Project Summary Hidradenitis suppurativa (HS) is an underrecognized common, immune-mediated skin disease characterized by inflammatory nodules, abscesses, and sinus tracts in the groin, buttocks, and axillae leading to devasting physical and emotional morbidity. Patients with HS display systemic inflammation with increased risk of co- morbidities such as cardiometabolic disease. In this application, we use single cell technology and novel bioinformatic and machine learning methods to identify dysregulated pathways in the circulating immune system of HS patients. This study will advance our knowledge of the immunobiology of HS and identify new biologic pathways that can be therapeutically targeted.