Pectins are dietary fibers that have shown a health effect on patients with food allergy, as they are capable of modifying the composition of gastrointestinal microbiota, and producing an immunomodulatory effect. Preliminary results by the investigators show that the intervention for 2 months with pectins produces an increase in tolerance to peach, and changes in the microbiota compared to the group of patients treated with placebo. In this project, the investigators aim to study these clinical effects and the involved mechanisms. Moreover, the long-term effect (clinical reactivity to nsLTP and immunomodulatory effect) of the dietary intervention will be prospectively evaluated 6 months after the intervention.
Adults with a clear clinical history of food allergy after eating peach (oral allergy syndrome and/or systemic symptoms) and with or without clinical history of food allergy with peanut.
Sensitization to Pru p 3 by positive skin prick test (SPT wheal area >7 mm2) and specific IgE (sIgE >0.35 kUA/L)
Positive DBPCFC with peach juice.
If clinical history of food allergy with peanut, sensitization must be confirmed by positive SPT to peanut and sIgE >0.35 kUA/L to Ara h 9 and clinical reactivity through a positive DBPCFC with peanut.
Food allergy to corn.
Food allergy to peanut due to sensitization to storage proteins.
Previous/active treatment with sublingual immunotherapy to Pru p 3.
Pregnancy/lactation.
Parallel
Apple pectin (DE 57%)
Dietary supplementDietary intervention with apple pectin. Participants will orally take the supplement once a day, after dissolving it in 100 ml of water, for 6 months.
Placebo
Dietary supplementDietary intervention with maltodextrin. Participants will orally take the placebo (maltodextrin) once a day, after dissolving it in 100ml of water, for 6 months.
Clinical efficacy of a six-month dietary intervention with pectins in patients with food allergy to peach and peanut due to sensitization to nsLTP.
Clinical efficacy will be defined as an increase in oral tolerance to peach and/or peanut determined through the DBPCFCs performed pre- and post- dietary intervention, compared to the Placebo.
Correlation between the induced changes in oral tolerance to peach and/or peanut and the reactivity in skin prick test (SPT).
Changes in oral tolerance to peach and/or peanut (see Primary outcome). Reactivity in SPT to Pru p 3 and peanut will be defined by the size of the papule area (mm2) measured pre- and post- dietary intervention.
Changes in Pru p 3 and Ara h 9 (nsLTP of peach and peanut, respectively) specific immunoglobulin production (IgE and IgG4) induced by the pectin dietary intervention.
Results will be expresses as kUA/L.
Changes in Pru p 3 and Ara h 9-specific basophil activation induced by the pectin dietary intervention
Results will be presented as the percentage of activated basophils (CD63+CD203c+CCR3+) and basophil allergen threshold sensitivity (CD-Sens).
Maturational changes in Pru p 3 and Ara h 9-specific dendritics cells induced by the pectin dietary intervention.
Results will be expressed as maturation index (MI).
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