Clinical Validation of a house dust mite environmental challenge chamber model

Publication date: Available online 24 February 2017
Source:Journal of Allergy and Clinical Immunology
Author(s): P. Zieglmayer, P. Lemell, K.W. Chen, R. Schmutz, R. Zieglmayer, O. Pfaar, F. Horak, S. Vrtala
Mite allergy causes significant socioeconomic burden. Environmental allergen exposure can be difficult to assess, and topical challenge offers limited value. In our investigation we evaluated a challenge chamber system in terms of correlation between mite allergen concentration and rhinitis symptoms, retest reproducibility as well as inter chamber variability. Data was obtained from adult mite allergic subjects from 4 different studies. Total nasal symptom score (TNSS) data was analysed for dose finding. TNSS and active anterior rhinomanometry (RMM) data was analyzed for retest reproducibility and inter chamber variability. Allergen dose deliveredand allergenic profile were specified, for dose quantification particle counting and weighing were correlated. In 85 subjects dose response was defined with five challenges of increasing allergen concentration and six challenges of stable allergen concentration. A clear dose response was shown with a mean TNSS of 6.6 at 0.3g mite material. For evaluation of retest reproducibility TNSS and RMM of 158 placebo- treated subjects were compared. Curves were matching with a mean plateau TNSS of 6.7 and a mean flow decrease of 34%. For definition of inter-chamber variability 28 subjects were challenged in two chamber systems. A mean TNSS without "nasal blockage"of 3.9 in VCC2 and of 4.0 in VCC3 with a SD of 0.2% each and a mean reduction in nasal flow sum of 36.3% in VCC2 and 39.6% in VCC3 with a SD of 1.2 and 2.3, respectively, was determined.. No bronchial adverse events were observed. Thus, a clear and reproducible dose response in terms of mite allergen concentration was demonstrated. Similar symptoms scores were elicited between studies and between chambers. We conclude that the mite challenge chamber model offers a safe and reproducible option for investigation of mite allergic subjects.

Teaser

In this dust mite allergen challenge chamber model a reproducible correlation between allergen concentration and nasal symptoms has been demonstrated. Retest reproducibility of nasal symptoms measured by TNSS and decreased nasal flow quantified by RMM at three different occasions was demonstrated. Inter-chamber variability of nasal symptoms and nasal flow between two different chamber rooms (VCC 2 and VCC3) was determined to be 2.5% (SD 0.2%) and 3.3% (SD of 1.2 and 2.3) respectively. Chamber exposure in this model was safe in mite allergic subjects with controlled asthma.


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