Introduction: Different clinical and molecular patterns of food allergy have been reported in different areas of the world. The aim of the study is to evaluate differences in allergen patterns among nut-allergic patients in two different areas of Spain. Material and methods: A total of 77 patients with nut allergy from two different regions of Spain (Madrid and Asturias) were evaluated. Results: Hazelnut, peanut, and walnut were the three most frequent nuts eliciting allergy in both regions, but in a different order. Patients from Madrid experienced systemic reactions more often than patients from Asturias (73.5% Madrid vs. 50.0%, p < 0.05). The percentage of sensitizations to LTP (Lipid Transfer Protein) was higher than Bet v 1 (p < 0.05) in the Madrid area. The percentage of sensitizations in Asturias area was similar to LTP than Bet v 1 (Pru p 3 46.4%, Bet v 1 42.9%, ns). Bet v 1 was the predominant allergen involved among hazelnut-allergic patients (56.2%), while LTP was more common in peanut-allergic patients (61.5%). Conclusion: Walnut, hazelnut, and peanut were the most frequent nuts eliciting allergy in Spain. Despite this, important differences in molecular pattern were appreciated not only between both regions, but also among nut-allergic patients in Asturias. The different molecular pattern was linked to the frequency of systemic symptoms.

Torres-Rojas I, et al. Allergy Asthma Immunol Res. 2023 Mar;15(2):201-213. https://doi.org/10.4168/aair.2023.15.2.201

The consumption of macadamia nuts has increased due to their cardioprotective and antioxidant properties. However, this rise is consistent with an increase in the cases of macadamia nut allergy, leading to severe reactions. Although two Macadamia integrifolia allergens (Mac i 1 and Mac i 2) have been identified in Australian and Japanese patients, the allergenic sensitization patterns in Western European populations, particularly in Spain, remain unclear. For this purpose, seven patients with macadamia nut allergy were recruited in Spain. Macadamia nut protein extracts were prepared and, together with hazelnut and walnut extracts, were used in Western blot and inhibition assays. IgE-reactive proteins were identified using MALDI-TOF/TOF mass spectrometry (MS). Immunoblotting assays revealed various IgE-binding proteins in macadamia nut extracts. Mass spectrometry identified three new allergens: an oleosin, a pectin acetylesterase, and an aspartyl protease. Cross-reactivity studies showed that hazelnut extract but not walnut extract inhibited macadamia nut oleosin-specific IgE binding. This suggests that oleosin could be used as marker for macadamia–hazelnut cross-reactivity. The results show an allergenic profile in the Spanish cohort different from that previously detected in Australian and Japanese populations. The distinct sensitization profiles observed highlight the potential influence of dietary habits and environmental factors exposure on allergenicity.

Haroun-Díaz E, et al. Ann Dermatol. 2017 Feb;29(1):127-129. https://doi.org/10.5021/ad.2017.29.1.127