(EN) The invention relates to processes for producing semi-purified and purified allergen extracts and pharmaceutical compositions and vaccines for use in the diagnosis and treatment of allergy. In one aspect of the invention, a process for producing a depigmented allergen extract is provided, the process comprising: a) basifying a native allergen extract; and b) removing molecules having a molecular size of less than 3.5 kDa; and c) adjusting the pH to neutrality; thereby to produce a depigmented allergen extract.