title: Determinants of venom-specific IgE antibody concentration during long-term wasp venom immunotherapy.
abstract: BACKGROUND
  Venom immunotherapy (VIT) is an effective treatment for subjects with systemic allergic reactions (SR) to Hymenoptera stings, however there are few studies concerning the relevance of the venom specific IgE changes to decide about VIT cessation. We assessed IgE changes during a 5-year VIT, in patients stung and protected within the first 3 years (SP 0-3) or in the last 2 years (SP 3-5), and in patients not stung (NoS), to evaluate possible correlations between IgE changes and clinical protection.
  
  
  METHODS
  Yellow jacket venom (YJV)-allergic patients who completed 5 years of VIT were retrospectively evaluated. Baseline IgE levels and after the 3rd and the 5th year of VIT were determined; all patients were asked about field stings and SRs.
  
  
  RESULTS
  A total of 232 YJV-allergic patients were included and divided into the following groups: 84 NoS, 72 SP 0-3 and 76 SP 3-5. IgE levels decreased during VIT compared to baseline values (χ(2) = 346.029, p < 0.001). Recent vespid stings accounted for significantly higher IgE levels despite clinical protection. IgE levels after 5 years of VIT correlated significantly with Mueller grade (F = 2.778, p = 0.012) and age (F = 6.672, p = 0.002). During follow-up from 1 to 10 years after VIT discontinuation, 35.2 % of the contacted patients reported at least one field sting without SR.
  
  
  CONCLUSIONS
  The yellow jacket-VIT temporal stopping criterion of 5 years duration did not result in undetectable IgE levels, despite a long-lasting protection. A mean IgE decrease from 58 to 70 % was observed, and it was less marked in elderly patients or in subjects with higher Mueller grade SR.
authors.affiliation: Clinical Allergy and Immunology Unit, Foundation IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy.
authors.forename: Valerio
authors.initials: V
authors.lastname: Pravettoni
authors.affiliation: Clinical Allergy and Immunology Unit, Foundation IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy.
authors.forename: Marta
authors.initials: M
authors.lastname: Piantanida
authors.affiliation: Clinical Allergy and Immunology Unit, Foundation IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Primavesi
authors.affiliation: Unit of Audiology, Foundation IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy.
authors.forename: Stella
authors.initials: S
authors.lastname: Forti
authors.affiliation: Unit of Allergology and Immunology, Niguarda Ca' Granda Hospital, Milan, Italy.
authors.forename: Elide A
authors.initials: EA
authors.lastname: Pastorello
keywords: Hymenoptera venom allergy; Hymenoptera venom immunotherapy; Specific IgE levels; VIT discontinuation; VIT long-lasting protection