Transcriptome patterns in hidradenitis suppurativa: support for the role of antimicrobial peptides and interferon pathways in disease pathogenesis

Background: Hidradenitis suppurativa (HS) is a recurrent inflammatory disease of the apocrine sweat glands. Immune dysregulation probably contributes to the pathogenesis of HS. Aim: To harness mRNA expression arrays to investigate the transcriptome profile in HS compared with control skin. Methods: Illumina HumanHT-12 v4 Expression BeadChips were used to measure mRNA expression in skin samples from HS (n = 10) and abdominoplasty (n = 11) skin specimens. Differentially expressed genes were detected by fitting genewise linear models to the normalized expression data and then modelling using the web-based software Ingenuity Pathway Analysis. Results: The antimicrobial peptide Dermcidin and the cytokine regulator interleukin (IL)-37 were both significantly downregulated in the HS specimens (Dermcidin expression log ratio −3.93, expression P = 0.04; IL-37 expression log ratio −3.29, expression P < 0.001). Pathway analysis revealed the interferon-signalling pathway, leucocyte extravasation pathway, T helper 1 and 2 pathways and nuclear factor of activated T cells as the top-five upregulated pathways in the HS samples. Conclusion: Evaluation of transcriptome patterns in HS compared with normal skin demonstrated downregulation of the antimicrobial peptide Dermcidin and the innate immune regulator IL-37, as well as upregulation of interferon pathways and pathways of leucocyte activation.