Effects of enzymatic hydrolysis combined with pressured heating on tree nut allergenicity.

Hazelnut, pistachio and cashew are tree nuts with health benefits but also with allergenic properties being prevalent food allergens in Europe. The allergic characteristics of these tree nuts after processing combining heat, pressure and enzymatic digestion were analyzed through in vitro (Western blot and ELISA) and in vivo test (Prick-Prick). In the analyzed population, the patients sensitized to Cor a 8 (nsLTP) were predominant over those sensitized against hazelnut seed storage proteins (Sprot, Cor a 9 and 14), which displayed higher IgE reactivity. The protease E5 effectively hydrolyzed proteins from hazelnut and pistachio, while E7 was efficient for cashew protein hydrolysis. When combined with pressured heating (autoclave and Controlled Instantaneous Depressurization (DIC)), these proteases notably reduced the allergenic reactivity. The combination of DIC treatment before enzymatic digestion resulted in the most effective methodology to drastically reduce or indeed eliminate the allergenic capacity of tree nuts.

Validation of the NUT CRACKER Diagnostic Algorithm and Prediction for Cashew and Pistachio Co-Allergy.

BACKGROUND: Because of the high cross-sensitization among tree nuts, the NUT CRACKER (Nut Co-reactivity-Acquiring Knowledge for Elimination Recommendations) study proposed a diagnostic algorithm to minimize the number of required oral food challenges (OFCs). OBJECTIVE: To validate the algorithm for cashew and pistachio allergy and determine markers for allergic severity. METHODS: Patients (n = 125) with a median age of 7.8 (interquartile range, 5.9-11.2) years with suspected tree nut allergy were evaluated prospectively with decision tree points on the basis of skin prick test (SPT), basophil activation test (BAT), and knowledge of the coincidence of allergies. Validation of allergic status was determined by OFC. Markers of clinical severity were evaluated using the combined original and prospective cohort (n = 187) in relationship to SPT, BAT, and Ana o 3-sIgE. RESULTS: Reactivity to cashew in SPT, BAT, and Ana o 3-sIgE and the incidence of abdominal pain on challenge were significantly higher in dual-allergic cashew/pistachio patients (n = 82) versus single cashew allergic patients (n = 18) (P = .001). All 3 diagnostic tests showed significant inverse correlation with log10 reaction doses for positive cashew OFC. The algorithm reduced overall the total number of OFCs by 72.0%, with a positive predictive value and negative predictive value of 93.0% and 99.0%, respectively. Cashew false-positives were observed primarily in hazelnut-allergic patients (P = .026). In this population, Ana o 3-specific IgE could diagnose cashew allergy with a sensitivity of more than 90% and a specificity of more than 95%. CONCLUSIONS: The NUT CRACKER diagnostic algorithm was validated and reduced the number of diagnostic OFCs required. Markers for severity phenotypes may guide oral immunotherapy protocols, improving the risk/benefit ratio for patients.

Cashew oral immunotherapy for desensitizing cashew-pistachio allergy (NUT CRACKER study).

BACKGROUND: Oral immunotherapy (OIT) is a treatment option for patients with milk, egg, and peanut allergy, but data on the efficacy and safety of cashew OIT are limited. METHODS: A cohort of 50 cashew-allergic patients aged ≥4 years, who were consecutively enrolled into cashew OIT (target dose 4000 mg protein) between 4/2016 and 12/2019. Fifteen cashew-allergic patients who continued cashew elimination served as observational controls. Co-allergy to pistachio and walnut was determined. Full desensitization rate and associated immunological changes in both groups were compared. Patients fully desensitized to cashew were instructed to consume a dose of 1200 mg cashew protein for 6 months and were then challenged to a full dose. Patients with co-allergy to pistachio or walnut were challenged to the respective nut. RESULTS: Forty-four of 50 OIT-treated patients (88%) compared to 0% in controls tolerated a dose of 4000 mg cashew protein at the end of the study (odds ratio 8.3, 95% CI 3.9-17.7, p < 0.001). An additional three patients were desensitized to 1200 mg cashew protein, and three patients stopped treatment. Three patients (6%) were treated with injectable epinephrine for home reactions. Desensitized patients had decreased SPT, sIgE, basophil reactivity, and increased sIgG4, following treatment. Following cashew desensitization, all pistachio (n = 35) and four of eight walnut co-allergic patients were cross-desensitized to the respective nut. All (n = 44) patients consuming a low cashew dose for ≥6 months following desensitization passed a full-dose cashew OFC. CONCLUSIONS: Cashew OIT desensitizes most cashew-allergic patients and cross-desensitizes to pistachio. Safety is similar to OIT for other foods.

Pistachio and cashew nut allergy in childhood: Predictive factors towards development of a decision tree.

BACKGROUND: Pistachio and cashew nut, which belong to the same botanical family, are tree nuts that induce serious allergic reactions. OBJECTIVE: We aimed to determine the predictive factors for pistachio and cashew nut reactivity during oral food challenge (OFC). METHODS: A total of 112 pistachio and/or cashew nut sensitized children, aged 58.45 (IQR:40.38-88.32) months, were included. Cutoff values and probability curves for skin prick test (SPT), sIgE, sIgE/Total IgE that predict reactivity were determined for pistachio and cashew nut. Additionally, a diagram was created that can be useful while making a decision for OFC based on SPT and sIgE values. RESULTS: A total of 73 patients underwent OFC with pistachio and/or cashew nut. Twelve children with current anaphylaxis history were not challenged and accepted as allergic. SPT was the only predictive factor for positive pistachio/ cashew nut OFC. According to area under curve (AUC) analysis, SPT was more predictive than sIgE and sIgE/Total IgE both for pistachio and cashew nut. Optimal cutoff values according to "Youden index" for pistachio SPT, sIgE, and sIgE/ Total IgE were 7.25 mm, 4.14 kUA/L, and 1.32%, respectively. And those values for cashew nut SPT, sIgE, and sIgE/Total IgE were 6.25 mm, 1.125 kUA/L, and 3.30%, respectively. The diagram showed that SPT predicted the reactivity together with sIgE better than only the SPT values. CONCLUSION: SPT was the best predictor for reactivity both for pistachio and cashew nut. Combined use of SPT and sIgE may improve the prediction of reactivity at pistachio and cashew nut OFCs in children.

Microbiological, Physicochemical, and Immunological Analysis of a Commercial Cashew Nut-Based Yogurt.

Nut-based milks and yogurts are gaining popularity, but may not offer the same benefits as dairy yogurts to consumers. Cashew nuts often cause severe allergic reactions, and cashew nut allergens are stable to several types of processing. To compare its characteristics to dairy yogurt and characterize the effects of fermentation on the Ana o 1-3 cashew nut allergens, a commercial yogurt made from cashew nuts (Cashewgurt) was evaluated for microbiological, physiochemical, and immunological properties. Average counts for lactobacilli and Streptococcus thermophilus were greater than 10 million colony forming units per milliliter, indicating the capacity to provide a health benefit. Cashewgurt pH and viscosity values were comparable to cow milk yogurts, and it was off white in color. SDS-PAGE analysis indicated a clear reduction in Ana o 1 and 2, and immuno-assay with polyclonal anti-cashew IgG antibody and cashew-allergic IgE indicated an overall reduction in allergen content. In contrast, SDS-PAGE, mass spectrometry, immunoblot, and ELISA all revealed that Ana o 3 was relatively unaffected by the fermentation process. In conclusion, Ana o 1 and Ana o 2 are sensitive to degradation, while Ana o 3 survives lactic acid bacterial fermentation during yogurt production. The analysis presented here indicates that cashew nut yogurt is not suitable for those with cashew nut allergy.

Predictive factors of allergy to pistachio in children allergic to cashew nut.

BACKGROUND: Cashew nut (CN) allergy prevalence has increased over the last few years. In children allergic to CN, complete avoidance of pistachio is usually recommended, but recent study showed that only one third of children allergic to CN were also allergic to pistachio. The aim of our study was to identify predictive factors of allergy to pistachio in children allergic to CN. METHODS: All children who had a positive oral food challenge (OFC) to CN between November 2013 and October 2017 in the Paediatric Allergy Department of the University Hospital of Nancy were included. Logistic regression models were used to predict the probability of allergy to pistachio. RESULTS: Among the 147 children included, tolerance or allergy to pistachio was known for 51. Out of these, 40 were allergic to pistachio (78.4%). Children allergic to pistachio had a larger weal size of skin prick test to CN (P = .01) and pistachio (P = .0007) and a lower reaction dose to CN (P < .0001). In multivariate analysis, only the reaction dose to CN was significantly associated with allergy to pistachio. Children with a low reaction dose to CN were significantly more at risk to have an allergy to pistachio (P = .01). CONCLUSION: A low reaction dose to CN seems to be a predictive factor of allergy to pistachio in children allergic to CN. In order to limit unnecessary food eviction, a pistachio OFC should be performed in children having high reaction dose whatever the importance of the skin or the specific IgE sensitization to pistachio.

Tree Nuts Anaphylaxis in Preschool Age Children.

Summary: Introduction. The incidence of food-induced anaphylaxis (FIA) is increasing in young children. Although the commonest culprits are cow's milk and egg, FIA to tree nuts (TNs) have been increasing. Objective. Characterization of children referred to our allergy department due to TNs-induced anaphylaxis (TNs-FIA) during preschool age. Materials and methods. We have retrospectively included 25 children with clinical history of preschool TNs-FIA, proven by allergological work-up. TNs sensitization was assessed by skin prick tests and/or specific IgE. Results. The mean age of the first anaphylactic episode was 3.1±1.2 years. The majority (92%) had an allergic disease (52% asthma). The implicated TNs were cashew (11 children), walnut (8), pine nut (5), hazelnut (2) and almond (1). The reaction occurred after the first known ingestion in 68%. In 92%, symptoms appeared within 30 minutes after exposure. The most frequent clinical symptoms were mucocutaneous (96%), respiratory (80%) and gastrointestinal (52%). Twenty-one children were admitted to the emergency department, although only 48% were treated with epinephrine. An underneath IgE-mediated mechanism was proven in all cases. Immunologic cross-reactivity with other TNs was identified in 84%, and with peanut in 36%. Overall, in our center, TNs-FIA represents 18% of all causes of FIA. Conclusions. In preschool age children with TNs-FIA, cashew and walnut were the commonest implicated nuts. Most reactions occurred briefly after exposure to minimal amounts of TNs, demonstrating the high potency of these allergens. About one-third also had peanut sensitization. Potentially life-threatening TNs allergy can occur early in childhood and adequate management should be undertaken.

Cashew Nut Allergy: Clinical Relevance and Allergen Characterisation.

Cashew plant (Anacardium occidentale L.) is the most relevant species of the Anacardium genus. It presents high economic value since it is widely used in human nutrition and in several industrial applications. Cashew nut is a well-appreciated food (belongs to the tree nut group), being widely consumed as snacks and in processed foods by the majority of world's population. However, cashew nut is also classified as a potent allergenic food known to be responsible for triggering severe and systemic immune reactions (e.g. anaphylaxis) in sensitised/allergic individuals that often demand epinephrine treatment and hospitalisation. So far, three groups of allergenic proteins have been identified and characterised in cashew nut: Ana o 1 and Ana o 2 (cupin superfamily) and Ana o 3 (prolamin superfamily), which are all classified as major allergens. The prevalence of cashew nut allergy seems to be rising in industrialised countries with the increasing consumption of this nut. There is still no cure for cashew nut allergy, as well as for other food allergies; thus, the allergic patients are advised to eliminate it from their diets. Accordingly, when carefully choosing processed foods that are commercially available, the allergic consumers have to rely on proper food labelling. In this sense, the control of labelling compliance is much needed, which has prompted the development of proficient analytical methods for allergen analysis. In the recent years, significant research advances in cashew nut allergy have been accomplished, which are highlighted and discussed in this review.

Origin and Processing Methods Slightly Affect Allergenic Characteristics of Cashew Nuts (Anacardium occidentale).

The protein content and allergen composition was studied of cashews from 8 different origins (Benin, Brazil, Ghana, India, Ivory Coast, Mozambique, Tanzania, Vietnam), subjected to different in-shell heat treatments (steamed, fried, drum-roasted). On 2D electrophoresis, 9 isoforms of Ana o 1, 29 isoforms of Ana o 2 (11 of the acidic subunit, 18 of the basic subunit), and 8 isoforms of the large subunit of Ana o 3 were tentatively identified. Based on 1D and 2D electrophoresis, no difference in allergen content (Ana o 1, 2, 3) was detected between the cashews of different origins (P > 0.5), some small but significant differences were detected in allergen solubility between differently heated cashews. No major differences in N- and C-terminal microheterogeneity of Ana o 3 were detected between cashews of different origins. Between the different heat treatments, no difference was detected in glycation, pepsin digestibility, or IgE binding of the cashew proteins.

Poly(anhydride) nanoparticles containing cashew nut proteins can induce a strong Th1 and Treg immune response after oral administration.

Cashew nut allergy is the second most commonly reported tree nut allergy. Traditional allergen immunotherapy presents several clinical drawbacks that can be reduced by using nanoparticles-basedallergen-delivery systems, modulating the immune response towards a protective one. In this context, the goal of this work was to assess the potential of poly(anhydride) nanoparticles (NP) for cashew nut oral immunization. Cashew nut allergens-loaded nanoparticles (CNE-NP) were prepared by solvent displacement method. After nanoparticles characterization, oral immunomodulation ability was evaluated in BALB/c mice. Our results demonstrated that CNE-NP induced a higher Th1/Th2 ratio in comparison with animals immunized with free cashew nut proteins. Indeed, a decrease in splenic Th2 cytokines (IL-4, IL-5, and IL-13), and an enhancement of pro-Th1 (IL-12 and IFN-γ) and regulatory (IL-10) cytokines was observed. Furthermore, mice orally immunized with CNE-NP presented an increased expansion of CD4+ T regulatory cells, such as CD4+Foxp3+ and CD4+LAP+, in the mesenteric lymph nodes. In conclusion, oral immunization with a single dose of poly(anhydride) nanoparticles loaded with cashew nut proteins leaded to a pro-Th1 and Treg immune response. Furthermore, their immunomodulatory properties could be introduced as a new approach for management of cashew nut allergy.

Risk Factors and Clinical Features in Cashew Nut Oral Food Challenges.

BACKGROUND: Cashew nuts (CN) are capable of causing severe allergic reactions. However, little has been reported about the details of CN oral food challenges (OFC). METHODS: CN-specific IgE (sIgE) levels were measured for 1 year in 66 patients who underwent an OFC with >3 g CN for diagnosis or confirmation of tolerance acquisition between June 2006 and August 2014. We retrospectively analyzed the OFC and patient background. RESULTS: The median (IQR) age of the 66 patients (48 boys/men and 18 girls/women) was 7.0 years (5.7-8.8). Twelve patients (18.2%) had a positive OFC result; 6 of 8 (75%) patients with a history of an immediate reaction to CN failed the OFC. Anaphylaxis was experienced by 5 of these 12 (42%) patients. A history of an immediate reaction to CN and the CN sIgE levels were significantly different for patients with a positive or negative OFC result (p < 0.01). Among patients without a previous immediate reaction to CN, the 95% positive predictive value (PPV) for the CN sIgE level for a positive OFC result was 66.1 kUA/L. CONCLUSIONS: A history of an immediate reaction to CN and high CN sIgE were risk factors for a positive OFC result. The number of positive OFC results was relatively low, but there was a high probability of anaphylaxis. We should consider the indication of OFC carefully for patients with a history of immediate reactions to CN and avoid OFC for patients without such a history whose CN sIgE values are >66.1 kUA/L (95% PPV).

Polyphenol-rich pomegranate juice reduces IgE binding to cashew nut allergens.

BACKGROUND: Food allergy negatively impacts quality of life and can be life-threatening. Cashew nuts can cause severe reactions in very small amounts, and they are included in a group of foods most commonly responsible for causing food allergy. Polyphenols and polyphenol-rich juices have been demonstrated to complex with peanut allergens. Here, the interaction between cashew nut allergens and polyphenol-rich juices is evaluated biochemically and immunologically. RESULTS: Various juices, including pomegranate (POM), blueberry (BB), and concord grape (CG) juices, were evaluated for polyphenol content and formation of polyphenol-cashew allergen complexes. Among the various juices studied, POM juice showed a greater capacity to form complexes with cashew proteins. Dynamic light scattering (DLS) demonstrated a sharp increase in cashew protein extract particle size to around 3580 nm, and fewer cashew proteins were resolved by electrophoresis after treatment with POM juice. Immunoassays demonstrated reduced IgG and IgE binding to cashew allergens due to allergen precipitation by POM juice. These observations support the formation of complexes between polyphenol and cashew proteins that can prevent antibody recognition of cashew allergens through allergen precipitation. CONCLUSION: POM juice treatment of cashew extract effectively reduces antibody binding through allergen precipitation, and these findings could be applied to the development of less allergenic cashew nut products and oral immunotherapy. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

Thermal processing effects on the IgE-reactivity of cashew and pistachio.

Thermal processing can modify the structure and function of food proteins and may alter their allergenicity. This work aimed to elucidate the influence of moist thermal treatments on the IgE-reactivity of cashew and pistachio. IgE-western blot and IgE-ELISA were complemented by Skin Prick Testing (SPT) and mediator release assay to determine the IgE cross-linking capability of treated and untreated samples. Moist thermal processing diminished the IgE-binding properties of both nuts, especially after heat/pressure treatment. The wheal size in SPT was importantly reduced after application of thermally-treated samples. For cashew, heat/pressure treated-samples still retain some capacity to cross-link IgE and degranulate basophils, however, this capacity was diminished when compared with untreated cashew. For pistachio, the degranulation of basophils after challenge with the harshest heat/pressure treatment was highly decreased. Boiling produced more variable results, however this treatment applied to both nuts for 60 min, led to an important decrease of basophil degranulation.

Butein inhibits IL-1ß-induced inflammatory response in human osteoarthritis chondrocytes and slows the progression of osteoarthritis in mice.

Osteoarthritis (OA) is a progressive degenerative disease characterized by irreversible articular cartilage destruction. Butein, a polyphenolic compound isolated from the stem bark of cashews and Rhus verniciflua Stokes, has been reported to have anti-inflammatory effects. This study aimed to assess the effect of butein on human OA chondrocytes and mice OA models induced by destabilization of the medial meniscus (DMM). In vitro, human OA chondrocytes were pretreated with butein at 10, 50µM and subsequently stimulated with IL-1ß (10ng/ml) for 24h. Production of NO, PGE2, TNF-α and IL-6 was evaluated by the Griess reaction and ELISAs. The mRNA expression of COX-2, iNOS, TNF-α, IL-6, MMP-1, MMP-3, MMP-13, ADAMTS-4, ADAMTS-5, COL-2 and SOX-9 were measured by real-time PCR. The protein expression of COX-2, iNOS, MMP-13, COL-2, SOX-9, p65 and IκB-α were detected by Western blot. P65 nuclear translocation was detected by immunofluorescence. In vivo, the severity of OA was determined by histological analysis. We found that butein significantly inhibited the IL-1ß-induced production of NO and PGE2, expression of COX-2, iNOS, TNF-α, IL-6 and MMP-13, degradation of COL-2 and SOX-9 at mRNA and protein levels as well as MMP-1, MMP-3, ADAMTS-4 and ADAMTS-5 gene expression. Furthermore, butein dramatically suppressed IL-1ß-stimulated IκB-α degradation and NF-kB p65 activation. In vivo, the cartilage in butein-treated mice exhibited less Safranin O loss, cartilage erosion and lower OARSI scores. Butein also reduced subchondral bone plate thickness and alleviated synovitis. Taken together, these findings indicate that butein may be a potential agent in the treatment of OA.