t205 Elder

IgE mediated reactions

Anecdotal evidence suggests that asthma, allergic rhinitis and allergic conjunctivitis are possible following exposure to pollen from this tree; however, few specific studies have been reported to date. Patients suffering from allergic rhinoconjunctivitis and dyspnoea during summer may exhibit these symptoms after contact with flowers or dietary products of the elder tree. Nine patients with a history of summer hay fever were tested in a routine setting for sensitisation to elder. 0.6% of 3668 randomly tested patients showed positive skin-prick test and/or IgE antibodies to elder. (1)

A retrospective, open and uncontrolled Croatian study attempting to identify the most common inhalant allergens associated with 1 097 patients with atopic dermatitis – and/or allergic rhinitis, and/or bronchial asthma – using skin-prick tests reported that 3 with asthma tested positive, as did 34 of those with atopic dermatitis and 12 of those with allergic rhinitis. (2)

Sam n 1, a 33.2 kDa, ribosomal inactivating protein, found in the pollen, flower and fruit. (1)

Thaumatin-like proteins (TLPs) have been isolated and characterised from fruits and leaves of the elder tree. Ripening berries accumulated a fruit-specific TLP during the final stages of maturation. The leaves expressed a TLP that closely resembled the fruit-specific homologue. These thaumatin-like proteins shared a high sequence similarity with group-5 pathogenesis-related proteins. (3) The clinical relevance of this protein was not evaluated, nor whether the allergenicity of these TLPs is similar to that of other TLPs.

Cross-reactivity

Extensive cross-reactivity between the different individual species of the genus could be expected. (4)

Last Reviewed-  April 2022