Background: Component-resolved diagnosis based on recombinant allergens facilitates treatment of multiple sensitization and/or crossreactivity in allergic patients.

Objective: To assess the usefulness of molecular diagnosis in childhood allergies.

Methods: A total of 162 children aged 4-16 years diagnosed with allergic rhinitis or asthma/rhinitis caused by pollen were referred for recombinant allergen–based diagnosis in 2006. Specific immunoglobulin (Ig) E against pollen allergens and purified recombinant Phleum pratense pollen allergens were measured using an in vitro quantitative assay, and considering the recombinant allergens Phl p 1+Phl p 5
as P pratense–specific allergens and Phl p 7+Phl p 12 as cross-reacting allergens. Conditional probability was calculated to determine the relationship between values for specific IgE against major allergens and those for cross-reacting allergens.

Results: Specific IgE antibodies against P pratense were detected in 99.4% of serum samples, and cross-reacting allergens in 46%. Multiple sensitization to pollen was documented in 38% of patients, with Plantago lanceolata as the main cause. Conditional probability calculations showed that patients with specific IgE values of 75-80 kUA/L to Phl p 1+Phl p 5 were 75% (95% confidence interval) more likely to present
values ≥2 kUA/L to Phl p 7+Phl p 12.

Conclusions: Our results show that recombinant DNA technology can help diagnose allergy in cases of multiple sensitization and crossreactivity, and is therefore a promising option for improving prognosis and management of allergic pediatric populations.

Key words: Allergens/immunology. Immunologic tests/methods. Recombinant proteins/immunology. Immunoglobulin E/analysis. Crossreactions.