Irisin, a novel metabolic biomarker in hidradenitis suppurativa: correlation with clinical responsivity to anti-TNF-α therapy

Background: Suppurative hidradenitis (HS) is a chronic, inflammatory skin disease of the hair follicle unit. Adalimumab (ADA), an anti-tumor necrosis factor (TNF) alpha, is the only FDA-approved biologic available for the management of HS. TNF-α can also affect glucose and lipid metabolism, promoting insulin resistance and obesity by negatively regulating irisin, a new adipomyokine. Methods: A total of 17 HS patients were enrolled in the study. Blood samples were collected from all patients at baseline and week-16. Plasma irisin levels were detected by ELISA assay. Results: Plasma irisin levels were significantly increased after 16 weeks of ADA therapy in HS patients compared to baseline. Interestingly, plasma irisin levels correlated with clinical response. Conclusions: The link between skin inflammatory diseases and metabolic disorders has aroused great interest in order to research new biomarkers able to early identify metabolic comorbidities. Among these emerging biomarkers, irisin is one of the most recently discovered. We examined a group of patients affected by moderate-severe HS treated with anti-TNF-α, demonstrating for the first time how a therapy able to block an inflammatory cytokine can also affect the metabolic profile by modifying levels of irisin.