001137 - IgE Reactivity to Passiflora Lipid Transfer Protein in a Patient With Eosinophilic Esophagitis After Herbal Supplement Intake

Introduction

Herbal supplements are widely used for stress and sleep disorders and are often perceived as harmless. However, they may contain botanicals with potent allergenic proteins, including lipid transfer proteins (LTPs), capable of inducing IgE-mediated reactions. In patients with eosinophilic esophagitis, identifying hidden allergenic sources may require detailed molecular and immunochemical analysis.

Methods

A 53-year-old man with a history of allergic rhinoconjunctivitis due to house dust mites during childhood, which resolved by the agenciales of 12, was referred for allergy evaluation after a diagnosis of eosinophilic esophagitis following food impaction episodes. Two months before symptom onset, he had started nightly intake of six tablets of a commercial herbal supplement containing Valeriana officinalis, Passiflora incarnata and Crataegus oxyacantha extracts. No respiratory or food-related allergic symptoms were reported.

Analytical evaluation included molecular allergy testing, serum IgE measurement and immunochemical studies. Protein extracts were prepared from the herbal supplement tablets, valerian root, passiflora leaves, and hawthorn leaves and berries using standard PBS-based extraction. Antigenic profiles were assessed by SDS-PAGE and IgE–Western blot under reducing conditions using the patient’s serum, including inhibition assays with recombinant Pru p 3.

Results

Protein quantification confirmed adequate extraction from all tested sources. SDS-PAGE demonstrated complex protein profiles, particularly in passiflora and the herbal supplement extract. IgE–Western blot revealed specific IgE binding to bands in the passiflora extract at approximately 10, 19 and 22 kDa, while no relevant IgE recognition was observed for valerian or hawthorn extracts. IgE–Western blot with recombinant Pru p 3 showed IgE recognition at 10 kDa, and inhibition experiments demonstrated dose-dependent inhibition of IgE binding to the 10 kDa passiflora band by Pru p 3. ALEX2 revealed total IgE of 117 kU/L and Pru p 3–specific IgE of 2.82 kU/L, confirming shared IgE epitopes between passiflora and peach LTP.

Conclusions

Passiflora LTP was identified as the main allergenic component responsible for IgE reactivity in a patient with eosinophilic esophagitis after intake of a valerian-based herbal supplement. Cross-reactivity with Pru p 3 highlights the allergenic risk of herbal preparations in LTP-sensitized individuals and underscores the value of immunochemical techniques for clinical decision-making.