Identification of the primary sensitizing mite (dominant mite) in patients with allergic respiratory disease sensitized to and .

Objective: To identify the dominant mite in patients with allergic respiratory disease (ARD) and double sensitization to (Dpt) and (Ld).

Methods: Cross-sectional study including patients with Dpt and Ld sensitization (skin prick test [SPT] and specific IgE [sIgE]), with ARD. We measured sIgE to Dpt and Ld major allergens and performed CAP Inhibition experiments. The dominant mite was determined considering the Dpt/Ld ratio (≥5 Dpt and ≤0.2 Ld dominance) and CAP inhibition results (heterologous inhibition ≥50% indicates dominance).

Results: We included 67 patients (62.7% men), with a mean (range) age of 35.8 (7-81) years. We found significant correlations between sIgE to Dpt whole extract (Dpt-sIgE) and sIgE to Der p 1, Der p 2, and Der p 23 ( < 0.0001) and between Ld-sIgE and Lep d 2-sIgE ( < 0.0001). No significant correlation was found between SPT wheal diameter and Dpt-sIgE and Ld-sIgE, nor between Ld-sIgE or Lep d 2-sIgE and Der p 23-sIgE. Patients were classified into group A (Dpt dominance), n = 31 (46.3%); group B (Ld dominance), n = 8 (11.9%); and group C (unclear dominance), n = 28 (41.8%). A Dpt/Ld ratio ≥3 diagnosed 90.3% of patients in group A, ≤0.2 diagnosed 87.5% of patients in group B, and a ratio between 0.4 and 3 diagnosed 78% of patients in group C.

Conclusions: In patients with ARD sensitized to Dpt and Ld, the sIgE Dpt/Ld ratio and, in specific situations, the Der p 1+Der p 23/Ld ratio, allow identification of the dominant mite in a high percentage of cases.