Neutralizing Anti‒DNase 1 and ‒DNase 1L3 Antibodies Impair Neutrophil Extracellular Traps Degradation in Hidradenitis Suppurativa.

Hidradenitis suppurativa (HS) is a debilitating inflammatory skin disorder characterized by abscess-like nodules and boils resulting in fistulas and tissue scarring. We previously reported evidence of an autoimmune signature in HS, characterized by enhanced neutrophil extracellular trap (NET) infiltration in HS skin lesions and dysregulation of the adaptive immune system characterized by the presence of autoantibodies. Timely removal of NETs is critical for tissue homeostasis to prevent a dysregulated generation of modified autoantigens and tissue damage. DNases 1 and 1L3 play important roles in proper NET removal. We tested the hypothesis that NETs in patients with HS are not effectively cleared owing to the presence of antibodies against DNase 1 and DNase 1L3. We report that HS serum poorly degraded NETs. Addition of exogenous DNase 1 restored NET degradation capabilities in a subset of HS samples. DNase 1 activity was significantly decreased in HS sera. Anti‒DNase 1 and ‒DNase 1L3 antibodies were detected in serum samples and skin lesions from patients with HS. Purified IgGs from HS decreased DNase 1 activity and NET degradation. Taken together, this identification of neutralizing antibodies against nucleases in HS expands the understanding of the pathogenesis of this disease to support an autoimmune mechanism in its underlying pathogenesis.