Biochemical composition of Phleum pratense pollen grains: A review

•Allergens of Phleum pratense pollen are classified in eleven groups from 1 to 13.•Allergens from groups 1 and 5 are the major contributors to Phl p pollen allergy.•Only one quantitative assessment exists for Phl p 1, 2 and 4 allergen groups.•Only 20 % of extractible lipids have been identified and quantified.•Only 7–8 % of total proteins have been quantified as group 2 and 5 allergens.