Clinical Relevance of Lepidoglyphus destructor Sensitisation in Allergic Rhinitis: Nasal Provocation Test as in vivo Assessment

Background: Dust mites are the leading cause of respiratory allergic diseases worldwide. Allergy to storage mites (SMs) has mostly been related to occupational exposures. However, recent studies have shown that sensitisation to SM, such as Lepidoglyphus destructor (Lep d), is of considerable importance also in urban populations, with high prevalence in dust samples of domestic environments. Co-sensitisation between house dust mites (HDMs) and SM is now regarded as very frequent in some regions, and cross-reactivity between them seems to be narrow. Therefore, SM allergenic capacity is increasingly a subject of study. The nasal provocation test (NPT), as an in vivo technique, could be considered the gold standard for the clinical relevance assessment of an allergen, in polysensitised rhinitis patients. Objective: The objective of this study was to analyse the clinical relevance of the SM Lep d, by assessing the relationship between in vivo sensitisation and expression of allergic respiratory disease in an urban setting. Patients and Methods: In our study, we enrolled a total of 32 allergic patients with rhinitis (with or without asthma) with proven sensitisation by skin prick test (SPT) and specific IgE (sIgE) to HDMs and/or SM. Patients underwent NPT with Lep d using subjective (Lebel Symptom Score Scale) and objective measurements (peak nasal inspiratory flow [PNIF]) for assessment of nasal response. Results: Most of the patients with positive SPT and sIgE to Lep d had a positive NPT (24/27; 89%). True Lep d allergy, assessed by a positive NPT, could be predicted by a SPT wheal size >9.7 mm and a sIgE >0.42 kUA/ L, with 100%/95.7% sensitivity and 75.0%/83.3% specificity, respectively. Co-sensitisation between Lep d and Der p was high, 75.0%. Asthma was more frequent in the positive Lep d NPT group (54 vs. 12%, p < 0.05). Significantly more patients from this group reported physical exercise, nonspecific irritants, and respiratory infections as relevant triggers of respiratory symptoms (p < 0.01–p < 0.05). Conclusions: To our knowledge, this is the first study to show that sensitisation to Lep d may have clinical relevance in a nonoccupational setting. In this group, there seems to be a relationship between allergy to Lep d and severity of respiratory disease, with more bronchial inflammation, when comparing with mite-allergic patients sensitised only to HDM. Therefore, the authors consider that sensitisation to Lep d should be considered when assessing and treating allergic respiratory disease in urban environments. as essential, not only in the research field but also when measuring therapeutic success clinically and when prescribing allergen immunotherapy [22]. It is a safe and reasonably priced technique that replicates an allergic reaction in the nose under standardised and controlled conditions [19]. NPT aims to demonstrate the causal role of an allergen [23], to diagnose local allergic rhinitis [24], and to identify the clinically relevant allergen(s) in polysensitised subjects [25]. Therefore, it could lead to the application of stratified and personalised medicine in rhinitis patients [26]. We aimed to analyse the clinical relevance of Lep d, by assessing the relationship between in vivo sensitisation, using NPT, and expression of allergic respiratory disease.