D2.213 - Unveiling Pitaya Pollen Allergenicity: A Case Study in Occupational Allergy

Occupational allergies to unconventional allergens are becoming increasingly recognized. This study focuses on a 50-year-old female who developed allergic rhinitis and conjunctivitis after regular exposure to pitaya (Selenicereus) pollen in her greenhouse. Despite negative reactions to common aeroallergens, the patient experienced significant improvement upon avoiding exposure, highlighting the need to investigate pitaya pollen allergenicity.

The patient presented with intense ocular and nasal symptoms, including obstruction, sneezing, and conjunctival pruritus, worsening during greenhouse work. Symptom resolution occurred with absence from the workplace. Skin prick tests showed positive reactions to pitaya pollen and dust mites but negative results to profilin and lipid transfer proteins (LTPs). IgE levels were below diagnostic thresholds, further suggesting a specific allergic sensitization to pitaya pollen.

Protein extracts from pitaya pollen were analyzed using SDS-PAGE, Western blot, and proteomics (LC-MS/MS) to identify allergenic proteins, with IgE reactivity assessed under reducing and non-reducing conditions.

Western blot revealed IgE binding to proteins of 11–12 kDa and 18 kDa under non-reducing conditions and a single 20 kDa protein under reducing conditions. Proteomic analysis identified the 11–12 kDa band as aspartate aminotransferase, implicated as the allergenic trigger. This represents the first case of pitaya pollen allergy reported in the literature.

This case highlights pitaya pollen as a novel occupational allergen with distinct allergenic proteins. Proteomic characterization supports the role of aspartate aminotransferase in the patient’s allergy. These findings underscore the importance of investigating emerging allergens in occupational settings to guide diagnosis and preventive measures.