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document
Presentation of allergen in different food preparations affects the nature of the allergic reaction -- a case series . BACKGROUND Characterization of fatal and non-fatal reactions to food indicates that the majority of reactions are due to the ingestion of prepared foods rather than the non-processed allergen . In an ongoing study that used a double-blind placebo-controlled food challenge to investigate peanut allergy and clinical symptoms , the observed reaction severity in four of the first six subjects was greater than anticipated . We hypothesized that this was due to differences in the composition of the challenge vehicle . OBJECTIVE The aim was to investigate whether the severity of observed challenge reactions would be repeated on re-challenge with a lower fat challenge vehicle . METHODS Peanut-allergic subjects were re-challenged with a lower fat recipe after reacting more severely than was anticipated to an initial peanut challenge . Similar challenge vehicle recipes were used , the only difference being the lower fat content ( 22.9 % compared with 31.5 % ) . The peanut content of the two recipes was analysed using RAST inhibition studies and ELISA tests . RESULTS Three of four subjects reacted to much smaller doses of peanut protein on re-challenge ( mean dose equivalence - 23 times less peanut ) with the lower fat recipe . RAST inhibition showed that neither recipe altered epitope recognition . The higher fat recipe required twice as much peanut to cause 50 % inhibition . ELISA detected far lower levels of peanut in the higher fat recipe ( 220 000 parts per million ( p.p.m . ) ) than in the lower fat recipe ( 990 000 p.p.m. ) . CONCLUSION The fat content of a challenge vehicle has a profound effect on the reaction experienced after allergen ingestion . This is another factor to be considered in assessing the risk of certain foods to food-allergic consumers and adds another dimension to clinical , research and regulatory practice .
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Intervention_Control
placebo-controlled
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Intervention_Educational
lower fat challenge vehicle
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Intervention_Other
lower fat recipe
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Intervention_Other
peanut
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Outcome_Physical
doses of peanut protein on re-challenge
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Outcome_Physical
RAST inhibition
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Outcome_Physical
epitope recognition
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Participant_Condition
allergic reaction
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Participant_Sample-size
six
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Participant_Condition
Peanut-allergic
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Participant_Condition
food-allergic