title: Side-effects of allergen-specific immunotherapy: a prospective multi-centre study.
abstract: OBJECTIVE
  The safety of allergen-specific immunotherapy (SIT) is a parameter of great interest in the overall assessment of the treatment. A clinical database was developed in order to obtain early warnings of changes in the frequency and severity of side-effects and sufficient data for the evaluation of possible risk factors.
  
  
  METHODS
  During a 3-year period, four allergy centres in Copenhagen, Denmark, included data from all patients initiating SIT to a common database. Information on initial allergic symptoms, allergens used for treatment, treatment regimens and systemic side-effects (SSEs) during the build-up phase was collected.
  
  
  RESULTS
  A total of 1,038 patients received treatment with 1,709 allergens (timothy, birch, mugwort, house dust mite (HDM), cat, and wasp and bee venom), 23,047 injections in total. Most SIT patients completed the updosing phase without side-effects, but there was a significant difference between allergens: wasp (89%), birch (82%), HDM (81%), cat (74%) and grass (70%) (P=0.004). A total of 582 SSEs were registered in 341 patients. Most side-effects were mild grade 2 reactions (78%). A difference in severity between allergens was observed (P=0.02), with grass giving most problems. The type of allergen but not patient- or centre-related parameters seemed predictive of side-effects.
  
  
  CONCLUSIONS
  Allergen extracts differ in their tendency to produce side-effects. Multi-centre studies like the present one allow more patients to be evaluated, and thereby provide a more efficient surveillance of side-effects. Online Internet-based registration to a central national database of every allergen injection would be an even more powerful tool for evaluation of risk factors and surveillance of side-effects.
authors.affiliation: Allergy Clinic, Copenhagen University Hospital, Rigshospitalet, Denmark. lone.winther@dadlnet.dk
authors.forename: L
authors.initials: L
authors.lastname: Winther
authors.forename: J
authors.initials: J
authors.lastname: Arnved
authors.forename: H-J
authors.initials: HJ
authors.lastname: Malling
authors.forename: H
authors.initials: H
authors.lastname: Nolte
authors.forename: H
authors.initials: H
authors.lastname: Mosbech
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000485:Allergens / Q000009:adverse effects*; D001249:Asthma / Q000150:complications / Q000628:therapy; D002648:Child; D003718:Denmark / Q000453:epidemiology; D003888:Desensitization, Immunologic / Q000009:adverse effects* / Q000379:methods; D004306:Dose-Response Relationship, Immunologic; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000453:epidemiology / Q000209:etiology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D011058:Pollen / Q000009:adverse effects; D012720:Severity of Illness Index
chemical_list: D000485:Allergens