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

Abstract

<b><i>Background:</i></b> 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 <i>Lepidoglyphus destructor (Lep d)</i>, 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. <b><i>Objective:</i></b> The objective of this study was to analyse the clinical relevance of the SM <i>Lep d</i>, by assessing the relationship between in vivo sensitisation and expression of allergic respiratory disease in an urban setting. <b><i>Patients and Methods:</i></b> 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 <i>Lep d</i> using subjective (Lebel Symptom Score Scale) and objective measurements (peak nasal inspiratory flow [PNIF]) for assessment of nasal response. <b><i>Results:</i></b> Most of the patients with positive SPT and sIgE to <i>Lep d</i> had a positive NPT (24/27; 89%). True <i>Lep d</i> allergy, assessed by a positive NPT, could be predicted by a SPT wheal size &gt;9.7 mm and a sIgE &gt;0.42 kUA/L, with 100%/95.7% sensitivity and 75.0%/83.3% specificity, respectively. Co-sensitisation between <i>Lep d</i> and <i>Der p</i> was high, 75.0%. Asthma was more frequent in the positive <i>Lep d</i> NPT group (54 vs. 12%, <i>p</i> &lt; 0.05). Significantly more patients from this group reported physical exercise, nonspecific irritants, and respiratory infections as relevant triggers of respiratory symptoms (<i>p</i> &lt; 0.01–<i>p</i> &lt; 0.05). <b><i>Conclusions:</i></b> To our knowledge, this is the first study to show that sensitisation to <i>Lep d</i> may have clinical relevance in a non-occupational setting. In this group, there seems to be a relationship between allergy to <i>Lep d</i> 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 <i>Lep d</i> should be considered when assessing and treating allergic respiratory disease in urban environments.