The invention relates to the treatment of a hypersensitivity immune response caused by a non-profilin allergen of a profilin-containing plant material (e.g. grass or tree pollen) by bystander suppression with a plant profilin (e.g. Phl p 12, Bet v 2, or Ole e 2) or a variant thereof. Also the invention features a particular variant of Phl p 12 with two of its cysteine residues replaced with another amino acid to increase its pharmaceutical properties.
