Published Online: May 3, 2016
Eosinophilic esophagitis (EoE) is an increasingly diagnosed disease with symptoms that are similar to common acid reflux but are not improved by antacid treatments. EoE has often been considered an allergic disorder, in which antibodies of the IgE subtype made by patients’ B cells react to specific food allergens or aeroallergens and lead to an inflammatory response composed predominantly of eosinophils. However, research into EoE mechanisms has been conflicting, and there is evidence in support of both antibody-driven pathways and antibody-independent pathways.
In a report recently published in The Journal of Allergy and Clinical Immunology: In Practice, Chen and colleagues present a case of EoE occurring in a patient with common variable immunodeficiency (CVID), a disorder defined by markedly reduced antibodies, impaired B cell development, and frequent respiratory infections. After having numerous episodes of bronchitis and pneumonia starting from childhood, this patient was diagnosed with CVID at age 28, when she was found to have significantly decreased antibody levels. She was then diagnosed with EoE at age 34 after years of worsening acid reflux-like symptoms despite antacid treatments. An endoscopy showed classic EoE patterns in her esophagus, and biopsy of her gastrointestinal (GI) tract also showed markedly decreased levels of mature antibody-producing B cells, consistent with CVID.
EoE occurred in this patient despite her having profoundly low antibody levels, impaired specific antibody responses, and significantly decreased antibody-producing B cells in the GI tract. This unique case supports the increasing evidence that EoE can develop independent of antibodies entirely. Indeed, studies have shown that T cells, rather than B cells, are indispensable for the development of EoE in mouse models. Additionally, allergic rhinitis and asthma have also been reported to occur in some CVID patients, illustrating that allergic disease may not be antibody-dependent in all cases.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.