The JAK/STAT signaling cascade comprises intracellular proteins through which numerous cytokines and growth factors regulate genes governing cell activation, proliferation, and differentiation. Although disruptions in this pathway have been reported in many inflammatory and autoimmune disorders, studies specifically addressing autoimmune bullous diseases remain scarce. This research aimed to investigate the expression levels of JAK3, STAT2, STAT4, and STAT6 in epithelial lesions from patients with pemphigus vulgaris (PV), bullous pemphigoid (BP), oral lichen planus (LP), and chronic ulcerative stomatitis (CUS), compared with healthy controls. Expression patterns were assessed using immunohistochemistry and immunoblotting techniques. Our results demonstrated a marked upregulation of the selected JAK/STAT proteins in affected oral mucosa, supporting their involvement in disease pathogenesis. Notably, STAT2 expression was not elevated in PV and BP, whereas STAT4 remained unchanged in CUS and LP. These expression differences suggest potential targets for therapeutic intervention.
