D1.74 - Molecular IgE sensitization profiling in a patient with Asteraceae weed pollen allergy and anaphylaxis to honey

Background: 

Anaphylaxis to honey is rare, commonly occurring in patients with late summer and fall pollinosis with IgE sensitization to anemophilous Asteraceae weed pollen. Raw polyfloral honey, labelled as artisanal, unheated, unfiltered and unpasteurized, usually contains various entomophilous pollen grains, including from Asteraceae plants.

We report the case of a 29-year-old female from Southern Romania with allergic rhinoconjunctivitis and IgE sensitization to ragweed and mugwort pollen with a personal history of different episodes of oral allergy symptoms to sunflower seeds and chamomile infusion, and anaphylaxis several minutes after the ingestion of raw local sunflower honey successfully treated with parenteral adrenaline in an emergency unit. Written informed consent was provided by the patient and skin prick testing with commercial extracts was used to reveal IgE sensitizations to Ambrosia artemisiifolia var. elatior, Artemisia vulgaris and Helianthus annuus pollen. A skin prick test was also positive for Matricaria chamomilla var. recutita commercial flos pulvis 30 mg/mL suspension obtained by mixing dried flowers in sterile saline. Prick-to-prick testing with honey, which is a heterogeneous mixture of pollen proteins, flower nectar, honeybee parts, sugars, and honeybee glandular enzymes, was not conducted, nor was a melissopalynology assessment. Molecular sensitization profiling was performed by a multiplex ELISA-based macroarray immunoassay using state-of-the-art nano-bead technology that revealed serum specific IgE antibodies to ragweed (2.43 kUA/L) and mugwort (2.86 kUA/L) pollen extracts and moderate levels of specific IgE against ragweed pectate lyase rAmb a 1 (3.79 kUA/L) and weed pollen defensins rAmb a 4 (1.20 kUA/L) and rArt v 1 (4.26 kUA/L), with no sensitisation detected against pollen profilins, polcalcins, non-specific lipid transfer proteins and sunflower seeds.

Conclusion: 

In a patient with allergic rhinoconjunctivitis to Asteraceae weed pollen presenting oral allergy syndrome to sunflower seeds contaminated with pollen grains and/or chamomile flower infusion, IgE sensitization to cross-reactive plant defensin-like proteins linked to polyproline-rich region represent a risk factor for anaphylaxis to monofloral sunflower honey and polyfloral raw honey from Northern Balkans. Such defensins with good thermal and pH stability are known to be present in ragweed and mugwort airborne pollen and pollen grains in honey from certain entomophilous Asteraceae plants.