False oat-grass
Summary
Sub family: Pooideae Tribe: Aveneae
There are two subspecies or varieties: one has swollen bases in the main shoots, resembling small onion bulbs, and is sometimes called 'Onion Couch'; the other lacks these swellings.
Pollen
A grass species producing pollen, which often induces hay fever, asthma and conjunctivitis in sensitised individuals.
Allergen
Allergen Description
The following allergens have been characterised:
Clinical Relevance
IgE-mediated reactions
Anecdotal evidence suggests that False Oat grass pollen may induce symptoms of asthma, allergic rhinitis and allergic conjunctivitis in sensitised individuals; however, no studies have been reported to date.
Cross-Reactivity
Extensive cross-reactivity among the different individual species of the genus may be expected, as well as to a certain degree among members of the family Poaceae, particularly in the tribe Aveneae (Sweet Vernal grass, Cultivated Oat, Velvet grass, Canary grass).
Early studies of the antigens in Meadow grass (Kentucky bluegrass) pollen, compared with False oat grass and the combined extracts of Timothy, Orchard (cocksfoot), Velvet and Rye grasses, indicated that these grasses contain many cross-reactive antigens. Similarly, immunological partial identity between isolated major allergens of Timothy pollen and the corresponding pollen allergens of False oat, Orchard and Rye grass were demonstrated.
The presence of group 1 and 5 grass allergens may result in variable degrees of cross-reactivity with pollen from other grasses, weeds and trees, depending on the similarity of these panallergens with those found in this pollen. However, these cross-reactions have not been fully elucidated yet.
For example, extensive IgE cross-reactivity has been observed between the allergens of the Pooideae grasses as a result of the presence of a group 1 grass allergen.
References
- Matthiesen F, Løwenstein H. Group V allergens in grass pollens. II. Investigation of group V allergens in pollens from 10 grasses. Clin Exp Allergy 1991;21(3):309-20.
- Standring R, Spackman V, Porter SJ. Distribution of a major allergen of rye grass (Lolium perenne) pollen between other grass species. Int Arch Allergy Appl Immunol. 1987;83(1):96-103.
- Hejl C, Wurtzen PA, Kleine-Tebbe J, Johansen N, Broge L, Ipsen H. Phleum pratense alone is sufficient for allergen-specific immunotherapy against allergy to Pooideae grass pollens. Clin Exp Allergy 2009;39(5):752-9.
- Yman L. Botanical relations and immunological cross-reactions in pollen allergy. 2nd ed. Pharmacia Diagnostics AB. Uppsala, Sweden. 1982: ISBN 91-970475-09.
- Yman L. Pharmacia: Allergenic Plants. Systematics of common and rare allergens. Version 1.0. CD-ROM. Uppsala, Sweden: Pharmacia Diagnostics, 2000.
- Chakrabarty S, Løwenstein H, Ekramoddoullah AK, Kisil FT, Sehon AH. Detection of cross-reactive allergens in Kentucky bluegrass pollen and six other grasses by crossed radioimmunoelectrophoresis. Int Arch Allergy Appl Immunol 1981;66(2):142-57.
- Løwenstein H. Immunological partial identity and in vitro inhibitory effect of two major timothy pollen allergens to whole pollen extract of four grasses. Int Arch Allergy Appl Immunol 1978;57(4):379-83.
- Van Ree R, Van Leeuwen WA, Aalberse RC. How far can we simplify in vitro diagnostics for grass pollen allergy?: A study with 17 whole pollen extracts and purified natural and recombinant major allergens. J Allergy Clin Immunol 1998;102(2):184-90.
- Johansen N, Weber RW, Ipsen H, Barber D, Broge L, Hejl C. Extensive IgE cross-reactivity towards the Pooideae grasses substantiated for a large number of grass-pollen-sensitized subjects. Int Arch Allergy Immunol 2009;150(4):325-34.