Allergens. Heterogeneity of molecular sensitization profiles in grass pollen allergy--implications for immunotherapy?

Background: Data on molecular allergy diagnostics in adults with grass pollen allergy with regard to conjunctival and nasal provocation test outcome and specific immunotherapy are lacking to date.

Objective: To assess whether molecular allergy diagnostics for grass pollen allergens could help with predicting provocation test outcomes and serve as a basis for future component-resolved specific immunotherapy.

Methods: Sera of 101 adults with grass pollen allergy was analysed for IgE against timothy grass pollen (Phleum pratense), rPhl p 1, rPhl p 2, nPhl p 4, rPhl p 5b, rPhl p 6, rPhl p 7, rPhl p 11 and rPhl p12 and correlated with the individuals' outcome in the nasal and conjunctival provocation tests and investigated in regard to a potential component-resolved specific immunotherapy.

Results: An increasing number of sensitizations to timothy grass allergens was correlated to a positive reaction in the conjunctival (4.9 vs. 3.6, P = 0.003) and nasal provocation tests (4.5 vs. 2.2, P = 0.0175). In molecular sensitization profiles, a substantial heterogeneity was detected, with none of the patients exactly matching the allergen composition of a previously published component-resolved specific immunotherapy containing Phl p 1, Phl p 2, Phl p 5a/b and Phl p 6. The results indicate that in 95% of the patients, a proportion of 50% of timothy-IgE would be targeted with such a specific immunotherapy, while in 50% and 10% of patients, 80% and 90% of timothy-IgE would be targeted, respectively.

Conclusion and clinical relevance: Molecular allergy diagnostics is a prerequisite for future component-resolved specific immunotherapy due to the high heterogeneity of sensitization profiles. However, of current clinical relevance is the observed correlation between the number of sensitizations and provocation test outcome.