The diagnosis and management of allergic reactions in patients sensitized to non‐specific lipid transfer proteins

Abstract

Sensitization to one or more non-specific lipid transfer proteins (nsLTPs), initially thought to exist mainly in southern Europe, is becoming accepted as a cause of allergic reactions to plant foods across Europe and beyond. The peach nsLTP allergen Pru p 3 is a dominant sensitizing allergen and peaches a common food trigger, although multiple foods can be involved. A frequent feature of reactions is the requirement for a cofactor (exercise, alcohol, non-steroidal anti-inflammatory drugs, Cannabis sativa) to be present for a food to elicit a reaction. The variability in the food and cofactor triggers makes it essential to include an allergy-focused diet and clinical history in the diagnostic workup. Testing on suspected food triggers should also establish whether sensitization to nsLTP is present, using purified or recombinant nsLTP allergens such as Pru p 3. The avoidance of known trigger foods and advice on cofactors is currently the main management for this condition. Studies on immunotherapy are promising, but it is unknown whether such treatments will be useful in populations where Pru p 3 is not the primary sensitizing allergen. Future research should focus on the mechanisms of cofactors, improving diagnostic accuracy and establishing the efficacy of immunotherapy.

LTP Allergy Follow-Up Study: Development of Allergy to New Plant Foods 10 Years Later

“…nsLTPs are found in high concentrations in the epidermal tissues of fruits and are the main allergens of fruits of the Rosaceae family. In addition, allergenic nsLTPs have been found in nuts, seeds, vegetables, pollen, and latex from Hevea brasiliensis [ 4 ]. Allergy to nsLTP involves several taxonomically unrelated plant-derived foods and heterogeneous sensitization profiles and can trigger severe systemic reactions.…”

“…The management of such patient heterogeneity continues to challenge the expertise of allergists despite the study by Asero et al [ 19 ] and the recommendations given by the EAACI Task Force on nsLTP Allergy Across Europe [ 4 ].…”

Medical algorithm: Diagnosis of plant food allergy

“…Sensitization to storage proteins may start in early childhood and these stable allergens are involved in systemic reactions including anaphylaxis to raw and processed foods. This has been shown for Cor a 9 and Cor a 14 (hazelnut), Jug r 1 and Jug r 4 (walnut), Ara h 2 and Ara h 6 (peanut), Ana o 3 (cashew nut), that are also markers of primary sensitization 4,5 .CRD increases the diagnostic accuracy of peanut and tree nut allergies, which is higher than that of SPT and sIgE to whole extracts, may reduce the number of OFC 5,6 , and help identify those at risk of severe reactions in OFC 7 . Basophil activation test (BAT) is a highly specific test but still a non-standarized research tool.…”

“…In allergy to peanut, tree nuts and seeds PR-10 proteins, profilins, nsLTP, and storage proteins may be involved with different clinical patterns. As discussed above nsLTPs may induce OAS and systemic reactions; PR-10 and profilins are involved in patients with a previous pollen allergy, usually adolescents or adults, and symptoms are predominantly OAS 3,4 . Sensitization to storage proteins may start in early childhood and these stable allergens are involved in systemic reactions including anaphylaxis to raw and processed foods.…”

“…Symptoms vary from OAS to anaphylaxis, and cofactors may be needed for a reaction to appear, or may increase reaction severity. Pru p 3 is an allergen marker of the LTP syndrome, but several nsLTPs can be tested (Table 1) 3,4 .…”