t206 Chestnut

Allergens within Tree Pollens

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  • Latin name: Castanea sativa
  • Family: Fagaceae
  • Common names: Chestnut, European chestnut
  • Source material: Pollen
The Chestnut belongs to the Fagaceae family, which consists of three important genera: Beech (Fagus), Chestnut (Castanea), and Oak (Quercus).
 
Not to be confused with Horse Chestnut tree (Aesculus hippocastanum) Rt203
 
A tree species producing pollen, which often induces hayfever, asthma and conjunctivitis in sensitised individuals.

Allergen Exposure

Geographical distribution
The European Chestnut tree in its natural form is a large spreading deciduous tree, growing to over 30 m tall. Mature leaves are 10-20 cm long, 3-7 cm broad, and have between 6 and 20 bristles on each of the deeply serrated margins. Both female and male flowers are borne on the current season's shoots in early to midsummer. The trees are cold-hardy, and can withstand temperatures as low as -25°C when dormant. The tree grows tall with a large spread, and produces glossy brown nuts in prickly husks. In the USA, the Chestnut pollen season extends from May to July. Chestnut trees are mainly insect-pollinated.
 
Several edible species of Chestnut are grown around the world, the 4 main species being: Castanea mollissima - Chinese Chestnut, C. sativa - European or Spanish Chestnut (sweet Chestnut), C. crenata - Japanese Chestnut, and C. dentata - American (which have been mostly destroyed). The nuts of all of these species are used as food in a similar fashion. The European Chestnut is also known as the sweet Chestnut.
 
In the USA, the Chestnut pollen season extends from May to July. Chestnut trees are insect-pollinated.
 
See Sweet Chestnut f299 for allergen information on these nuts.
 
Environment
It is cultivated in groves for fruit and in coppices for wood. Up to 500,000 tonnes of Chestnuts are produced each year around the world, with the biggest proportion coming from the northern hemisphere. The fruit (Chestnut) is a spiny husk containing 2 or 3 Chestnuts, which are consumed fresh, boiled, grilled or preserved in sugar (iced Chestnuts). The tannin and the very hard wood of the tree are also used.
 
Unexpected exposure
European Chestnut pollen has been shown to be present in honey and may contribute to allergic reactions (1).
 
Allergens
The major allergen has been identified as Cas s 1, a 22 kDa protein, a Bet v 1 homolog(2). A 14 kD protein allergen, identified as a profilin, has also been isolated from European Chestnut tree pollen (3).

Potential Cross-Reactivity

Profilin from pollen of the European Chestnut would be expected to cross-react with other plants containing profilin (3-4). There is a relatively high degree of cross-reactivity between species of the family Fagaceae (5).

Clinical Experience

IgE mediated reactions
IgE mediated allergy, resulting in hayfever and asthma, to pollen of the European Chestnut represents  an important cause of pollinosis in Mediterranean and sub-Mediterranean areas (6-8).
 
Skin prick tests to Chestnut pollen were positive in 17/47 patients with seasonal symptoms of allergy in a study conducted in Paris. Eight patients had total IgE  levels above 300 IU/ml, 15 were found to have serum specific IgE to the pollen, and 14 were positive on nasal provocation testing(7). In the southern part of Switzerland (Canton Ticino), where Chestnut pollens represent about 30% of the airborne pollens, 37% of 503 patients with allergic rhinitis were sensitised to European Chestnut pollen (6).
 
In determining the profilin allergen, it was found that 92% of 14 patients with established allergy to pollen of the European Chestnut tree demonstrated specific IgE to the profilin allergen in this pollen. Fourteen percent displayed additional binding to a 14 kD protein and 1 (7%) bound only to the 14 kD protein of this extract (3).
 
The Chestnut tree has also been shown to result in occupational asthma in wood workers (9).
 
Compiled by Dr Harris Steinman, harris@zingsolutions.com

References:

    1. Bauer L, Kohlich A, Hirschwehr R, Siemann U, Ebner H, Scheiner O, Kraft D, Ebner C. Food allergy to honey: pollen or bee products? Characterization of allergenic proteins in honey by means of immunoblotting. J Allergy Clin Immunol 1996;97(1 Pt 1):65-73  
    2. Kos T, Hoffmann Sommergruber K, et al. Purification, characterization and N-terminal amino acid sequence of a new major allergen from European chestnut pollen--Cas s 1. Biochem Biophys Res Commun 1993;196(3):1086-92  
    3. Hirschwehr R, Jager S, Horak F, Ferreira F, Valenta R, Ebner C, Kraft D, Scheiner O. Allergens from birch pollen and pollen of the European chestnut share common epitopes. Clin Exp Allergy 1993;23(9):755-761  
    4. Steinman H, Lee S. Concomitant clinical sensitivity (CCS) and Cross-reactivity. (In press)  
    5. Yman L. Botanical relations and immunological cross-reactions in pollen allergy. 2nd ed. Pharmacia Diagnostics AB. Uppsala. Sweden. 1982: ISBN 91-970475-09   
    6. Gilardi S, Torricelli R, Peeters AG, Wuthrich B. Pollinosis in Canton Ticino. A prospective study in Locarno. [German] Schweiz Med Wochenschr 1994;124(42):1841-1847  
    7. Laurent J, Lafay M, Lattanzi B, Le Gall C, Sauvaget J. Evidence for chestnut pollinosis in Paris. Clin Exp Allergy 1993;23(1):39-43   
    8. Sutra JP, Ickovic MR, De Luca H, Peltre G, David B. Chestnut pollen counts related to patients pollinosis in Paris. Experientia Suppl 1987;51:113-117   
    9. De Zotti R, Gubian F. Asthma and rhinitis in wooding workers. Allergy Asthma Proc 1996;17(4):199-203

2002



Further Reading