Distinguishing gastroesophageal reflux disease and eosinophilic esophagitis in adults: The role of esophageal mucosal immunoglobulin G4

Biomarkers for a less invasive strategy to predict children with eosinophilic esophagitis

BACKGROUND

Noninvasive biomarkers for diagnosing and monitoring eosinophilic esophagitis (EoE) are currently lacking. This study evaluates 20 biomarkers in serum and saliva, aiming to assess their diagnostic potential in pediatric EoE patients and healthy individuals.

METHODS

Blood and saliva from children undergoing upper endoscopy were analyzed for biomarkers, including absolute eosinophil count (AEC), eosinophil-derived neurotoxin (EDN), total and specific IgG4-antibodies (sIgG4), specific IgE-antibodies (sIgE) and 15-hydroxyeicosatetraenoic acid (15(S)-HETE). Some patients participated twice, forming a longitudinal cohort. The ability to use the biomarkers to predict the EoE diagnosis was evaluated.

RESULTS

Analysis from 105 children divided into active EoE, remission, and healthy, revealed elevated levels of serum biomarkers (AEC, EDN, 15(S)-HETE, sIgG4, and sIgE) in active EoE compared to healthy individuals. A combination of biomarkers (AEC, EDN, sIgE to egg white and wheat) and symptoms showed an AUC of 0.92 in distinguishing between the three groups. We further showed that optimal cutoff values for these biomarkers could discriminate between active EoE and healthy with a sensitivity of 88% and a specificity of 100% in distinguishing EoE (active and in remission) from healthy. Longitudinally, levels of EDN, sIgG4 to Bos d 4, Bos d 5, Bos d 8, gliadin, and birch, and sIgE to milk decreased in patients progressing from active EoE to remission (p <.05).

CONCLUSIONS

This study identified novel biomarkers associated with EoE and proposes a panel, together with symptoms, for effective discrimination between active EoE, EoE in remission, and healthy individuals. The findings may contribute to a less invasive diagnostic method and may be a potential surveillance tool for pediatric EoE patients.

Outcomes of Serum Food-Specific Immunoglobulin G 4 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 G 4 (FS-IgG 4 ) rather than immunoglobulin E antibodies. This study aimed to evaluate the role of serum FS-IgG 4 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-IgG 4 titers, esophageal eosinophil counts, and dysphagia symptom questionnaire scores were assessed, and participants with elevated FS-IgG 4 (ImmunoCAP, cutoff of 10 mgA/L) commenced 6-week targeted elimination diet. Repeat serum FS-IgG 4 and endoscopic and histologic examination were performed at 6-week follow-up.

RESULTS

Twenty-two patients with active EoE and 13 controls were recruited. Serum FS-IgG 4 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-IgG 4 to 1 or more food groups (median 2) was identified in 21/22 (95.4%) patients with EoE; 20/21 underwent 6-week dietary elimination. Median reductions in dysphagia symptom questionnaire score and EoE endoscopic reference score after elimination were 8 ( P = 0.0007) and 1 ( P = 0.002), respectively. Nine (45%) patients 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-IgG 4 did not decline by 6-week follow-up.

DISCUSSION

Serum FS-IgG 4 to milk, wheat, soy, egg, and nuts was present at higher levels in EoE, with targeted elimination resulting in 45% histologic remission rate. Serum FS-IgG 4 has potential as a noninvasive biomarker in EoE. When successful, FS-IgG 4 -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.

Non-Invasive and Minimally Invasive Biomarkers for the Management of Eosinophilic Esophagitis beyond Peak Eosinophil Counts: Filling the Gap in Clinical Practice

Eosinophilic esophagitis (EoE) is a chronic esophageal disease that needs lifelong management and follow-up. The diagnosis requires an upper endoscopy with at least one esophageal biopsy demonstrating >15 eosinophils/high-power field, and often occurs with a diagnostic delay of up to ten years, partly due to the absence of valid non-invasive screening tools. In addition, serial upper endoscopies with esophageal biopsies are mandatory to assess the efficacy of any ongoing treatment in patients with EoE. These procedures are invasive, costly, and, when performed without sedation, are often poorly tolerated by patients. Therefore, there is the clinical need to identify reliable non-invasive or minimally invasive biomarkers that could be used to assess disease activity in clinical practice as a surrogate of peak eosinophil counts on esophageal biopsies. This review summarizes evidence on investigational non-invasive or minimally invasive biomarkers for the diagnosis and follow-up of EoE to report on the state of the art in the field and support future research. We discussed eosinophil-derived mediators including eosinophil cationic protein (ECP), eosinophil-derived neurotoxin (EDN, also known as eosinophil protein X), eosinophil peroxidase (EPO), and major basic protein (MBP) as well as other promising non-eosinophil-derived biomarkers. Although several studies have shown the utility of most biomarkers collected from the serum, esophageal luminal secretions, and feces of EoE patients, numerous limitations currently hamper the integration of such biomarkers in clinical practice. Future studies should aim at validating the utility of non-invasive and minimally invasive biomarkers using rigorous protocols and updated consensus criteria for EoE.

Food antigen consumption and disease activity affect food-specific IgG4 levels in patients with eosinophilic esophagitis (EoE)

INTRODUCTION

High levels of serum food-specific IgG4 (sIgG4) have been reported in patients with EoE. The objective of this study was to examine whether serum sIgG4 levels to foods and aeroallergens are higher in EoE patients than allergic controls and to investigate the association between sIgG4 and EoE clinical characteristics.

METHODS

This was a case-control study nested in a prospective EoE Cohort. EoE cases were defined per consensus guidelines, and controls were individuals with symptoms who were confirmed to be EoE-negative on upper endoscopy. Demographic and clinical information was prospectively collected. Serum IgE and sIgG4 were measured to foods and aeroallergens by ImmunoCAP. Mean levels of sIgG4 were compared between cases and controls, and logistic regression models were used to examine predictors of elevated milk sIgG4 levels.

RESULTS

The analysis included 123 individuals (EoE n = 93, control n = 30) with a similar distribution of allergic disease between EoE patients and controls (86% vs. 93%; p = .30). EoE patients had significantly higher sIgG4 levels to all allergens evaluated, with the exception of birch (p = .24). Milk sIgG4 levels were independently associated with milk consumption (OR 4.95; p = .01) and the presence of sIgE to milk (OR 4.23; p = .008).

CONCLUSION

Serum sIgG4 levels to food and aeroallergen proteins were higher in patients with EoE than non-EoE controls, and higher levels of milk sIgG4 were independently associated with milk consumption and the presence of sIgE to milk proteins. Whether sIgG4 plays a pathogenic role in EoE or could be used as an EoE biomarker remains unknown and warrants further study.

IgG4+ cells are increased in the gastrointestinal tissue of pediatric patients with active eosinophilic gastritis and duodenitis and decrease in remission

BACKGROUND

Recent studies have shown that IgG4 is increased in the esophageal tissue of eosinophilic esophagitis patients, including the presence of IgG4+ plasma cells.

AIMS

Our aim was to determine whether IgG4 is elevated in the gastric or duodenal tissue of pediatric patients with eosinophilic gastritis or duodenitis (EoG or EoD).

METHODS

This was a retrospective single center study. Pediatric patients were characterized as having active EoG, EoD, or as controls based on clinical symptoms and histologic features. Immunohistochemistry for IgG4 was performed in gastric and duodenal tissue, and peak IgG4+ cells were compared between groups and after treatment.

RESULTS

The frequency of IgG4+ cells was significantly higher in patients with EoG and EoD compared to controls in the stomach [EoG 6.5 cells/hpf (3.6-10.9), control 0 cells/hpf (0-0.7), p<0.0001] and duodenum [EoD 7.5 cells/hpf (2.8-37), control 0.5 cells/hpf (0.3-1.3), p<0.001)] respectively, and positively correlated with eosinophil counts (stomach: r 0.74, p<0.0001; duodenum: r 0.57, p<0.0001). The amount of tissue IgG4 was significantly decreased in patients in remission but not in persistently active disease.

CONCLUSIONS

These data suggest local tissue production of IgG4 may be a universal feature of eosinophilic gastrointestinal disease that tracks with disease activity.

Gastrointestinal IgG4 Deposition Is a New Histopathological Feature of Eosinophilic Gastroenteritis

BACKGROUND

The pathogenesis of eosinophilic esophagitis involves immunoglobulin G4 (IgG4) deposition. However, the relationship between IgG4 and eosinophilic gastroenteritis (EGE) is unclear.

AIMS

To investigate gastrointestinal deposition of IgG4 in EGE.

METHODS

Biopsies of the esophagus, stomach, and small intestine were evaluated in patients with and without EGE. Immunohistochemical staining for IgG4 was performed, and the proportions of the stained areas were compared. Sera from patients with EGE were assayed for food-specific IgG4, including egg white, wheat, rice, soy, and cow milk.

RESULTS

Seventeen patients were included in this study (EGE group, n = 10; control group, n = 7). Compared with the control group, the proportion of IgG4-stained area in the EGE group was approximately threefold higher (40.2% [32.3-49.5]) vs. 12.1% [4.0-21.9], p = 0.014) in the esophagus, fivefold higher in the stomach (17.3% [11.1-26.2] vs. 3.7% [1.5-5.2], p = 0.014), and sixfold higher in the small intestine (28.0% [15.0-33.2] vs. 4.5% [2.6-9.8], p = 0.019). There was no significant association between the proportion of IgG4-stained area and the number of infiltrating eosinophils. Serum egg white-specific IgG4 levels were correlated with the proportion of IgG4-stained areas in the small intestine (R = 0.7, p = 0.035).

CONCLUSIONS

IgG4 accumulated within the gastrointestinal mucosa in EGE. The positive correlation between serum egg white-specific IgG4 levels and the proportion of IgG4-stained areas in the small intestine suggests a role for IgG4 in the disease pathophysiology.

Eosinophilic Esophagitis and IgG4: Is There a Relationship?

Our knowledge of the pathophysiology of eosinophilic esophagitis is constantly evolving. There is significant association between eosinophilic esophagitis and atopy; however, multiple studies have refuted the role of IgE in its pathogenesis. Instead, new data have demonstrated an elevated IgG4 level in patients with eosinophilic esophagitis. We review the current understanding of eosinophilic esophagitis pathogenesis and highlight the increasing evidence for the role of IgG4.