Table 2.
Nut allergen molecules according to the WHO/IUIS allergen nomenclature (97) including information regarding biochemical, immunological and clinical features with key references.
| Species | Allergen name | Protein family | Function | MW (SDS-PAGE): | Route of sensitization | Prevalence | Clinical relevance | References |
|---|---|---|---|---|---|---|---|---|
| Arachis hypogaea (peanut) | Ara h 1 | Vicilin | Seed storage protein | 64 kDa | Food | Major allergen in the US, central and northern Europe | Risk of severe allergic reactions up to anaphylaxis | (94, 98–100) |
| Ara h 2 | 2S albumin | Seed storage protein | 17 kDa | Food | Major allergen in the US, central and northern Europe | Risk of severe allergic reactions up to anaphylaxis | (94, 99–104) | |
| Ara h 3 | Legumin | Seed storage protein | 60 kDa, 37 kDa (fragment) | Food | Prevalence varies between studies, but generally more prevalent in Central and North America and Northern Europe than in Mediterranean regions | Risk of severe allergic reactions up to anaphylaxis | (105) | |
| Ara h 5 | Profilin | Actin-binding protein | 15 kDa | Food | Panallergen (class II food allergy) | Pollen-food allergy syndrome | (100, 106) | |
| Ara h 6 | 2S albumin | Seed storage protein | 15 kDa | Food | Reactivity usually in patients who are primarily sensitized to Ara h 2, but monosensitization possible | Risk of severe allergic reaction up to anaphylaxis | (100, 103) | |
| Ara h 7 | 2S albumin | Seed storage protein | 15 kDa | Food | Reactivity usually in patients who are primarily sensitized to Ara h 2, but monosensitization possible | Predictive ability for peanut allergy similar to Ara h 2 and Ara h 6 | (100, 107, 108) | |
| Ara h 8 | PR-10 (Bet v 1-like) | Plant defense, stress mechanisms | 17 kDa | Food | Panallergen (class II food allergy) | Pollen-food allergy syndrome | (94, 104, 109) | |
| Ara h 9 | nsLTP1 | Transfer of lipids across membranes, plant defense, response to environmental stress | 9.8 kDa | Food | Major allergen in the Mediterranean region | Severe allergic reaction | (94, 110, 111) | |
| Ara h 10 | Oleosin | Structural protein of oil bodies | 16 kDa | Food | Not yet reported | Might be associated with severe allergic reactions | (112, 113) | |
| Ara h 11 | Oleosin | Structural protein of oil bodies | 14 kDa | Food | Not yet reported | Might be associated with severe allergic reactions | (112, 113) | |
| Ara h 12 | Defensin | Plant defense | 8 kDa (reducing), 12 kDa (non-reducing), 5.184 kDa (mass) | Food | Not yet reported | Might be associated with severe allergic reactions | (114) | |
| Ara h 13 | Defensin | Plant defense | 8 kDa (reducing), 11 kDa (non-reducing), 5.472 kDa (mass) | Food | Not yet reported | Might be associated with severe allergic reactions | (114) | |
| Ara h 14 | Oleosin | Structural protein of oil bodies | 17.5 kDa | Food | Not yet reported | Might be associated with severe allergic reactions | (112, 113) | |
| Ara h 15 | Oleosin | Structural protein of oil bodies | 17 kDa | Food | Not yet reported | Might be associated with severe allergic reactions | (112, 113) | |
| Ara h 16 | nsLTP2 | Transfer of lipids across membranes, plant defense, environmental stress | 8.5 kDa by SDS-PAGE reducing | Food | Not yet reported | Not yet reported | (97) | |
| Ara h 17 | nsLTP1 | Transfer of lipids across membranes, plant defense, environmental stress | 11 kDa by SDS-Page reducing | Food | Not yet reported | Not yet reported | (97) | |
| Ara h 18 | Cyclophilin | Peptidyl-prolyl cis-trans isomerase | 21 kDa | Food | Not yet reported | Not yet reported | (97) | |
| Juglans regia (English walnut) | Jug r 1 | 2S albumin | Seed storage protein | 15-16 kDa | Food | Major allergen in the US | Risk of severe allergic reactions | (115, 116) |
| Jug r 2 | Vicilin | Seed storage protein | 44 kDa | Food | Major allergen in the US | Risk of severe allergic reactions up to anaphylaxis | (117, 118) | |
| Jug r 3 | nsLTP | Transfer of lipids across membranes, plant defense, response to environmental stress | 9 kDa | Food | Major allergen in the Mediterranean region | Severe allergic reactions | (118) | |
| Jug r 4 | Legumin | Seed storage protein | 58.1 kDa | Food | Major allergen in patients with objective symptoms | Risk of severe allergic reactions up to anaphylaxis | (119, 120) | |
| Jug r 5 | PR-10 (Bet v 1-like) | Plant defense, stress mechanisms | 20 kDa | Food | Panallergen (class II food allergen) | Pollen-food allergy syndrome | (121) | |
| Jug r 6 | Vicilin | Seed storage protein | 47 kDa | Food | Minor allergen | Might be associated with severe allergic reactions | (122) | |
| Jug r 7 | Profilin | Actin-binding protein | 13 kDa | Food | Panallergen (class II food allergen) | Pollen-food allergy syndrome | (97) | |
| Jug r 8 | nsLTP2 | Transfer of lipids across membranes, plant defense, response to environmental stress | 9 kDa | Food | Not yet reported | Not yet reported | (97) | |
| Juglans nigra (black walnut) | Jug n 1 | 2S albumin | Seed storage protein | Food | Not yet reported | Not yet reported | (97) | |
| Jug n 2 | Vicilin | Seed storage protein | Food | Not yet reported | Not yet reported | (97) | ||
| Jug n 4 | Legumin | Seed storage protein | 34 kDa, 22 kDa | Food | Not yet reported | Not yet reported | (123) | |
| Corylus avellana (hazel) | Cor a 1: Cor a 1.01 major hazel pollen allergen; Cor a 1.04 major allergen in hazelnut | PR-10 (Bet v 1-like) | Plant defense, stress mechanisms | 17 kDa | Airway, Food (seed and pollen) | Panallergen (class II food allergy) | Pollen-food allergy syndrome | (124–126) |
| Cor a 2 | Profilin | Actin-binding protein | 14 kDa | Airway, Food (seed and pollen) | Panallergen (class II food allergy) | Pollen-food allergy syndrome | (127) | |
| Cor a 6 | Isoflavone reductase homologue | 35 kDa | Airway (pollen) | Not yet reported | Not yet reported | (97) | ||
| Cor a 8 | nsLTP | Transfer of lipids across membranes, plant defense, response to environmental stress | 9 kDa | Food | Major allergen in the Mediterranean region; might also be associated with severe allergy in birch-endemic regions | Risk of severe allergic reactions | (124, 128–130) | |
| Cor a 9 | Legumin | Seed storage protein | 40 kDa | Food | Major allergen in patients with objective symptoms unrelated to pollen; predominantly in children | Risk of severe allergic reactions | (131, 132) | |
| Cor a 10 | Luminal binding protein | 70 kDa | Airway (pollen) | Not yet reported | Not yet reported | (133) | ||
| Cor a 11 | Vicilin | Seed storage protein | 48 kDa | Food | Minor allergen, predominantly in children | Might be associated with severe allergic reactions | (132, 134, 135) | |
| Cor a 12 | Oleosin | Structural protein of oil bodies | 17 kDa | Food | Not yet reported | Might be associated with severe allergic reactions | (136) | |
| Cor a 13 | Oleosin | Structural protein of oil bodies | 14-16 kDa | Food | Not yet reported | Might be associated with severe allergic reactions | (136) | |
| Cor a 14 | 2S albumin | Seed storage protein | 10 kDa reducing | Food | Major relevance in patients with severe allergy unrelated to pollen; predominantly in children | Risk of severe allergic reactions | (137–139) | |
| Cor a 15 | Oleosin | Structural protein of oil bodies | 17 kDa | Food | Not yet reported | Might be associated with severe allergic reactions | (136) | |
| Pistacia vera (pistachio) | Pis v 1 | 2S albumin | Seed storage protein | 7 kDa | Food | Major allergen | Not defined on single molecule level; pistachio allergy can lead to severe allergic reactions | (140) |
| Pis v 2 | Legumin | Seed storage protein | 32 kDa | Food | Major allergen | Not defined on single molecule level; pistachio allergy can lead to severe allergic reactions | (140) | |
| Pis v 3 | Vicilin | Seed storage protein | 55 kDa | Food | Minor allergen | Not defined on single molecule level; pistachio allergy can lead to severe allergic reactions | (141) | |
| Pis v 4 | Manganese superoxide dismutase | Prevention of oxidative damage | 25.7 kDa | Food | Major allergen in study by Ayuso et al.; minor allergen in study by Noorbakhsh et al. | Not defined on single molecule level; pistachio allergy can lead to severe allergic reactions | (142, 143) | |
| Pis v 5 | Legumin | Seed storage protein | 36 kDa (acidic subunit) | Food | Minor allergen according to Willison et al. (referring to unpublished data) | Not defined on single molecule level; pistachio allergy can lead to severe allergic reactions | (97, 144) | |
| Anacardium occidentale (cashew) | Ana o 1 | Vicilin | Seed storage protein | 50 kDa | Food | Major allergen | Not defined on single molecule level; cashews are associated with severe allergic reactions | (145) |
| Ana o 2 | Legumin | Seed storage protein | 55 kDa | Food | Major allergen | Not defined on single molecule level; cashews are associated with severe allergic reactions | (146) | |
| Ana o 3 | 2S albumin | Seed storage protein | 14 kDa | Food | Major allergen | Not defined on single molecule level; cashews are associated with severe allergic reactions | (147) | |
| Prunus dulcis (almond) | Pru du 3 | nsLTP1 | Transfer of lipids across membranes, plant defense, response to environmental stress | 9 kDa | Food | LTPs usually prevalent in Mediterranean region | Might lead to severe allergic reactions, based on allergenicity of other nsLTPs | (97) |
| Pru du 4 | Profilin | Actin-binding protein | 14 kDa | Airway (pollen) | Panallergen (class II food allergy) | Pollen-food allergy syndrome | (148) | |
| Pru du 5 | 60s acidic ribosomal protein. P2 | 10 kDa | Airway (pollen) | Possibly major allergen, but more studies needed | Not yet reported | (149) | ||
| Pru du 6 | Legumin | Seed storage protein | 60 kDa (360 kDa hexamer) | Food | Major allergen | Might be a specific marker for almond allergy | (150–152) | |
| Pru du 8 | Antimicrobial seed storage protein | Seed storage protein | 31 kDa | Food | Not yet reported | Not yet reported | (153) | |
| Pru du 10 | Mandelonitrile lyase 2 | 60 kDa | Food | Not yet reported | Not yet reported | (97) | ||
| Bertholletia excelsa (Brazil nut) | Ber e 1 | 2S albumin | Seed storage protein | 9 kDa | Food | Major allergen | Risk of severe allergic reactions up to anaphylaxis | (154, 155) |
| Ber e 2 | Legumin | Seed storage protein | 29 kDa | Food | Major allergen | More studies needed for clinical evaluation | (156, 157) | |
| Carya illinoinensis (pecan) | Car i 1 | 2S albumin | Seed storage protein | 16 kDa | Food | Major allergen | More studies on single-molecule level needed for clinical evaluation | (158) |
| Car i 2 | Vicilin | Seed storage protein | 55 kDa | Food | Minor allergen | More studies on single-molecule level needed for clinical evaluation | (159) | |
| Car i 4 | Legumin | Seed storage protein | Subunit of hexameric protein: 55.4 kDa | Food | Major allergen | More studies on single-molecule level needed for clinical evaluation | (160) | |
| Macadamia integrifolia (macadamia) | Mac i 1 | Vicilin | Seed storage protein | 50 kDa | Food | Not yet reported | More studies on single-molecule level needed for clinical evaluation | (97) |
| Mac i 2 | Legumin | Seed storage protein | 60 kDa non reducing; 20 kDa and 40 kDa reducing | Food | Not yet reported | More studies on single-molecule level needed for clinical evaluation | (97) |
Confirmed (light blue) and putative (dark blue) cross-reactive class II allergens are highlighted.