title: Reproducibility of the effects of intranasal ragweed challenges in allergic subjects.
abstract: BACKGROUND
  Intranasal allergen challenges have been used to study the pathogenesis of disease expression, to evaluate the efficacy of therapies and to make diagnosis of allergic status. Few data, however, are available regarding the reproducibility of the responses to such provocative challenges.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate the reproducibility of selected responses of allergic subjects to intranasal pollen challenge.
  
  
  METHODS
  Eighteen adults with ragweed allergy completed three dose-response challenge sessions at a minimum interval of 1 week. Sessions were single blinded and randomized to include two intranasal ragweed challenges (doses 10, 100, and 1000 PNU) and one placebo challenge conducted out of the ragweed season. Additionally, 12 of these subjects completed a third ragweed challenge session conducted during the ragweed season. Following administration of each dose, symptoms were scored, sneezes counted, and nasal patency measured by active posterior rhinomanometry. Total nasal secretion weight for each session was measured.
  
  
  RESULTS
  For all measures, average dose response curves were identical for the two extra-seasonal ragweed challenges and these were significantly different from those of the placebo challenge session. Intra-individual responses to the two ragweed challenges were highly correlated between sneeze count and secretion weight, and were moderately correlated for objective and subjective measures of rhinorrhea and congestion. No significant increases in these responses were observed for the intra-seasonal ragweed challenge session.
  
  
  CONCLUSIONS
  These results document a reproducible symptomatic and physiologic response to intranasal ragweed challenge.
authors.affiliation: Department of Otolaryngology, Children's Hospital of Pittsburgh, USA.
authors.forename: W J
authors.initials: WJ
authors.lastname: Doyle
authors.forename: D P
authors.initials: DP
authors.lastname: Skoner
authors.forename: J T
authors.initials: JT
authors.lastname: Seroky
authors.forename: P
authors.initials: P
authors.lastname: Fireman
mesh_terms: D000328:Adult; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000175:diagnosis* / Q000276:immunology; D008297:Male; D009299:Nasal Provocation Tests / Q000592:standards*; D011058:Pollen / Q000276:immunology; D011237:Predictive Value of Tests; D016037:Single-Blind Method