Eosinophilic Esophagitis and IgG4: Is There a Relationship?

Advances and ongoing challenges in eosinophilic gastrointestinal disorders presented at the CEGIR/TIGERs Symposium at the 2024 American Academy of Allergy, Asthma & Immunology meeting

The Consortium of Eosinophilic Gastrointestinal disease Researchers (CEGIR) and The International Gastrointestinal Eosinophil Researchers (TIGERs) organized a daylong symposium at the 2024 annual meeting of the American Academy of Allergy, Asthma & Immunology. The symposium featured new discoveries in basic and translational research as well as debates on the mechanisms and management of eosinophilic gastrointestinal diseases. Updates on recent clinical trials and consensus guidelines were also presented. We summarize the updates on eosinophilic gastrointestinal diseases presented at the symposium.

A rare manifestation of IgG4-related disease and secondary hypereosinophilic syndrome: A case report

We report a case of IgG4-related disease (IgG4-RD) with marked eosinophilia. A 79-year-old woman was admitted due to diarrhoea and weight loss. Cervical lymphadenopathy, bilateral submandibular glands swelling, anaemia (Hb8.5 g/dl), hypereosinophilia (9750/μl), elevated serum creatinine (1.57 mg/dl), pancreatic amylase (191 IU/l), and IgG4 (3380 mg/dl) were found. Diffusion-weighted image on magnetic resonance imaging showed high-intensity signals inside both the pancreas and the kidneys. The echogram of submandibular glands revealed cobblestone pattern. Kidney biopsy revealed acute tubulointerstitial nephritis. Biopsies of lip, gastrointestinal tract, and bone marrow showed infiltration of lymphoplasmacytic cells and IgG4-positive plasma cells (30-67/HPF). Gastrointestinal and bone marrow biopsies also showed eosinophilic infiltration. Adrenal insufficiency, rheumatic disease, tuberculosis, parasite infection, drug-induced eosinophilia, and eosinophilic leukaemia were all ruled out. We started treatment with 40 mg of prednisolone (PSL) and her general condition rapidly improved. The eosinophil count, serum IgG4, and serum creatinine decreased. We gradually tapered PSL and maintained 5 mg/day. During the 5 years of treatment, she had no recurrence of the symptom. According to the 2019 American College of Rheumatology/European League Against Rheumatism classification criteria for IgG4-RD, eosinophils >3000/μl is one of the exclusion criteria. If we comply with this criterion, the diagnosis of IgG4-RD should be avoided. However, our case fit the diagnostic criteria of type I autoimmune pancreatitis, IgG4-related sialadenitis, and global diagnosis of IgG4-RD. We finally diagnosed our case as IgG4-RD with secondary hypereosinophilic syndrome. This case suggests that IgG4-RD with eosinophils >3000/μl does exist in the real world.

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.

Food-specific IgG4-guided diet elimination improves allergy symptoms in children

Allergic diseases in children are major public health concerns due to their widespread and rising prevalence. Food-specific immunoglobulin G4(FS-IgG4) has been detected in patients with allergic diseases, but its clinical significance is still debated. In the present study, 407 children with allergic diseases were recruited and categorized into three groups according to the different systems involved: the respiratory system group, the skin system group, and a multiple system group, with the collection of clinical symptoms and serum antibodies, including total immunoglobulin E (IgE), house dust mite (HDM) IgE, food-specific IgE (FS-IgE), and FS-IgG4. Part of these patients were followed up with the intervention of FS-IgG4-guided diet elimination with or without add-on probiotics supplement. The analysis at baseline revealed distinct serum levels of different antibodies. The positive rate of FS-IgG4 in all groups was more than 80%, and the proportion of total IgE and FS-IgG4 both positive in the multi-system group was the highest (p=0.039). Egg and milk were the foods with the highest positive rate of FS-IgG4 in all groups. After diet elimination for more than 3 months, serum FS-IgG4 in children significantly decreased (P<0.05) along with the improvement of clinical symptoms, regardless of the add-on of probiotics. However, the intervention did not impact the serum levels of total IgE, FS-IgE, and HDM IgE. There was no further decrease of serum FS-IgG4 level in children followed up for more than 1 year, which may be related to noncompliance with diet elimination. Multivariate regression analysis revealed that the decline of serum FS-IgG4 was an independent predictable factor for the improvement of clinical symptoms (adjusted OR:1.412,95%CI 1.017-1.96, p=0.039). The add-on of probiotics showed less efficiency in reducing the FS-IgG4 level in more patients with relief of clinical symptoms. Our results confirmed the correlation between FS-IgG4 and allergic diseases, and the decreased FS-IgG4 could be a useful predictor for the improvement of allergic symptoms. FS-IgG4-guided diet elimination is an efficient treatment for allergic diseases. Our study adds solid data to the clinical significance of FS-IgG4 in allergic diseases.

Oesophageal wall thickness assessment at endoscopic ultrasound in children and adolescents with eosinophilic oesophagitis: a case-control study

PURPOSE

Eosinophilic oesophagitis (EoE) is a chronic immune-mediated disease, and an endosonographic evaluation may help the diagnosis. The main objectives of this study were to measure the thickness of the oesophageal wall using a radial endoscopic ultrasound (EUS), mucosa/submucosa (MSM), muscularis propria (MP) and mucosa to muscularis propria (MMP); to compare these measurements between patients with and without EoE; to correlate them with the Endoscopic Reference Score (EREFS); and to evaluate the diagnostic accuracy of these measurements.

METHODS

Children and adolescents (aging from 4 to 17 years) were evaluated in this prospective cross-sectional study. A radial EUS at 12 MHz frequency was used, and EREFS was employed to grade macroscopic findings. Accuracy of the measurements for the diagnosis of EoE was assessed by receiver operating characteristics (ROC) curve.

RESULTS

Twenty-six (19 M/7 F) patients (median age 10.83 years, range 5.65-17.46) were evaluated. EoE was diagnosed in 6 patients. The mean (and SD) oesophageal wall thicknesses in the distal oesophagus in millimetres in groups with and without EoE, respectively, were: MSM 1.07 (0.44) and 1.11 (0.33); MP 0.67 (0.25) and 0.60 (0.19); and MMP 1.73 (0.46) and 1.72 (0.32). Mid-oesophagus: MSM 1.16 (0.34) and 1.15 (0.34); MP 0.63 (0.16) and 0.60 (0.2); and MMP 1.79 (0.41) and 1.74 (0.34). In the ROC curve, the distal MP layer thickness presented better discriminative performance, with an area under the curve of 0.61 (95% CI 0.28-0.93) at 0.73 mm cut-off (66.67% sensitivity, 80% specificity, likelihood ratios of 3.33 for positive and 0.42 for negative test).

CONCLUSION

The evaluation of oesophageal thickness measurements by EUS is not useful for diagnosing EoE.

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.

Eosinophilic Esophagitis-What Do We Know So Far?

Eosinophilic esophagitis is a Th-2 antigen-mediated disease in which there is an influx of eosinophils to all layers of the esophagus, triggering an inflammatory response. Chronic inflammatory process causes esophageal remodeling, leading to difficulties in swallowing. Food impaction, heartburn, and chest pain are other characteristic (but not pathognomonic) symptoms in adults. Although the disease has only been described since in the early 1970s, its incidence and prevalence are rapidly growing, especially in Western countries. According to the diagnostic guidelines, there should be at least 15 eosinophils visible per high-power field in biopsies obtained from different sites in the esophagus upon endoscopy with relevant esophageal symptoms. Other diseases that can cause esophageal eosinophilia should be ruled out. Eosinophilic esophagitis treatment may be challenging; however, new methods of management have recently emerged. The currently used proton pump inhibitors, topical corticosteroids, and elimination diet are combined with biological treatment. New methods for disease diagnostics and clinical course assessment are also available. This review presents current knowledge about the disease, supported by the latest research data.

Roles of IgG4 and IgG4/IgG ratio to IgG4-related disease in patients with elevated serum IgG4 level

OBJECTIVE

To evaluate the performance of elevated serum IgG4 and IgG4/IgG in IgG4-related disease (IgG4-RD) and other diseases.

METHODS

Seven hundred seventy-three patients with elevated serum IgG4 level (> 2.01 g/L) were reviewed in Zhongda Hospital of Southeast University from 1 July 2016 to 31 December 2021. Demographic, disease distribution and the role of elevated serum IgG4 and IgG4/IgG in IgG4-RD and other diseases were analysed. The alteration of IgG4 and IgG4/IgG in pre-therapy and post-treatment were also assessed in IgG4-RD.

RESULTS

Patients with elevated serum IgG4 were principally observed in older males. Chronic diseases of various organs (21.7%), rheumatic immune diseases (19.4%), bacterial infection disease (11.5%) and malignant tumor (5.2%) were the common diseases with elevated serum IgG4, but only 3.2% was IgG4-RD. The level of IgG4 and IgG4/IgG in IgG4-RD was significantly higher than that in various diseases except for eosinophilia group. Serum IgG4 and IgG4/IgG manifested a similar diagnostic capacity for IgG4-RD among this study cohort and the optimal cut-off values were 3.345 g/L and 0.295 respectively. The sensitivity and specificity were 96% and 71% for the optimal cut-off value of IgG4, and 80% and 88.8% for the optimal cut-off value of IgG4/IgG4. IgG4 and IgG4/IgG both were remarkably reduced in IgG4-RD after therapy compared with prior treatment (P < 0.05).

CONCLUSIONS

Elevated serum IgG4 was found in a variety of diseases, especially in chronic diseases of various organs. IgG4 and IgG4/IgG manifest a great value for IgG4-RD diagnosis, and are available for the treatment evaluation of IgG4-RD. Key Points • Elevated serum IgG4 level was not a specific marker to IgG4-related disease and can be observed in various diseases. • Patients with IgG4-related disease or eosinophilia manifest a higher level of serum IgG4 and IgG4/IgG. • Both of IgG4 and IgG4/IgG are available for the diagnosis and the clinical treatment evaluation of IgG4-related disease.

Allergy-Test-Based Elimination Diets for the Treatment of Eosinophilic Esophagitis: A Systematic Review of Their Efficacy

Eosinophilic esophagitis (EoE) is an immune-mediated esophageal disorder, linked with sensitization to food and airborne allergens. Dietary manipulations are proposed for the management of EoE inflammation and are often successful, confirming the etiological role of food allergens. Three different dietary approaches are widely used: the elemental, the empirical, and the allergy-test-driven approach. We performed a systematic review to assess the evidence on the association of allergens, detected by allergy tests, with clinically confirmed triggers of EoE. We systematically searched PubMed, Scopus, Embase, and the Cochrane Library, through 1 June 2021. We sought studies examining the correlation of skin-prick tests (SPT), atopy patch tests (APT), specific IgE, and serum-specific IgG4, with confirmed triggers of EoE. Data on the use of prick–prick tests were also extracted. Evidence was independently screened by two authors against predefined eligibility criteria. Risk of bias was assessed with the ROBINS-I tool. Of 52 potentially eligible studies, 16 studies fulfilling quality criteria were included. These studies used one to three different allergy tests detecting food sensitization. The positive predictive value was generally low to moderate but higher when a combination of tests was used than single-test evaluations. None of the selected studies used serum-specific IgG4. Although an extreme methodological variability was noticed in the studies, allergy-based elimination diets were estimated to be efficient in 66.7% of the cases. The efficacy of targeted elimination diets, guided by SPT, sIgE, and/or APT allergy tests, does not appear superior to empirical ones. In the future, tests using esophageal prick testing or ex vivo food antigen stimulation may prove more efficient to guide elimination diets.

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.

Current Guidelines and Future Strategies for the Management of Cow's Milk Allergy

ABSTRACT

Exclusive breast feeding is recommended in all guidelines as the first choice feeding. Cow milk allergy (CMA) can be diagnosed by a diagnostic elimination diet for 2 to 4 weeks with a hypo-allergenic formula, followed by a challenge test with intact cow milk protein. The most often used hypo-allergenic formula for the diagnostic elimination diet and the therapeutic diet is a CM based extensive hydrolysate. CM-based partial hydrolysates cannot be recommended in the management of CMA because of insufficient efficacy and possible reactions, but about half of the infants with CMA may tolerate a partial hydrolysate. The pros and cons of other dietary options are discussed in this paper. The use of an amino acid-based formula and/or rice based hydrolysate formula during the diagnostic elimination and therapeutic diet is debated. When available, there is sufficient evidence to consider rice hydrolysates as an adequate alternative to CM-based hydrolysates, since some infants will still react to the CM hydrolysate. The pros and cons of dietary options such as soy formula, buckwheat, almond, pea or other plant based dietary products are discussed. Although the majority of the plant-based beverages are nutritionally inadequate, some are nutritionally adapted for toddlers. However, accessibility and content vary by country and, thus far there is insufficient evidence on the efficacy and tolerance of these plant-based drinks (except for soy formula and rice hydrolysates) to provide an opinion on them.

CONCLUSION

A diagnostic elimination diet, followed by a challenge remains the diagnostic standard. The use of an awareness tool may result in a decrease of delayed diagnosis. Breastmilk remains the ideal source of nutrition and when not available a CM extensively hydrolyzed formula, rice hydrolysate or amino acid formula should be recommended. More evidence is needed regarding plant-based drinks.

A Systematic Review and Meta-Analysis of Immunoglobulin G Abnormalities and the Therapeutic Use of Intravenous Immunoglobulins (IVIG) in Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a neurodevelopmental disorder affecting approximately 2% of children in the United States. Growing evidence suggests that immune dysregulation is associated with ASD. One immunomodulatory treatment that has been studied in ASD is intravenous immunoglobulins (IVIG). This systematic review and meta-analysis examined the studies which assessed immunoglobulin G (IgG) concentrations and the therapeutic use of IVIG for individuals with ASD. Twelve studies that examined IgG levels suggested abnormalities in total IgG and IgG 4 subclass concentrations, with concentrations in these IgGs related to aberrant behavior and social impairments, respectively. Meta-analysis supported possible subsets of children with ASD with low total IgG and elevated IgG 4 subclass but also found significant variability among studies. A total of 27 publications reported treating individuals with ASD using IVIG, including four prospective, controlled studies (one was a double-blind, placebo-controlled study); six prospective, uncontrolled studies; 2 retrospective, controlled studies; and 15 retrospective, uncontrolled studies. In some studies, clinical improvements were observed in communication, irritability, hyperactivity, cognition, attention, social interaction, eye contact, echolalia, speech, response to commands, drowsiness, decreased activity and in some cases, the complete resolution of ASD symptoms. Several studies reported some loss of these improvements when IVIG was stopped. Meta-analysis combining the aberrant behavior checklist outcome from two studies demonstrated that IVIG treatment was significantly associated with improvements in total aberrant behavior and irritability (with large effect sizes), and hyperactivity and social withdrawal (with medium effect sizes). Several studies reported improvements in pro-inflammatory cytokines (including TNF-alpha). Six studies reported improvements in seizures with IVIG (including patients with refractory seizures), with one study reporting a worsening of seizures when IVIG was stopped. Other studies demonstrated improvements in recurrent infections, appetite, weight gain, neuropathy, dysautonomia, and gastrointestinal symptoms. Adverse events were generally limited but included headaches, vomiting, worsening behaviors, anxiety, fever, nausea, fatigue, and rash. Many studies were limited by the lack of standardized objective outcome measures. IVIG is a promising and potentially effective treatment for symptoms in individuals with ASD; further research is needed to provide solid evidence of efficacy and determine the subset of children with ASD who may best respond to this treatment as well as to investigate biomarkers which might help identify responsive candidates.