Meadow foxtail

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Code: g16
Latin name: Alopecurus pratensis
Source material: Pollen
Family: Poaceae (Graminae)
Sub family: Pooideae
Tribe: Agrostideae
Common names: Meadow Fox-tail

Pollen

A grass species producing pollen, which may induce hay fever, asthma and conjunctivitis in sensitised individuals.

Allergen Exposure

Geographical distribution

This plant is native to non-Mediterranean Europe and temperate Asia, and perhaps also to non-desert parts of North Africa. It is cultivated for forage in Australia, New Zealand and North America.

A long-lived, tufted perennial grass, with short rhizomes and short ascending stolons, it grows to over a meter in height. The leafblades, mostly basal, and rolled when young, are abundant, flat, dark-green, smooth and up to 30cm long and 8mm wide. At the top of the shoot, spikelets are packed into a cylindrical 3 to 8cm-long loose or compact spike-like panicle narrowing to a fairly sharp point. The one-flowered spikelets are greyish but turn straw-coloured with age.

Meadow Foxtail is one of the first grasses to begin growth in the spring, and in mild climates it can grow throughout the winter season. In colder Northern Hemisphere climates it blooms from April to July. The flowers are hermaphrodite, having both male and female organs. The stamens are first yellow, then become orange. It is not considered to be a major pollen-producer. Reproduction is through the abundant tiny seed.

Alopecurus pratensis may be distinguished from Phleum pratense by its more scabrous blade margins, absence of cilia on the collar and absence of notches on the ligule.

Environment

Wet meadows and pastures, and other marshy places; old orchards.

Allergen Description

Meadow Foxtail grass contains at least 24 antigens, of which 12 have been shown to bind to sera from patients with well-established allergic rhinitis (1).

The following allergens have been characterised:

Alo p 1, a 27-32 kDa protein, a Group 1 grass allergen, an expansin (2, 3).

Alo p 5, a 27-33 kDa protein, a Group 5 grass allergen (3).

Potential Cross-reactivity

Extensive cross-reactivity among the different individual species of the genus may be expected, as well as among members of the family Poaceae to a certain degree, in particular in the subfamily Pooideae (Rye grass (g5), Canary grass (g71), Meadow grass (g8), Timothy (g6), Cocksfoot (g3), Meadow Fescue (g4), Velvet (g13), Redtop (g9), Meadow Foxtail (g16), Wild Rye grass (g70)) (4, 5).

Variable degrees of cross-reactivity may occur between grass pollen species sharing Group 1 and/or 5 Grass allergens (2, 3). A high homology of amino acid sequences have been reported to occur among group 1 allergens, although N-glycosylation sites may be distinct as between Jun a 1 and from those of Cry j 1 (2, 6, 7).

Clinical Experience

IgE-mediated reactions

Anecdotal evidence suggests that Meadow Foxtail grass pollen may induce asthma, allergic rhinitis and allergic conjunctivitis in sensitised individuals; however, few studies have been reported to date (8).

In Norway, in 770 patients with seasonal and perennial nasal symptoms, pollens from Timothy, Meadow Foxtail, Meadow grass and Meadow Fescue were found to be very important causative factors (9).

Meadow Foxtail grass was reported to be a relevant potential pollen allergen in a study conducted in the Sarajevo region (10).

Compiled by Dr Harris Steinman, developer of Allergy Advisor, http://allergyadvisor.com

References

  1. Diener C, Skibbe K, Jager L. Identification of allergens in 5 grasses using crossed radioimmunoelectrophoresis (CRIE). [German] Allerg Immunol (Leipz) 1984;30(1):14-22.
  2. 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.
  3. 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.
  4. Yman L. Botanical relations and immunological cross-reactions in pollen allergy. 2nd ed. Pharmacia Diagnostics AB. Uppsala, Sweden. 1982: ISBN 91-970475-09.
  5. Yman L. Pharmacia: Allergenic Plants. Systematics of common and rare allergens. Version 1.0. CD-ROM. Uppsala, Sweden: Pharmacia Diagnostics, 2000.
  6. Weber RW. Cross-reactivity of Pollen Allergens. Curr Allergy Asthma Rep 2004;4(5):401-8.
  7. 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.
  8. Löfkvist T, Svensson G. Cutaneous reactions to pollen extracts in patients with hay fever. Special references to grass pollen recommended for treatment in fixed combination. Acta Allergol 1975;30(2-3):96-105.
  9. Holopainen E, Salo OP, Tarkiainen E, Malmberg H. The most important allergens in allergic rhinitis. Acta Otolaryngol Suppl 1979;360:16-8.
  10. Saracević E, Redzić S, Telacević A. The frequency of pollen allergy at the population of Sarajevo region during the 2002 year. [Bosnian] Med Arh 2005;59(4):221-3.

 

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