Allergy information for: Pear (Pyrus communis )

  • Name: Pear
  • Scientific Name: Pyrus communis
  • Occurrence: As fruit, juices, jams, jellies, preserves.
  • Allergy Information:

    Like many other allergies to fresh fruits and vegetables, pear allergy can take two different forms. In the North of Europe, people with birch-pollen allergy can develop a pear allergy due to the similarity between a protein in birch that causes birch-pollen allergy and a pear protein. This is called the birch-fruit syndrome with symptoms generally appearing within 5-15 min after consuming raw pear and comprising local reactions in the mouth and throat with itching and inflammation (called oral allergy syndrome, OAS). The molecule, known as an allergen, involved in this kind of allergy does not survive cooking. Therefore, people who react to this allergen can tolerate cooked pear. Individuals often develop adverse reactions to other fruits including apple, apricot, cherry, melon, banana, nuts such as hazelnut, or vegetables such as celeriac (celery tuber) and carrot.

    In Mediterranean countries, people with pear allergy do not have birch-pollen allergy. Instead they often have allergy to peach. Symptoms are more severe including generalised urticaria, abdominal pain, vomiting and life-threatening symptoms, sometimes in addition to the OAS. These individuals tend to have more frequent and severe reactions when fruits are eaten with the peel. They also tend to develop adverse reactions to other fruits including apple, peach, apricot, plum, cherry and nuts (such as hazelnut and walnut). The allergen that causes this kind of allergy is tough and the allergenicity survives in processed foods such as juices. As a result, individuals with this kind of allergy cannot eat even cooked pear.

  • Other Information:
  • Taxonomic Information: NEWT http://www.ebi.ac.uk/newt/display?from=null&search=23211
  • Last modified: 18 October 2006

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    References (0)

      Clinical History

      • Number of Studies:1-5
      • Number of Patients:>50
      • Symptoms:

        Oral allergy syndrome in patients recruited from middle and Northern Europe (Karamloo et al. 2001) [84] (Florido Lopez et al. 2002) [1059] or generalised anaphylaxis in patients from Southern Europe (Rodriguez et al. 2000) [491] (Florido Lopez et al. 2002) [1059]

      Skin Prick Test

      • Number of Studies:1-5
      • Food/Type of allergen:

        Fresh fruit (Fernandez-Rivas et al. 1997) [1060], (Rodriguez et al. 2000) [491], (Florido Lopez et al. 2002)

        Commercial pear extract and fresh fruit (Asero, 1999) [1033]

      • Protocol: (controls, definition of positive etc)

        SPTs were carried out by the prick-prick technique. Histamine (10 mg/mL) and saline solution were used as positive and negative controls repectively. A positive SPTresult was defined as a mean (average of orthogonal to largest diameter) wheal of 3 mm or greater (after subtracting the diameter of the wheal induced by the diluent control). (Fernandez-Rivas et al. 1997) [1060], (Rodriguez et al. 2000) [491], (Florido Lopez et al. 2002)

        SPTs were carried out on the volar side of the forearm with a sterile, 1 mm-tip lancet pricking through the drop of the extract. Readings were taken after 15 min. Histamine (10 mg/mL) and saline solution were used as positive and negative controls repectively. Wheals with a diameter below 50% of the positve control were considered negative. (Asero, 1999) [1033]

      • Number of Patients:

        11 patients (Fernandez-Rivas et al. 1997) [1060]

        237 patients (Asero, 1999) [1033]

        28 patients (Rodriguez et al. 2000) [491]

        134 patients divided in 3 groups. Group A comprised 21 patients with oral allergy syndrome after eating fruits belonging to the Rosacea, Cucurbitaceae or Actinidiaceae families. Group B included 19 patients with a convincing history of anaphylaxis due to any fresh fruit or nut and group C (control group) comprised of 94 olive pollen allergic patients suffering only seasonal respiratory symptoms in spring time, in absence of any adverse reaction to vegetables foods (Florido Lopez et al. 2002)

      • Summary of Results:

        SPTs were positive in all patients (Fernandez-Rivas et al. 1997) [1060]

        6/237 patients had a positive SPT (Asero, 1999) [1033]

        SPTs were positive in 18 patients (Rodriguez et al. 2000) [491]

        SPTs were positive in 15/21 (71.4%) group A patients, in 6/19 (31.5%) group B patients and negative in the control group (Florido Lopez et al. 2002)

      IgE assay (by RAST, CAP etc)

      • Number of Studies:0
      • Food/Type of allergen:

        In-house extracts of pear (cv. Blanquilla) were prepared in 10 mM potassium phosphate buffer, pH 7.0 , 2% (w/v) polyvinylpolypyrrolidone, 2 mM ethylenediaminetetraacetic acid disodium salt, 10 mM sodium diethyldithiocarbamate and 3 mM sodium azide. Pear pieces were homogenised in extraction buffer for 1 min, centrifuge for 30 min at 40 000 x g at room temperature, and dialysed for 20 h at 4°C against 10 mM potassium phosphate buffer, pH 7.0 , 3 mM sodium azide (Fernandez-Rivas et al. 1997) [1060]

        Commercial pear extract (Rodriguez et al. 2000) [491]

        Extracts and recombinant Pyr c 1 and Pyr c 5. Extracts were prepared as follows: Pieces of fresh fruit were frozen with liquid nitrogen and ground in an analytical mill. The plant material was transferred into pre-cooled acetone, homogenized, and stored at -20 °C overnight. The precipitate was washed twice with acetone (-20 °C) and once with a mixture of acetone and diethylether (1 : 1, v/v, -20 °C), filtered and lyophilized. Then, the freeze-dried acetone powder was extracted with 0.15 m NaCl/0.01 m NaH2PO4 pH 7.4, the supernatant was centrifuged, passed through a glass fibre prefilter, and either freeze-dried or stored at -20 °C until used. (Karamloo et al. 2001) [84].(Karamloo et al. 2001) [83].

      • IgE protocol:

        RAST (Fernandez-Rivas et al. 1997) [1060]

        CAP (Rodriguez et al. 2000) [491]

        EAST and histamine release (Karamloo et al. 2001) [84] (Karamloo et al. 2001) [83].

      • Number of Patients:

        11 patients (Fernandez-Rivas et al. 1997) [1060]

        28 patients (Rodriguez et al. 2000) [491]

        11 sera from birch-pollen-allergic patients including 2 pooles of sera (Karamloo et al. 2001) [84]

        16 patients allergic to birch pollen and with allergic symptoms after ingestion of fresh pears (Karamloo et al. 2001) [83].

      • Summary of Results:

        8/11 patients had specific IgE to pear (Fernandez-Rivas et al. 1997) [1060]

        10/28 patients had specific IgE to pear (Rodriguez et al. 2000) [491]

        All sera had a positive EAST (> 0.35 U·mL -1) to pear extract and the recombinant major pear allergen, rPyr c 1. All sera but one had IgE specific for rPyr c 5. Recombinant Pyr c 5 triggered a strong, dose-dependent mediator release from basophils of a pear-allergic subject (Karamloo et al. 2001) [84].

        Fifteen (94%) of the patients had a positive EAST for pear extract, and all showed IgE binding to rPyr c 1. Dose-related histamine release experiments were undertaken in two patients who were allergic to birch pollen and pears. The response to allergen stimulation showed the same ranking in both patients, as graded by the protein concentration required to stimulate a histamine release of 50%. This concentration was highest for pear extract protein (0.05–0.1 µg/ml), and about 10-fold lower amounts of rPyr c 1 were required to elicit the same effect (Karamloo et al. 2001) [83].

      Immunoblotting

      • Immunoblotting separation:Sodium dodecylsulfate-polyacrylamide gel electrophoresis (12% homogeneous gels, 140 × 115 × 1 mm, 5% stacking gels) was performed in a vertical slab gel apparatus (Ebner et al. 1995) [46]
      • Immunoblotting detection method:

        The proteins were electroblotted to a nitrocellulose sheets with pore size 0.2 µm. The sheets were cut into 5 mm strips and blocked with phosphate-buffered saline pH 7.5 with 0.5% (v/v) Tween 20 and 0.5% (w/v) bovine serum albumin for 30 min. Strips were incubated with diluted (1:4 v:v) sera overnight. The IgE-binding components were detected with iodine 125–labeled rabbit anti-human IgE antiserum. Blots were visualised by autoradiography (Ebner et al. 1995) [46].

      • Immunoblotting results:18/20 sera displayed IgE binding to pear extract. 14 sera reacted with a protein of 17 kDa, and 4 sera reacted with an polypeptide of 14 kDa. Sera from 7 patients recognized proteins in the higher MW range (Ebner et al. 1995) [46]

      Oral provocation

      • Number of Studies:1-5
      • Food used and oral provocation vehicle:

        A total of 17 g of dehydrated whole fruit was masked in a mix of orange (200 mL) and pineapple (200 mL) juices, sugar (16 g), wheat meal (13 g), and liquid coloring (Rodriguez et al. 2000) [491]

        100 g of fresh pear fruit was masked, mixing it with sugar (13 g), cookies (20 g), coffee (50 ml), peppermint syrup and saffron (amount on point of knife). The same recipe except the fresh fruit was used to prepare the placebo food (Florido Lopez et al. 2002)

      • Blind:

        Open and DBPCFC (Rodriguez et al. 2000) [491]

        Yes (Florido Lopez et al. 2002)

      • Number of Patients:

        28 patients with positive skin prick tests or CAP to Rosaceae (Rodriguez et al. 2000) [491]

        21 patients with oral allergy syndrome after eating fruits belonging to the Rosacea, Cucurbitaceae or Actinidiaceae families. (Florido Lopez et al. 2002)

      • Dose response:

        Subjects were first challenged randomly with either food or placebo. After an interval of at least 24 hours, the second part of the DBPCFC took place with subjects receiving either food or placebo depending on what they had recieved in the first challenge. Confirmation by DBPCFC was accepted if the subject had symptoms after provocation with the active substance and no symptoms after the placebo challenge. (Rodriguez et al. 2000) [491]

        Each dose of active or placebo food was chewed for a minute and then swallowed. The doses were gradually increased until a positive response was obtained or until a 60 ml (105 ml accumulate dose) of food (active or placebo) was ingested without any symptoms. Patients were challenged with fruit or placebo in two separated days (Florido Lopez et al. 2002)

      • Symptoms:3 out of 28 patients were positive after DBPCFC with pear. 1 patient (33%) had generalised anaphylaxis (Rodriguez et al. 2000) [491]

        A total of 84 DBPCFC were performed in group A patients (21 subjects) with 33.3% of positive results showing oral allergy syndrome after challenged with pear fruit . 33.3% of patients with a positive SPT were also positive when challenged (Florido Lopez et al. 2002).

      IgE cross-reactivity and Polysensitisation

      Preincubation of a serum pool with rBet v 1 led to complete blocking of IgE binding to a 17 kDa band in pear extract, whereas IgE binding to the 14 kDa band was not affected. Preincubation of the serum pool with rBet v 2 led to complete inhibition of IgE binding to the 14 kDa band; IgE binding to the 17 kDa band and to high MW proteins was not affected (Ebner et al. 1995)

      In a pear RAST, IgE binding was inhibited with mugwort pollen (68%), and weakly with peach and apple extracts (Fernandez-Rivas et al. 1997)

      Other Clinical information

      Reviews (0)

        References (7)

        • Karamloo, F., Wangorsch, A., Kasahara, H., Davin, L.B., Haustein, D., Lewis, N.G., and Vieths, S.
          Phenylcoumaran benzylic ether and isoflavonoid reductases are a new class of cross-reactive allergens in birch pollen, fruits and vegetables
          European Journal of Biochemistry 268 (20), 5310-5320. 2001
          PUBMEDID: 11606193
        • Karamloo F, Scheurer S, Wangorsch A, May S, Haustein D, Vieths S
          Pyr c 1, the major allergen from pear (Pyrus communis), is a new member of the Bet v 1 allergen family.
          J Chromatog B 756: 281-293.. 2001
          PUBMEDID: 11419719
        • Asero R.
          Detection and clinical characterization of patients with oral allergy syndrome caused by stable allergens in Rosaceae and nuts
          Ann Allergy Asthma Immunol. 83(5):377-83.. 1999
          PUBMEDID: 10582717
        • Rodriguez J; Crespo JF; Lopez-Rubio A; de la Cruz-Bertolo J; Ferrando-Vivas P; Vives R; Daroca P
          Clinical cross-reactivity among foods of the Rosaceae family.
          J Allergy Clin Immunol 106:183-189. 2000
          PUBMEDID: 10887323
        • Ebner C, Hirschwehr, R, Bauer L, Breiteneder H, Valenta R, Ebner, H, Kraft D, Scheiner O.
          Identification of allergens in fruits and vegetables: IgE cross-reactivities with the important birch pollen allergens Bet v 1 and Bet v 2 (birch profilin).
          J Allergy Clin Immunol 95: 962-9.. 1995
          PUBMEDID: 7751517
        • Florido Lopez JF, Quiralte Enriquez J, Arias de Saavedra Alias JM, Saenz de San Pedro B, Martin Casanez E
          An allergen from Olea europaea pollen (Ole e 7) is associated with plant-derived food anaphylaxis
          Allergy. 57 Suppl 71:53-9. 2002
          PUBMEDID: 12173271
        • Fernandez-Rivas M, van Ree R, Cuevas M
          Allergy to Rosaceae fruits without related pollinosis
          J Allergy Clin Immunol. 100(6 Pt 1):728-33. 1997
          PUBMEDID: 9438478

        Biochemical Information for Pyr c 1

        • Allergen Name:Pyr c 1
        • Alternatve Allergen Names:
        • Allergen Designation:Major
        • Protein Family:Pathogenesis-related protein Bet v I family, Pfam PF00407
        • Sequence Known?:Yes
        • Allergen accession No.s:

          O65200 :Swissprot:http://ca.expasy.org/cgi-bin/niceprot.pl?O65200

          AF057030; AAC13315.1; EMBL / GenBank

        • 3D Structure Accession No.:Not determined
        • Calculated Masses:17581 Da
        • Experimental Masses:17 kDa
        • Oligomeric Masses:
        • Allergen epitopes:Not known
        • Allergen stability:
          Process, chemical, enzymatic:          This is not known, but it is probably that like other Bet v 1 homologues in fruit, Pyr c 1 is destroyed on cooking.
        • Nature of main cross-reacting proteins:

          IgE cross-reactivity between Pyr c 1, Bet v 1 from birch pollen and Mal d 1 from apple, but not to the celery allergen Api g 1, has been reported indicating epitope differences between Bet v 1-related food allergens (Karamloo et al. 2001) [83]

          IgE cross-inhibition studies between Pyr c 1 and Bet v 1 indicate the presence of common epitopes (Ebner et al. 1995) [46] (Karamloo et al. 2001) [83].

        • Allergen properties & biological function:

          The deduced sequence of Pyr c 1 shares a high degree of identity (57%) with Bet v 1 (the major birch pollen allergen) and with the family PR 10 pathogenesis related proteins. Consequently Pyr c 1 may have a role in plant protection against insect pests and microbial pathogens (Karamloo et al. 2001) [83].

          There is experimental evidence that Bet v 1-homologues, eg Pru av 1 from cherry, are plant steroid carriers (Neudecker et al. 2001) [130].

        • Allergen purification:

          Recombinant Pyr c 1 has been purified using a heterologous expression system, E. coli, as a His tag fusion portein and further purified by metal chelate affinity chromatography (Scheurer et al. 1997) [176] (Karamloo et al. 2001) [83].

        • Other biochemical information:

        References (5)

        • Scheurer S, Metzner K, Haustein D, Vieths S.
          Molecular cloning, expression and characterisation of Pru a 1, the major cherrry allergen.
          Mol. Immunol. 34:619-629.. 1997
          PUBMEDID: 9393965
        • Scheurer S, Son DY, Boehm M, Karamloo F, Franke S, Hoffmann A, Haustein D, Vieths S
          Cross-reactivity and epitope analysis of Pru a 1, the major cherry allergen.
          Mol Immunol 36:155-67.. 1999
          PUBMEDID: 10403481
        • Karamloo F, Scheurer S, Wangorsch A, May S, Haustein D, Vieths S
          Pyr c 1, the major allergen from pear (Pyrus communis), is a new member of the Bet v 1 allergen family.
          J Chromatog B 756: 281-293.. 2001
          PUBMEDID: 11419719
        • Ebner C, Hirschwehr, R, Bauer L, Breiteneder H, Valenta R, Ebner, H, Kraft D, Scheiner O.
          Identification of allergens in fruits and vegetables: IgE cross-reactivities with the important birch pollen allergens Bet v 1 and Bet v 2 (birch profilin).
          J Allergy Clin Immunol 95: 962-9.. 1995
          PUBMEDID: 7751517
        • Neudecker P, Schweimer K, Nerkamp J, Scheurer S, Vieths S, Sticht H, Rosch P.
          Allergic Cross-reactivity Made Visible. Solution structure of the major cherry allergen Pru av 1.
          J Biol Chem 276:22756-63.. 2001
          PUBMEDID: 11287426

        Biochemical Information for Pyr c 4

        • Allergen Name:Pyr c 4
        • Alternatve Allergen Names:Previously known as Pyr c 3 but now renamed
        • Allergen Designation:Major
        • Protein Family:

          Profilin Pfam PF00235

        • Sequence Known?:Yes
        • Allergen accession No.s:

          Q9XF38 :Swissprot:http://ca.expasy.org/cgi-bin/niceprot.pl?Q9XF38

          AF129424; AAD29410.1; -. EMBL / GenBank

        • 3D Structure Accession No.:None
        • Calculated Masses:14064 Da
        • Experimental Masses:14 kDa
        • Oligomeric Masses:
        • Allergen epitopes:Not known
        • Allergen stability:
          Process, chemical, enzymatic:

          There are only few studies on the stability of profilins most of them on celery profilin. Compared to other allergens, profilin is a moderately stable protein, more resistant than Bet v 1 homologues to thermal treatment and proteolysis but less stable than lipid transfer proteins or cross-reactive carbohydrate deteminants of glycoprotein allergens.

        • Nature of main cross-reacting proteins:

          IgE cross-reacts with profilins from other plant species such as Bet v 2 from birch pollen and other fruit profilin allergens. Pry c 4 shows a 82.7% sequence identity with Bet v 2 and 82.1% with Api g 4 (Scheurer et al. 2001) [181]

          IgE cross reactivity between a 14 kDa polypeptide from peach extract and rBet v 2 has been reported (Ebner et al. 1995) [46]

        • Allergen properties & biological function:Profilin is an actin-binding protein of the cytoskeleton
        • Allergen purification:Pyr c 4 has been cloned by polymerase chain reaction, produced in Escherichia coli BL21, and purified as non-fusion proteins by affinity chromatography on poly-(L-proline)-Sepharose (Scheurer et al. 2001) [181]
        • Other biochemical information:

          Pyr c 4 has a pI of 5.05 (Scheurer et al. 2001) [181]

        References (2)

        • Scheurer S, Wangorsch A, Nerkamp J, Skov PS, Ballmer-Weber B, Wuthrich B, Haustein D, Vieths S.
          Cross-reactivity within the profilin panallergen family investigated by comparison of recombinant profilins from pear (Pyr c 4), cherry (Pru av 4) and celery (Api g 4) with birch pollen profilin Bet v 2.
          J Chromatogr B Biomed Sci Appl May 756:315-325.. 2001
          PUBMEDID: 11419723
        • Ebner C, Hirschwehr, R, Bauer L, Breiteneder H, Valenta R, Ebner, H, Kraft D, Scheiner O.
          Identification of allergens in fruits and vegetables: IgE cross-reactivities with the important birch pollen allergens Bet v 1 and Bet v 2 (birch profilin).
          J Allergy Clin Immunol 95: 962-9.. 1995
          PUBMEDID: 7751517

        Biochemical Information for Pyr c 5

        • Allergen Name:Pyr c 5
        • Alternatve Allergen Names:
        • Allergen Designation:Minor
        • Protein Family:Isoflavone reductase Pfam PF02716
        • Sequence Known?:

          yes

        • Allergen accession No.s:

          O81355; Swissprot, http://us.expasy.org/cgi-bin/niceprot.pl?O81355

          AF071477; AAC24001.1; -. EMBL / GenBank

        • 3D Structure Accession No.:None
        • Calculated Masses:33822 Da
        • Experimental Masses:34 kDa
        • Oligomeric Masses:
        • Allergen epitopes:Not known
        • Allergen stability:
          Process, chemical, enzymatic:          Not known
        • Nature of main cross-reacting proteins:

          Pyr c 5 and Bet v 6 share 80% amino-acid sequence identity. IgE cross-reactivity between both allergens has been demonstrated by EAST inhibition experiments (Karamloo et al. 2001) [84]. These authors also suggested that homologous allergens may be present in many vegetable foods such as apple, peach, orange, lychee fruit, strawberry, persimmon, zucchini (courgette), and carrot.

          IgE cross-reactivity between a 30 kDa protein in latex and in pear has been demonstrated by immunoblotting (Lavaud et al. 1995) [102]

        • Allergen properties & biological function:Pyr c 5 is a phenylcoumarin benzylic ether reductase and it might be involved in plant defense (Gang et al., 1999) (Karamloo et al. 2001) [84].
        • Allergen purification:The recombinant protein was expressed as His-Tag fusion proteins in Eschershia coli and purified by Ni-chelate affinity chromatography under native conditions. (Karamloo et al. 2001) [84].
        • Other biochemical information:

          The theoretical pI of Pyr c 5 is 5.9 (Karamloo et al. 2001) [84].

        References (3)

        • Gang, D.R., Kasahara, H., Xia, Z.-Q., Vander Mijnsbrugge, K., Bauw, G., Boerjan, W., Van Montagu, M., Davin, L.B., Lewis, N.G
          Evolution of plant defense mechanisms: relationships of phenylcoumaran benzylic ether reductases to pinoresinol-lariciresinol and isoflavone reductases
          J. Biol. Chem. 274, 7516-7527. 1999
          PUBMEDID: 10066819
        • Lavaud F, Prevost A, Cossart C, Guerin L, Bernard J, Kochman S
          Allergy to latex, avocado pear, and banana: Evidence for a 30Kd antigen in immunoblotting.
          J. Allergy Clin Immunol 95: 557-564.. 1995
          PUBMEDID: 7852672
        • Karamloo, F., Wangorsch, A., Kasahara, H., Davin, L.B., Haustein, D., Lewis, N.G., and Vieths, S.
          Phenylcoumaran benzylic ether and isoflavonoid reductases are a new class of cross-reactive allergens in birch pollen, fruits and vegetables
          European Journal of Biochemistry 268 (20), 5310-5320. 2001
          PUBMEDID: 11606193