Validation of novel recipes for masking peanuts in double-blind, placebo-controlled food challenges

Background: As the use of multiplex-specific immunoglobulin E (sIgE) detection methods becomes increasingly widespread, proper comparative validation assessments of emerging new platforms are vital. Objective: To evaluate the clinical and technical performance of a newly introduced microarray platform, Allergy Explorer (ALEX) (MacroArray Diagnostics), in the diagnosis of pollen (cypress, grass, olive), dust mite (Dermato- phagoides pteronyssinus), mold (Alternaria alternata), fruit (apple, peach), and nut (walnut, hazelnut and peanut) allergies and to compare it with those of the ImmunoCAP Immuno Solid-phase Allergen Chip (ISAC) 112 microar- ray and the ImmunoCAP singleplex method (ThermoFisher Scientific). Methods: We enrolled 153 patients with allergy and 16 controls without atopy. The sIgE assays were conducted using ISAC112, ALEX version 2 (ALEX2), and ImmunoCAP for whole extracts and major components. Technical validation of ALEX2 was performed by measuring repeatability and interassay, interbatch, and interlaboratory reproducibility. Results: When measured globally (detection by 1 or more allergen components), ALEX2 had adequate sensitivity and specificity for most of the allergens studied, comparable in general with that of ISAC112 (except for olive pol- len and walnut) and similar to that of ImmunoCAP whole extract measurements. Component-by-component analysis revealed comparable results for all techniques, except for Ole e 1 and Jug r 3, in both ISAC112 and Immu- noCAP comparisons, and Alt a 1, when compared with ISAC112. Continuous sIgE levels correlate with sIgE by ImmunoCAP. Good reproducibility and repeatability were observed for ALEX2. Conclusion: ALEX2 has sound technical performance and adequate diagnostic capacity, comparable in general with that of ISAC112 and ImmunoCAP

Unraveling the Diagnosis of Kiwifruit Allergy: Usefulness of Current Diagnostic Tests

Objectives: To determine the usefulness of the in vitro and in vivo methods used in the diagnosis of kiwifruit allergy and to specifically assess the impact of seed proteins on sensitivity. Methods: We performed skin prick tests (SPTs) using various commercial extracts, homemade pulp, and seed extracts and prick-prick tests with kiwifruit on 36 allergic patients. The presence of specific IgE (sIgE) was assessed using the ImmunoCAP (kiwifruit extract), ELISA (Act d 1, Act d 2), ISAC, and FABER assays. Immunoblotting of seed extract was carried out, and a single-blind oral food challenge was performed with whole seeds in seed-sensitized individuals. Results: The prick prick test with kiwifruit demonstrated the highest diagnostic capacity (81.8% sensitivity and 94.1% specificity) among the in vivo tests. The sIgE levels measured using ImmunoCAP (kiwifruit extract) showed a similar sensitivity to that of global ISAC and FABER (63.9%, 59.5%, and 58.3%, respectively). Act d 1 was the major allergen. Sensitization to Act d 1 was associated with positive sIgE results to whole kiwifruit extract detected by ImmunoCAP (P<.000). A positive SPT result to kiwifruit seeds was associated with severe symptoms induced by kiwifruit (P=.019) as a marker of advanced disease, but not with clinically relevant sensitization. Challenge testing with kiwifruit seeds performed on 8 seed-sensitized patients yielded negative results. Conclusions: Sensitization to Act d 1 is associated with a positive result in conventional diagnostic techniques, whereas kiwifruit seed sensitization does not increase the sensitivity of the diagnostic techniques evaluated.Objetivos: Determinar la rentabilidad diagnóstica de las técnicas in vitro e in vivo utilizadas en el diagnóstico de alergia al kiwi y estudiar la influencia de las proteínas alergénicas de las semillas en su sensibilidad. Métodos: Se seleccionaron 36 pacientes alérgicos a kiwi. Se les realizó prick test con cuatro extractos comerciales diferentes y prick-prick con kiwi. Se determinó IgE específica mediante ImmunoCAP (extracto de kiwi), ELISA (Act d 1, Act d 2), las micromatrices ISAC y FABER e Immunoblotting de extracto de semilla de kiwi. Se realizó exposición oral simple ciego frente a semilla de kiwi en pacientes sensibilizados a la semilla. Resultados: El prick-prick de kiwi fue la prueba in vivo con mayor rendimiento (sensibilidad 81,8%, especificidad 94,1%). El ImmunoCAP de extracto de kiwi mostró una sensibilidad similar a la global del ISAC y del FABER (63,9%, 59,5% y 58,3%, respectivamente). Act d 1 fue el alérgeno mayoritario. Se encontró asociación entre los niveles de IgE específica frente a Act d 1 (ISAC) y el extracto de kiwi mediante ImmunoCAP (p <0,000). La prueba cutánea positiva con semilla se asoció con mayor gravedad de síntomas frente a kiwi (p = 0,019), como marcador de enfermedad avanzada, pero no como sensibilización clínicamente relevante. La prueba de provocación con semillas fue negativa en los ocho pacientes provocados. Conclusiones: La sensibilización a Act d 1 se asocia con resultados positivos con las técnicas diagnósticas convencionales. La sensibilización frente a semillas no mejora el rendimiento de las técnicas evaluadas

Is Microarray Analysis Really Useful and Sufficient to Diagnose Nut Allergy in the Mediterranean Area?

Background: Component-based diagnosis on multiplex platforms is widely used in food allergy but its clinical performance has not been evaluated in nut allergy. Objective: To assess the diagnostic performance of a commercial protein microarray in the determination of specific IgE (sIgE) in peanut, hazelnut, and walnut allergy. Methods: sIgE was measured in 36 peanut-allergic, 36 hazelnut-allergic, and 44 walnut-allergic patients by ISAC 112, and subsequently, sIgE against available components was determined by ImmunoCAP in patients with negative ISAC results. ImmunoCAP was also used to measure sIgE to Ara h 9, Cor a 8, and Jug r 3 in a subgroup of lipid transfer protein (LTP)-sensitized nut-allergic patients (positive skin prick test to LTP-enriched extract). sIgE levels by ImmunoCAP were compared with ISAC ranges. Results: Most peanut-, hazelnut-, and walnut-allergic patients were sensitized to the corresponding nut LTP (Ara h 9, 66.7%; Cor a 8, 80.5%; Jug r 3, 84% respectively). However, ISAC did not detect sIgE in 33.3% of peanut-allergic patients, 13.9% of hazelnut-allergic patients, or 13.6% of walnut-allergic patients. sIgE determination by ImmunoCAP detected sensitization to Ara h 9, Cor a 8, and Jug r 3 in, respectively, 61.5% of peanut-allergic patients, 60% of hazelnut-allergic patients, and 88.3% of walnut-allergic patients with negative ISAC results. In the subgroup of peach LTP–sensitized patients, Ara h 9 sIgE was detected in more cases by ImmunoCAP than by ISAC (94.4% vs 72.2%, P<.05). Similar rates of Cor a 8 and Jug r 3 sensitization were detected by both techniques. Conclusions: The diagnostic performance of ISAC was adequate for hazelnut and walnut allergy but not for peanut allergy. sIgE sensitivity against Ara h 9 in ISAC needs to be improved.Introducción: La utilidad clínica del diagnóstico por componentes no ha sido evaluada en el estudio de la alergia a frutos secos (FS). Objetivo: Evaluar la capacidad diagnóstica de una micromatriz comercial de proteínas alergénicas en la alergia a cacahuete, avellana y nuez. Métodos: Se determinó la sIgE en pacientes alérgicos a FS mediante la micromatriz ISAC 112, e ImmunoCAP en los pacientes con sIgE negativa frente a los componentes de ISAC. Además, se realizó ImmunoCAP frente a Ara h 9, Cor a 8 y Jug r 3 en un subgrupo de pacientes sensibilizados a LTP. La sIgE detectada por ImmunoCAP fue comparada con los rangos de ISAC. Resultados: La mayoría de los alérgicos a cacahuete (66,7%), avellana (80,5%) y nuez (84%) estaba sensibilizados a su LTP. Sin embargo, no se detectó sIgE frente a los componentes de ISAC en el 33,3% de alérgicos a cacahuete, 13,9% de alérgicos a avellana y 13,6% de los alérgicos a nuez. El ImmunoCAP permitió detectar sIgE a Ara h 9 en 61,5%, Cor a 8 en 60% y Jug r 3 en 83,3% de los ISAC negativo. En el subgrupo LTP, ImmunoCAP (94,4%) fue superior a ISAC (72,2%) en la detección de sIgE a Ara h 9 (p<0,05). La sIgE frente a Cor a 8 y Jug r 3 fue detectada de forma similar por ambas técnicas. Conclusiones: La micromatriz ISAC es adecuada para el diagnóstico de alergia a avellana y nuez. La sensibilidad del componente Ara h 9 de ISAC debe ser mejorada

Efficacy and Safety of Omalizumab (Xolair) for Cholinergic Urticaria in Patients Unresponsive to a Double Dose of Antihistamines: A Randomized Mixed Double-Blind and Open-Label Placebo-Controlled Clinical Trial

Background: Cholinergic urticaria (UCOL) is a highly disabling inducible urticaria triggered by an increase in core body temperature. Objective: To explore the safety and efficacy of omalizumab in controlling UCOL. Methods: We conducted a multicenter randomized mixed double-blind and open-label (first 4 months blinded followed by 8 months open-label) placebo-controlled clinical trial in 22 patients suffering from UCOL who were unresponsive to a double dose of antihistamines. We performed an exercise challenge test during each visit as our main outcome variable. Results: The overall rate of exercise challenge test negative at week 48 was 31.3%, with an average increase in exercise challenge test negative rate of 2.9% points (95% CI, 1.5-4.2) per visit. Statistically significant differences in the negative exercise challenge test rate between the placebo and active intervention groups were not observed during the blinded period (first 4 months of the study). However, from the fourth dose, a progressive improvement was observed. When comparing before and after treatment, statistically significant improvements in all secondary outcome measures were noted after 4 doses (UCOL score: P = .0015; visual analog scale score: P = .0108; days with symptoms: P = .0125) and after 8 doses (UCOL score: P = .0005; chronic urticaria quality of life questionnaire: P = .0105; visual analog scale score: P = .0008; and days with symptoms: P = .0144). In the follow-up visit after the cessation of treatment, the symptoms reappeared, with positive exercise challenge test result and significant increases in all variables. Only 4 of 22 patients remained asymptomatic after 3 months of no treatment. No adverse effects were reported. Conclusions: This randomized mixed double-blind and open-label placebo-controlled trial showed evidence of the safety and potential efficacy of omalizumab in patients with UCOL

Efficacy and safety of Omalizumab (Xolair) for cholinergic urticaria in patients unresponsive to a double dose of antihistamines: A randomized mixed double-blind and open-label placebo-controlled clinical trial

Background Cholinergic urticaria (UCOL) is a highly disabling inducible urticaria triggered by an increase in core body temperature. Objective To explore the safety and efficacy of omalizumab in controlling UCOL. Methods We conducted a multicenter randomized mixed double-blind and open-label (first 4 months blinded followed by 8 months open-label) placebo-controlled clinical trial in 22 patients suffering from UCOL who were unresponsive to a double dose of antihistamines. We performed an exercise challenge test during each visit as our main outcome variable. Results The overall rate of exercise challenge test negative at week 48 was 31.3%, with an average increase in exercise challenge test negative rate of 2.9% points (95% CI, 1.5-4.2) per visit. Statistically significant differences in the negative exercise challenge test rate between the placebo and active intervention groups were not observed during the blinded period (first 4 months of the study). However, from the fourth dose, a progressive improvement was observed. When comparing before and after treatment, statistically significant improvements in all secondary outcome measures were noted after 4 doses (UCOL score: P = .0015; visual analog scale score: P = .0108; days with symptoms: P = .0125) and after 8 doses (UCOL score: P = .0005; chronic urticaria quality of life questionnaire: P = .0105; visual analog scale score: P = .0008; and days with symptoms: P = .0144). In the follow-up visit after the cessation of treatment, the symptoms reappeared, with positive exercise challenge test result and significant increases in all variables. Only 4 of 22 patients remained asymptomatic after 3 months of no treatment. No adverse effects were reported. Conclusions This randomized mixed double-blind and open-label placebo-controlled trial showed evidence of the safety and potential efficacy of omalizumab in patients with UCOL