Mast Cells In Patients Research Articles

Multiple Aspects of Irritable Bowel Syndrome and the Role of the Immune System: An Overview of Systematic Reviews with a Focus on Polyphenols

Irritable bowel syndrome (IBS) is a complex and often debilitating condition that significantly impacts the gastrointestinal system and the overall quality of life of those affected. IBS is characterized by a variety of distressing symptoms, including cramping, abdominal pain, and irregular bowel movements, underlined by an intricate interplay of immune system dysfunction in its pathology. Numerous studies highlight an increased cellular immune response, with elevated levels of proinflammatory cytokines, mucosal alterations due to immune imbalance, and visceral hypersensitivity. Notably, studies indicate increased levels of proinflammatory cytokines, immune imbalances that lead to mucosal changes, and heightened visceral sensitivity. The roles of effector and regulatory T cells are particularly intriguing, as their modification appears to amplify inflammation and may even contribute to autoimmune disorders. This overview of systematic reviews explores the connections between IBS and immune responses, with a focus on immune cell alterations and proliferation of lymphocytes and mast cells in affected individuals. Furthermore, we explore various aspects of IBS management, including its pharmacological approaches. A systematic search of PubMed and Web of Science yielded 676 articles, which were ultimately narrowed down to 9 key studies that met our inclusion criteria. These studies collectively underscore the activation of the immune system with the degranulation of the mast cells in patients with IBS, where the release of inflammatory mediators can compromise intestinal permeability, exacerbating symptoms further. Additionally, we examine the multifaceted management strategies for IBS, emphasizing the potential therapeutic benefits of dietary polyphenols as antioxidants. The present study aims to enhance our understanding of IBS and offer insights into more effective treatment strategies for this challenging condition.

Characteristics and outcomes associated with CD2 and CD25 expression on bone marrow mast cells in patients with systemic mastocytosis.

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Residual Mast Cells Can Explain Persistent Molecular Positivity in Difference from Normal Flow Cytometric-Defined MRD Negative Core Binding Factor AML

Introduction: Core binding factor acute myeloid leukemia (CBF-AML) accounts for 30% of pediatric and 15% adult AMLs and is defined by fusions involving RUNX1 or CBFB. RT-PCR is commonly used to monitor measurable residual disease (MRD) in patients with CBF-AML. However, it has been reported that these fusions can be detected in patients during complete remission (CR) or after hematopoietic cell transplant (HCT). This raises the question of if these patients should be considered MRD positive, given they appear otherwise disease free. We utilized flow cytometric cell sorting and fluorescent in situ hybridization (FISH) to determine the source of persistent CBF fusions. Methods: Flow cytometry was used to isolate mast cells (CD117 bright/CD34 negative) from 13 patients with CBF-AML fusions (8 RUNX1:: RUNX1T1 and 5 CBFB:: MYH11) alongside progenitor cells (CD34+/CD117 heterogeneous, 12 patients) and T cells (CD3+, 11 patients) as available for FISH analysis. These patients were fusion positive by RT-PCR but had no evidence of MRD by difference from normal multidimensional flow cytometry (ΔN), the gold standard for determination of residual disease in Children's Oncology Group-sponsored clinical trials for AML. Cells were sorted from 6 additional patients with a history of RUNX1:: RUNX1T1 CBF-AML who were MRD negative by ΔN but without RT-PCR results available. Results: In 11/13 patients, the mast cell fraction was positive for the CBF fusion but all other sorted cell fractions tested were negative. In the remaining two specimens, all cell fractions were negative, likely due to FISH sensitivity compared to RT-PCR. Both CBF fusions exhibited the same pattern, with fusions detected only in the mast cell fractions (7 RUNX1:: RUNX1T1 and 4 CBFB:: MYH11). The additional 6 patients who were MRD negative by ΔN but without RT-PCR data followed the same pattern, with RUNX1:: RUNX1T1 detected by FISH in the mast cells (6/6 patients) and not in other sorted populations (5/6 patients sorted for progenitor and T cells). Two patients had a clinical history of CBF-AML and systemic mastocytosis (SM). ΔN revealed no evidence of residual AML but showed abnormal mast cells with expression of CD2 and CD25, consistent with abnormalities associated with SM. FISH analysis of sorted mast cells revealed the presence of the RUNX1:: RUNX1T1 fusion, while progenitor and T cells were both negative. In all other patients the mast cells showed no phenotypic abnormalities, demonstrating that CBF fusions can be detected in both phenotypically normal and abnormal mast cells in patients who are free of residual AML. Two patients with CBFB:: MYH11 fusions had specimens evaluated by FISH on sorted cells over a month apart where the fusion persisted only in the mast cells. Two patients with RUNX1:: RUNX1T1 fusions had serial specimens analyzed at 4 different timepoints. One patient had fusion positive mast cells for over 8 months after residual disease was last detected by ΔN. The other patient, who had previously undergone HCT, harbored fusion positive mast cells for 13 months. Both patients remained MRD negative by ΔN over the course of testing. Discussion: These data demonstrate that in CBF-AML, fusions can be detected exclusively in the mast cells of otherwise leukemia-free patients, resulting in positive RT-PCR results in the absence of any other disease pathology. These mast cells can be normal or abnormal and can persist after successful HCT. Given that these patients are free of disease by other measures, these fusion positive mast cells do not appear to contribute to AML pathogenesis. Additionally, this post-HCT fusion positive persistence demonstrates a potential clinical implication: if patients such as reported here are assessed pre-transplant using RT-PCR on unsorted specimens alone, they may not be considered candidates for HCT even though the fusion is confined to terminally differentiated cells and successful transplant can be achieved. For these reasons, while RT-PCR is a specific and accurate assay, caution is required for CBF-AML patients. Flow cytometry and cell sorting in combination with genetic testing, in this case FISH, protect against these mast cell driven positive results and provide an accurate assessment of disease status. These data highlight the importance of considering AML biology and combining multiple testing methods to monitor AML patients comprehensively and accurately.

Interactions between Siglec-8 and endogenous sialylated cis ligands restrain cell death induction in human eosinophils and mast cells.

Sialic acid-binding immunoglobulin-like lectin (Siglec)-8 is a sialoside-binding receptor expressed by eosinophils and mast cells that exhibits priming status- and cell type-dependent inhibitory activity. On eosinophils that have been primed with IL-5, GM-CSF, or IL-33, antibody ligation of Siglec-8 induces cell death through a pathway involving the β2 integrin-dependent generation of reactive oxygen species (ROS) via NADPH oxidase. In contrast, Siglec-8 engagement on mast cells inhibits cellular activation and mediator release but reportedly does not impact cell viability. The differences in responses between cytokine-primed and unprimed eosinophils, and between eosinophils and mast cells, to Siglec-8 ligation are not understood. We previously found that Siglec-8 binds to sialylated ligands present on the surface of the same cell (so-called cis ligands), preventing Siglec-8 ligand binding in trans. However, the functional relevance of these cis ligands has not been elucidated. We therefore explored the potential influence of cis ligands of Siglec-8 on both eosinophils and mast cells. De-sialylation using exogenous sialidase profoundly altered the consequences of Siglec-8 antibody engagement on both cell types, eliminating the need for cytokine priming of eosinophils to facilitate cell death and enabling Siglec-8-dependent mast cell death without impacting anti-Siglec-8 antibody binding. The cell death process licensed by de-sialylation resembled that characterized in IL-5-primed eosinophils, including CD11b upregulation, ROS production, and the activities of Syk, PI3K, and PLC. These results implicate cis ligands in restraining Siglec-8 function on eosinophils and mast cells and reveal a promising approach to the selective depletion of mast cells in patients with mast cell-mediated diseases.

Airway hyperresponsiveness reflects corticosteroid-sensitive mast cell involvement across asthma phenotypes

Airway hyperresponsiveness is a hallmark of asthma across asthma phenotypes. Airway hyperresponsiveness to mannitol specifically relates to mast cell infiltration of the airways, suggesting inhaled corticosteroids to be effective in reducing the response to mannitol, despite low levels of type 2 inflammation. We sought to investigate the relationship between airway hyperresponsiveness and infiltrating mast cells, and the response to inhaled corticosteroid treatment. In 50 corticosteroid-free patients with airway hyperresponsiveness to mannitol, mucosal cryobiopsies were obtained before and after 6 weeks of daily treatment with 1600 μg of budesonide. Patients were stratified according to baseline fractional exhaled nitric oxide (Feno) with a cutoff of 25 parts per billion. Airway hyperresponsiveness was comparable at baseline and improved equally with treatment in both patients with Feno-high and Feno-low asthma: doubling dose, 3.98 (95% CI, 2.49-6.38; P< .001) and 3.85 (95% CI, 2.51-5.91; P< .001), respectively. However, phenotypes and distribution of mast cells differed between the 2 groups. In patients with Feno-high asthma, airway hyperresponsiveness correlated with the density of chymase-high mast cells infiltrating the epithelial layer (ρ, -0.42; P= .04), and in those with Feno-low asthma, it correlated with the density in the airway smooth muscle (ρ, -0.51; P= .02). The improvement in airway hyperresponsiveness after inhaled corticosteroid treatment correlated with a reduction in mast cells, as well as in airway thymic stromal lymphopoietin and IL-33. Airway hyperresponsiveness to mannitol is related to mast cell infiltration across asthma phenotypes, correlating with epithelial mast cells in patients with Feno-high asthma and with airway smooth muscle mast cells in patients with Feno-low asthma. Treatment with inhaled corticosteroids was effective in reducing airway hyperresponsiveness in both groups.

In Obese Patients With Type 2 Diabetes, Mast Cells in Omental Adipose Tissue Decrease the Surface Expression of CD45, CD117, CD203c, and FcϵRI.

The paradigm of mast cells in type 2 diabetes is changing. Although they were first considered deleterious inflammatory cells, now they seem to be important players driving adipose tissue homeostasis. Here we have employed a flow cytometry-based approach for measuring the surface expression of 4 proteins (CD45, CD117, CD203c, and FcϵRI) on mast cells of omental (o-WAT) and subcutaneous white adipose tissue (s-WAT) in a cohort of 96 patients with morbid obesity. The cohort was split into three groups: non-T2D, pre-T2D, and T2D. Noteworthy, patients with T2D have a mild condition (HbA1c <7%). In o-WAT, mast cells of patients with T2D have a decrease in the surface expression of CD45 (p=0.0013), CD117 (p=0.0066), CD203c (p=0.0025), and FcϵRI (p=0.043). Besides, in s-WAT, the decrease was seen only in CD117 (p=0.046). These results indicate that T2D affects more to mast cells in o-WAT than in s-WAT. The decrease in these four proteins has serious effects on mast cell function. CD117 is critical for mast cell survival, while CD45 and FcϵRI are important for mast cell activation. Additionally, CD203c is only present on the cell surface after granule release. Taking together these observations, we suggest that mast cells in o-WAT of patients with T2D have a decreased survival, activation capacity, and secretory function.

Levels of circulating mast cell progenitors and tumour‑infiltrating mast cells in patients with colorectal cancer.

The role of mast cells in colorectal cancer (CRC) has been an area of intense interest. Mast cell density is closely related to CRC development and prognosis. The identification of mast cell progenitors (MCps) in peripheral blood provides an opportunity to explore the frequency and distribution of mast cells in the circulation and tumour microenvironment of patients with CRC at different disease stages. The aim of the presents study was to investigate the changes of MCps and mast cells in CRC. Flow cytometry was used to measure the circulating frequency of MCps in 37 patients with CRC and 12 healthy control (HC) patients, and the frequency of mast cells in tissue from 15 patients with CRC and 7 patients with haemorrhoids. In the present study, lower levels of circulating MCps in patients with CRC were found, which was significantly related to CRC development. After surgery, the frequency of circulating MCps was significantly increased. However, the frequency of mast cells in tumour tissues was lower than that in adjacent normal tissues and compared with HC tissues and was not associated with CRC progression.

Local immune response in patients with classic and nonulcer type of interstitial cystitis/bladder pain syndrome

Several hypotheses regarding the pathophysiology of interstitial cystitis/bladder pain syndrome (IC/BPS) have been put forward, but no consensus has yet been reached. It is suggested that cytokines are involved in IC/BPS, as well as in inflammatory autoimmune diseases. Examining various biomarkers of bladder tissue, including mast cells is underway. However, few reports on a consistent immune activity profile are available. The aim of the study was to assess the cytokine profile, counts of mast cells and plasma cells as well as their relationship in patients with IC/BPS with and without Hunner’s lesions. 44 women with Hunner’s lesions (group I) and 82 women with non-ulcer type (group II) were examined. Patients were questioned on the Pelvic Pain Symptom Scale, Urinary Frequency Scale (PUF), Visual Analogue Scale (VAS) and O’Leary–Santa Interstitial Cystitis Symptom Index (ICSI). Cystoscopy and hydrodistension of the bladder were performed under general anesthesia. In biopsies of the bladder wall, the number of plasma cells and mast cells was assessed, in urine — IL-1β, IL-6, IL-8, TNFα. Statistical processing of the results was carried out using the Statistica 6 software (StatSoft, USA). The Student’s t-test, Spearman’s correlation coefficient were calculated. In patients with Hunner's ulcer, there was an insignificant increase in the scale indices and decreased magnitude for average volume, urination frequency, and maximum emptying volume. The maximum bladder capacity during hydrodistension was lowered by 42.01% (p 0.001). The level of IL-8 in group I was higher on average by 28.57% (p = 0.434) as compared with that in group II, IL-6 — by 13.46% (p = 0.638), TNFα — by 9.09% (p = 0.244) and IL-1β — by 4.13% (p = 0.859). The number of mast cells in patients of group I vs. group II was higher by 40.65% (p 0.05). In group I, a marked relationship was found between count of mast cells and plasma cells (r = –0.555, p 0.05), as well as between count of plasma cells and IL-6 level (r = –0.639, p 0.05). In group II, a significant connection was found between count of mast cells and TNFα level (r = +0.562, p 0.05). Patients with Hunner’s IC/BPS are characterized by severe inflammation, wherein mast cells are involved in induction. Determination of cytokines in urine can provide a non-invasive division of IC/BPS into ulcerative and non-ulcerative groups.

Novel Insights on MRGPRX2-Mediated Hypersensitivity to Neuromuscular Blocking Agents And Fluoroquinolones.

Neuromuscular blocking agents (NMBAs) like atracurium and rocuronium as well as fluoroquinolones (FQs) cause mast cell-mediated anaphylaxis by activating Mas-related G protein-coupled receptor X2 (MRGPRX2), but many questions remain unanswered. Here, we address three of them, namely whether primary human mast cells show similar activation by these drugs as murine mast cells and mast cell lines, how sugammadex protects from atracurium-induced MRGPRX2-mediated mast cell activation, and why some but not all patients treated with rocuronium develop anaphylaxis. We used peripheral blood-derived cultured mast cells from healthy donors and patients, assessed mast cell activation and degranulation by quantifying intracellular calcium and CD63 expression, respectively, and made use of MRGPRX2-silencing, via electroporation with Dicer-substrate small interfering RNAs, and single cell flow cytometric analyses. Atracurium, ciprofloxacin, and levofloxacin activated and degranulated primary human mast cells, but only MRGPRX2-positive and not MRGPRX2-negative or -silenced mast cells. Sugammadex attenuated the atracurium-induced and MRGPRX2-mediated activation and degranulation of human mast cells by reducing free atracurium levels. The mast cells of patients with IgE-independent anaphylaxis to rocuronium were similar, in their MRGPRX2 expression and function, to those of patients with IgE-mediated anaphylaxis. These findings further improve our understanding of the role and relevance of MRGPRX2-driven mast cell activation in anaphylactic reactions to NMBAs and FQs and may help to improve their prediction, prevention, and treatment.

Elevated MRGPRX2 Levels Related to Disease Severity in Patients With Chronic Spontaneous Urticaria.

Mas-related G-protein coupled receptor-X2 (MRGPRX2), a receptor on mast cells, basophils, and eosinophils associated with immunoglobulin E (IgE)-independent degranulation, has been reported to be highly expressed on cutaneous mast cells in patients with severe chronic spontaneous urticaria (CSU). We sought to investigate whether MRGPRX2 levels in the sera from CSU patients differ from those in healthy control subjects and to evaluate the clinical utility of MRGPRX2 levels in CSU patients. Severe CSU was defined as urticaria activity score over 7 days (UAS7) ≥ 28. Serum samples from 116 (73 severe and 43 non-severe) CSU patients and 50 healthy subjects were screened for MRGPRX2 using enzyme-linked immunosorbent assay. Serum MRGPRX2 levels were significantly higher in patients with severe CSU (median [interquartile range], 16.5 [10.8–24.8]) than in healthy controls (11.7 [6.5–21.2], P = 0.036) and in non-severe CSU patients (8.7 [4.5–18.8], P = 0.002), although they did not differ between healthy subjects and non-severe CSU patients. Serum MRGPRX2 levels in CSU patients showed positive correlations with UAS7 and specific IgE against Dermatophagoides farinae in CSU subjects, whereas no correlations were observed for age, sex, urticaria duration, atopy, combined angioedema, autologous serum skin test positivity, or total IgE levels. Logistic regression analysis identified serum MRGPRX2 ≥ 12 ng/mL (odds ratio, 6.421; P = 0.002) as an independent risk factor for severe CSU, along with increased serum total IgE levels, peripheral basophil percentage, and angioedema. In conclusion, we suggest that serum MRGPRX2 could help indicate severe CSU.

The relationship between dectin-1 and mast cells in patients with diarrhea-predominant irritable bowel syndrome

Background/Aims: Currently, the role of the microbiome GBA is being widely studied in the pathogenesis of visceral hypersensitivity in IBS. To investigate the role of fungus, the current study aimed to i) investigate the expression of Syk/CARD9-coupled Dectin-1 receptors in the ileocecal mucosa in D-IBS patients and (ii) explore the relationships between Dectin-1 and plasma MCT levels as well as anorectal sensory function in patients with D-IBS.Methods: Thirty-eight D-IBS patients who met the Rome III criteria and 2 groups of age- and sex-matched asymptomatic healthy controls were recruited from March 2015 to January 2017. Anorectal sensory function was quantified by HR-ARM. Plasma MCT titers were identified by ELISA, while the expression of Syk/CARD9 Dectin-1 receptors in ileocecal mucosa was identified by RT-qPCR.Results: (i) The expression of Syk/CARD9-coupled Dectin-1 receptors was significantly higher in D-IBS patients than in controls (p < .001). ii) The threshold values of first sensation and desire to defecate were significantly lower in D-IBS patientsthan in controls (the P value was0.007 and 0.001 respectively). (iii) There were negative correlations between plasma MCT levels and first sensation thresholds in D-IBS patients (r = −0.513, p = .012) and the desire to defecate thresholds (r = −0.423, p = .044). (iiii) There was a positive correlation between plasma MCT titers and the expression of Dectin-1 receptors in D-IBS patients (r = 0.565, p = .005).Conclusions: These results suggested that fungi may partially participate in the genesis of visceral hypersensitivity by activating mast cells, which is mediated by activation of the Dectin-1 receptor-mediated Syk/CARD9 signaling pathway.

Activation of Siglec-7 results in inhibition of in vitro and in vivo growth of human mast cell leukemia cells

Advanced systemic mastocytosis is a rare and still untreatable disease. Blocking antibodies against inhibitory receptors, also known as "immune checkpoints", have revolutionized anti-cancer treatment. Inhibitory receptors are expressed not only on normal immune cells, including mast cells but also on neoplastic cells. Whether activation of inhibitory receptors through monoclonal antibodies can lead to tumor growth inhibition remains mostly unknown. Here we show that the inhibitory receptor Siglec-7 is expressed by primary neoplastic mast cells in patients with systemic mastocytosis and by mast cell leukemia cell lines. Activation of Siglec-7 by anti-Siglec-7 monoclonal antibody caused phosphorylation of Src homology region 2 domain-containing phosphatase-1 (SHP-1), reduced phosphorylation of KIT and induced growth inhibition in mast cell lines. In SCID-beige mice injected with either the human mast cell line HMC-1.1 and HMC-1.2 or with Siglec-7 transduced B cell lymphoma cells, anti-Siglec-7 monoclonal antibody reduced tumor growth by a mechanism involving Siglec-7 cytoplasmic domains in “preventive” and “treatment” settings. These data demonstrate that activation of Siglec-7 on mast cell lines can inhibit their growth in vitro and in vivo. This might pave the way to additional treatment strategies for mastocytosis.

Mast Cells in Patients with Hereditary α-Tryptasemia Promote HLA-DR Expression and a Th2-Polarizing Microenvironment in the Gastrointestinal Tract

Abstract Hereditary α-tryptasemia (HαT) is a recently identified, genetic disorder characterized by multisystem comorbidities resulting from increased monoallelic α-tryptase copy number (CN) at TPSAB1 (α-TPSAB1). Affected individuals frequently exhibit heterogeneous multisystem symptoms and comorbidities which negatively impact daily functioning and quality of life. In the cohorts examined thus far, functional dyspepsia and irritable bowel syndrome, were most frequently reported. However, the mechanism by which increased α-TPSAB1 CN produces GI disease is unknown. Tryptase is almost exclusively produced by mast cells (MC). In the gut, MC play important roles in immune responses, leukocyte recruitment, neuroimmune inflammation, and tissue repair. MC can also promote T-cell activation and polarization via cytokine secretion, co-stimulatory marker expression and MHC II antigen presentation. MCs also release exosomes, nanosized vesicles secreted by most cell types present in biological fluids such as blood, cerebrospinal fluid, and urine, which have a reported influence on T cell differentiation. In early experiments, we found increased numbers of GI MCs, activated T cells, and urinary exosomes in HαT patients compared to healthy donors. Thus, we evaluated MC surface antigen expression, exosome proteomics, and cytokine expression of exosome-treated T cells. We found increased HLA-DR and FcɛR1α expression in HαT-patient GI MCs, increased Th2 associated signaling proteins in HαT urinary exosomes, and elevated Th2 cytokine expression in HαT-exosome treated T cells. These results suggest that HαT GI morbidity involves aggravated MC hyperplasia and antigen presentation which promotes T cell activation and Th2 polarization.

861 – Effect of Ketotifen on Abdominal Symptoms, Visceral Sensitivity and Intestinal Mast Cell in Patients with Irritable Bowel Syndrome with Diarrheal

861 – Effect of Ketotifen on Abdominal Symptoms, Visceral Sensitivity and Intestinal Mast Cell in Patients with Irritable Bowel Syndrome with Diarrheal

Oncogenic D816V-KIT signaling in mast cells causes persistent IL-6 production.

Persistent dysregulation of IL-6 production and signaling have been implicated in the pathology of various cancers. In systemic mastocytosis, increased serum levels of IL-6 associate with disease severity and progression, although the mechanisms involved are not well understood. Since systemic mastocytosis often associates with the presence in hematopoietic cells of a somatic gain-of-function variant in KIT, D816V-KIT, we examined its potential role in IL-6 upregulation. Bone marrow mononuclear cultures from patients with greater D816V allelic burden released increased amounts of IL-6 which correlated with the percentage of mast cells in the cultures. Intracellular IL-6 staining by flow cytometry and immunofluorescence was primarily associated with mast cells and suggested a higher percentage of IL-6 positive mast cells in patients with higher D816V allelic burden. Furthermore, mast cell lines expressing D816V-KIT, but not those expressing normal KIT or other KIT variants, produced constitutively high IL-6 amounts at the message and protein levels. We further demonstrate that aberrant KIT activity and signaling are critical for the induction of IL-6 and involve STAT5 and PI3K pathways but not STAT3 or STAT4. Activation of STAT5A and STAT5B downstream of D816V-KIT was mediated by JAK2 but also by MEK/ERK1/2, which not only promoted STAT5 phosphorylation but also its long-term transcription. Our study thus supports a role for mast cells and D816V-KIT activity in IL-6 dysregulation in mastocytosis and provides insights into the intracellular mechanisms. The findings contribute to a better understanding of the physiopathology of mastocytosis and suggest the importance of therapeutic targeting of these pathways.

Aspirin Is an Enhancing Factor for Food-Dependent Exercise-Induced Anaphylaxis in Children

To determine the effect of aspirin on challenge tests for food-dependent exercise-induced anaphylaxis (FDEIA) and food allergies with and without exercise in children who are suspected of having FDEIA on the basis of medical histories.Pediatric patients from the outpatient clinic of the department of pediatrics at Fukuoka National Hospital were recruited between 2006 and 2015. Inclusion criteria included age <18 years, no history of drug allergies, and all patients had experienced more than a single episode of anaphylaxis after exercise. Recruitment resulted in 51 children (38 boys and 13 girls, age 4–16 years, median age 11 years).Patients were instructed to discontinue antihistamines 3 to 7 days before the challenge. The exercise challenge started 30 minutes after food ingestion and was standardized to 30 minutes of aerobic exercise followed by 6 minutes of anaerobic exercise. The goal heart rate was 80% of the child’s maximum predicted heart rate. On day 1 of the study, patients underwent a causal food and exercise challenge by using an ergometer or treadmill. On day 2 of the study, patients underwent aspirin and causal food. On day 3 of the study, patients underwent aspirin, causal food, and exercise. Aspirin dosing was 10 mg/kg up to a maximum of 500 mg and was administered 30 minutes before food intake. Patient’s history and results of serum specific immunoglobulin E levels and skin prick testing determined causal food. None of the patients had reactions to the causal food by itself. Outcomes were recorded as objective symptoms, including urticaria, cough, dyspnea, edema, nausea, vomiting, and shock. The challenge was considered positive when patients exhibited any one of these symptoms. Severe reactions resulted in termination of the challenge and appropriate treatment.Out of the 51 patients, 26 had allergic reactions during at least 1 of the 3 challenge scenarios (21 boys, 6–16 years, median age of 13 years). Challenge-positive symptoms included urticaria in 21 cases (81%), cough and wheeze in 14 cases (54%), angioedema in 7 cases (27%), shock in 3 cases (12%), and nausea and vomiting in 2 cases (8%). The foods responsible for positive FDEIA reactions were shrimp in 35% (n = 9), wheat in 27% (n = 7), milk in 15% (n = 4), and peach, orange, sesame seed, onion, and fish in the remaining challenges. In the food-and-exercise-only challenges, allergic reactions occurred for 14 (54%) of the 26 patients. Two patients reacted with aspirin and causal food without exercise. In the challenge group with all 3 cofactors, all 26 patients experienced symptoms. This was statistically significant in the positive rates of the test when pretreated with and without aspirin (P < .01).Pretreatment with aspirin increased the frequency and severity of allergic reactions during challenges with causal food and exercise in pediatric patients with suspected FDEIA.In this study, the researchers demonstrate aspirin can enhance the allergic reaction in FDEIA in the pediatric population. Similar findings have previously been demonstrated in adult studies. The mechanisms for this augmented effect are thought to be twofold. First, it is felt that aspirin in conjunction with exercise increases the amount of food antigens absorbed in the intestines. Additionally, aspirin accelerates histamine release from mast cells in patients with FDEIA. Both aspirin and nonsteroidal anti-inflammatory drugs inactivate the cyclooxygenase enzyme, and nonsteroidal anti-inflammatory drugs in adults have also been shown previously to act as a third cofactor with food and exercise, triggering FDEIA. For several years, it has been recommended that aspirin should be avoided in children age <12 years because of the risk of Reye syndrome. Because of these concerns, aspirin use in US children is uncommon. It is suggested in the findings of this study that adding aspirin to pediatric exercise challenge protocols may be useful when food and exercise fail to produce symptoms and may reduce the rate of false-negative challenges. When obtaining histories from pediatric patients with FDEIA, possible medication cofactors should be explored.

Changes of gastric mucosal mast cells in patients with functional dyspepsia after Hylicobacter pylori infection

Objective To investigate the changes of gastric mucosal mast cells in patients with functional dyspepsia (FD) after Helicobacter pylori (H.pylori) infection, and to explore the correlation between the changes and dyspeptic symptoms. Methods From November 2012 to March 2014, 32 patients with FD and 16 asymptomatic patients (control group) from Beijing Jishuitan Hospital were enrolled. H. pylori infection situation was examined. The mucosal biopsies from gastric antrum and gastric body were taken for histological examination. The mast cells of gastric mucosa were detected by immunohistochemical stain. T test was performed for statistical analysis. Results Among 32 FD patients, 17 had H. pylori infection (one with gastric body involved, two with gastric antrum involved, 14 with both gastric antrum and gastric body involved), and 15 had no H. pylori infection. Among 16 asymptomatic patients, 12 had H. pylori infection and four had no H. pylori infection. Among FD patients, the percentage of degranulated mast cells in gastric mucosa with H. pylori infection group was (61.45±24.86)%, which was higher than that without H. pylori infection group ((48.34±21.63)%), and the difference was statistically significant (t=-2.145, P=0.036). The percentage of degranulated mast cells in gastric mucosa with H. pylori infection group was (29.73±12.99)%, which was higher than that without H. pylori infection group ((20.77±10.86)%), and the difference was statistically significant (t=-2.856, P=0.006). In H. pylori infection group, the percentage of degranulated mast cells in gastric body mucosa of FD patients was (66.99±18.85)%, which was higher than that of asymptomatic patients in control group ((46.77±8.43)%), and the difference was statistically significant (t=3.642, P=0.002). The ratio of degranulated mast cells in gastric body mucosa and the density of mast cells in gastric antrum mucosa of prandial distress syndrome (PDS) patients, the density of mast cells in gastric body mucosa of epigastric pain syndrome (EPS) patients and the ratio of degranulated mast cells in gastric body mucosa and the degree of degranulation of mast cells of PDS and EPS patients were all higher than those of asymptomatic patients in control group, and the differences were statistically significant (t=2.750, 3.601, 2.799, 9.522 and 5.755, all P<0.05). Conclusions The dyspeptic symptoms of FD patients with H. pylori infection is correlated with the changes of mast cells. With the infection of H. pylori, dyspeptic symptoms of different subtypes of FD may be correlated with the changes of mast cells in different gastric region. H. pylori infection may cause the dyspeptic symptoms of FD patients by increase the number and activation of mast cells. Key words: Helicobacter pylori; Mast cells; Functional dyspepsia; Dyspeptic symptom

Abstract A64: Mast cell expressed FcεR beta subunit (MS4A2) is prognostic in lung adenocarcinoma

Abstract Background: The context of immune cell infiltrates within the tumor is associated with cancer prognosis. The type of immune cells and their activation state can provide mediators that either promote or inhibit tumor growth. A growing body of evidence suggest the presence of innate immune cells play a role in shaping early tumor growth. In attempts to gain insight into the immune networks that regulate tumorigenesis, we used genome wide expression datasets of patients with resected early stage non-small cell lung cancer (NSCLC) to identify immune-related genes associated with patient survival. Methods: Gene expression analysis was conducted on microarray datasets from 128 early-stage NSCLC adenocarcinoma resected tumor samples. Limiting analysis to immune-related genes, we identified a minimum gene set that is prognostic for lung adenocarcinoma and validated the gene signature in additional published microarray NSCLC datasets. Using pathway analysis and immunohistochemistry (IHC), we identified a role for mast cell-expressed IgE receptor beta subunit, MS4A2, in lung adenocarcinoma progression. Results: From an immune-related gene list, we identified a minimal gene signature that was able to separate patients into high or low-risk survival groups. This gene signature was shown to be prognostic for NSCLC adenocarcinoma in nine validation datasets (n=1264, hazard ratio 2.07, 95% confidence interval 1.69-2.53, p&amp;lt;0.0001). Pathway analysis of differentially expressed genes within high or low-risk survival subgroups reveals gene ontologies and immune signatures that are enriched for IgE receptor signaling and mast cells in patients with favourable prognosis. Univariate analysis shows that the IgE receptor complex genes, as well as mast cell specific protease, mast cell carboxypeptidase A, are highly prognostic for survival. We are currently using IHC of matched patient samples to validate receptor localization. Conclusion: By limiting gene expression analysis to immune-related genes, we identified a minimal gene set that indicate an important role for IgE receptor signaling and mast cells in favourable lung cancer prognosis. Our data highlights the importance of innate immune cells in shaping lung cancer development. Citation Format: Dalam Ly, Chang-Qi Zhu, Michael Cabanero, Ming-Sound Tsao, Li Zhang. Mast cell expressed FcεR beta subunit (MS4A2) is prognostic in lung adenocarcinoma. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2016 Oct 20-23; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2017;5(3 Suppl):Abstract nr A64.

Effect of KIT Inhibition by Imatinib on Airway Mast Cells in Patients with Severe Refractory Asthma (KIA)

Effect of KIT Inhibition by Imatinib on Airway Mast Cells in Patients with Severe Refractory Asthma (KIA)

Proteome analysis identifies L1CAM/CD171 and DPP4/CD26 as novel markers of human skin mast cells.

The function of skin mast cells has been well documented in IgE-mediated allergic reactions, whereas other mast cell functions are poorly defined. This study aimed at identifying novel mast cell proteins by proteome analysis of primary human skin mast cells. The proteome of skin mast cells was compared to other cell types and analyzed using bioinformatics. The expression and function of two proteins hitherto not described in skin mast cells was investigated in isolated mast cells as well as in mast cells in situ. Within the mast cell proteome, we identified 49 highly expressed proteins previously not described in mast cells; 21 of these proteins were found to be selectively expressed in mast cells. Two proteins, the neural cell adhesion molecule L1 and dipeptidyl peptidase 4, were further studied. L1 was found to be highly expressed in mast cells in normal, psoriasis, and mastocytosis skin. Dipeptidyl peptidase 4 was found to be expressed in mast cells in normal, psoriasis, and mastocytosis skin as well as in bone marrow mast cells in patients with systemic mastocytosis. In normal skin, mast cells were identified as a major source of dipeptidyl peptidase 4 and we also found that skin mast cells and fibroblasts secrete an active form of this enzyme. In a systematic proteomics approach we identified two novel mast cell proteins potentially relevant to skin homeostasis: neural cell adhesion molecule L1 and dipeptidyl peptidase 4.