The Role of B Cells and Antibodies in Eosinophilic Esophagitis.

Background: Eosinophilic esophagitis (EoE) is a chronic, immune-mediated inflammatory disease affecting the esophagus, characterized by esophageal dysfunction, dysphagia, and tissue remodeling, leading to significant impairment in quality of life. The pathogenesis of EoE involves a complex interplay of genetic, environmental, and immunological factors. Although the disease is strongly associated with type 2 immune responses, emerging evidence suggests that B cells and antibody responses, particularly IgG4, also play a crucial role in disease development and progression. Summary: This review explores the pathogenesis of EoE with a focus on the role of B cells, plasma cells, and antibodies. Epithelial barrier dysfunction is a pivotal factor in EoE, influenced by genetic predisposition, environmental triggers, and immune responses. The impaired barrier allows for antigen penetration, triggering type 2 immune responses, and chronic inflammation. Elevated levels of IgG4 in esophageal tissues and their potential to drive inflammation and tissue remodeling are highlighted. Animal models and clinical studies provide insights into the involvement of B cells and antibodies in EoE, suggesting that these components may contribute to the chronic inflammatory state and disease severity. Key Messages: B cells are increasingly recognized for their role in EoE, particularly through their production of antibodies and cytokines that contribute to the inflammatory milieu. EoE is primarily driven by type 2 immune responses involving cytokines such as IL-4, IL-5, and IL-13, which promote eosinophil recruitment and chronic inflammation. Regulatory B cells, which produce anti-inflammatory cytokines such as IL-10 and IL-35, may play a role in modulating immune responses in EoE and contribute to the production of IgG4 antibodies. Elevated levels of IgG4 in esophageal tissues of EoE patients are linked to chronic inflammation and tissue remodeling, suggesting a potential role in disease pathogenesis. Further studies are needed to elucidate the specific mechanisms by which B cells and antibodies contribute to EoE.