Pru p 3-specific IgE affinity is crucial in severe peach-allergy patients.

Background: Peach allergy is common food allergen. Allergen components-specific antibodies of different isotypes in peach-allergy patients are poorly studied. Factors other than Pru p 3-sIgE levels may be related to severe symptoms. Objective: To evaluated peach component-specific-IgE, IgG1, and IgG4 characteristics in individuals with and without peach allergy, and Pru p 3-sIgE affinity in patients with different clinical symptoms. Methods: Fifteen healthy controls and 32 peach-allergy patients were enrolled. sIgE, sIgG1, and sIgG4 to 5 Escherichia coli-expressed peach-allergen components were determined by enzyme-linked immunosorbent assays. Pru p 3-sIgE affinity was measured in Pru p 3-sIgE-positive patients, using immunoadsorbance. Results: Patients were divided into oral allergy syndrome (OAS) and peach-induced anaphylaxis (PIA) groups. Serum Pru p 1-, Pru p 2-, Pru p 3-, Pru p 4-, and Pru p 7-sIgG1s were detected. Pru p 1- and Pru p 2-sIgG1 levels were higher in healthy controls, but Pru p 3-sIgG1 levels were significantly higher in peach-allergy patients. Pru p 1-, Pru p 3-, and Pru p 4-sIgG4-positivity was significantly greater among patients than among controls. Pru p 3 was the predominant allergen in peach-allergy patients. Allergen-sIgG1 and sIgG4 were similar between OAS and PIA patients. Pru p 3-sIgE levels were significantly higher in PIA patients, but Pru p 3-sIgE-positivity was similar in both groups. In Pru p 3-sIgE-positive patients, Pru p 3-sIgE affinity was significantly higher in PIA than OAS patients. Conclusions: Allergen-sIgG1 was associated with allergen exposure. Both Pru p 3-sIgE levels and affinity are key factors in severe peach-allergy patients.

Worldwide Heterogeneity of Food Allergy: Focus on Peach Allergy in Southern Italy.

Food allergy (FA) has shown an increasing prevalence in the last decades, becoming a major public health problem. However, data on the prevalence of FA across the world are heterogeneous because they are influenced by several factors. Among IgE-mediated FA, an important role is played by FA related to plant-derived food which can result from the sensitization to a single protein (specific FA) or to homologous proteins present in different foods (cross-reactive FA) including non-specific lipid transfer proteins (nsLTPs), profilins, and pathogenesis-related class 10 (PR-10). In addition, the clinical presentation of FA is widely heterogeneous ranging from mild symptoms to severe reactions up to anaphylaxis, most frequently associated with nsLTP-related FA (LTP syndrome). Considering the potential life-threatening nature of nsLTP-related FA, the patient's geographical setting should always be taken into account; thereby, it is highly recommended to build a personalized approach for managing FA across the world in the precision medicine era. For this reason, in this review, we aim to provide an overview of the prevalence of nsLTP-mediated allergies in the Mediterranean area and to point out the potential reasons for the different geographical significance of LTP-driven allergies with a particular focus on the allergenic properties of food allergens and their cross reactivity.

A European-Japanese study on peach allergy: IgE to Pru p 7 associates with severity.

BACKGROUND: Pru p 3 and Pru p 7 have been implicated as risk factors for severe peach allergy. This study aimed to establish sensitization patterns to five peach components across Europe and in Japan, to explore their relation to pollen and foods and to predict symptom severity. METHODS: In twelve European (EuroPrevall project) and one Japanese outpatient clinic, a standardized clinical evaluation was conducted in 1231 patients who reported symptoms to peach and/or were sensitized to peach. Specific IgE against Pru p 1, 2, 3, 4 and 7 and against Cup s 7 was measured in 474 of them. Univariable and multivariable Lasso regression was applied to identify combinations of parameters predicting severity. RESULTS: Sensitization to Pru p 3 dominated in Southern Europe but was also quite common in Northern and Central Europe. Sensitization to Pru p 7 was low and variable in the European centers but very dominant in Japan. Severity could be predicted by a model combining age of onset of peach allergy, probable mugwort, Parietaria pollen and latex allergy, and sensitization to Japanese cedar pollen, Pru p 4 and Pru p 7 which resulted in an AUC of 0.73 (95% CI 0.73-0.74). Pru p 3 tended to be a risk factor in South Europe only. CONCLUSIONS: Pru p 7 was confirmed as a significant risk factor for severe peach allergy in Europe and Japan. Combining outcomes from clinical and demographic background with serology resulted in a model that could better predict severity than CRD alone.

Evolution of laboratory parameters in patients with lipid transfer protein syndrome after 3 years of immunotherapy.

Lipid transfer protein (LTP) syndrome is an increasingly prevailing disease, especially in the young population, with severely affected quality of life. Since 2013, a specific treatment, called sublingual immunotherapy (SLIT), with peach extract (SLIT-peach®) has been used, but with no long-term effectiveness studies. The main objective of the present study was to assess the long-term effectiveness of SLIT-peach® and to relate the clinical evolution of patients. This was an ambispective study conducted for 3 years. A total of 25 patients with LTP syndrome were selected and treated with SLIT-peach®. They underwent a provocation test in the first year with reintroduced foods that had produced symptoms in the past. Analytical determination of specific immunoglobulin E (IgE) and immunoglobulin G4 (IgG4) to peach (Pru p 3) was performed at the beginning of treatment, at the first year of initiation, and at the end of treatment. These data were compared with the control group comprising 14 patients with LTP syndrome without treatment. A statistically significant decrease in specific IgE to Pru p 3 at the end of the treatment and an increase in specific IgG4 to Pru p 3 1 year after treatment initiation were observed in the active group in relation to tolerance to foods with LTPs. These results indicate that food tolerance begins after the first year and is maintained after the end of 3 years of treatment. In conclusion, treatment with SLIT-peach® for 3 years is effective for patients with LTP syndrome, preventing the evolution of the disease, allowing patients to restart a diet with plant foods, and improving their quality of life.

Evolution of laboratory parameters in patients with lipid transfer protein syndrome after 3 years of immunotherapy

Lipid transfer protein (LTP) syndrome is an increasingly prevailing disease, especially in the young population, with severely affected quality of life. Since 2013, a specific treatment, called sublingual immunotherapy (SLIT), with peach extract (SLIT-peach®) has been used, but with no long-term effectiveness studies. The main objective of the present study was to assess the long-term effectiveness of SLIT-peach® and to relate the clinical evolution of patients. This was an ambispective study conducted for 3 years. A total of 25 patients with LTP syndrome were selected and treated with SLIT-peach®. They underwent a provocation test in the first year with reintroduced foods that had produced symptoms in the past. Analytical determination of specific immunoglobulin E (IgE) and immunoglobulin G4 (IgG4) to peach (Pru p 3) was performed at the beginning of treatment, at the first year of initiation, and at the end of treatment. These data were compared with the control group comprising 14 patients with LTP syndrome without treatment. A statistically significant decrease in specific IgE to Pru p 3 at the end of the treatment and an increase in specific IgG4 to Pru p 3 1 year after treatment initiation were observed in the active group in relation to tolerance to foods with LTPs. These results indicate that food tolerance begins after the first year and is maintained after the end of 3 years of treatment. In conclusion, treatment with SLIT-peach® for 3 years is effective for patients with LTP syndrome, preventing the evolution of the disease, allowing patients to restart a diet with plant foods, and improving their quality of life (AU)

Corrigendum: Suitability of potyviral recombinant virus-like particles bearing a complete food allergen for immunotherapy vaccines.

[This corrects the article DOI: 10.3389/fimmu.2022.986823.].

Suitability of potyviral recombinant virus-like particles bearing a complete food allergen for immunotherapy vaccines.

Virus-like particles (VLPs) have been gaining attention as potential platforms for delivery of cargos in nanomedicine. Although animal viruses are largely selected due to their immunostimulatory capacities, VLPs from plant viruses constitute a promising alternative to be considered. VLPs derived from Turnip mosaic virus (TuMV) have proven to present a tridimensional structure suited to display molecules of interest on their surface, making them interesting tools to be studied in theragnostic strategies. Here, we study their potential in the treatment of food allergy by genetically coupling TuMV-derived VLPs to Pru p 3, one of the most dominant allergens in Mediterranean climates. VLPs-Pru p 3 were generated by cloning a synthetic gene encoding the TuMV coat protein and Pru p 3, separated by a linker, into a transient high-expression vector, followed by agroinfiltration in Nicotiana benthamiana plants. The generated fusion protein self-assembled in planta to form the VLPs, which were purified by exclusion chromatography. Their elongated morphology was confirmed by electron microscopy and their size (~400 nm), and monodispersity was confirmed by dynamic light scattering. Initial in vitro characterization confirmed that they were able to induce proliferation of human immune cells. This proliferative capability was enhanced when coupled with the natural lipid ligand of Pru p 3. The resultant formulation, called VLP-Complex, was also able to be transported by intestinal epithelial cells, without affecting the monolayer integrity. In light of all these results, VLP-Complex was furtherly tested in a mouse model of food allergy. Sublingual administration of VLP-Complex could effectively reduce some serological markers associated with allergic responses in mice, such as anti-Pru p 3 sIgE and sIgG2a. Noteworthy, no associated macroscopic, nephritic, or hepatic toxicity was detected, as assessed by weight, blood urea nitrogen (BUN) and galectin-3 analyses, respectively. Our results highlight the standardized production of allergen-coated TuMV-VLPs in N. benthamiana plants. The resulting formula exerts notable immunomodulatory properties without the need for potentially hazardous adjuvants. Accordingly, no detectable toxicity associated to their administration was detected. As a result, we propose them as good candidates to be furtherly studied in the treatment of immune-based pathologies.

Identification of Major B-Cell Linear Epitopes of Peach Allergen Pru p 3 Using Immune Slot-Blot Microarray Assay.

Pru p 3, one of the most representative proteins of the lipid transfer proteins (LTPs), is responsible for clinical allergic reactions to food of peach origin. The identification of Pru p 3 epitopes is not comprehensive due to different methods and principles of epitope screening. In addition, evaluation of the stability of the epitopes and the validation of the immunological key amino acids still need further research. Therefore, in the present study, an immune slot-blot microarray assay was performed to screen the epitopes from Pru p 3 overlapping peptide library, and a new epitope (P-1, AA1-16, ITCGQVSSALAPCIPY) was identified and two identified epitopes were deeply investigated (P-2, AA12-27, PCIPYVRGGGAVPPAC; P-3, AA23-38, VPPACCNGIRNVNNLA). The stability of these epitopes was then verified by thermal processing treatment and digestion experiments. Moreover, the key amino acids of the three identified epitopes were obtained by epitope amino acid mutation combined with slot-blot experiments. These findings may contribute to the further understanding of Pru p 3 and the prevention of peach allergy.

Basophil Activation Test Utility as a Diagnostic Tool in LTP Allergy.

Plant-food allergy is an increasing problem, with nonspecific lipid transfer proteins (nsLTPs) triggering mild/severe reactions. Pru p 3 is the major sensitizer in LTP food allergy (FA). However, in vivo and in vitro diagnosis is hampered by the need for differentiating between asymptomatic sensitization and allergy with clinical relevance. The basophil activation test (BAT) is an ex vivo method able to identify specific IgE related to the allergic response. Thus, we aimed to establish the value of BAT in a precise diagnosis of LTP-allergic patients. Ninety-two individuals with peach allergy sensitized to LTP, Pru p 3, were finally included, and 40.2% of them had symptoms to peanut (n = 37). In addition, 16 healthy subjects were recruited. BAT was performed with Pru p 3 and Ara h 9 (peanut LTP) at seven ten-fold concentrations, and was evaluated by flow cytometry, measuring the percentage of CD63 (%CD63+) and CD203c (%CD203chigh) cells, basophil allergen threshold sensitivity (CD-Sens), and area under the dose−response curve (AUC). Significant changes in BAT parameters (%CD63+ and %CD203chigh) were found between the controls and patients. However, comparisons for %CD63+, %CD203chigh, AUC, and CD-Sens showed similar levels among patients with different symptoms. An optimal cut-off was established from ROC curves, showing a significant positive percentage of BAT in patients compared to controls and great values of sensitivity (>87.5%) and specificity (>85%). In addition, BAT showed differences in LTP-allergic patients tolerant to peanut using its corresponding LTP, Ara h 9. BAT can be used as a potential diagnostic tool for identifying LTP allergy and for differentiating peanut tolerance, although neither reactivity nor sensitivity can distinguish the severity of the clinical symptoms.

Fucodendropeptides induce changes in cells of the immune system in food allergic patients via DC-SIGN receptor.

Food allergy induced by lipid transfer proteins (LTPs) of Rosacea fruit family, such as peach, is becoming an important health problem in the Mediterranean area. Current treatments, such as allergen specific immunotherapy (AIT) with allergenic extracts show promising, but in many cases, they need an improvement in homogeneity, availability and induction of tolerant responses. Peptide-based vaccines containing adjuvants, such as carbohydrates for C-type lectin receptors (CLRs) are presented as an alternative approach. In this work, we have prepared fucosylated glycodendropeptides (GDPs) functionalized with Pru p 3 peptides via click chemistry. These GDPs, DnFuc9Prup3, induced changes in moDC maturation and lymphocyte proliferation in food allergic patients, indicating specific recognition via DC-SIGN receptor. From these data, D4Fuc9Prup3 can be considered a promising candidate for specific immunotherapy development.

Phenotypes and Endotypes of Peach Allergy: What Is New?

Peach allergy is emerging as a common type of fresh-fruit allergy in Europe, especially in the Mediterranean area. The clinical manifestations of peach allergy tend to have a peculiar geographical distribution and can range from mild oral symptoms to anaphylaxis, depending on the allergic sensitization profile. The peach allergen Pru p 7, also known as peamaclein, has recently been identified as a marker of peach allergy severity and as being responsible for peculiar clinical features in areas with high exposure to cypress pollen. This review addresses the latest findings on molecular allergens for the diagnosis of peach allergy, the clinical phenotypes and endotypes of peach allergy in adults and children, and management strategies, including immunotherapy, for peach allergy.

IgE epitopes of Ara h 9, Jug r 3, and Pru p 3 in peanut-allergic individuals from Spain and the US.

Non-specific lipid transfer proteins (LTPs) are well studied allergens that can lead to severe reactions, but often cause oral allergy syndrome in the Mediterranean area and other European countries. However, studies focused on LTP reactivity in allergic individuals from the United States are lacking because they are not considered major allergens. The goal of this study is to determine if differences in immunoglobulin (Ig) E binding patterns to the peanut allergen Ara h 9 and two homologous LTPs (walnut Jug r 3 and peach Pru p 3) between the US and Spain contribute to differences observed in allergic reactivity. Synthetic overlapping 15-amino acid-long peptides offset by five amino acids from Ara h 9, Jug r 3, and Pru p 3 were synthesized, and the intact proteins were attached to microarray slides. Sera from 55 peanut-allergic individuals from the US were tested for IgE binding to the linear peptides and IgE binding to intact proteins using immunofluorescence. For comparison, sera from 17 peanut-allergic individuals from Spain were also tested. Similar IgE binding profiles for Ara h 9, Jug r 3, and Pru p 3 were identified between the US and Spain, with slight differences. Certain regions of the proteins, specifically helices 1 and 2 and the C-terminal coil, were recognized by the majority of the sera more often than other regions of the proteins. While serum IgE from peanut-allergic individuals in the US binds to peptides of Ara h 9 and its homologs, only IgE from the Spanish subjects bound to the intact LTPs. This study identifies Ara h 9, Jug r 3, and Pru p 3 linear epitopes that were previously unidentified using sera from peanut-allergic individuals from the US and Spain. Certain regions of the LTPs are recognized more often in US subjects, indicating that they represent conserved and possible cross-reactive regions. The location of the epitopes in 3D structure models of the LTPs may predict the location of potential conformational epitopes bound by a majority of the Spanish patient sera. These findings are potentially important for development of peptide or protein-targeting diagnostic and therapeutic tools for food allergy.

LTP Allergy Follow-Up Study: Development of Allergy to New Plant Foods 10 Years Later.

INTRODUCTION: Allergy to nonspecific lipid transfer protein (nsLTP) is the main cause of plant-food allergy in Spain. nsLTPs are widely distributed in the plant kingdom and have high cross-reactivity but extremely variable clinical expression. Little is known about the natural evolution of this allergy, which complicates management. The objective of this study was to assess the development of allergy to new plant foods in nsLTP-sensitized patients 10 years after diagnosis. METHODS: One hundred fifty-one patients showing specific IgE to nsLTP determined by ISAC (Thermofisher) were included. After clinical workup (i.e., anamnesis, skin test, and challenge when needed), these patients were divided into two groups: 113 patients allergic to one or more plant food (74.5%) and 38 patients not allergic to any plant food (25.1%). Ten years later, a telephone interview was conducted to check whether patients had developed additional allergic reactions to plant foods. RESULTS: Ten years after diagnosis, 35 of the 113 (31%) plant-food-allergic patients sensitized to nsLTP reported reactions to new, previously tolerated plant foods, mainly Rosaceae/Prunoideae fruits and nuts followed by vegetables, Rosacea/Pomoideae fruits, legumes, and cereals. Five out of 38 (13.2%) patients previously sensitized to nsLTP but without allergy to any plant food had experienced allergic reactions to some plant food: two to Rosaceae/Prunoideae fruits, two to Rosaceae/Prunoideae fruit and nuts, and one to legumes. CONCLUSION: Patients sensitized to nsLTP developed allergic reactions to other plant foods, mainly Rosaceae-Prunoideae fruits and nuts. This was more frequent among plant-food-allergic patients than among those who had never had plant-food allergy.

The Role of Lipid Transfer Proteins as Food and Pollen Allergens Outside the Mediterranean Area.

PURPOSE OF REVIEW: To provide an overview of the prevalence and clinical manifestation of non-specific lipid transfer proteins (LTP)-mediated allergies outside the Mediterranean area and to address potential reasons for the different geographical significance of LTP-driven allergies. RECENT FINDINGS: LTPs are major allergens in the Mediterranean area, which frequently can elicit severe reactions. Pru p 3 the LTP from peach is reported as genuine allergen and is considered a prototypic marker for LTP-mediated allergies. However, both food and pollen LTP allergies exist outside the Mediterranean area, but with lower clinical significance, different immunogenicity, and less clarified role. Evidence has been reported that in areas with high exposure to pollen, in particular to mugwort, pollen-derived LTPs can act as a primary sensitizer to trigger secondary food allergies. Co-sensitization to unrelated allergens might be causative for less severe reactions in response to LTPs. However, the reason for the geographical different sensitization patterns to LTPs remains unclear.

Lipid Transfer Protein Sensitization: Risk of Anaphylaxis and Molecular Sensitization Profile in Pru p 3-Sensitized Patients.

BACKGROUND: Component-resolved diagnosis reveals the IgE response to many inhaled, food, and other allergens, improving the understanding and diagnosis of allergic diseases. OBJECTIVE: The aims of the study are to study the recognition of different lipid transfer proteins (LTPs) and other allergen families in a large group of people sensitized to Pru p 3 and to analyze the relationship between the clinical entities and the allergens. METHODS: This cross-sectional study included a large cohort of patients with positive skin tests to peach fruit and Pru p 3 specific IgE antibodies. Respiratory and food allergy symptoms were collected, and we performed prick tests with pollen, plant food, and other allergens plus the ImmunoCAP ISAC assay. RESULTS: Our sample consisted of 421 people with a mean age of 33.25 years (range 16-68); 54.6% were women. Clinical entities included anaphylaxis (37.1%), urticaria (67.9%), and oral allergy syndrome (59.1%). Rhinitis, rhinoconjunctivitis, and/or asthma were diagnosed in 71.8% of the participants. The most pronounced correlation existed between sensitization to Pru p 3 and to Jug r 3, Pla a 3, Ara h 9, and Cor a 8. We found a higher incidence of anaphylaxis in people with 5 or more recognized LTPs. No association was observed between inhaled and food allergies. CONCLUSION: Most Pru p 3-sensitized participants were sensitized to additional allergens from the same family and, to a lesser extent, to other allergens, mainly in the profilin and PR-10 protein families. Anaphylaxis occurred in more than a third of the cases evaluated, and almost three-quarters of them had respiratory symptoms. Respiratory and food allergies involving LTPs do not seem to be associated.

Does the Food Ingredient Pectin Provide a Risk for Patients Allergic to Non-Specific Lipid-Transfer Proteins?

Pectin, a dietary fiber, is a polysaccharide that is widely used in food industry as a gelling agent. In addition, prebiotic and beneficial immunomodulatory effects of pectin have been demonstrated, leading to increased importance as food supplement. However, as cases of anaphylactic reactions after consumption of pectin-supplemented foods have been reported, the present study aims to evaluate the allergy risk of pectin. This is of particular importance since most of the pectin used in the food industry is extracted from citrus or apple pomace. Both contain several allergens such as non-specific lipid transfer proteins (nsLTPs), known to induce severe allergic reactions, which could impair the use of pectins in nsLTP allergic patients. Therefore, the present study for the first time was performed to analyze residual nsLTP content in two commercial pectins using different detection methods. Results showed the analytical sensitivity was diminished by the pectin structure. Finally, spiking of pectin with allergenic peach nsLTP Pru p 3 led to the conclusion that the potential residual allergen content in both pectins is below the threshold to induce anaphylactic reactions in nsLTP-allergic patients. This data suggests that consumption of the investigated commercial pectin products provides no risk for inducing severe reactions in nsLTP-allergic patients.