Strong impact of in vitro Molecular Diagnosis on prescription of specific immunotherapy

Published Online: May 2, 2014

Guidelines state that specific immunotherapy prescription (SIT) efficacy requires proper matching of the SIT preparation against the pollen sources causing all or most symptoms in the individual patient. Unfortunately, many patients with pollen allergy are nowadays sensitized to many pollen sources with overlapping seasonality. Moreover, many patients are sensitized to profilin or other highly cross-reacting molecules, shared by many unrelated pollen sources. Thus, the identification of the disease-eliciting pollen sources by means of extracts-based skin-prick-tests (SPT) in patients sensitized to multiple pollens with overlapping seasonality is often difficult. In these patients, component resolved diagnosis (CRD) might modify SIT prescription by improving the identification of the disease-eliciting pollen sources.

In a study recently published in The Journal of Allergy & Clinical Immunology (JACI), Stringari, Tripodi, Caffarelli and colleagues measured the impact of CRD on SIT prescription in children with pollen-AR. They recruited 651 children with moderate-severe pollen- Allergic rhino-conjunctivitis (AR) in 16 Italian outpatient clinics. SPT reactivity to Grass, Cypress, Olive, Mugwort, Pellitory and/or Birch pollen was considered clinically relevant if symptoms occurred during the corresponding peak pollen season. IgE sensitization to the respective major allergens of these pollens and to profilin or other cross-reacting allergens was measured by ImmunoCAP. SIT prescription was modeled according to the traditional “European” GA2LEN-EAACI guidelines (1 to 3 pollens) or to the unlimited “American” model of prescription (both using extracts for diagnosis with SPT or in vitro IgE assays). The prescription was then re-modeled considering also the molecular diagnosis. Similarly, the opinion of 14 pediatric allergists was expressed after a traditional, extract-based diagnosis and after its integration with a molecular diagnosis.

In significant proportions of patients, sensitization detected with extracts was not confirmed by molecular specific assays. Moreover, IgE to highly cross-reacting molecules (profilins and/or polcalcins) were associated with almost 40% of these inconsistencies. Consequently, the SPT-based decision on SIT prescription, or its composition, was changed in 42% or in 48% children according to the “European” or the “American” approach, respectively. Similarly, the opinion about SIT prescription was modified in 47% of the children participating in the study by the 14 local pediatric allergists participating in the survey.

The authors concluded that CRD has a strong potential impact on SIT prescriptions in a large proportion of children affected by pollen related allergic rhinitis and living in a Mediterranean country such as Italy. They suggest that in countries with high and prolonged exposure to many allergenic pollen sources CRD should be considered as an important diagnostic step after SPT or in vitro tests based on allergenic extracts. The authors conclude also that, given their impressive results, the hypothesis that a CRD-guided prescription also improves the efficacy of SIT in a cost-effective fashion deserves to be tested.

The Journal of Allergy and Clinical Immunology (JACI) is the official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.

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