i. Main findings
We identify three main strategies addressing the modification of tree
nut allergy: the sublingual immunotherapy, the oral immunotherapy,
single or multiple, with or without omalizumab, and the use of
monoclonal antibodies interfering with allergic responses.
Sublingual immunotherapy was investigated in a small number of patients
with LTP hazelnut allergy, with moderate efficacy but a favorable safety
profile19,22,28. Single OIT was investigated for
hazelnut, walnut and cashew allergy. Efficacy and safety varied
according to protocol, population, and tree nut
tested23,24,30,31,33. Multi-OIT studies included
participants with variable tree nut allergy
profile17,18,20,21,25,26. Multi-OIT was not
significantly more or less effective than single-nut
OIT21. The use of omalizumab appeared to allow for
faster desensitization with fewer adverse reactions, especially during
the build-up phase, and does not affect efficacy17.
Overall, the efficacy and the safety of tree nut OIT was found to be
similar to that demonstrated by peanut OIT
trials34,35. Omalizumab and dupilumab were
investigated in a case report and two small cohort studies of multi-food
allergic children and adults, with favorable
outcomes27,29,32.
Cross-desensitization between cashew and pistachio, or walnut and pecan,
was described17,18,20,23,24, attributed to the close
phylogenetic affinity of the respective nuts36.
Interestingly, cross desensitization to distant phylogenetic nuts
through walnut and cashew OIT was also
documented23,24. Linear and structural homologies of
vicilin, legumin, and 2S albumin epitopes of tree nuts belonging to
different botanical families36 could contribute to the
observed cross-desensitization, which, additionally to multi-OIT
results, straightly affects the management options for multi-nut
allergic patients.
Sustained unresponsiveness depended on the length of avoidance, with
fewer participants maintaining their desensitization over
time18,33.
Managing tree nut allergy had a positive effect on the quality of life
of patients and families, especially when desensitization to more nuts
was achieved24,27,29.