Granzyme B inhibition reduces autoantibody-induced dermal–epidermal separation in an ex vivo model of epidermolysis bullosa acquisita

The pemphigoid disease epidermolysis bullosa acquisita (EBA) is an autoimmune blistering skin disease characterized by autoantibodies against type VII collagen (COL7), immune cell infiltrates at the dermal–epidermal junction and subepidermal blistering. Proteases, particularly granzyme B (GzmB), have been established as therapeutic targets for the treatment of EBA and other pemphigoid diseases. We investigated the impact of the novel GzmB inhibitor SNT-6935 on anti-COL7 IgG-induced subepidermal blistering in a well-established EBA ex vivo model. Our findings demonstrate that pharmacological targeting of GzmB with its selective inhibitor SNT-6935 significantly reduced autoantibody-induced dermal–epidermal separation in human skin cryosections. Interestingly, treatment of skin cryosections with recombinant human GzmB alone did not cause dermal–epidermal separation, suggesting that additional mechanisms alongside GzmB are required for tissue damage in EBA. In conclusion, our study highlights the significant contribution of GzmB to the pathogenesis of EBA and supports the notion of GzmB as a therapeutic target in EBA and other pemphigoid diseases.