LIGHT, SHADOW AND FUTURE PERSPECTIVE
Summary, AIT in children with AD cannot be used as first-line therapy, but it may be considered to reduce the progression of concomitant respiratory pathology as well as to prevent new sensitizations.12
As opposite to controversial evidence of effectiveness, safety of AIT was always one of the most important aspects to be carefully investigated since it was the primary reason to use this route. As a matter of fact, SLIT was introduced as a safer variant of SCIT to solve the rare problem of systemic reactions (SRs). Sublingual administration is well-tolerated, adverse reactions are predominantly local, and SRs are considered extremely rare and anecdotal.13,14Noteworthy, protocol doses schedule and type of product of AIT may influence safety; thus, moderate-dose of AIT and tyrosine-adsorbed HDM extract should always be preferred.13,15 Moreover, considering that patients keep up improving after one year of treatment, future clinical studies should evaluate the long-term efficacy of HDM-AIT for at least three years.6 Due to the duration and relatively high cost of immunotherapy, poor compliance is the principal reason for the failure of AIT. In a recent meta-analysis, Hankin et al. highlighted the evidence that AIT produced cost savings in place of conventional therapy, in both asthma and AR, in terms of fewer drugs used and fewer hospitalizations.3 The main issue is the absence of biomarkers for predicting efficacy before and during treatment. Since the late 1990s, several attempts have been made to find biomarker candidates, such as cell adhesion molecules, chemokines or serological parameters, total or specific IgE, and IgG4-blocking subtype antibodies, but none of these is certainly reliable based on evidence.5,6,12 In conclusion, several controversial points need to be clarified:
- eligible patients (e.g., age, type and severity of AD, type of sensitization, if perennial and/or pollen sensitization);
- route of administration of AIT (considering that SLIT should be preferred then SCIT in children);
- type of product of AIT chosen (standardized product should be preferred);
- duration of AIT course and age limit to start AIT (considering that AD have been shown to improve spontaneously throughout childhood and if AIT ;
- standard protocol schedule of administration for both SCIT and SLIT;
- cost-effectiveness ratio;
- clinical or immunological biomarkers for predicting efficacy.
Considering the lack of clear recommendations, starting AIT in AD patients should be decided by the pediatric allergist taking into account benefits, cost, possible risks, and the agreement of the patient/family that should be educated to ensure close adherence to AIT. Further researches are needed to recommend the proper use of AIT in AD for children.