Keratinocyte-secreted SAA1 induces a population of long-lived antigen-presenting neutrophils that drives Sweet Syndrome

Sweet syndrome (also known as acute febrile neutrophilic dermatosis), is a rare inflammatory skin disorder characterized by erythematous plaques with a dense dermal neutrophilic infiltrate. It remains unknown how neutrophils, which are generally short-lived, persist in the skin of patients with Sweet syndrome. We report that Sweet syndrome skin contains a unique population of long-lived antigen-presenting cell (APC)-neutrophils that are not present in blood or unaffected skin. Overall design: scRNA-seq of Human neutrophils and skin cells from patient lesional and non lesional skin