ABSTRACT
Allergenic reaction to melon, Cucumis melo [belongs to Cucurbitaceae family], has been reported in some allergic patients. Oral allergy syndrome was the most common clinical features associated with melon allergy. This study was aimed to confirm allergenicity of Mashadi melon, identify allergenic protein[s] of melon and allergenic cross reactivity of melon with other allergens. Prick test was performed with the extract of different parts of melon [Peel, pulp and loose layer on pulp] on the 35 patients who suffered from allergic symptoms after the ingestion of melon. Total IgE and specific IgE to melon %ere nieasurcd in 21 sera from patients with positive sicin prick test and 15 healthy controls' sera by means of ELISA. The IgE reactive protein of melon extract was detected by westeni blotting, using the 13 patient's sera [with high levels of IgE]. ELISA inhibition carried out in order to detect cross-reactivity between melon and kiwi, banana, Cynodon dactylon and Poa pratensis. Clinical reactions to melon were oral allergy syndrome 61% [immediate oral itching with or without angioedema of the lips and oral mucosa], rhinitis 38%, itching 19% and gastrointestinal symptoms 4.8%. Twenty one of the 35 patients showed positive skin prick test [SPT] to loose layer on pulp. Three patients also showed reaction to pulp and loose layer. Increased specific IgE levels to melon were observed in 18 patients with positive SPT to melon extract. Inhibition experiments showed a strong cross-reactivity of melon specific IgE with two species of ragweed pollen, especially with Cynodon doctylon, but banana and kiwi extract did not inhibit melon specific IgE in inhibition ELISA method. Immunoblot analyses of aqueous protein extract from melon were showed an IgE-binding protein of - 14.4 kDa with 8 of 12 melon-allergic patients' sera. In conclusion, we confirmed IgE-mediated hypersensitivity to melon with common clinical feature of oral allergy syndrome [OAS] and presence of an IgE-binding protein of - 14.4 kDa in melon extract. These findings suggest that main allergen of melon could be profilin