Anaphylaxis to pine nuts and immunological cross-reactivity with pine pollen proteins

Despite the wide use of pine nuts, the fruit of Pinus pinea, only a few reports of allergic reactions to them have been published. We present herein a case of food allergy to pine nuts in a patient who showed no clinical symptoms to pine pollen despite the presence in her serum of specific IgE antibodies. In order to verify whether the reaction against pine nuts was IgE mediated, specific IgE against pine nuts and pollen were evaluated by skin-prick test, prick by prick and RAST. Immunoblotting and immunoblotting-inhibition were used to evaluate the allergenic components of both extracts and their cross-reactivity. Prick by prick with fresh pine nuts and RAST with pine nut and pine pollen extracts showed that the patient had high levels of specific IgE against both extracts. Immunoblotting experiments showed the presence in serum of IgE antibodies against several components in pine nuts and pollen. Immunoblotting-inhibition experiments demonstrated the presence of some cross-reacting components. These data confirm the existence of food allergy induced by pine nuts. This sensitization to pine nuts developed with no symptoms of pine pollinosis. Development of pollinosis may require a longer time of exposure to allergens. Based on the cross-reactivity between pine nut and pine pollen extracts, cosensitization to these two allergens could be possible.