Microarray Gene Expression Analysis of Lesional Skin in Canine Vesicular Cutaneous Lupus Erythematosus ( <scp>VCLE</scp> )

BACKGROUND: Vesicular cutaneous lupus erythematosus (VCLE) is a rare autoimmune disease in dogs and is considered the canine counterpart of human subacute cutaneous lupus erythematosus (SCLE). However, the molecular mechanisms underlying VCLE remain incompletely defined. OBJECTIVE/HYPOTHESIS: To characterise gene expression changes in lesional skin from dogs with VCLE and identify immune pathways involved in disease pathogenesis. ANIMALS: Six client-owned dogs with clinically and histopathologically confirmed VCLE, and five healthy control dogs. MATERIALS AND METHODS: Formalin-fixed, paraffin-embedded lesional and control skin samples were analysed using the NanoString nCounter Canine Immuno-Oncology Panel, targeting 780 immune-related genes. Data were normalised using geNorm-selected housekeeping genes. Differential expression, cell type profiling and pathway enrichment analyses were also performed. RESULTS: T cells, cytotoxic T cells, natural killer cells, dendritic cells, macrophages and neutrophils. Pathway enrichment analysis identified activation of interferon signalling, Janus kinase signal transducer and activator of transcription (JAK-STAT) signalling, chemotaxis and cytotoxic immune pathways. CONCLUSIONS AND CLINICAL RELEVANCE: VCLE lesions feature a dominant interferon-stimulated gene signature, with downstream activation of JAK-STAT signalling and cytotoxic lymphocyte-mediated immune responses, suggesting that interferon and JAK-STAT signalling are potential therapeutic targets.