Lupin is a legume considered as an emerging food allergen, but the true prevalence of lupin allergy is not known.¹ Due to the increasing consumption of lupin and its potential cross-reactivity with peanut, the Allergy-Vigilance Network® (AVN) aimed to report lupin-induced anaphylaxis cases and compare their main characteristics to other foods (See Data S1 for Material and Methods).

Of the 2708 cases of food-induced anaphylaxis documented by AVN (2002-2020), 62 (2.3%) cases were induced by lupin and cases are presented by time periods and according to total number of food-induced anaphylaxis cases (Figure S1). The main characteristics of these 62 cases (mean age: 32.1 years [SD: 21.4], 35% in children <18 years, 66% in females) are presented in Table 1. Nine (15%) patients had a history of lupin allergy confirmed by an allergist and 4 (6%) a known sensitization to lupin; 22 (35%) patients had a known food allergy (peanut, n = 16). Allergic sensitizations according to foods and families of component-resolved reactivity are presented in the Figure S2. Of the 62 patients, a history of asthma was reported in 14 (23%), and allergic rhinitis in 12 (19%).

Regarding the description of the anaphylaxis reaction, Grade 2 (according to Ring and Messmer²) reactions were recorded in 36 cases (58%), Grade 3 in 26 cases (42%). A cofactor was identified in 10 (16%) and 7 (11%) anaphylaxis reactions were biphasic. Reactions occurred mainly at home (n = 26, 42%) (See Data S1 for additional results).

Foods identified as responsible of the 62 cases of lupin-induced anaphylaxis are presented in the Figure S3. Fifty-nine (95%) cases involved prepacked food products, mainly pastries, biscuits, and breads (n = 47, 76%). In 8 (13%) cases, the diagnosis of lupin-induced anaphylaxis was highly suspected (previous allergic reactions to lupin in 7 cases–missing data in one patient-, anaphylaxis after the consumption of an industrial bakery product in 8 cases, confirmation of lupin sensitization and exclusion of other food allergy after allergy work up in 8 cases), but lupin was undeclared as an ingredient in the consumed prepacked food product.

Compared to adults, children (<18 years) with lupin-induced anaphylaxis were more likely to be males (p < 10⁻³), to have a history of asthma (p = .003), and a peanut allergy (p < 10⁻³) (Table 1). Compared to other foods, lupin-induced anaphylaxis was more frequent in females (p = .003), in adults (p = .004), in individuals with a peanut allergy (p < 10⁻³) and after prepacked food products consumption (p < 10⁻³) (Table 2). Hypotension (p < 10⁻³), laryngeal oedema (p = 0.048), bronchospasm (p < 10⁻³), and biphasic reaction (p < 10⁻³) were more frequent in lupin-induced anaphylaxis compared to other foods (Table 2).

Our data shows that lupin is involved in around 2.3% of anaphylaxis cases in France over the two last decades, with a stable frequency at around 1.2%–1.4% over the last decade, whereas it is reported in 0.8% of cases in Europe over the same time period.³ We strongly believe that this data highlights an under recognition and underestimation of lupin allergy in Europe.

In our study, a quarter of patients with a lupin-induced anaphylaxis had a history of peanut allergy, and 8% a history of another legume allergy. This suggests a significant degree of cross-reactivity between lupin and other legumes, particularly peanut. In the Netherlands, in 39 peanut-sensitized adults, 82% were sensitized to lupin, of whom 35% reacted during a food challenge.⁴ In a French survey conducted in 195 children with peanut allergy, 122 (63%) were sensitized to at least one legume, lupin was the most frequent (n = 63, 33%) and 12 were allergic to lupin.⁵ There is a need to better understand the relevance of cross-reactivity between lupin and legumes, the potential clinical impact of different lupin species at a molecular level as well as the diversity of the allergen composition using proteomics.^{6, 7}

Our data supports that there are specificities of lupin-induced anaphylaxis cases compared to other food allergens. Compared to peanut-induced anaphylaxis reported by the European Anaphylaxis Registry, lupin-induced anaphylaxis seems to occur more frequently in adulthood, in females, with less severity and a higher ingested amount of food allergen.⁸

One limitation of our study is that our data may not be representative of all European countries. There were also missing data because some questions were not asked from the beginning of the data collection.

Lupin is an emerging food allergen over the last two decades that may be present in prepacked food products. Allergists should be aware of lupin cross-reactivity with peanut and other legumes, and lupin should be systematically tested if not regularly consumed in peanut allergic patients. Patients with a history of food anaphylaxis without any obvious trigger should be systematically tested for lupin.

羽扇豆是一种豆类，被认为是一种新兴的食物过敏原，但羽扇豆过敏的真正患病率尚不清楚。¹由于羽扇豆消费量的增加及其与花生潜在的交叉反应，过敏警戒网络® (AVN) 旨在报告羽扇豆引起的过敏反应病例，并将其与其他食品的主要特征进行比较（材料和方法见数据 S1） ）。

在 AVN（2002-2020 年）记录的 2708 例食物引起的过敏反应病例中，62 例 (2.3%) 是由羽扇豆引起的，病例按时间段和食物引起的过敏反应病例总数呈现（图 S1） 。这 62 例病例的主要特征（平均年龄：32.1 岁 [SD：21.4]，35% 为 18 岁以下儿童，66% 为女性）如表 1 所示。 9 例 (15%) 患者有羽扇豆过敏史经过敏症专家证实，4 名 (6%) 已知对羽扇豆过敏； 22 名 (35%) 患者已知食物过敏（花生，n  = 16）。图 S2 显示了根据食物和成分分解反应性家族的过敏反应。在 62 名患者中，14 名（23%）有哮喘病史，12 名（19%）有过敏性鼻炎病史。

关于过敏反应的描述，2级反应（根据Ring和Messmer ²）有36例（58％），3级反应有26例（42％）。 10 例（16%）和 7 例（11%）双相过敏反应中发现了辅助因子。反应主要发生在家里（n  = 26, 42%）（有关其他结果，请参阅数据 S1）。

图 S3 列出了 62 例羽扇豆诱发过敏反应的食物。五十九 (95%) 起案件涉及预包装食品，主要是糕点、饼干和面包 ( n  = 47, 76%)。在 8 例 (13%) 病例中，高度怀疑羽扇豆引起的过敏反应（7 例患者既往有羽扇豆过敏反应，其中 1 例患者数据缺失，8 例患者食用工业烘焙产品后出现过敏反应，确认羽扇豆致敏并在 8 例过敏检查后排除其他食物过敏），但羽扇豆未申报为食用预包装食品中的成分。

与成人相比，患有羽扇豆引起的过敏反应的儿童（<18 岁）更有可能是男性 ( p  < 10 ^-3 )、有哮喘病史 ( p  = .003) 和花生过敏 ( p  < 10 ⁻³）（表1）。与其他食物相比，羽扇豆引起的过敏反应在女性 ( p  = .003)、成人 ( p  = .004)、花生过敏个体 ( p  < 10 ⁻³ ) 以及食用预包装食品后 (p = .004)中更为常见。p  < 10 ^-3）（表2）。与其他食物相比，羽扇豆引起的过敏反应中低血压（p <  10 ^-3）、喉头水肿（ p  = 0.048）、支气管痉挛（ p  < 10 ^-3）和双相反应（p  < 10 ^-3 ）更常见（表2）。

我们的数据显示，过去 20 年法国约 2.3% 的过敏反应病例与羽扇豆有关，过去 10 年频率稳定在 1.2%–1.4% 左右，而据报道，欧洲 20 世纪 0.8% 的过敏反应病例中羽扇豆与羽扇豆有关。同一时间段。³我们坚信，这一数据凸显了欧洲对羽扇豆过敏的认识不足和低估。

在我们的研究中，四分之一的羽扇豆引起的过敏反应患者有花生过敏史，8% 的患者有另一种豆类过敏史。这表明羽扇豆和其他豆类（特别是花生）之间存在显着程度的交叉反应。在荷兰，39 名对花生过敏的成年人中，82% 对羽扇豆过敏，其中 35% 在食物挑战中出现反应。⁴在法国对 195 名花生过敏儿童进行的一项调查中，122 名儿童 (63%) 对至少一种豆类过敏，其中羽扇豆过敏最常见 ( n  = 63, 33%)，12 名儿童对羽扇豆过敏。⁵需要利用蛋白质组学更好地了解羽扇豆和豆类之间交叉反应的相关性、不同羽扇豆物种在分子水平上的潜在临床影响以及过敏原成分的多样性。^{6, 7}

我们的数据表明，与其他食物过敏原相比，羽扇豆引起的过敏反应病例具有特殊性。与欧洲过敏反应登记处报告的花生引起的过敏反应相比，羽扇豆引起的过敏反应似乎更常见于成年女性，且严重程度较低，摄入的食物过敏原量较高。⁸

我们研究的一个局限性是我们的数据可能无法代表所有欧洲国家。还存在数据缺失的情况，因为从数据收集之初就没有提出一些问题。

羽扇豆是过去二十年中新兴的食品过敏原，可能存在于预包装食品中。过敏症专家应意识到羽扇豆与花生和其他豆类的交叉反应，如果花生过敏患者不定期食用羽扇豆，则应进行系统测试。有食物过敏史但没有任何明显诱因的患者应系统地检测羽扇豆。