title: Elevated basal serum tryptase and hymenoptera venom allergy: relation to severity of sting reactions and to safety and efficacy of venom immunotherapy.
abstract: BACKGROUND
  Mastocytosis and/or elevated basal serum tryptase may be associated with severe anaphylaxis.
  
  
  OBJECTIVE
  To analyse Hymenoptera venom-allergic patients with regard to basal tryptase in relation to the severity of sting reactions and the safety and efficacy of venom immunotherapy.
  
  
  METHODS
  Basal serum tryptase was measured in 259 Hymenoptera venom-allergic patients (158 honey bee, 101 Vespula). In 161 of these (104 honey bee, 57 Vespula), a sting challenge was performed during venom immunotherapy.
  
  
  RESULTS
  Nineteen of the 259 patients had an elevated basal serum tryptase. Evidence of cutaneous mastocytosis as documented by skin biopsy was present in 3 of 16 patients (18.8%). There was a clear correlation of basal serum tryptase to the grade of the initial allergic reaction (P<0.0005). Forty-one of the 161 sting challenged patients reacted to the challenge, 34 to a bee sting and 7 to a Vespula sting. Thereof, 10 had an elevated basal serum tryptase, i.e. 1 (2.9%) of the reacting and 2 (2.9%) of the non-reacting bee venom (BV) allergic individuals, as compared to 3 (42.9%) of the reacting and 4 (8%) of the non-reacting Vespula venom-allergic patients. Thus, there was a significant association between a reaction to the sting challenge and an elevated basal serum tryptase in Vespula (chi2=6.926, P<0.01), but not in BV-allergic patients. Systemic allergic side-effects to venom immunotherapy were observed in 13.9% of patients with normal and in 10% of those with elevated basal serum tryptase.
  
  
  CONCLUSIONS
  An elevated basal serum tryptase as well as mastocytosis are risk factors for severe or even fatal shock reactions to Hymenoptera stings. Although the efficacy of venom immunotherapy in these patients is slightly reduced, most of them can be treated successfully. Based on currently available data, lifelong treatment has to be discussed in this situation.
authors.affiliation: Department of Medicine, Spital Bern Ziegler, Bern, Switzerland.
authors.forename: G
authors.initials: G
authors.lastname: Haeberli
authors.forename: M
authors.initials: M
authors.lastname: Brönnimann
authors.forename: T
authors.initials: T
authors.lastname: Hunziker
authors.forename: U
authors.initials: U
authors.lastname: Müller
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000707:Anaphylaxis / Q000201:enzymology / Q000276:immunology*; D000818:Animals; D001180:Arthropod Venoms / Q000276:immunology*; D001514:Bee Venoms / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D006927:Hymenoptera / Q000276:immunology*; D007167:Immunotherapy / Q000009:adverse effects / Q000379:methods*; D007299:Insect Bites and Stings / Q000201:enzymology / Q000276:immunology*; D008297:Male; D034701:Mastocytosis, Cutaneous / Q000276:immunology; D008875:Middle Aged; D012697:Serine Endopeptidases / Q000097:blood*; D053802:Tryptases; D014862:Wasp Venoms / Q000276:immunology
chemical_list: D001180:Arthropod Venoms; D001514:Bee Venoms; D014862:Wasp Venoms; D012697:Serine Endopeptidases; D053802:Tryptases