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|Route of Exposure||Ingestion|
|Source Material||Peel from fresh fruit|
|Latin Name||Prunus persica|
|Other Names||Cultivar Crimson Lady|
|Categories||Fruits, Food Of Plant Origin|
Peach (Prunus persica) is the fruit of the Prunus trees, belonging to the Rosaceae family and is among the most desired fruits consumed worldwide. Peach-sensitive patients may suffer from allergic reactions such as oral allergy syndrome (OAS) symptoms, urticaria and in worst cases anaphylaxis. Individuals with Pru p 1 sensitization show milder symptoms than those sensitized to Pru p 3 and Pru p 7. Since Pru p 1 is heat-labile, those affected with an allergy to raw peach can instead consume pasteurized forms of peach. However, this cannot be followed for individuals sensitized to Pru p 3 a lipid transfer protein (LTP), which is heat stable. Cross-reactivity has been reported between Pru p 1 and birch pollen, Pru p 2 and plane pollen, Pru p 3 and various fruits of the Rosaceae family such as cherry and plum, and Pru p 7 with apricot, orange, and pomegranate. Pru p 7 is a marker for severe fruit-induced allergy and may be the link between severe allergic reaction to fruits and cypress pollen.
Peach is a popular fruit consumed for its nutritional value with health benefits and is known to bear an important economic value in the market around the world (1). Peach tree is deciduous which can grow up to a height of 10 meters. The tree bark is ideally grey or ash in color (2). The leaves are narrow oval in shape, 8-15 cm (length) and 1.5-3.5 cm (width) (3). Each of the peach flowers are featured with pink petals having a thickness between 2.5-3 cm, which are either solitary or paired (3). The peach fruit has a unique shape, color ranging from yellow to red (2), with a velvety texture (3). Peach fruit usually ripens between August-September. Peach belongs to the Prunus species and are known as stone fruits (3). It is because peach has an outer fleshy part (exocarp and mesocarp) that surrounds a hard stone (endocarp) which has a seed inside it (2, 3). Peach can be treated and eaten in form of canned, dried, juices, and jams (2).
Peach originated from the temperate zones and can also be cultivated in the subtropics and tropics as well (4). China and Persia were the important historical peach producer areas. Later peach was cultivated in other countries such as USA, New Zealand, Australia, Temperate Asia (3), Spain, and Turkey (2). Peach often grows in warm climate (3) at an altitude of up to 1000 ft (2). It can also be grown in different climatic conditions and soil types (3). More than 3000 varieties of peach are cultivated in the world (1).
Peach fruit belongs to the Rosaceae family consisting of approximately 90-125 genera and around 3370-3500 species of trees, shrubs, and herbs. Rosaceae is divided into four subfamilies (2).
|Taxonomic tree of Peach (5)|
The peach skin holds around 7 times higher concentration of lipid transfer protein (LTP) per mg of freeze-dried material than the pulp. Peach skin contains higher protein and LTP content than the pulp (6). Peach fuzz is also rich in Pru p 3 (7).
A study reported the presence of Pru p 3, a LTP, in the peach leaves and skin extracts. Identification of monoclonal anti-Pru p 3 from the leaves and peach suggests that LTP from non-pollen structures (like leaf) can cause occupational respiratory allergy (8).
Pru p 7 or peamaclein, has been found both in the pulp and the peel of peaches (9).
Two European based large surveys (2014 and 2010) revealed the overall sensitization for fruits in Europe (10). In one survey, highest (13.4%) and lowest (2.3%) weighted prevalence of peach was reported in Zurich (Switzerland) and in Reykjavik (Iceland) respectively (11).In the other, the highest (11.7%) and lowest (0.3%) prevalence of sensitization to peach was in Germany and Iceland, respectively. Overall, the prevalence of sensitization to peaches increased from 5.4% (2010) to 7.9% (2014) (10). Sensitization to peach is common in Western Europe, the USA, and Australia (12).
Ando et al. (2020) conducted a study using Japanese children and adolescents and suggested that individuals sensitized to Pru p 1 and Pru p 4 are likely to develop oral allergy symptoms. In contrast, those sensitized to Pru p 7 show severe systemic reactions such as anaphylaxis in the presence of factors like exercise (13).
The peach plant is cultivated in different parts of the world now. It is believed to have originated from China and transported via the silk route to India, mid-east, and Persia, and then its cultivation quickly spread towards Europe. The leading peach-producing countries are China, Italy, Spain, Turkey and the USA (2).
In Northern and Central Europe, peach allergy is common among people allergic to birch pollen (10) since Bet v 1, a major allergen of birch pollen, resembles the structure of peach protein (Pru p 1) (14) . Pru p 1 causes oropharyngeal or systemic symptoms in these birch-fruit allergic patients (15). On the contrary, in Mediterranean areas peach allergy is common and mostly associated with severe systemic symptoms because of sensitization to Pru p 3 (16).
However, recent evidence have identified peach allergy due to Pru p 3 (LTP) in Central and Northern Europe as well (17, 18).
Peach allergy occurs mainly through ingestion (19).
Allergic reactions to peach sensitization may include symptoms of oral allergy syndrome (OAS) such as oropharyngeal symptoms (oral itching, swelling), anaphylaxis, systemic symptoms (gastrointestinal involvement - nausea, vomiting, and diarrhea, swelling, and sometimes severe asthma) (20) .
A cross-sectional study evaluated 127 OAS patients diagnosed using a skin prick test or a serum IgE test. Only 56 patients responded to the questionnaire regarding the allergy-causing foods and their associated symptoms (OAS or allergic rhino conjunctivitis (ARC)). Patients with OAS symptoms experienced itchiness and swelling in the oral mucosa, lips, and throat, systemic skin symptoms, respiratory symptoms, gastrointestinal symptoms, and shock (collapse). ARC patients complained of rhinorrhea, nasal congestion, sneezing, and eye itching. Forty-three of 56 patients (14 in the subcutaneous immunotherapy (SCIT) group and 29 in non-SCIT group) selected peach as the causative agent for OAS. (21).
A retrospective chart review study conducted on 1,427 patients showed that peach was one of the frequent contributors (56%) for OAS manifestation. 96.2% of 26 patients developed OAS as a symptom of food allergy. Patients with OAS symptoms exhibited reactions such as itchiness or swelling of the mouth, face, lip, tongue, and throat. Of 25 patients with OAS, 72% had rhino conjunctivitis (n=18), 20% had asthma (n=5), 12% chronic urticaria (n=3), 12% anaphylaxis (n=3), 4% atopic dermatitis (AD), (n=1) (22).
One case reported a 62-year-old woman having an episode of anaphylaxis while eating a peach. She experienced nausea, vomiting, itchiness of the mouth, face and hands, facial edema, and dizziness. Though she did not complain of hives, but had redness on her hands, feet and face (23).
Another case study reported a 25-year-old woman developing an anaphylactic reaction upon moderate physical exertion after consuming peach. Additionally, massive facial swelling (particularly on the eyelids) and labored breathing, due to swelling of the lower throat was observed (24).
In a prospective cross-sectional study, oral food challenge (OFC) using peach pulp were done in all patients, except one, as he had cardiopathy and developed anaphylaxis after consuming peach on two different occasions. Children presented allergic reactions such as mucocutaneous symptoms (angioedema, urticaria, OAS, conjunctivitis), vomiting, and respiratory symptoms (cough, bronchospasm, rhinitis, etc.) (25).
A study evaluated the allergic response to various inhalant allergens in 37 peach crop workers diagnosed with seasonal occupational ARC and asthma. This study showed that all patients had varying severity of ARC symptoms, and most reported (33/37) persistent rhino conjunctivitis. Six patients with both ARC and asthma underwent a specific bronchial challenge test with peach leaf extract. Four of these patients were sensitized to leaf extract. Two patients reported a decrease in decline in lung function. Twenty-five (67.5% of 37) patients reported asthma, of which 12 suffered from severe asthma. (8).
A double-blind placebo-controlled food challenges (DBPCFCs) was conducted with peach and apple in 289 patients. In the DBPCFC group with peach-allergic patients, 92.9% had OAS (66/71), 19.7% abdominal pain (14/71), 7% vomiting (5/71), 1 patient complained of diarrhea, 14% showed skin pruritis (10/71), 9.8% had urticaria (7/71), 14% with rhino conjunctivitis (10/71), and 4.2% complained of cough (3/71) (26).
Gonzalez Perez et al. (2020) demonstrated tolerance in patients with LTP syndrome along with symptom burden using a sublingual Pru p 3 extract. These patients reported better quality of life after treatment (27).
The peach allergenic components differ from each other in their nature. Peach allergic patients with Pru p 1 sensitization can tolerate peach in the form of pasteurized juices and jams. This is because Pru p 1 is a member of PR-10 proteins family (10) , which is heat labile (28) and tend to lose its allergenicity upon heat treatment (10).
However, since LTPs are resistant to high temperature and pH changes, consumption of pasteurized peach product is ineffective in patients suffering from peach allergy due to Pru p 3 sensitization (10).
Patients sensitive to peach must try to avoid ingestion of the fruit and its product and/or permanently eliminate it from diet to prevent peach allergy (19).
Six peach allergens have been identified in peach fruit till date (29). Four of these proteins were identified in the last decade (9). The table below provides detailed information on each of the allergenic proteins.
|Allergen||Biochemical Name||Molecular Weight (kDa)||Allergenicity|
|Pru p 1||Pathogenesis-related protein group 10, (PR-10), Bet v 1 family member||18||
|Pru p 2||Thaumatin-like protein (TLP)||25-28||
|Pru p 3||Non-specific lipid transfer protein 1 (nsLTP1)||10||
|Pru p 4||Profilin||14||
|Pru p 7||Gibberellin-regulated protein (GRP) (PF02704)||6910.84 Da (Mass spectrometry)||
|Pru p 9||Pathogenesis-related protein PR-1||18||
• kDa: kilodaltons, IgE: Immunoglobulin E; sIgE: specific IgE
Pru p 1
Peach allergy in birch allergic individuals occurs due to Pru p 1 sensitization as it is structurally similar to Bet v 1. Mild to moderate symptoms related to oral cavity is one of the main clinical manifestations seen in these patients. Severe systemic symptoms with Bet v 1-related food allergens are relatively rare due to their labile nature that gets these allergens digested easily in the gastrointestinal tract (14).
Pru p 4
Profilin is a clinically relevant marker for pollen-food allergy syndrome (PFAS) (36). Cross-reactivity has been reported between Pru p 4 and Bet v 2, which are profilin allergens from peach fruit and birch pollen (37).
Pru p 3
Patients primarily monosensitized to Pru p 3 usually suffer from severe symptoms. When individuals are secondarily sensitized to Pru p 3, i.e., due to cross-reactivity to Pru p 1 and/or Pru p 4, it results in OAS symptoms (38).
Pru p 7
A recent study proposed that Pru p 7 sensitivity can pose a risk factor for severe fruit-induced allergic reactions (33). Another study showed that Pru p 7 sensitivity could be a characteristic of a sub-type of cypress (Cupressaceae) pollen allergy, where cypress pollen is the primary sensitizer triggering severe peach allergy (39).
Similar to clinical symptoms, cross-reactivity prevalence patterns seen with peach allergy are geographically influenced. For example, cross-sensitization with Pru p 1 is higher in countries with high pollen exposure of the birch trees (Central and Northern Europe) (10). (14,16).
Pru p 1
A study in Northern Europe showed that 19 of 30 patients sensitized to birch pollen (Bet v 1) reported cross-reactivity to peach via PR-10 proteins (30).
Pru p 2
Testing sera from 329 allergic patients showed that Pru p 2 tends to cross-react with chestnut and plane pollen. (31).
Pru p 4
Sankian et al. (2005) revealed in their study that peach and melon profilins could cross-react (40).
Pru p 3
Peaches often cross-react with other members of the Rosaceae family such as cherry, plum, almond, apricot, due to non-specific LTPs (41, 42).
Pru p 3 IgE antibodies can also cross-react with fruits from unrelated families like citrus fruits, grapes. It can also react with nuts such as walnut, hazelnut. Pru p 3 cross-reactivity with vegetables such as asparagus, lettuce, tomato, maize, onion, and carrot may also be seen (43).
Co-sensitization of Pru p 3 with either Pru p 1 or Pru p 4 may lower the risk of severe systemic reactions in peach allergic individuals (38).
Pru p 7
Pru p 7 in peach often cross-reacts with proteins from several fruits of the Rosaceae (Japanese apricots, pomegranate) and Rutaceae (orange) families. IgE-mediated cross-reactivity is seen between the fruit GRPs Pru p 7, Pru m 7 (Japanese apricot) (44), Cit s 7 (orange) (45) and Pun g 7 (pomegranate) (46).
A study showed that high IgE-mediated cross-reactivity exists between Pru p 7 and the GRP BP14 allergens, present in the Cupressaceae family's pollens (47). Klingebiel et al. (2019) identified that sensitization to Pru p 7 is related with sensitization to cypress pollen in peach allergic patients. Cypress pollen acts as the primary sensitizer in Pru p 7 induced peach allergy (33).
Author: Turacoz Healthcare Solutions
Reviewer: Dr. Christian Fischer
Last reviewed: January 2021