The number of individuals developing immunoglobulin E (IgE) dependent allergic reactions against different substances is increasing at a high rate in the industrial countries. At the same time new foods, food additives and genetically modified (GM) foods are being produced and introduced to the consumers, in many cases with poor evaluation of the probability of inducing allergic reactions.

So far no one has been able to predict whether an antigen will be allergenic, or in what way. It also remains unexplained why some patients react to grass, for example, while others react to mugwort, and some to both (1). For this reason, both in vivo and in vitro methods must be used to determine the reactivity of a specific protein (2).

Nangai is an edible tree nut cultivated by people on the islands in the Pacific. Its Latin name is Canarium indicum and it belongs to the Burseraceae family. There is some interest in the introduction of Nangai to the European market and, although the European Union (EU) has classified the nut as a novel food, no studies have been reported on its potential allergenicity. No other members of this family are frequently imported to Europe as food.

By using both serological and biological methods we have evaluated the risk of IgE-mediated food allergic reactions against Nangai, in a previously non-exposed population (3). We found that a group of pollen allergic patients had specific IgE against Nangai and that this IgE seemed to mediate biological reactivity. According to our results we conclude that Nangai contains epitopes that bind to cross-reactive IgE specificities and that these IgE molecules have biological relevance.