Benralizumab versus Mepolizumab for Eosinophilic Granulomatosis with Polyangiitis.

BACKGROUND: Eosinophilic granulomatosis with polyangiitis (EGPA) is a vasculitis characterized by eosinophilic inflammation. Benralizumab, a monoclonal antibody against the interleukin-5α receptor expressed on eosinophils, may be an option for treating EGPA. METHODS: We conducted a multicenter, double-blind, phase 3, randomized, active-controlled noninferiority trial to evaluate the efficacy and safety of benralizumab as compared with mepolizumab. Adults with relapsing or refractory EGPA who were receiving standard care were randomly assigned in a 1:1 ratio to receive benralizumab (30 mg) or mepolizumab (300 mg) subcutaneously every 4 weeks for 52 weeks. The primary end point was remission at weeks 36 and 48 (prespecified noninferiority margin, -25 percentage points). Secondary end points included the accrued duration of remission, time to first relapse, oral glucocorticoid use, eosinophil count, and safety. RESULTS: A total of 140 patients underwent randomization (70 assigned to each group). The adjusted percentage of patients with remission at weeks 36 and 48 was 59% in the benralizumab group and 56% in the mepolizumab group (difference, 3 percentage points; 95% confidence interval [CI], -13 to 18; P = 0.73 for superiority), showing noninferiority but not superiority of benralizumab to mepolizumab. The accrued duration of remission and the time to first relapse were similar in the two groups. Complete withdrawal of oral glucocorticoids during weeks 48 through 52 was achieved in 41% of the patients who received benralizumab and 26% of those who received mepolizumab. The mean (±SD) blood eosinophil count at baseline was 306.0±225.0 per microliter in the benralizumab group and 384.9±563.6 per microliter in the mepolizumab group, decreasing to 32.4±40.8 and 71.8±54.4 per microliter, respectively, at week 52. Adverse events were reported in 90% of the patients in the benralizumab group and 96% of those in the mepolizumab group; serious adverse events were reported in 6% and 13%, respectively. CONCLUSIONS: Benralizumab was noninferior to mepolizumab for the induction of remission in patients with relapsing or refractory EGPA. (Funded by AstraZeneca; MANDARA ClinicalTrials.gov number, NCT04157348.).

Body mass index affects the association between plasma lipids and peripheral eosinophils in a general chinese population: a cross-sectional survey.

BACKGROUND: Lipid metabolism affects type 2 immunity; however, the association between plasma lipids and eosinophilic inflammation in humans is uncertain. This study analysed the relationship between plasma lipids and peripheral eosinophils and whether patterns differ with different body mass indexes (BMI). METHODS: A cross-sectional survey including 62,441 healthy participants recruited from a regular health screening programme was conducted. Participants were divided into normal weight, overweight and obese subgroups according to BMI. RESULTS: Multiple linear regression analysis revealed that elevated logarithmic-transformed eosinophil counts (log(EOS)) significantly correlated with high total cholesterol(TC), triglyceride(TG), low-density lipoprotein-cholesterol (LDL-C), and low high-density lipoprotein-cholesterol (HDL-C)levels in the overall population, as well as in men and women, while certain associations between peripheral blood eosinophil percentage and serum lipids varied by gender. These correlations existed across almost all BMI subgroups, and standardised ß values decreased sequentially with increasing BMI. HDL-C had the most significant effect on eosinophils in obese women. Two-factor analysis of variance showed log(EOS) increased with higher BMI and hyperlipidemia whether in male or female and a synergistic effect exists of lipid levels (TG and LDL-C) and BMI in men. CONCLUSIONS: Blood eosinophil counts were correlated with blood lipid levels and modified by body mass index status. The effects of lipid levels and body mass index on blood eosinophil counts were synergistic. Therefore, lipid metabolism may be involved in systemic eosinophil inflammation.

Neuromedin U programs eosinophils to promote mucosal immunity of the small intestine.

Eosinophils are granulocytes that play an essential role in type 2 immunity and regulate multiple homeostatic processes in the small intestine (SI). However, the signals that regulate eosinophil activity in the SI at steady state remain poorly understood. Through transcriptome profiling of eosinophils from various mouse tissues, we found that a subset of SI eosinophils expressed neuromedin U (NMU) receptor 1 (NMUR1). Fate-mapping analyses showed that NMUR1 expression in SI eosinophils was programmed by the local microenvironment and further enhanced by inflammation. Genetic perturbation and eosinophil-organoid coculture experiments revealed that NMU-mediated eosinophil activation promotes goblet cell differentiation. Thus, NMU regulates epithelial cell differentiation and barrier immunity by stimulating NMUR1-expressing eosinophils in the SI, which highlights the importance of neuroimmune-epithelial cross-talk in maintaining tissue homeostasis.

Dupilumab for COPD with Type 2 Inflammation Indicated by Eosinophil Counts.

BACKGROUND: In some patients with chronic obstructive pulmonary disease (COPD), type 2 inflammation may increase exacerbation risk and may be indicated by elevated blood eosinophil counts. Dupilumab, a fully human monoclonal antibody, blocks the shared receptor component for interleukin-4 and interleukin-13, key drivers of type 2 inflammation. METHODS: In a phase 3, double-blind, randomized trial, we assigned patients with COPD who had a blood eosinophil count of at least 300 per microliter and an elevated exacerbation risk despite the use of standard triple therapy to receive dupilumab (300 mg) or placebo subcutaneously once every 2 weeks. The primary end point was the annualized rate of moderate or severe exacerbations of COPD. Key secondary and other end points that were corrected for multiplicity were the change in the prebronchodilator forced expiratory volume in 1 second (FEV1) and in the scores on the St. George's Respiratory Questionnaire (SGRQ; range, 0 to 100, with lower scores indicating a better quality of life) and the Evaluating Respiratory Symptoms in COPD (E-RS-COPD; range, 0 to 40, with lower scores indicating less severe symptoms). RESULTS: A total of 939 patients underwent randomization: 468 to the dupilumab group and 471 to the placebo group. The annualized rate of moderate or severe exacerbations was 0.78 (95% confidence interval [CI], 0.64 to 0.93) with dupilumab and 1.10 (95% CI, 0.93 to 1.30) with placebo (rate ratio, 0.70; 95% CI, 0.58 to 0.86; P<0.001). The prebronchodilator FEV1 increased from baseline to week 12 by a least-squares (LS) mean of 160 ml (95% CI, 126 to 195) with dupilumab and 77 ml (95% CI, 42 to 112) with placebo (LS mean difference, 83 ml; 95% CI, 42 to 125; P<0.001), a difference that was sustained through week 52. At week 52, the SGRQ score had improved by an LS mean of -9.7 (95% CI, -11.3 to -8.1) with dupilumab and -6.4 (95% CI, -8.0 to -4.8) with placebo (LS mean difference, -3.4; 95% CI, -5.5 to -1.3; P = 0.002). The E-RS-COPD score at week 52 had improved by an LS mean of -2.7 (95% CI, -3.2 to -2.2) with dupilumab and -1.6 (95% CI, -2.1 to -1.1) with placebo (LS mean difference, -1.1; 95% CI, -1.8 to -0.4; P = 0.001). The numbers of patients with adverse events that led to discontinuation of dupilumab or placebo, serious adverse events, and adverse events that led to death were balanced in the two groups. CONCLUSIONS: Among patients with COPD who had type 2 inflammation as indicated by elevated blood eosinophil counts, those who received dupilumab had fewer exacerbations, better lung function and quality of life, and less severe respiratory symptoms than those who received placebo. (Funded by Sanofi and Regeneron Pharmaceuticals; BOREAS ClinicalTrials.gov number, NCT03930732.).

Exposure to violence and asthma in Puerto Rican youth with high Th2 immunity.

BACKGROUND: Little is known about the determinants of asthma among youth with high T helper 2 (Th2) immunity. We hypothesized that exposure to violence (ETV) and violence-related distress are associated with asthma in children and adolescents with high Th2 immunity. METHODS: We analyzed data from Puerto Ricans with high Th2 immunity aged 9-20 years in the Puerto Rico Genetics of Asthma and Lifestyle (PR-GOAL) and the Epigenetic Variation of Childhood Asthma in Puerto Ricans (EVA-PR) studies, and in a prospective study (PROPRA). High Th2-immunity was defined as ≥1 positive allergen-specific IgE and/or a total IgE ≥ 100 IU/mL and/or an eosinophil count ≥ 150 cells/µL. Asthma was defined as physician-diagnosed asthma and current wheeze. ETV and violence-related distress were assessed with the validated ETV Scale and Checklist of Children's Distress Symptoms (CCDS) questionnaires, respectively. RESULTS: In multivariable analyses, each 1-point increment in ETV score was significantly associated with 1.13-1.17 times increased odds of asthma in PR-GOAL and in EVA-PR (both at p ≤ 0.01), and each 1-point increment in CCDS score was significantly associated with 1.53-1.54 increased odds of asthma in PR-GOAL and in EVA-PR (both at p ≤ 0.03). Further, a persistently high ETV score was significantly associated with asthma in PROPRA (odds ratio [OR] = 2.83, 95% confidence interval [CI] = 1.10-7.29). Similar results were obtained in a sensitivity analysis using an eosinophil count ≥ 300 cells/µL instead of ≥150 cells/µL to define high Th2 immunity. CONCLUSIONS: ETV during childhood is associated with increased risk of persistent or new-onset asthma in youth with high Th2 immunity.

Group 2 Innate Lymphoid Cells Protect Mice from Abdominal Aortic Aneurysm Formation via IL5 and Eosinophils.

Development of abdominal aortic aneurysms (AAA) enhances lesion group-2 innate lymphoid cell (ILC2) accumulation and blood IL5. ILC2 deficiency in Rorafl/fl Il7rCre/+ mice or induced ILC2 depletion in Icosfl-DTR-fl/+ Cd4Cre/+ mice expedites AAA growth, increases lesion inflammation, but leads to systemic IL5 and eosinophil (EOS) deficiency. Mechanistic studies show that ILC2 protect mice from AAA formation via IL5 and EOS. IL5 or ILC2 from wild-type (WT) mice, but not ILC2 from Il5-/- mice induces EOS differentiation in bone-marrow cells from Rorafl/fl Il7rCre/+ mice. IL5, IL13, and EOS or ILC2 from WT mice, but not ILC2 from Il5-/- and Il13-/- mice block SMC apoptosis and promote SMC proliferation. EOS but not ILC2 from WT or Il5-/- mice block endothelial cell (EC) adhesion molecule expression, angiogenesis, dendritic cell differentiation, and Ly6Chi monocyte polarization. Reconstitution of WT EOS and ILC2 but not Il5-/- ILC2 slows AAA growth in Rorafl/fl Il7rCre/+ mice by increasing systemic EOS. Besides regulating SMC pathobiology, ILC2 play an indirect role in AAA protection via the IL5 and EOS mechanism.

Active eosinophils regulate host defence and immune responses in colitis.

In the past decade, single-cell transcriptomics has helped to uncover new cell types and states and led to the construction of a cellular compendium of health and disease. Despite this progress, some difficult-to-sequence cells remain absent from tissue atlases. Eosinophils-elusive granulocytes that are implicated in a plethora of human pathologies1-5-are among these uncharted cell types. The heterogeneity of eosinophils and the gene programs that underpin their pleiotropic functions remain poorly understood. Here we provide a comprehensive single-cell transcriptomic profiling of mouse eosinophils. We identify an active and a basal population of intestinal eosinophils, which differ in their transcriptome, surface proteome and spatial localization. By means of a genome-wide CRISPR inhibition screen and functional assays, we reveal a mechanism by which interleukin-33 (IL-33) and interferon-γ (IFNγ) induce the accumulation of active eosinophils in the inflamed colon. Active eosinophils are endowed with bactericidal and T cell regulatory activity, and express the co-stimulatory molecules CD80 and PD-L1. Notably, active eosinophils are enriched in the lamina propria of a small cohort of patients with inflammatory bowel disease, and are closely associated with CD4+ T cells. Our findings provide insights into the biology of eosinophils and highlight the crucial contribution of this cell type to intestinal homeostasis, immune regulation and host defence. Furthermore, we lay a framework for the characterization of eosinophils in human gastrointestinal diseases.

A different starting line for allergic march: food protein-induced allergic proctocolitis

Objective: The aim of this study is to investigate the long-term prognosis of food protein--induced allergic proctocolitis (FPIAP) patients, the risk of developing both allergic and gastrointestinal diseases, and to evaluate whether it leads to allergic march. Methods: A total of 149 children who were diagnosed with FPIAP and developed tolerance at least 5 years prior to the study and 41 children (with no history of food allergy) as a control group were enrolled. Both groups were re-evaluated for allergic diseases as well as gastrointestinal disorders. Results: The mean age of diagnosis for the FPIAP group was 4.2 ± 3.0 months, while the mean age of tolerance was 13.9 ± 7.7 months. The mean age of both FPIAP and control groups at the last visit was 101.6 ± 24.4 and 96.3 ± 24.1 months, respectively (P = 0.213). At the final evaluation of both groups, the comorbid allergic disease was significantly higher in the FPIAP group (P < 0.001). There was no significant difference between the two groups in terms of functional gastrointestinal disorders (FGIDs), eosinophilic gastrointestinal diseases, and inflammatory bowel disease (P = 0.198, 0.579, and 0.579, respectively). In the FPIAP group, the allergic disease was significantly higher at the final visit in patients with comorbid allergic disease at diagnosis (P < 0.001). In the FPIAP group, FGID was significantly higher in the group that developed allergic diseases in the future, compared to the group that did not develop allergic diseases in the future (P = 0.034). The proportion of both FGID and allergic diseases was significantly higher in subjects that developed tolerance at >18 months, compared to subjects that developed tolerance at >18 months (P < 0.001 and <0.001, respectively). Conclusions: Patients with FPIAP may develop allergic diseases as well as FGID in the long term (AU)

Inulin fibre promotes microbiota-derived bile acids and type 2 inflammation.

Dietary fibres can exert beneficial anti-inflammatory effects through microbially fermented short-chain fatty acid metabolites^1,2, although the immunoregulatory roles of most fibre diets and their microbiota-derived metabolites remain poorly defined. Here, using microbial sequencing and untargeted metabolomics, we show that a diet of inulin fibre alters the composition of the mouse microbiota and the levels of microbiota-derived metabolites, notably bile acids. This metabolomic shift is associated with type 2 inflammation in the intestine and lungs, characterized by IL-33 production, activation of group 2 innate lymphoid cells and eosinophilia. Delivery of cholic acid mimics inulin-induced type 2 inflammation, whereas deletion of the bile acid receptor farnesoid X receptor diminishes the effects of inulin. The effects of inulin are microbiota dependent and were reproduced in mice colonized with human-derived microbiota. Furthermore, genetic deletion of a bile-acid-metabolizing enzyme in one bacterial species abolishes the ability of inulin to trigger type 2 inflammation. Finally, we demonstrate that inulin enhances allergen- and helminth-induced type 2 inflammation. Taken together, these data reveal that dietary inulin fibre triggers microbiota-derived cholic acid and type 2 inflammation at barrier surfaces with implications for understanding the pathophysiology of allergic inflammation, tissue protection and host defence.

Alt a 1 Promotes Allergic Asthma In Vivo Through TLR4-Alveolar Macrophages.

The mold Alternaria alternata is one of the main sources of asthma exacerbation, being its major allergen, Alt a 1, indispensable for its development. The main objective of this work was to answer two main questions: 1) can Alt a 1 by itself (without any other context) induce an asthmatic profile in vivo?; and 2) Which molecular mechanisms take place during this phenomenon? To answer both questions, we have developed a mouse model of allergic asthma using only Alt a 1 for mice sensitization. We also made use of in-vitro cellular models and computational studies to support some aspects of our hypothesis. Our results showed that Alt a 1 can induce an asthmatic phenotype, promoting tissue remodeling and infiltration of CD45+ cells, especially eosinophils and macrophages (Siglec F+ and F4/80+). Also, we have found that Alt a 1 sensitization is mediated by the TLR4-macrophage axis.

Neuromedin U promotes human type 2 immune responses.

Type 2 immunity mediates the immune responses against parasites and allergic stimuli. Evidence from studies of cell lines and animals implies that neuromedin U (NmU) acts as a pro-inflammatory mediator of type 2 inflammation. However, the role of NmU in human type 2 immunity remains unclear. Here we investigated the expression of NmU in human blood and airways, and the expression of NmU receptors by human immune cells in blood and lung tissue. We detected human NmU (hNmU-25) in blood and airways with higher concentrations in the latter. NmU receptor 1 (NmUR1) was expressed by most human immune cells with higher levels in type 2 cells including type 2 T helpers, type 2 cytotoxic T cells, group-2 innate lymphoid cells and eosinophils, and was upregulated in lung-resident and activated type 2 cells. We also assessed the effects of NmU in these cells. hNmU-25 elicited type 2 cytokine production by type 2 lymphocytes and induced cell migration, including eosinophils. hNmU-25 also enhanced the type 2 immune response to other stimuli, particularly prostaglandin D2. These results indicate that NmU could contribute to the pathogenic processes of type 2 immunity-mediated diseases in humans via its pro-inflammatory effects on type 2 lymphocytes and eosinophils.

The regulatory role of eosinophils in viral, bacterial, and fungal infections.

Eosinophils are innate immune cells typically associated with allergic and parasitic diseases. However, in recent years, eosinophils have also been ascribed a role in keeping homeostasis and in fighting several infectious diseases. Indeed, these cells circulate as mature cells in the blood and can be quickly recruited to the infected tissue. Moreover, eosinophils have all the necessary cellular equipment such as pattern recognition receptors (PRRs), pro-inflammatory cytokines, anti-bacterial proteins, and DNA traps to fight pathogens and promote an efficient immune response. This review summarizes some of the updated information on the role of eosinophils' direct and indirect mediated interactions with pathogens.

Eosinophils are an essential element of a type 2 immune axis that controls thymus regeneration.

Therapeutic interventions used for cancer treatment provoke thymus damage and limit the recovery of protective immunity. Here, we show that eosinophils are an essential part of an intrathymic type 2 immune network that enables thymus recovery after ablative therapy. Within hours of damage, the thymus undergoes CCR3-dependent colonization by peripheral eosinophils, which reestablishes the epithelial microenvironments that control thymopoiesis. Eosinophil regulation of thymus regeneration occurs via the concerted action of NKT cells that trigger CCL11 production via IL4 receptor signaling in thymic stroma, and ILC2 that represent an intrathymic source of IL5, a cytokine that therapeutically boosts thymus regeneration after damage. Collectively, our findings identify an intrathymic network composed of multiple innate immune cells that restores thymus function during reestablishment of the adaptive immune system.

RSV Infection in Neonatal Mice Induces Pulmonary Eosinophilia Responsible for Asthmatic Reaction.

Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infections in infants and young children. Severe respiratory viral infection in early life is intimately associated with childhood recurrent wheezing and is a risk factor for asthma later in life. Although eosinophilic airway inflammation is an important trait in asthma of children, the roles of pulmonary eosinophils in the disease have been inadequately understood. Here, we show that RSV infection in neonatal mice causes eosinophilia after allergen stimulation. We showed that RSV infection in neonatal mice exacerbated allergic asthma to allergen stimulation that was accompanied with increased detection of eosinophils in the lungs. In addition, we also detected accumulation of ILC2, CD4+ T cells, and macrophages. Importantly, adoptive transfer of eosinophils from asthmatic mice with early-life RSV infection exacerbated pulmonary pathologies associated with allergic respiratory inflammation in naive mice in response to foreign antigen. The induction of asthmatic symptoms including AHR, tracheal wall thickening, and mucus production became more severe after further stimulation in those mice. The expression of antigen presentation-related molecules like CD80, CD86, and especially MHC II was markedly induced in eosinophils from OVA-stimulated asthmatic mice. The accumulation of CD4+ T cells in the lungs was also significantly increased as a result of adoptive transfer of eosinophils. Importantly, the deterioration of lung pathology caused by adoptive transfer could be effectively attenuated by treatment with indomethacin, a nonsteroidal anti-inflammatory drug. Our findings highlight the significance of eosinophil-mediated proinflammatory response in allergic disease associated with early-life infection of the respiratory tract.

Blocking the human common beta subunit of the GM-CSF, IL-5 and IL-3 receptors markedly reduces hyperinflammation in ARDS models.

Acute respiratory distress syndrome (ARDS) is triggered by various aetiological factors such as trauma, sepsis and respiratory viruses including SARS-CoV-2 and influenza A virus. Immune profiling of severe COVID-19 patients has identified a complex pattern of cytokines including granulocyte macrophage-colony stimulating factor (GM-CSF) and interleukin (IL)-5, which are significant mediators of viral-induced hyperinflammation. This strong response has prompted the development of therapies that block GM-CSF and other cytokines individually to limit inflammation related pathology. The common cytokine binding site of the human common beta (ßc) receptor signals for three inflammatory cytokines: GM-CSF, IL-5 and IL-3. In this study, ßc was targeted with the monoclonal antibody (mAb) CSL311 in engineered mice devoid of mouse ßc and ßIL-3 and expressing human ßc (hßcTg mice). Direct pulmonary administration of lipopolysaccharide (LPS) caused ARDS-like lung injury, and CSL311 markedly reduced lung inflammation and oedema, resulting in improved oxygen saturation levels in hßcTg mice. In a separate model, influenza (HKx31) lung infection caused viral pneumonia associated with a large influx of myeloid cells into the lungs of hßcTg mice. The therapeutic application of CSL311 potently decreased accumulation of monocytes/macrophages, neutrophils, and eosinophils without altering lung viral loads. Furthermore, CSL311 treatment did not limit the viral-induced expansion of NK and NKT cells, or the tissue expression of type I/II/III interferons needed for efficient viral clearance. Simultaneously blocking GM-CSF, IL-5 and IL-3 signalling with CSL311 may represent an improved and clinically applicable strategy to reducing hyperinflammation in the ARDS setting.

CCR3 gene knockout in bone marrow cells ameliorates combined allergic rhinitis and asthma syndrome (CARAS) by reducing airway inflammatory cell infiltration and Th2 cytokines expression in mice model.

The present study aims to investigate the effects of CCR3 gene knockout in bone marrow cells (CCR3-KO) on the mouse model of combined allergic rhinitis and asthma syndrome (CARAS). It was found that CCR3-KO significantly reduced eosinophil (EOS) migration into the nasal (NALF) and bronchoalveolar (BALF) cavities of mice, and decreased Th2 cytokines (such as, IL-4, IL-5 and IL-13) levels in nasal mucosa and lung tissues. In addition, histological analysis showed that the damage degree of nasal mucosa structure in ovalbumin (OVA) modulated CCR3-KO mice was significantly less than that in OVA modulated Wild type (WT) mice, with reduced inflammatory cell infiltration and nasal mucus secretion. The infiltration of inflammatory cells in lung tissue was significantly reduced, and the proliferation of lung smooth muscle layer and extracellular matrix (ECM) production were decreased. Symptom analysis showed that CCR3-KO can reduced allergic rhinitis (AR) signals as nose scratching and sneezing. It was also found CCR3-KO reduce OVA-induced weight loss. The results showed that CCR3-KO could reduce the symptoms of allergic inflammation in CARAS mice by reducing airway inflammatory cell infiltration and down-regulating the expression of Th2 cytokines, and CCR3 gene could be used as a target gene for the treatment of CARAS.

Eosinophil counts can be a predictive marker of immune checkpoint inhibitor-induced secondary adrenal insufficiency: a retrospective cohort study.

Immune checkpoint inhibitors (ICIs) treatment can result in endocrine immune-related adverse events (irAEs), including pituitary dysfunction. Quick diagnosis of secondary adrenal insufficiency (AI) is challenging because no universal definition of ICI-induced secondary AI has been agreed. The aim of this study was to clarify the clinical features of ICI-induced secondary AI that can be used for screening in standard clinical practice. This retrospective study was performed using the medical records of patients who received ICIs at Hirosaki University Hospital between 1 September 2014 and 31 January 2021. Longitudinal clinical data of patients who developed AI were analyzed and compared with the data of thyroid irAEs. Regression analysis showed a significant correlation between ICI-induced secondary AI and absolute or relative eosinophil counts at pre-onset of AI, as well as differences or rate of increase in eosinophil counts at baseline and at pre-onset. Absolute eosinophil counts > 198.36/µL or relative eosinophil counts > 5.6% at pre-onset, and a difference of 65.25/µL or a rate of eosinophil count increase of 1.97 between the baseline and at pre-onset showed the best sensitivity and specificity. This is the first report to demonstrate that eosinophil counts can be a predictor of ICI-induced secondary AI.

Presence of Increased Mast Cells in Infants and Children with Volume and Variety Limited Intake.

BACKGROUND: Reports indicate patients with feeding difficulties demonstrate signs of inflammation on biopsies, notably eosinophilia, but it is unknown whether mast cell density contributes to variety or volume limitation symptoms. The aim of our study was to evaluate eosinophil and mast cell density of EGD biopsies in pediatric patients with symptoms of decreased volume or variety of ingested foods. METHODS: We conducted a single-center, retrospective chart review of EMRs for all new feeding clinic patients between 0 and 17 years of age. Patients were categorized by symptoms at the initial visit as well as eosinophil and mast cell densities in those with EGD biopsies. Ten patients were identified as controls. RESULTS: We identified 30 patients each with volume and variety limitation. Antral mast cell density was increased in 32.1% of variety-limited patients, 37.5% of volume limited patients, and in no controls; Duodenal mast cell density was increased in 32.1% of variety-limited patients, 40.6% of volume-limited patients, and in no controls. CONCLUSIONS: In both variety- and volume-limited patients, antral and duodenal mast cell densities were increased. These associations warrant further investigation of the mechanism between mast cells and development of feeding difficulties, allowing more targeted pediatric therapies.