Immunopathogenesis of IgG4-related disease in the era of single-cell RNA sequencing and highly multiplex immunofluorescence

Introduction IgG4-related disease (IgG4-RD) is a chronic immune-mediated fibroinflammatory disorder characterized by dense lymphoplasmacytic infiltration and storiform fibrosis, often resulting in organ dysfunction. Although glucocorticoids provide initial clinical improvement, relapse is common, underscoring the need for targeted therapies. B-cell depletion therapy has emerged as a promising approach, shedding light on the roles of plasmablasts and cytotoxic T lymphocytes in disease pathogenesis.