Identification of the primary sensitizing mite (dominant mite) in patients with allergic respiratory disease sensitized to Dermatophagoides pteronyssinus and Lepidoglyphus destructor

Objective To identify the dominant mite in patients with allergic respiratory disease (ARD) and double sensitization to Dermatophagoides pteronyssinus (Dpt) and Lepidoglyphus destructor (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 ( p < 0.0001) and between Ld-sIgE and Lep d 2-sIgE ( p < 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.