Timothy Grass

Timothy grass (Phleum pratense) is one of the most common grass species in Europe and it produces pollen allergens that cause symptoms from mild rhinitis to severe asthma. Up to twenty allergen epitopes for Timothy grass (Phl p allergens) have been identified such as Phl p 1, 2, 4, 5, 6, 7, 11, 12, and 13 and they account for up to 80% of the allergic response in TG-allergic individuals. Of those allergen molecules, Phl p 1 and Phl p 5 are the main ones to trigger a specific IgE reaction in more than 90% and 65-90% of grass pollen allergic patients, respectively. Other epitopes such as Phl p 7 and Phl p 12 appear to be age-related with Phl p7 sensitization not observed in children under the age of 5 years and Phl p 12 sensitization found to increase with age. Diagnosis of an allergy to Timothy grass generally relies on a skin prick test or nasal antigen challenge test using allergen extracts or recombinant antigens.