# Kiwifruit Allergy--Molecular Basis, Diagnostics and Treatment
## 6 Patterns of Sensitization in Kiwifruit Allergy  
The development of component-resolved kiwifruit allergy diagnostics improved our ability to investigate sensitization patterns. In studies that involved 92 kiwi-sensitized patients from Spain, it was shown that Act d 1, Act d 2, and Act d 3 were major allergens in the studied population [47]. It was also noticed that high levels of IgE to Act d 1 and Act d 3 were linked with severe symptoms after kiwifruit ingestion. Another study that included 30 Swiss individuals with suspected kiwifruit allergy divided patients into three groups: monosensitized to kiwifruit (n = 8), individuals with concomitant pollen allergy (n = 17), and a group that had kiwifruit, pollen, and latex allergies (n = 5) [28]. It was shown that monosensitized patients reacted more often to Act d 1 in comparison with polysensitized individuals, who reacted more often to Act d 8. This study also did not find any significant correlation between IgE reactivity and reaction severity in kiwifruit allergy. Later, a large European study reported that only Act d 1 was associated with disease severity, and individuals with severe symptoms (when compared with patients with mild symptoms) were often sensitized to actinidin [108]. It was also noticed that sensitization to Act d 1 was less frequent in patients that had kiwifruit allergy for more than 5 years. The same study highlighted differences in sensitization profiles in patients living in different parts of Europe. For example, individuals from Iceland were mainly affected by Act d 1, living in southern Europe was associated with sensitization to Act d 9 and Act d 10, and individuals sensitized to Act d 8 were most frequently living in western, central, and eastern Europe. Sensitization to Act d 8 in Europe is quite frequent, and it is related to cross-reactivity with Bet v 1 as well as other allergens from the PR-10 family. Interestingly, a group from Japan showed that, among the local population, a negative specific response to Act d 8 was linked with more severe kiwifruit allergy [109]. Some exemplary cases of kiwifruit allergy with \(\mathrm{ALEX^{2}}\) results, detailed in Table 2, are provided below to illustrate different patterns of allergic reactions. The reactions are not exclusive to kiwifruit, and they can be explained by analyzing the multiplex assay results. The selected patients provided a history of an allergic response to kiwifruit, but they were not necessarily allergic solely to kiwifruit. _Patient 1:_ A 25-year-old female experienced multiple allergic reactions upon eating foods containing vegetables, corn, cereals, and nuts. Symptoms seemed to be more severe with physical activity after meals but occurred even without exercise. The patient consumed kiwifruit assuming she was not allergic to it; however, consumption resulted in anaphylaxis. The patient profile showed selective sensitization to nsLTP and no sensitization to specific kiwifruit allergens Act d 1, Act d 2, Act d 5, or cross-reactive 11S globulins or 2S albumins, which are homologous to Act d 12 or Act d 13, respectively. _Patient 2:_ A 19-year-old male suffered from seasonal allergic rhinitis and conjunctivitis for 10 years. The rhinitis and conjunctivitis symptoms were exasperated during tree pollen season (March-May). The patient experienced PFAS to hazelnuts and apples, and underwent unexpected anaphylaxis after eating kiwifruit. No known cofactors were identified. The patient profile showed sensitization to Act d 1. PR-10 co-sensitization did not seem to be responsible for anaphylaxis. Not sensitized to nsLTP, 11S globulins, or 2S albumins. _Patient 3_: A 35-year-old male suffered from seasonal allergic rhinitis and conjunctivitis for more than 20 years. The rhinitis and conjunctivitis symptoms increased during tree, grass, and weed pollen season (March-October). Symptoms of PFAS were noted to many fruits (stone fruits) and hazelnuts. The patient was on a strict diet, excluding stone fruits, nuts, carrot, celery, tomato, and corn.