CRD and AIT safety:
There are different heterogeneous evidence showing an association of
risk factors for adverse events during AIT associated to particular IgE
sensitization profiles. The most studied model is grass pollen allergy.
Adverse reactions with subcutaneous immunotherapy, both local and
systemic, correlate with sensitization progression (Phl p 1+5+12
>Phl p 1+5 > Phl p 1/5)117. In sublingual
AIT, adverse events were also related with highest levels of Phl p 5 or
Phl p 1 2727 and with allergen
sensitivity 118. Under
extreme exposure to grass pollen, patients are frequently sensitized to
profilin and present severe adverse reactions to foods caused by
profilin. Interestingly, this type of these reactions to
profilin-containing foods are similar to the infrequent reactions
observed during SLIT. This rare phenotype constitutes therefore a unique
model to understand disease severity and limits for AIT. Profilin severe
reactors undergo extensive oral mucosa damage and present a unique
systemic metabolic status that points to T cell proliferation, sustained
inflammation and altered repair function. The fact that
profilin-sensitized patients in Spain present an enhanced T cell
proliferation compared with similar patients from Denmark suggests that
progression to severe phenotypes might be linked to an uncontrolled
inflammation and T cell proliferation. Interestingly, in the other
severity models previously mentioned systemic barrier damage,
uncontrolled effector cell response, and altered repair-associated
biomarkers have been described. In all cases, might be explained by T
cell cross-reactive allergens: Profilin, Ole e 7 (a nsLTP from pollen)
and Lep d 2 (a frequent food contaminant inducing reactions in patients
with storage mite sensitization).