Cultivated oat

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Code: g14
Latin name: Avena sativa
Source material: Pollen
Family: Poaceae (Gramineae)
Sub family: Pooideae
Tribe: Aveneae
Common names: Cultivated Oat, Cultivated Oats, Common Oat.

Cultivated Oat (Avena sativa) g14 must be differentiated from False Oat grass (Arrhenatherum elatius) Rg204 and Oats (Avena sativa) f7, the food.

Pollen

A grass species producing pollen, which often induces hay fever, 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 two-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 may be found in dry wasteland, alien crops and meadows, especially jn heavier soils.

Oats are used as a cereal, or in making biscuits, sourdough, etc., but usually not bread. Oats are also one of the basic ingredients of whisky, and may be used in a coffee substitute. 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 boards and thatching, and as a stuffing and bedding material. The hulls are used for filtering in breweries.

Allergen Description

The following allergens have characterised:

Ave s 1, a Group 1 grass allergen, an expansin (1, 2).

Ave s 2, a Group 2 grass allergen (1, 3, 4).

Ave s 4, a Group 4 grass allergen, a pectate lyase (1).

Ave s 5, a Group 5 grass allergen (1, 5).

Ave s 7, a Group 7 grass allergen, a calcium-binding protein, polcalcin (6, 7).

Ave s 12, a profiling (1).

Ave s 13, a Group 13 grass allergen, a polygalacturonase (8).

Potential Cross-reactivity

Extensive cross-reactivity among the different individual species of the genus may be expected, and to a certain degree among members of the family Poaceae, especially in the subfamily Pooideae (Ryegrass, Canary grass, Meadow grass, Cocksfoot and Timothy), as a result of the variable degree of cross-reactivity from the sharing of Group 1-13 grass allergens, and profiling (4, 5, 8-10).

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).

Group 1 and Group 5 allergens were shown to be present in Dactylis glomerata (Cocksfoot), Festuca rubra (similar to Meadow Fescue), Phleum pratense (Timothy), Anthoxanthum odoratum (Sweet Vernal), Secale cereale (Cultivated Rye), Zea mays (Maize/Corn), and Phragmites communis (Common Reed). The degree of cross-reactivity of IgE antibodies against Lol p 1 or Lol p 5, and these grasses was demonstrated to be highly variable. Individual sera were not always equally cross-reactive to all pollen species. 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 (xTriticosecale cereale), Oats (Avena sativa), Canola (Brassica napus) and Sunflower (Helianthus annus) pollens contained numerous allergen-cognate proteins (11).

Cross-reactivity between Cultivated Oat pollen and Oat seed has not been established as yet.

Clinical Experience

IgE-mediated reactions

Anecdotal evidence suggests that Cultivated Oat pollen may induce asthma, allergic rhinitis and allergic conjunctivitis in sensitised individuals; however, few studies have been reported to date.

A review of the records of asthmatics attending a hospital clinic in Cova da Beira, Portugal, found that of 335 female and 130 male asthmatic patients with asthma, 70% had allergic asthma and 30 % had non-allergic asthma. Skin-prick testing demonstrated that the major allergens involved were grasses (Lolium perenne, Phleum pratense, Dactylis glomerata and Poa pratensis), cereal pollens (Secale cereale, Triticum sativum and Avena sativa), mites (Dermatophagoides pteronyssinus and Dermatophagoides farinae), trees (Olea europea and Platanus acerifolia), the weed Parietaria judaica and the mould Alternaria alternate (12). In the same area, in an evaluation of 371 paediatric patients, 86.5% were sensitised to at least one allergen extract, as tested by skin-prick test. However, in contrast to the adults, only 0.1% were shown to be sensitised to pollen from Avena sativa (13).

In an evaluation of sensitisation to pollens in 32 children under 8 years attending an allergy unit in Portugal (suffering from allergic rhinitis (72%), conjunctivitis (66%), asthma (50%) and allergic rhinitis and bronchial asthma (34%)), all children were sensitised to grass pollen, of which 38% were monosensitised. Grass pollen sensitisation in order was Dactylis (94%), Hordeum (75%), Phleum (72%), Poa (69%), Avena (66%), Festuca (63%), Triticum (59%), Secale (53%), Lolium (50%) and Zea (31%) (14).

Specific IgE determination demonstrated that Oat pollen may be an occupational allergen among dairy farmers (15).

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 (16).

Compiled by Dr Harris Steinman, developer of Allergy Advisor, http://allergyadvisor.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. Flicker S, Steinberger P, Norderhaug L, Sperr WR, Majlesi Y, Valent P, Kraft D, Valenta R. Conversion of grass pollen allergen-specific human IgE into a protective IgG(1) antibody. Eur J Immunol 2002;32(8):2156-62.
  4. Marth K, Focke M, Flicker S, Valenta R. Human monoclonal antibody-based quantification of group 2 grass pollen allergens. J Allergy Clin Immunol 2004;113(3):470-4.
  5. Ramirez J, Obispo TM, Duffort D, Carpizo JA, Chamorro MJ, Barber D, Ipsen H, Carreira J, Lombardero M. Group 5 determination in Pooideae grass pollen extracts by monoclonal antibody-based ELISA. Correlation with biologic activity. Allergy 1997;52(8):806-13.
  6. Smith PM, Xu H, Swoboda I, Singh MB. Identification of a Ca2+ binding protein as a new Bermuda grass pollen allergen Cyn d 7: IgE cross-reactivity with oilseed rape pollen allergen Bra r 1. Int Arch Allergy Immunol 1997;114(3):265-71.
  7. Wopfner N, Dissertori O, Ferreira F, Lackner P. Calcium-binding proteins and their role in allergic diseases. Immunol Allergy Clin North Am 2007;27(1):29-44.
  8. Grote M, Swoboda I, Valenta R, Reichelt R. Group 13 allergens as environmental and immunological markers for grass pollen allergy: studies by immunogold field emission scanning and transmission electron microscopy. Int Arch Allergy Immunol 2005;136(4):303-10.
  9. Yman L. Botanical relations and immunological cross-reactions in pollen allergy. 2nd ed. Pharmacia Diagnostics AB. Uppsala. Sweden. 1982: ISBN 91-970475-09.
  10. Yman L. Pharmacia: Allergenic Plants. Systematics of common and rare allergens. Version 1.0. CD-ROM. Uppsala, Sweden: Pharmacia Diagnostics, 2000.
  11. 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.
  12. Lourenco O, Fonseca AM, Taborda-Barata L. Demographic, laboratory and clinical characterisation of adult portuguese asthmatic patients. Allergol Immunopathol (Madr) 2007;35(5):177-83.
  13. Loureiro G, Rabaca M, Blanco B, Andrade S, Chieira C, Pereira C. Aeroallergens sensitization in an allergic paediatric population of Cova da Beira, Portugal. Allergol Immunopathol (Madr) 2005;33(4):192-8.
  14. Diamantino C, Caeiro E, Martins L, Almeida F, Lopes ML. Pollen sensitisation in children less than 8 years old Rev Port Imunoalergol 2006;14(3):245-9.
  15. 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.
  16. L'Hirondel J. Bedding allergens in children and infants: feathers and oat chaff. [French] Pediatrie 1966;21(2):169-85.

As in all diagnostic testing, the diagnosis is made by the physican based on both test results and the patient history.