# Kiwifruit Allergy--Molecular Basis, Diagnostics and Treatment
## 1 Introduction  
Kiwifruit from the _Actitidialicace_ family, also known as Chinese gooseberry, is a popular exotic fruit. The fruit is native to China, but commercial cultivation and global exportstarted in the 1950-1960s from New Zealand, from where the fruit obtained its popular nickname, \"kiwi\" [1]. Today, the commercial value of kiwifruit as an economic crop has increased significantly due to its rich nutritional and medicinal benefits. Kiwifruit is rich in antioxidants, vitamins, and dietary fiber, and has been found to be effective for digestive and metabolic health [2]. Additionally, kiwifruit is also popular in the baking and food-processing industries. With the growing use of kiwifruit and its derived products, cases of allergic reaction to this fruit have grown significantly, making it an increasingly common food allergy source [2]. Overall, there are approximately 70 kiwifruit species that belong to the _Actinidia_ genus [3]. However, only two species of this fruit are known to be sources of allergens registered by the World Health Organization and International Union of Immunological Societies (WHO/IUIS), because their capability to cause allergic reactions in humans has been demonstrated. In fact, the Allergen Nomenclature Sub-Committee of the WHO/IUIS (accessed June 2025) recognizes 13 kiwifruit allergens belonging to the species _Actinidia delicosa_ (green kiwifruit), and 3 allergens belonging to the species _Actinidia chinensis_ (golden kiwifruit) [4; 5]. Initially classified as one species, _A. delicosa_ and _A. chinensis_ differ slightly in physical characteristics; _A. chinensis_ generally has less hair, more yellowish flesh, and tastes sweeeter [6]. Moreover, the two species differ in allergenicity and immunogenicity. While both can elicit an allergic response, allergenicity to _A. chinensis_ appears to be milder than that to _delicosa_[7]. The kiwifruits differ in their protein compositions and have discrete immunoglobulin E (IgE) recognition patterns [7]. Kiwifruit allergens belong to 13 protein families, detailed in Table 1. While this review focuses on allergens and allergies associated with _A. delicosa_ and _A. chinensis_, Allergome [8] also reports potential allergens, originating from _Actinidia arguta_ (hardy kiwi or kiwberry) and _Actinidia eriantlua_, which are not yet registered by the WHO/IUIS Allergen Nomenclature Sub-Committee. Medically, hypersensitivity to kiwifruit was first recorded in 1981 in a woman in the USA, who developed allergic symptoms, including hives, whee \begin{table}
\begin{tabular}{c c c} \hline _Actinidia delicosa_ & _Actinidia chinensis_ & **Protein Family** \\ **(Green Kiwifruit)** & **(Golden Kiwifruit)** & **Biochemical Name** \\ \hline Act d 1 & Act c 1 * & Cysteine protease (actinidin) \\ Act d 2 & Act c 2 * & Thaumatin-like protein (TLP) \\ Act d 3 & – & – \\ Act d 4 & Act c 4 * & Phytocyanin \\ Act d 5 & Act c 5 & Kiwellin (kissper + KiTH) \\ Act d 6 & – & Pectin methylesterase \\ Act d 7 & – & Pectin methylesterase (PME) \\ Act d 8 & Act c 8 & Patheogenesis-related \\ Act d 9 & – & Pectin (PR-10) \\ Act d 10 & Act c 10 & Non-specific lipid transport \\  & & protein (nsLTP1) \\  & & Major latex \\ Act d 11 & – & protein/ripening-related \\  & & protein (MLP/RRP) \\ Act d 12 & – & 11S globulin (cupin) \\ Act d 13 & – & 2S albumin \\ \hline \end{tabular}
\end{table} 
Table 1: List of allergens originating from green and golden kiwifruits. Allergens marked with asterisks (*) are included in Allergome [8] but not registered by the Allergen Nomenclature Sub-Committee of the International Union of Immunological Societies. difficulty breathing, after peeling and slicing the fruit [9]. Subsequently, a growing number of clinical cases of kiwifruit allergies have been reported globally. A study by [PERSON] et al.