This work aimed at investigating expression levels and secretory responses of Hsp90 in skin and blood of patients with BP in comparison to healthy subjects and a control cohort of autoimmune bullous disease patients with pemphigus vulgaris, studies that may shed light on whether Hsp90 could play a role in the pathogenesis of human BP and represent a potential novel target for treatment of these patients. The gene discussed is HSP90AA1; the disease is pemphigus vulgaris.