title: No matrix effect in double-blind, placebo-controlled egg challenges in egg allergic children.
abstract: BACKGROUND
  Diagnostic and accidental food allergic reactions may be modified by the matrix containing the allergenic food. Previous studies of double-blind, placebo-controlled food challenges (DBPCFCs) with peanut found an effect of the fat content of the challenge matrix on the severity of the challenge reactions.
  
  
  OBJECTIVE
  The aim of this study was to examine whether the fat content of the food matrix is related to eliciting dose and reaction severity in DBPCFCs with heated hen's egg.
  
  
  METHODS
  Sensitized egg allergic children (n = 59) undergoing DBPCFCs with egg as a routine diagnostic procedure in our tertiary care centre were evaluated retrospectively. Three different recipes were used for the food matrix: vanilla pudding, pancake and minced meat, containing 22.8%, 31.9% and 52.7% fat (weighted average), respectively. The eliciting dose (i.e. the highest cumulative dose to which the child reacted) was analyzed by Kaplan-Meier log-rank statistic and by Cox regression. Reaction severity was quantified by using an index (range 1-12) and was analysed by multiple linear regression analysis.
  
  
  RESULTS
  The overall influence of type of recipe on eliciting dose was not significant (P = 0.12). The rate of response to minced meat (with the highest fat content) was not significantly different from pudding [HR = 0.61 (0.26-1.45, P = 0.26) or pancake (HR = 1.41 (0.50-3.99), P = 0.52] after adjustment for confounders. The type of recipe did not influence the severity of the challenge reaction. The severity of the challenge reaction for minced meat compared to pudding and pancake was 1.06 (0.52-2.16), P = 0.87 and 0.81 (0.32-2.01), P = 0.64, respectively, after correction for confounders.
  
  
  CONCLUSIONS
  In contrast to similar research with peanut, no significant influence of the fat content of the matrix was found on the eliciting dose or severity of the reaction in 59 DBPCFCs with hen's egg. Matrix fat content differences comparable to those reported here may not be an important co-determinant of reaction severity for all allergenic foods.
authors: Department of Paediatric Pulmonology and Paediatric Allergy, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors: L
authors: L
authors: Libbers
authors: B M J
authors: BM
authors: Flokstra-de Blok
authors: B J
authors: BJ
authors: Vlieg-Boerstra
authors: S
authors: S
authors: van der Heide
authors: G N
authors: GN
authors: van der Meulen
authors: J
authors: J
authors: Kukler
authors: M
authors: M
authors: Kerkhof
authors: A E J
authors: AE
authors: Dubois
mesh_terms: D000485:Allergens / Q000276:immunology*; D002675:Child, Preschool; D004041:Dietary Fats / Q000009:adverse effects*; D004306:Dose-Response Relationship, Immunologic; D004531:Eggs / Q000009:adverse effects; D005260:Female; D005502:Food; D005512:Food Hypersensitivity / Q000175:diagnosis*; D006801:Humans; D007223:Infant; D008297:Male; D012189:Retrospective Studies; D012720:Severity of Illness Index
chemical_list: D000485:Allergens; D004041:Dietary Fats
keywords: children; double-blind placebo-controlled food challenge (DBPCFC); egg allergy; matrix effect