Die Pizza: eine Quelle von unerwarteten Allergenen – anaphylaktische Reaktion auf Lupinenmehl im Pizzateig und in einem Lebkuchen

Lupine (Lupinus albus) belongs to the family of the legumes (Leguminosae) and, therefore, demonstrates strong cross-reactivity with peanuts, chickpeas and white beans. Due to the high protein and lipid content, lupine flour is extensively used in food industry. It is added to cereal flours and used as emulsifier. Concomitant with the increasing intake of lupine, a rising prevalence of allergic reactions after ingestion as well as inhalation of lupine flour has been observed. We here present a patient with known severe peanut allergy who reacted after eating a pizza with severe respiratory symptoms, which required an intubation in the emergency room. Our investigations revealed that the pizza dough used in this take-away pizza was enriched with lupine flour. The sensitization to lupine could be proven by means of the skin prick test (SPT) with native lupine flour and also serologically as 44.30 kU/l (class 4) of specific IgE antibodies were measured by means of CAP-FEIA to lupine seed (f335, Pharmacia Diagnostics). A peanut contamination of the pizza was excluded by the manufacturer as well as by analysis in an immunoassay. IgE binding to major proteins at 20, 34, 60 and 62 kDa was detected by means of immunoblotting. In inhibition experiments, IgE-binding to lupine proteins was partially inhibited by peanut extract. Shortly after that first observation of a lupine allergy, a patient was admitted to our clinic who experienced allergic reactions including edema in the face and abdominal pain after ingestion of gingerbread that was declared to contain lupine flour. Apart from a slight pollinosis in childhood, the patient had no history of allergic reactions and no history of food allergy at all. She revealed a positive reaction to lupine flour in skin prick test and was positive for specific IgE against lupine flour in CAP-FEIA (class 3; 7.59 kU/l). Contrary to the first case, the IgE binding to lupine flour was not inhibited by peanut extract. On the basis of our observations in the two patients and further cases described in the literature, we conclude that allergic reactions to lupine can be mediated by cross-reacting IgE antibodies to peanut, chickpea and white beans or may occur due to an isolated sensitization as well. Because of the increasing use of lupine flour in the food industry and its high allergenic properties, lupine flour should be regarded as a highly allergenic food. Similar to peanut and soy, lupine should be added to the list of allergenic foods of the EU and Swiss Food Regulation that have to be mandatory declared.