Previous studies suggest cross-reactivity between specific
ragweed pollen and melon
allergens. This study was designed to clarify the origin of the cross-reactivity between
ragweed pollen and the gourd family. One thousand ragweed-allergic subjects were interviewed about the presence of oral
allergy syndrome (OAS) induced by melon or watermelon and were divided into reactive to ≤3 seasonal
allergen sources or >3 seasonal
allergen sources. Patients reporting melon and/or watermelon
allergy underwent a skin-prick test (SPT) with fresh melon and, after 2006, also with
profilin-enriched date palm pollen extract. Because no
IgE reactivity to melon extract was detected in vitro, ELISA was performed using date palm pollen extract, and inhibition experiments were performed using grass pollen, date palm
profilin, and
bovine serum albumin (BSA) as inhibitors. Six hundred forty-six and 354 subjects reacted to ≤3 seasonal
allergens or >3 seasonal
allergens, respectively; 4/646 (1%) and 81/354 (23%) reported a history of melon/watermelon-induced OAS (p < 0.0001). Forty-three of 46 (93%) melon reactors scored positive on SPT with the
profilin-enriched extract, which was positive in 0/2 (0%) versus 43/44 (98%) reactive to ≤3 or >3 seasonal
allergen sources, respectively (p < 0.0001). in vitro, serum from melon-allergic subjects showed a strong
IgE reactivity to the
profilin-enriched date palm pollen extract, which was abolished by preabsorption with both grass pollen extract and date palm pollen extract, but not by BSA. In
ragweed pollen-allergic subjects, melon
allergy is most likely associated with cross-sensitization to the plant pan-
allergen profilin and not to specific
ragweed pollen allergens. This study confirms the association between
profilin sensitization and melon
allergy.