Background: The pollen grain of the Areca catechu L. tree is airborne and allergenic. This study aimed to know the role of this pollen as a source of aeroallergen with effect on emergency asthma hospitalization, to isolate its important allergic fraction and to check its cross-reaction with betel nut. Methods:Areca pollen was monitored with a Burkard sampler. Determination of allergenic activities was studied by in vivo and in vitro analyses. Asthma hospitalization data were collected from two nearby hospitals. The pollen extract was fractionated by a combination of DEAE-Sephadex and Sephacryl S-200 column. The protein components were observed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Cross-reactivity of Areca pollen and betel nut was shown by IgE enzyme-linked immunosorbent assay (ELISA) inhibition. Results: The Areca pollen was perennially airborne. Skin test results of respiratory allergic patients showed 38.6% positivity. The detected aeroallergen spots in particle immunoblotting correlated significantly with airborne pollen count. Areca pollen showed a significant positive correlation with asthma hospitalization. There are 6 IgE-reactive protein components in the whole-pollen extract. IgE-reactive fraction 1 was resolved into 4 subfractions. Subfraction 1a showing IgE reactivity contained 3 protein components, among which 2 of 48 and 118 kDa were IgE reactive. The 48-kDa component was reported to be cross-reactive with other palm pollen types. In IgE ELISA inhibition, the betel nut extract showed 50% inhibition with about 110 ng/ml concentration. Conclusion:A. catechu pollen is a significant contributor to the aeroallergen load in India. Its partially purified IgE-reactive fraction may be useful in therapeutics. The betel nut extract showed remarkable cross-reactivity with Areca pollen.

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To study the role of atmospheric pollen on respiratory allergy and asthma-related hospitalization (ARH), a pollen calendar was prepared for a suburban area (Habra) of West Bengal, near India-Bangladesh border on the basis of seven-year (2007-2013) aeropollen monitoring with Burkard slide-sampler. Among 40 pollen types, Poaceae/grass showed highest contribution (12.32%) followed by Trema orientalis (11.45%) and others. Among 30 allergenic pollen types, Poaceae/ grass showed the highest sensitivity in skin-prick test (>50%) and IgE-ELISA. ARH of local population (n = 9492) showed significant positive correlation (P < 0.05) with airborne pollen of grass, Bombax ceiba, Mangifera indica and total aeropollen too.