Occupational respiratory allergy in peach crop workers.

BACKGROUND: Occupational respiratory diseases in workers of peach tree crops have been reported punctually and have been associated with sensitization to proteins present in both pollen and leaf tree. We report the study of 37 workers with respiratory symptoms related to occupational exposure to peach trees.
METHODS: Prick tests and specific IgE determinations were performed with extracts from leaves and branches of peach tree. Immunodetection in leaf extract was realized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis SDS-PAGE-immunoblotting with patient sera and rabbit serum anti-Pru p 3. Immunodetection inhibition was performed with rPru p 3 and pollen profilins. The clinical relevance of sensitization was demonstrated by specific bronchial challenge test (SBCT) with peach leaf extract.
RESULTS: Most patients suffered symptoms when peach trees had leaves, specifically during thinning and harvesting fruit (rhinoconjunctivitis: 100% and asthma: 67.5%). Sensitization to leaf extract was demonstrated in 86% of patients. IgE-immunoblotting with peach leaf extract revealed in six patient sera a pair of bands of 10 and 16 kDa, and in nine a 16-kDa band. Those bands could be two isoforms of peach leaf lipid transfer proteins( LTP), so the recognition frequency of some LTP isoform by our patient sera was 42%. 33% of the sera recognized a doubled band of about 14.5 kDa and this recognition was inhibited by nPho d 2. The SBCT with peach leaf extract was positive in the asthmatic sensitized patients tested.
CONCLUSIONS: Sensitization to peach leaves was the cause of occupational respiratory symptoms in our patients. Some patient sera revealed IgE-binding proteins matching LTP and/or profilin.