Microarray-Based Detection of Allergen-Reactive IgE in Patients with Mastocytosis.

Background: Because of a high risk to develop fatal anaphylaxis, early detection of immunoglobulin E (IgE)-dependent allergy is of particular importance in patients with mastocytosis.

Objective: We examined whether microarray-based screening for allergen-reactive IgE (allergen-chip) is a sensitive and robust approach to detect specific IgE in patients with mastocytosis.

Methods: Sera for 42 patients were analyzed, including 4 with cutaneous mastocytosis, 2 with mastocytosis in the skin, and 36 with systemic mastocytosis. In addition, sera from an age- and sex-matched control cohort (n = 42) were analyzed.

Results: In 15 of 42 patients with mastocytosis (35.7%), specific IgE was detected by allergen-chip profiling. Ves v 5 and Bet v 1 were the most frequently detected allergens (Ves v 5: 16.7% of patients; Bet v 1: 11.9% of patients). Allergen reactivity was confirmed by demonstrating upregulation of CD203c on blood basophils upon exposure to the respective allergen(s) in these patients. Specific IgE was identified by chip studies in 11 of 26 patients with mastocytosis with mediator-related symptoms (42.3%) and in 4 of 14 patients with mastocytosis without symptoms (28.6%). In the cohort with known allergy, 9 of 9 patients (100%) had a positive allergen-chip result. In patients with mastocytosis without a known allergy (n = 31), the chip identified 6 positive cases (19.5%). The prevalence of chip-positive patients was slightly lower in the mastocytosis group (35.7%) compared with age- and sex-matched controls (40.5%).

Conclusions: Although specific IgE may not be detectable in all sensitized patients with mastocytosis, allergy chip-profiling is a reliable screening approach for the identification of patients with mastocytosis suffering from IgE-dependent allergies.