Esophagus to Small Intestine
Am J Gastroenterol. 2024;119(6):1066–73
Outcomes of serum food-specific immunoglobulin G4 to guide elimination diet in patients with eosinophilic esophagitis
Introduction: Eosinophilic esophagitis (EoE) is associated with atopy; however, recent studies have identified an association with food-specific immunoglobulin G4 (FS-IgG4) rather than immunoglobulin E antibodies. This study aimed to evaluate the role of serum FS-IgG4 in guiding an elimination diet and its outcomes.
Methods: Patients with and without EoE were enrolled in a prospective, controlled, single tertiary center trial. Serum FS-IgG4 titers, esophageal eosinophil counts, and dysphagia symptom questionnaire scores were assessed, and participants with elevated FS-IgG4 (cutoff of 10 mgA/L) commenced 6-week targeted elimination diet. Repeat serum FS-IgG4 and endoscopic and histologic examination were performed at 6-week follow-up.
Results: 22 patients with active EoE and 13 controls were recruited. Serum FS-IgG4 to milk, wheat, soy, eggs, and nuts was significantly higher in EoE (p = 0.0002, p = 0.002, p = 0.003, p = 0.012, and p < 0.001, respectively). Elevated serum FS-IgG4 to 1 or more food groups (median 2) was identified in 21 of 22 patients (95.4%) with EoE; 20 of 21 underwent 6-week dietary elimination. Median reductions in Dysphagia Symptom Questionnaire score and Eosinophilic Esophagitis Endoscopic Reference Score after elimination were 8 (p = 0.0007) and 1 (p = 0.002), respectively. Nine patients (45%) had histological remission (< 15 eosinophils per high-power field). Fall in median esophageal eosinophil count was not statistically significant (50 vs. 23; p = 0.068). Serum FS-IgG4 did not decline by 6-week follow-up.
Discussion: Serum food-specific immunoglobulin G4 (FS-IgG4) to milk, wheat, soy, egg, and nuts was present at higher levels in eosinophilic esophagitis (EoE), with targeted elimination resulting in 45% histologic remission rate. Serum FS-IgG4 has potential as a non-invasive biomarker in EoE. When successful, FS-IgG4-led elimination diet can negate need for medications and be viewed more favorably by patients because of its smaller endoscopic burden compared with empirical elimination diets.