Background: House dust mite/HDM atopy patch test/APT elicits positive reactions in a high fraction of atopic dermatitis/AD and healthy individuals. Experimental systems for new-onset/chronic AD are needed to support rapid therapeutic development, particularly since animal models representing human AD are lacking. While HDM APT has been considered to simulate AD, its suitability to model AD's emerging Th2/Th22 phenotype with Th1 and Th17 components is unknown.
Objective: To assess whether HDM APT reproduces AD.
Methods: Positive HDM APTs (n = 15) from patients with and without AD were evaluated, using genomic and immunohistochemistry studies, against intrapersonal control skin.
Results: APT lesions showed higher T cell and dendritic cell infiltrates vs.
Controls: Seven hundred and forty-three up- and 326 downregulated genes were differentially expressed in HDM APT (fold change >2 and false discovery rate < 0.05), with increased expression of Th2, Th9, Th17/Th22 polar cytokines (i.e. IL-5, IL-13, IL-9, IL-17, IL-22).
Conclusion: While HDM caused significant Th2 skewing, it also illustrated differences in Th2 induction and barrier defects; thus, HDM APT does not fully simulate AD. Given its widespread availability and sensitization rates, HDM may potentially be a useful tool that represents select aspects of AD, psoriasis, or contact dermatitis.
Keywords: allergic contact dermatitis; atopic dermatitis; atopy patch test; house dust mite; psoriasis.
© 2017 John Wiley & Sons Ltd.