IL17A and histiocytic sarcoma: Moreover, in HS-patients, the presence in the affected skin areas and/or in the serum of increased expression of several cytokines, such as interleukin (IL)-1β, IL-6, IL-17, interferon-gamma, and tumor necrosis factor-alpha (TNF-α) suggest a role for the autoinflammation in HS pathogenesis [9].