g14 Cultivated oat

Allergens within Grass Pollens

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  • Latin name: Avena sativa
  • Family: Poaceae (Gramineae)
  • Subfamily: Pooideae
  • Tribe: Aveneae
  • Common names: Cultivated Oat, Cultivated Oats, Common Oat
  • Source material: Pollen
Cultivated Oat (Avena sativa) g14 must be differentiated from False Oat grass (Arrhenatherum elatius) Rg204 and Oats (Avena sativa) f7, the food.
 
A grass species producing pollen, which often induces hayfever, asthma and conjunctivitis in sensitised individuals.

Allergen Exposure

Geographical distribution
Oats are of uncertain origin, but probably originated in Europe from two species of Wild Oats (A. fatua L.) and Wild Red Oats (A. sterilis L.). Oats are now cultivated throughout the temperate zones of the world. The major growing areas are the USA, southern Canada, the USSR and Europe, particularly around the Mediterranean.
 
Oats are an erect, tufted annual grass, growing to 1.2 m. The culms are smooth or scabrous beneath the panicle. The leaves are 15 to 30 cm long and 0.6 to 1.2 cm wide, with loose sheaths. The spikelets, usually 2-flowered, are up to 2.5 cm long, and the kernel is 0.6 to 0.8 cm long, narrow, with nearly parallel sides, and hairy.

Oats are in flower between early spring and early summer, and the seeds ripen between late summer and mid-autumn, depending on the environment. The flowers are hermaphrodite (have both male and female organs). Self-pollination is normal, but cross-pollination by wind also occurs.
 
Environment
Oats may escape cultivated fields and are found in dry wasteland, alien crops and meadows, especially on heavier soils.
 
Oats are used as a cereal, or in making biscuits, sourdough, etc., but usually not bread. Oats are also one of basic ingredients of whisky, and a coffee substitute. An edible oil obtained from the seed is used in the manufacture of commercial breakfast cereals.
 
Unexpected exposure
The straw has a wide range of uses, such as for biomass, fibre, mulch, paper-making, building board and thatching, and as a stuffing and bedding material. The hulls can serve as a filter in breweries.
 
Allergens
No allergens from this plant have yet been characterised.
 
Cultivated Oat appears to contain Group 1, Group 2 and Group 5 allergens (1-2).  

Potential Cross-Reactivity

An extensive cross-reactivity among the different individual species of the genus could be expected, as well as to a certain degree among members of the family Poaceae, especially in the subfamily Pooideae (Rye grass, Canary grass, Meadow grass, Cocksfoot and Timothy) (3-4).  
 
Natural pollen extracts from Anthoxanthum odoratum (Sweet Vernal grass), Avena sativa (Cultivated Oat), Cynodon dactylon (Bermuda grass), Lolium perenne (Rye grass), Phragmites communis (Common Reed), Poa pratensis (Meadow grass), Secale cereale (Cultivated Rye grass), Triticum sativum (Cultivated Wheat), and Zea mays (Maize/Corn) were characterised regarding their allergen contents by means of specific antibodies and by IgE immunoblot inhibition with recombinant allergens from Phl p 1, Phl p 2, Phl p 5, and Bet v 2 using sera of 193 European, American, and Asian subjects. Immunologically detectable Group 5 and Group 2 allergens were found in all these species except for C. dactylon and Z. mays (1).
 
A high degree of cross-reactivity for Group 1 allergens did not necessarily imply the same for Group 5 (2).
 
Pollen from 10 agricultural plant species was surveyed for the presence of proteins cross-reactive with Group 1, Group 4 and Group 9 allergens. Barley (Hordeum vulgare), Maize (Zea mays), Rye (Secale cerale), Triticale (Triticosecale cereale), Oats (Avena sativa), Canola (Brassica napus) and Sunflower (Helianthus annus) pollens contained numerous allergen-cognate proteins (5).
 
Cross-reactivity between Cultivated Oat pollen and Oat seed has not been established as yet.

Clinical Experience

IgE mediated reactions
Cultivated Oat pollen can induce asthma, allergic rhinitis and allergic conjunctivitis.

Specific IgE determination demonstrated that Oat pollen may be an occupational allergen among dairy farmers (6).
 
Other reactions
Oats, the seed of Cultivated Oat, may result in food allergy, see Oats (Avena sativa) f7. Feathers and Oat chaff have been used as bedding materials, and may result in allergic symptoms in children and infants (7).

Compiled by Dr Harris Steinman, harris@zingsolutions.com

References:

    1. Niederberger V, Laffer S, Froschl R, Kraft D, Rumpold H, Kapiotis S, Valenta R, Spitzauer S. IgE antibodies to recombinant pollen allergens (Phl p 1, Phl p 2, Phl p 5, and Bet v 2) account for a high percentage of grass pollen-specific IgE. J Allergy Clin Immunol 1998;101(2 Pt 1):258-64 
    2. Van Ree R, Driessen MN, Van Leeuwen WA, Stapel SO, Aalberse RC. Variability of crossreactivity of IgE antibodies to group I and V allergens in eight grass pollen species. Clin Exp Allergy 1992;22(6):611-7 
    3. Yman L. Botanical relations and immunological cross-reactions in pollen allergy. 2nd ed. Pharmacia Diagnostics AB. Uppsala. Sweden. 1982: ISBN 91-970475-09 
    4. Yman L. Pharmacia: Allergenic Plants. Systematics of common and rare allergens. Version 1.0. CD-ROM. Uppsala, Sweden: Pharmacia Diagnostics, 2000. 
    5. Astwood JD, Mohapatra SS, Ni H, Hill RD. Pollen allergen homologues in barley and other crop species. Clin Exp Allergy 1995;25(1):66-72 
    6. Rautalahti M, Terho EO, Vohlonen I, Husman K. Atopic sensitization of dairy farmers to work-related and common allergens. Eur J Respir Dis Suppl 1987;152:155-64 
    7. L'Hirondel J. Bedding allergens in children and infants: feathers and oat chaff. [French] Pediatrie 1966;21(2):169-85

2002



Further Reading