A Novel Allergen-Specific Immune Signature-Directed Approach to Dietary Elimination in Eosinophilic Esophagitis

Abstract

Objectives: Dietary elimination for treatment of eosinophilic esophagitis (EoE) is limited by lack of accuracy in current allergy tests. We aimed to develop an immunologic approach to identify dietary triggers and prospectively test allergen-specific immune signature-guided dietary elimination therapy.

Methods: In the first phase, we developed and assessed 2 methods for determining selected food triggers using samples from 24 adults with EoE: a CD4+ T-cell proliferation assay in peripheral blood and food-specific tissue IgG4 levels in esophageal biopsies. In the second phase, we clinically tested elimination diets created from these methods in a prospective cohort treated for 6 weeks (NCT02722148). Outcomes included peak eosinophil counts (eos/hpf), endoscopic findings (measured by the EoE Endoscopic Reference Score), and symptoms (measured by the EoE Symptom Activity Index).

Results: Parameters were optimized with a positive test on either assay, yielding agreements of 60%, 75%, 53%, 58%, and 53% between predicted and known triggers of peanut, egg, soy, wheat, and milk, respectively. In clinical testing, the mean number of foods eliminated based on the assays was 3.4, and 19 of 22 subjects were compliant with treatment. After treatment, median peak eosinophil counts decreased from 75 to 35 (P = 0.007); there were 4 histologic responders (21%). The EoE Endoscopic Reference Score and EoE Symptom Activity Index score also decreased after treatment (4.6 vs 3.0; P = 0.002; and 32.5 vs 25.0; P = 0.06, respectively).

Discussion: We successfully developed a new testing approach using CD4 T-cell proliferation and esophageal food-specific IgG4 levels, with promising accuracy rates. In clinical testing, this led to improvement in eosinophil counts, endoscopic severity, and symptoms of dysphagia, but a smaller than expected number of patients achieved histologic remission.

Figure 1.

Representative flow data from peripheral blood mononuclear cells cultured with indicated antigens. Lymphocytes are gated, then CD4+ CFSE-low cells are selected. (a) Negative control (media) with 0.04% stimulated CD4+ CSFE-low cells and positive control (anti-CD3/CD28) with 11.1% stimulated cells. (b) Two representative subjects. The subject in the top line has elevated responses to soy and milk at 6.67% and 4.57% stimulated, respectively. The subject in the bottom line has elevated responses to wheat and milk, at 3.23% and 5.60% stimulated, respectively. CFSE, carboxyfluorescein succinimidyl ester.

Figure 2.

Comparison of assay results by presence or absence of food triggers. (a) Results of the CD4⁺ T-cell proliferation assay show the mean proportion of T cells stimulated by those who have a food trigger present (gray bars) compared with those who do not (black bars). None of the comparisons are statistically significant, although there was a trend with egg (P = 0.07) and peanut (P = 0.10). (b) Results for food-specific IgG4 (normalized to total tissue IgG4). The comparison for wheat is significant (P = 0.04), and there is a trend for egg (P = 0.08). CFSE, carboxyfluorescein succinimidyl ester.

Figure 3.

Outcomes before and after dietary elimination: (a) peak eosinophil counts; (b) total EREFS; and (c) EEsAI score. EEsAI, Eosinophilic Esophagitis Symptom Activity Index; EREFS, Eosinophilic Esophagitis Endoscopic Reference Score.