[Allergies associated with both food and pollen].
Recent progress in understanding structural relationships between allergens has allowed their classification into molecular families. Proteins belonging to a molecular family often show some degree of IgE cross-reactivity. These cross-reactions can lead to a clinical association like birch-apple syndrome whose basis is a sensitization to a PR-10 protein (birch pollen Bet v 1) and then oral symptoms in contact to apple Mal d 1, another PR-10 family member. Food allergens implicated into pollen-food allergy syndromes differ from those linked to crustacea or milk cross-allergies: they seem unable to sensitize the patient through oral route. As a result, they most often induce weaker clinical reactions than complete allergens like those present in shrimp or cow milk. Numerous molecular families have been isolated from pollens. PR-10 and profilins have a well established role in inducing clinical reactions to food like fruits and vegetables. Some molecular families need more studies to delineate their true impact on pollen-driven food reactions: polygalacturonases, pectate lyases, isoflavone reductases, thaumatin-like, cyclophilins.... Others are found in pollen but not in eaten products: 2-EF-hand calcium binding proteins, beta expansins,... Lipid transfer proteins (LTP) are widespread plant food allergens (e.g. in peach): these proteins seem able to directly sensitize the patient through oral route. But recent data have suggested a possible additional effect of some LTP present in pollens (mugwort, olive, pellitory).
Malandain
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Laboratoire de Biochimie-C.H. Chubert-20, boulevard Guillaudot 56017 Vannes.
D000485:Allergens / Q000009:adverse effects* / Q000737:chemistry; D003429:Cross Reactions; D004044:Dietary Proteins / Q000009:adverse effects; D005512:Food Hypersensitivity / Q000209:etiology*; D006801:Humans; D015394:Molecular Structure; D010940:Plant Proteins / Q000009:adverse effects / Q000737:chemistry; D011058:Pollen / Q000009:adverse effects* / Q000737:chemistry; D006255:Rhinitis, Allergic, Seasonal / Q000209:etiology*; D013329:Structure-Activity Relationship
D000485:Allergens; D004044:Dietary Proteins; D010940:Plant Proteins