Adalimumab (anti-TNF-α monoclonal antibody(mAb)) [12], secukinumab ((mAb targeting interleukin(IL)-17A) [13] and bimekizumab (mAb selectively inhibiting both IL-17A and IL-17F) [14] are the only approved biologic agents for the treatment of moderate-to-severe HS and provide a clinical benefit in approximately 40% of HS patients, still resulting in a high unmet clinical need. Here, IL17A is linked to histiocytic sarcoma.