Hand eczema (HE) is a common inflammatory skin disorder whose pathogenesis is largely unknown. Among the clinical subtypes of HE, vesicular HE (VHE) and hyperkeratotic HE (HHE) are the most well described. We aimed to profile the transcriptome of lesional palmar skin of VHE compared to non-lesional VHE and healthy control palmar skin. After RNA-sequencing, gene expression was validated by RT-qPCR, and protein expression was studied using immunohistochemistry. High expression of genes/proteins involved in keratinocyte host defense and inflammation in lesional palmar skin was observed. Genes involved in epidermal differentiation were either up- or downregulated, while immune signaling genes were upregulated. No significant differences were found between non-lesional VHE and healthy palmar skin. A large overlap between the lesional VHE skin transcriptome and earlier reported atopic dermatitis (AD) transcriptome was found. In addition, expression of keratins, epidermal barrier proteins, and adhesion molecules in HHE were investigated. Immunofluorescence staining showed an upregulation of keratins involved in hyperproliferation and hyperkeratosis, and a downregulation of keratins involved in terminal differentiation and mechanical integrity of palmar epidermis in lesional HHE skin compared to non-lesional and healthy palmar skin. No decreased expressions of skin barrier-associated proteins were found, suggesting that skin barrier dysfunction plays a less significant role in the pathogenesis of HHE. Future studies should focus on transcriptome analysis of other subtypes of HE as this can provide insight into specific pathways, which may lead to new therapeutic targets.

ESDR114 - Insight into the pathogenesis of vesicular and hyperkeratotic hand eczema

50th Annual Meeting of the European Society for Dermatological Research. VIRTUAL MEETING