Refractory Bullous Pemphigoid Successfully Treated with Reslizumab: A Possible Novel Therapeutic Modality

Bullous pemphigoid (BP) is a chronic, autoimmune blistering disease that has concerning morbidity and mortality rates. Recently, several studies have focused on eosinophils due to their significant role in the pathogenesis of BP, considering that they are ubiquitous in the serum, tissue, and blister fluids of patients with BP. With this context, precision therapy that targets mediators of eosinophil activity could be a possible novel therapeutic strategy. Interleukin (IL)-5 is crucial for B-cell maturation, which consequently results in immunoglobulin production, and promotes eosinophil differentiation, proliferation, and activation. To our best knowledge, reslizumab has not yet been reported to treat BP. Herein, we report a case of steroid- and omalizumab-resistant BP treated successfully using reslizumab. Our data suggest that IL-5 could be a novel specific biologic target within the entire immunopathogenesis of BP, and reslizumab would be a novel therapeutic modality.