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There is strong evidence of an association between severe anaphylaxis, especially hymenoptera venom induced, and mast cell (MC) disorders. It has been thought that intrinsic abnormalities in MCs, including the presence of the activating KIT D816V mutation in mastocytosis or of genetic trait, hereditary alpha-tryptasemia, may influence susceptibility to severe anaphylaxis. This article evaluates the potential mechanisms leading to severe MC activation, as well as the differential diagnosis of and range of symptoms attributable to MC mediator release. Also, we offer a global classification for disorders related to MC activation.

The diagnosis of mast cell activation syndrome (MCAS) is defined by 3 criteria: (1) typical clinical signs and symptoms of acute, recurrent (episodic), and systemic mast cell activation (MCA); (2) increase in tryptase level to >20% + 2 ng/mL within 1-4 hours after onset of the acute crisis; and (3) response of MCA symptoms to antimediator therapy. Classification of MCAS requires highly sensitive and specific methodological approaches for the assessment of clonal bone marrow mast cells at low frequencies. The Spanish Network on Mastocytosis score has been used successfully as a predictive model for selecting MCAS candidates for bone marrow studies based on a high probability of an underlying clonal mast cell disorder. In this article, we propose a diagnostic algorithm and focus on the practical evaluation and management of patients with suspected MCAS. Key words: Anaphylaxis. Antimediator therapy. Mast cell activation syndrome. Mast cell mediator release–related symptoms. Tryptase.

Objective To describe our current understanding of hereditary α-tryptasemia (HαT), how HαT fits into the evolutionary context of tryptases and contemporary framework of mast cell–associated disorders, and to discuss the future clinical and therapeutic landscape for symptomatic individuals with HαT. Data Sources Primary peer-reviewed literature. Study Selections Basic, clinical, and translational studies describing tryptase gene composition, generation, secretion, and elevation and the associated clinical impacts of HαT and treatment of such individuals were reviewed. Results HαT is a common autosomal dominant genetic trait caused by increased TPSAB1 copy number encoding α-tryptase. Approximately 1 in 20 White individuals have HαT, making it by far the most common cause for elevated basal serum tryptase levels. Although many individuals with HαT may not manifest associated symptoms, the prevalence of HαT is increased in patients with clonal and nonclonal mast cell–associated disorders wherein it is linked to more prevalent and/or severe anaphylaxis and increased mast cell mediator-associated symptoms. Increased generation of mature α/β-tryptase heterotetramers, and their unique physiochemical properties, may be responsible for some of these clinical findings. Conclusion HαT is a common modifier of mast cell–associated disorders and reactions. Nevertheless, whether HαT may be an independent cause of clinical phenotypes with which it has been associated remains unproven. Correct identification of HαT is critical to accurate interpretation of serum tryptase levels in the clinical evaluation of patients. Beyond HαT, we foresee tryptase genotyping as an important parameter in the standard workup of patients with mast cell–associated disorders and development of therapeutic modalities targeting these patients and associated clinical phenotypes.

Hymenoptera venom anaphylaxis is the most frequent cause of anaphylaxis and responsible for about 20% of all fatal anaphylaxis cases in adults. We report two cases of fatal hymenoptera venom anaphylaxis with undiagnosed underlying mastocytosis and review the risk factors for severe or fatal hymenoptera venom anaphylaxis, as well as the specificities of its association with mastocytosis. As hymenoptera venom allergic patients with underlying clonal mast cell disorder generally lack typical skin lesions of mastocytosis, its diagnosis can easily be missed, underscoring the importance and need for diagnostic strategies in order to correctly identify these patients. Predominant cardiovascular symptoms in the absence of urticaria or angioedema following an insect sting are suggestive of underlying clonal mast cell disorder, and should be distinguished from panic attack or vasovagal syncope. Similarly, an unexplained syncope or an "idiopathic" anaphylaxis might reveal mastocytosis or hereditary alpha-tryptasemia. Acute and basal serum tryptase measurements should always be integrated in the diagnostic work-up of an insect sting reaction or unexplained syncope or shock of any origin.

Background Pituitary adenylate cyclase-activating polypeptide-38 (PACAP38) and vasoactive intestinal polypeptide can provoke cluster headache attacks in up to half of cluster headache patients in their active phase. At present, it is unknown whether provoked attacks are mediated via calcitonin gene-related peptide or mast cell activation. Methods All enrolled patients with cluster headache were randomly allocated to receive a continuous infusion of either PACAP38 (10 pmol/kg/min) or vasoactive intestinal polypeptide (8 pmol/kg/min) over 20 min. We collected clinical data and measured plasma levels of calcitonin gene-related peptide and markers of mast cell activation (tryptase and histamine) at fixed time points: at baseline (T0), at the end of the infusion (T20), 10 min after the infusion (T30), and 70 min after the infusion (T90). Results Blood was collected from episodic cluster headache patients in active phase (n = 14), episodic cluster headache patients in remission (n = 15), and chronic cluster headache patients (n = 15). At baseline, plasma levels of calcitonin gene-related peptide, tryptase, and histamine were not different among the three study groups. Plasma levels of calcitonin gene-related peptide ( p = 0.7074), tryptase ( p = 0.6673), or histamine ( p = 0.4792) remained unchanged during provoked attacks compared to attack-free patients. Conclusion Cluster headache attacks provoked by either PACAP38 or vasoactive intestinal polypeptide were not accompanied by alterations of plasma calcitonin gene-related peptide, tryptase or histamine. The provoked attacks may not be mediated by calcitonin gene-related peptide or mast cell activation. Trial Registration: The study is registered at ClinicalTrials.gov (NCT03814226).

Anaphylaxis is a rapid, potentially fatal, immediate hypersensitivity reaction. Preformed and newly formed biochemical mediators, including histamine, tryptase, carboxypeptidase A, prostaglandin D2, leukotrienes, and platelet-activating factor (PAF) are released systematically during the degranulation of mast cells and basophils. PAF is a proinflammatory phospholipid, synthesized and secreted by mast cells, monocytes and fixed tissue macrophages whose binding to its receptor on target cell-platelet, monocytes, macrophages, and neutrophils results in many of the manifestation of acute allergic reaction and anaphylaxis.

Dengue, with four viral serotypes, causes epidemics in tropical and sub-tropical regions. Allopathic antiviral therapies and a vaccine of general use are lacking. The homeopathic medicine Apis mellifica, advised in anaphylaxis from honeybee sting, is proposed to address the life-threatening dengue shock syndrome, which develops from dengue hemorrhagic fever and has features of anaphylaxis. In both dengue and anaphylaxis, immunoglobulin E activates, and released vasoactive mediators (importantly histamine, tryptase and platelet-activating factor) cause, a vascular permeability enabling shock. In dengue, another mechanism, namely antibody-dependent enhancement, due to secondary infection with a heterologous dengue serotype, is associated with release of vasoactive mediators. The homeopathic medicine Apis mellifica indicates plasma leak, shock, and the serous effusion that is noted in dengue patients, and is a suggested prophylactic and therapeutic medicine for dengue shock syndrome.

Summary Background Tezepelumab is a human monoclonal antibody that blocks the activity of thymic stromal lymphopoietin (TSLP), an epithelial cell-derived cytokine. In phase 2b and 3 studies, tezepelumab significantly reduced exacerbations versus placebo in patients with severe uncontrolled asthma, irrespective of baseline levels of type 2 inflammatory biomarkers. We investigated the mechanism of action of tezepelumab by assessing its effects on airway inflammatory cells, airway remodelling, and airway hyperresponsiveness. Methods CASCADE was an exploratory, double-blind, randomised, placebo-controlled, parallel-group, phase 2 study done in 27 medical centres in Canada, Denmark, Germany, the UK, and the USA. Adults aged 18–75 years with uncontrolled, moderate-to-severe asthma were randomly assigned (1:1) to receive tezepelumab 210 mg or placebo administered subcutaneously every 4 weeks for a planned 28 weeks, extended to up to 52 weeks if COVID-19-related disruption delayed participants' end-of-treatment assessments. Randomisation was balanced and stratified by blood eosinophil count. The primary endpoint was the change from baseline to the end of treatment in the number of airway submucosal inflammatory cells in bronchoscopic biopsy samples. Eosinophils, neutrophils, CD3+ T cells, CD4+ T cells, tryptase+ mast cells, and chymase+ mast cells were evaluated separately. This endpoint was also assessed in subgroups according to baseline type 2 inflammatory biomarker levels, including blood eosinophil count. Airway remodelling was assessed via the secondary endpoints of change from baseline in reticular basement membrane thickness and epithelial integrity (proportions of denuded, damaged, and intact epithelium). Exploratory outcomes included airway hyperresponsiveness to mannitol. All participants who completed at least 20 weeks of study treatment, had an end-of-treatment visit up to 8 weeks after the last dose of study drug, and had evaluable baseline and end-of-treatment bronchoscopies were included in the primary efficacy analysis. All participants who received at least one dose of study drug were included in the safety analyses. This study is registered with ClinicalTrials.gov, NCT03688074. Findings Between Nov 2, 2018, and Nov 16, 2020, 250 patients were enrolled, 116 of whom were randomly assigned (59 to tezepelumab, 57 to placebo). 48 in the tezepelumab group and 51 in the placebo group completed the study and were assessed for the primary endpoint. Treatment with tezepelumab resulted in a nominally significantly greater reduction from baseline to the end of treatment in airway submucosal eosinophils versus placebo (ratio of geometric least-squares means 0·15 [95% CI 0·05–0·41]; nominal p 0·10). In assessment of secondary endpoints, there were no significant differences between treatment groups in reticular basement membrane thickness and epithelial integrity. In an exploratory analysis, the reduction in airway hyperresponsiveness to mannitol was significantly greater with tezepelumab versus placebo (least-squares mean change from baseline in interpolated or extrapolated provoking dose of mannitol required to induce ≥15% reduction in FEV1 from baseline: tezepelumab 197·4 mg [95% CI 107·9 to 286·9]; placebo 58·6 mg [−30·1 to 147·33]; difference 138·8 [14·2 to 263·3], nominal p=0·030). Adverse events were reported in 53 (90%) patients in the tezepelumab group and 51 (90%) patients in the placebo group, and there were no safety findings of concern. Interpretation The improvements in asthma clinical outcomes observed in previous studies with tezepelumab are probably driven, at least in part, by reductions in eosinophilic airway inflammation, as shown here by reduced airway eosinophil counts regardless of baseline blood eosinophil count. Tezepelumab also reduced airway hyperresponsiveness to mannitol, indicating that TSLP blockade might have additional benefits in asthma beyond reducing type 2 airway inflammation. Funding AstraZeneca and Amgen.

Background : Mastocytosis is a risk factor for hymenoptera venom anaphylaxis (HVA). Current guidelines recommend measuring tryptase in HVA patients and that those with mastocytosis pursue lifelong venom immunotherapy (VIT). Available data on HVA and mastocytosis largely derives from European single-center studies and the prevalence of HVA with and without mastocytosis in the United States (US) is unknown. Objective : We sought to determine the prevalence of HVA and mastocytosis in the US using an insurance claims database and evaluate the impact of mastocytosis on VIT in HVA patients in a US cohort. Methods :The IBM Watson Database, consisting of insurance claims from approximately 27 million US patients in 2018, was queried to identify patients with HVA and/or mastocytosis. Further, a retrospective study of 161 patients undergoing VIT between 2015 – 2018 at the University of Michigan (U-M) was conducted. Results :In the IBM Watson Database, the prevalence of HVA was 167 per 100,000 (0.167%) and the prevalence of mastocytosis 10 per 100,000 (0.010%) overall and 97 per 100,000 (0.097%) among those with HVA. Mastocytosis showed a 9.7-fold increase among HVA patients versus the general population. In the U-M cohort, 2.6% of VIT patients had mastocytosis. Tryptase level did not correlate with venom reaction severity but was higher in patients with systemic VIT reactions. Conclusions :We observed a lower US HVA prevalence than previously reported. Mastocytosis was more common in US HVA patients, though at lower rates than previously reported. In VIT patients there was no correlation between tryptase level and reaction severity. Key words :Tryptasevenom allergyvenom immunotherapyanaphylaxismastocytosismast cell activation syndromemast cell disease Abbreviations Hymenoptera venom allergyHVAUnited StatesUSVenom immunotherapyVITMast Cell DiseaseMCDAmerican Academy of Allergy, Asthma, and Immunology WOS:000717466600002 2-s2.0-85106369702 PMID: 33895259 Science Citation Index Expanded Q1 Article Uluslararası işbirliği ile yapılan - EVET Kasım 2021 YÖK - 2021-22

Background/aims Some inflammatory bowel disease (IBD) patients in remission suffer from irritable bowel syndrome (IBS)-like symptoms (IBD-IBS). The pathogenesis has not yet been elucidated. The study aim is to evaluate relationships among quality of life (QOL), psychological status, and visceral sensitivity, and explore the formation mechanism of IBD-IBS. Methods Forty-seven patients with Crohn's disease in remission, 24 ulcerative colitis in remission, 26 IBS, and 20 healthy controls were included in the study. The abdominal pain, QOL, anxiety, and depression were evaluated through questionnaires. Visceral sensitivity was measured by rectal balloon distension. The serum levels of 5-hydroxytryptamine (5-HT) and nerve growth factor (NGF) were measured by enzyme-linked immunosorbent assay. The expressions of tryptase, 5-HT, NGF, and related receptors in colonic tissues were detected by immunohistochemistry and western blot. Results Prevalence of IBS-like symptoms in Crohn's disease and ulcerative colitis patients in clinical remission was 29.8% and 50.0%, respectively. The QOL was lower, the anxiety/depression scores were higher in IBD-IBS patients than those without IBS-like symptoms. Additionally, patients with IBD-IBS existed visceral hypersensitivity. Besides, abdominal pain was associated with poor QOL, visceral hypersensitivity, anxiety, and depression in IBD-IBS patients. The number of mast cells (MCs) and expressions of 5-HT, NGF, and related receptors were higher in IBD-IBS patients than those with no such symptoms. The serum levels of 5-HT and NGF positively correlated with abdominal pain and visceral hypersensitivity. Conclusion IBD-IBS patients may have low QOL and psychological abnormalities, as wells as visceral hypersensitivity which may be related to increased 5-HT and NGF levels released from activated mast cells.

Perioperative anaphylaxis is a severe adverse event during anesthesia that requires prompt diagnosis and treatment by physicians, including anesthesiologists. Muscle relaxants and antibiotics are the most common drugs that cause perioperative anaphylaxis in Japan, as in many countries. In addition, sugammadex appears to be a primary causative agent. Obtaining previous anesthesia records is necessary in a patient with a history of allergic reactions during anesthesia, whenever possible, to avoid recurrence of anaphylaxis. Although medical staff are likely to notice abnormal vital signs because of complete monitoring during anesthesia, surgical drapes make it difficult to notice the appearance of skin symptoms. Even if there are no skin symptoms, anaphylaxis should be suspected, especially when hypotension resistant to inotropes and vasopressors persists. For improving the diagnostic accuracy of anaphylaxis, it is helpful to collect blood samples to measure histamine/tryptase concentrations immediately after the events and at baseline. The first-line treatment for anaphylaxis is adrenaline. In the perioperative setting, adrenaline should be administered through the intravenous route, which has a faster effect onset and is secured in most cases. Adrenaline can cause serious complications including severe arrhythmias if the appropriate dose is not selected according to the severity of symptoms. The anesthesiologist should identify the causative agent after adverse events. The gold standard for identifying the causative agent is the skin test, but in vitro tests including specific IgE antibody measurements and basophil activation tests are also beneficial. The Working Group of the Japanese Society of Anesthesiologists has developed this practical guide to help appropriate prevention, early diagnosis and treatment, and postoperative diagnosis of anaphylaxis during anesthesia. Grade of recommendations and levels of evidence Anaphylaxis is a relatively rare condition with few controlled trials, and thus a so-called evidence-based scrutiny is difficult. Therefore, rather than showing evidence levels and indicating the level of recommendation, this practical guideline only describes the results of research available to date. The JSA will continue to investigate anaphylaxis during anesthesia, and the results may lead to an amendment of this practical guideline.

A 20-year-old female presented with dysphagia at 8 years of age. She underwent esophagogastroduodenoscopy with biopsies (EGD), which was diagnostic of eosinophilic esophagitis. Diet elimination resulted in improvement in symptoms, reduction in eosinophilia, and resolution of basal zone hyperplasia (BZH) on repeat EGD; however, food reintroduction resulted in recurrence of eosinophilia. Subsequently her pulmonologist started benralizumab, a monoclonal antibody against the interleukin-5 receptor (IL5Rα) on eosinophils, for her asthma. Seven months after starting benralizumab, she underwent EGD for persistent dysphagia, which was notable for resolution of esophageal eosinophilia but demonstrated marked BZH in association with high numbers of CD3+ T-cells and tryptase+ mast cells. She transitioned to dupilumab and had resolution of dysphagia. EGD was performed 10 months after starting dupilumab and demonstrated resolution of BZH and mast cell inflammation with significant reduction in T-cells. Review of other patients at our center treated with biologics, most commonly dupliumab, reveals varying degrees of BZH in association with mostly CD3+ lymphocyte inflammation. Mast cells and T-cells appear to be capable of coordinating mucosal inflammation and symptoms of EoE independent of eosinophilia in a subset of patients.

Dysregulated mast cell-mediated inflammation and/or activation have been linked to a number of human diseases, including asthma, anaphylaxis, chronic spontaneous urticaria, and mast cell activation syndromes. As a major mast cell granule protein, tryptase is a biomarker commonly used in clinical practice to diagnose mast cell-associated disorders and -mediated reactions, but its mechanistic roles in disease pathogenesis remains incompletely understood. Here, we summarize recent advances in the understanding of human tryptase genetics and the effects that different genetic composition may have on the quaternary structure of tetrameric mature tryptases. We also discuss how these differences may impact clinical phenotypes including allergic inflammation, immediate hypersensitivity, and others seen in patients with mast cell-associated disorders. With the increased application of next-generation sequencing, we foresee that human genetic approaches will be a major focus of understanding human tryptase functions in various human mast cell disorders and in new therapeutic development.

Context Aldosterone-producing adenomas (APAs) are a common cause of primary aldosteronism (PA). Despite the discovery of somatic mutations in APA and the characterization of multiple factors regulating adrenal differentiation and function, the sequence of events leading to APA formation remains to be determined. Objective We investigated the role of Wnt/β-catenin and adrenocorticotropin signaling, as well as elements of paracrine regulation of aldosterone biosynthesis in adrenals with APA and their relationship to intratumoral heterogeneity and mutational status. Methods We analyzed the expression of aldosterone-synthase (CYP11B2), CYP17A1, β-catenin, melanocortin type 2 receptor (MC2R), phosphorlyated cAMP response element-binding protein (pCREB), tryptase, S100, CD34 by multiplex immunofluorescence, and immunohistochemistry-guided reverse transcription–quantitative polymerase chain reaction. Eleven adrenals with APA and 1 with micronodular hyperplasia from patients with PA were analyzed. Main outcome measures included localization of CYP11B2, CYP17A1, β-catenin, MC2R, pCREB, tryptase, S100, CD34 in APA and aldosterone-producing cell clusters (APCCs). Results Immunofluorescence revealed abundant mast cells and a dense vascular network in APA, independent of mutational status. Within APA, mast cells were localized in areas expressing CYP11B2 and were rarely colocalized with nerve fibers, suggesting that their degranulation is not controlled by innervation. In these same areas, ß-catenin was activated, suggesting a zona glomerulosa cell identity. In heterogeneous APA with KCNJ5 mutations, MC2R and vascular endothelial growth factor A expression was higher in areas expressing CYP11B2. A similar pattern was observed in APCC, with high expression of CYP11B2, activated β-catenin, and numerous mast cells. Conclusion Our results suggest that aldosterone-producing structures in adrenals with APA share common molecular characteristics and cellular environment, despite different mutation status, suggesting common developmental mechanisms.

Cryptococcus neoformans is an important pathogen causing opportunistic fungal meningitis. The pathogenic mechanism of cryptococcal meningitis remains unclear. We aimed to describe a practical approach for studying the pathologic features of cryptococcal central nervous system infection by immunofluorescence on paraffin-embedded brain of mice using different antigen retrieval methods. After 14 days of intratracheal inoculation of green fluorescent protein-tagged C. neoformans (H99-GFP), C57BL/6J mice brains were fixed in 4% paraformaldehyde and embedded in paraffin. Antigen retrieval methods such as microwaves, 1% sodium lauryl sulfate, 1 N HCl, pepsase, and tryptase were used on 5-μm paraffin sections and the effects were compared. The green fluorescence of H99-GFP persisted with antigen retrieval using 1% sodium lauryl sulfate. After immunofluorescent staining, H99-GFP, glial fibrillary acidic protein-tagged astrocytes, and ionized calcium-binding adapter molecule 1-tagged microglia could be observed clearly. Based on our results, we provide a practical approach for the further study of the interaction between C. neoformans and brain cells.

Hyaluronic acid (HA) is the main component of the extracellular matrix (ECM) of joints, and it is important for a lubricating joint during body movement. Degradation is the main metabolic process of HA in vivo. Hyaluronidases (HAase) were known for HA degradation. The inflammation-induced HA rapid-metabolism can reduce HA viscosity and concentration in joints. Mast cells (MC) containing their specific proteases were found in synovium tissue. It is unclear if MC-proteases could be involved in HA degradation pathways. This study aims to explore the correlations between HA concentration vs mast cell proteases, or matrix metalloproteinase-2/9 (MMP-2/9) and to investigate the association of MC-specific proteases with disrupted synovial HA homeostasis in rheumatoid arthritis (RA) or collagen-induced arthritis rats. The synovial fluid samples from no-RA and RA patients were collected; the collagen-induced arthritis (CIA) rat model was established; HA concentration and the activities of MC-protease and MMP-2/9 in the samples were detected, and the correlations were analyzed. In vitro interaction experiment was carried out by mixing MC-proteases with HA to observe the degradation speed. The HA concentrations in synovial fluids were decreased in RA patients and CIA rats compared with those in no-RA subjects or normal rats respectively. The activities of mast cell proteases in synovial fluids were increased and positively correlated with MMP-9, but negatively correlated with HA concentrations. In vitro study, the addition of MC-chymase and tryptase promoted the speed in HA degradation. MC-proteases may influence HA degradation pathway.

Background Mastocytosis encompasses a heterogeneous group of disorders characterized by accumulation of clonal mast cells (MCs) in the skin and/or internal organs. Patients typically present with a broad variety of recurrent mediator-related clinical symptoms, including severe anaphylaxis. However, not all patients with mastocytosis experience anaphylactic reactions. Objective We sought to identify disease-specific biomarkers in plasma that could be used to predict patients with mastocytosis with increased risk of anaphylaxis. Methods Nineteen patients (≥18 years) and 2 control groups (11 subjects with allergic asthma and 13 healthy volunteers without history of atopy) were recruited. In total, 248 plasma proteins were analyzed by Proximity Extension Assay using Olink Proseek Multiplex panels. Results We identified 4 novel proteins, in addition to tryptase, E-selectin, adrenomedullin, T-cell immunoglobulin, and mucin domain 1, and CUB domain–containing protein 1/CD138 to be significantly increased in patients with mastocytosis compared with both patients with asthma and healthy controls. Furthermore, we investigated whether we could discriminate between patients with mastocytosis with or without anaphylaxis. In addition to tryptase, we identified 3 novel proteins, that is, allergin-1, pregnancy-associated plasma protein-A, and galectin-3, with significantly different levels in patients with mastocytosis with anaphylaxis compared with those without anaphylaxis. Conclusions Newly identified proteomic biomarkers may be used to predict patients with mastocytosis with increased risk of anaphylaxis.

Mast cells (MCs) are immune cells that are distributed in all tissues throughout the body, and their cytoplasm is rich in granules containing histamine and tryptase. When MCs recognize antigens through IgE bound to FceRI, they release these mediators by degranulation. Because degranulation induces various type I allergic reactions, such as anaphylactic shock and hay fever, elucidation of the control mechanism of degranulation is important to the development of a therapeutic strategy for allergic diseases. It is known that the antigen-induced degranulation response is fine-tuned by various humoral factors via the activation of G protein-coupled receptors. We found that extracellular ATP enhanced antigen-dependent and -independent MC degranulation via activation of ionotropic P2X4 receptors. P2X4 receptor activation itself had no effect on MC degranulation, but significantly enhanced antigen-triggered degranulation. Stimulation of the P2X4 receptor potentiated the FceRI-mediated tyrosine kinase signaling cascade. In addition to antigen-induced responses, P2X4 receptor signaling also affected antigen-independent MC responses. Thus, co-stimulation of ATP and Gi-coupled receptor agonists, such as prostaglandin E2 (PGE2) and adenosine, resulted in synergistic degranulation. The significance of P2X4 receptor signaling in allergic and inflammatory responses in vivo was confirmed by impaired responses of antigen-induced passive anaphylaxis and PGE2-induced increases in vascular permeability in P2rx4 knockout mice compared to that of wild-type mice. These results suggest that the P2X4 receptor is a potential therapeutic target for both antigen-dependent and -independent allergic reactions.

Background: Mastocytosis is characterized by clonal proliferation of mast cells in various organs and can have isolated cutaneous or systemic involvement. Childhood-onset mastocytosis (COM) is usually cutaneous and regresses spontaneously, while adult-onset mastocytosis (AOM) is often persistent with systemic involvement. There is limited data on COM from India. Objective: To elucidate the clinicopathological profile of COM. Methods: We conducted a retrospective chart review of all the patients with histologically proven COM (≤16 years), presenting over 11 years (January 2009 to December 2019) to the Dermatology Department. We compiled the demographic data, clinical characteristics (morphology, extent, distribution), laboratory investigations, histopathology findings, imaging (ultrasound abdomen), c-KIT mutation results, where available, and other associated abnormalities, and grouped them according to the WHO classification for mastocytosis. Results: Among the 66 patients with COM (M: F–1.6:1), 89.4% had onset before 2 years of age. The subtypes were: maculopapular cutaneous mastocytosis (MPCM: 44, 66.7%); mastocytoma of the skin (MOS: 19, 28.8%); diffuse cutaneous mastocytosis (DCM: 2, 3%) and indolent systemic mastocytosis (ISM: 1, 1.5%). Blistering was observed in 29 (43.9%) and Darier sign was elicited in 47 (71.2%) patients. Serum tryptase was elevated in 9/21 (42.9%) patients, but none had systemic mastocytosis. Three patients had c-KIT mutations (two in exon 8 and one in exon 17). Most patients were managed symptomatically and the patient with ISM improved with imatinib. Conclusion: MPCM is the most common variant of COM and most patients had a disease onset before 2 years. Overall, COM had a good prognosis with rare systemic involvement, mitigating the need for extensive evaluation routinely in children.

Degeneration of motor neurons, glial cell reactivity, and vascular alterations in the CNS are important neuropathological features of amyotrophic lateral sclerosis (ALS). Immune cells trafficking from the blood also infiltrate the affected CNS parenchyma and contribute to neuroinflammation. Mast cells (MCs) are hematopoietic-derived immune cells whose precursors differentiate upon migration into tissues. Upon activation, MCs undergo degranulation with the ability to increase vascular permeability, orchestrate neuroinflammation and modulate the neuroimmune response. However, the prevalence, pathological significance, and pharmacology of MCs in the CNS of ALS patients remain largely unknown. In autopsy ALS spinal cords, we identified for the first time that MCs express c-Kit together with chymase, tryptase, and Cox-2 and display granular or degranulating morphology, as compared with scarce MCs in control cords. In ALS, MCs were mainly found in the niche between spinal motor neuron somas and nearby microvascular elements, and they displayed remarkable pathological abnormalities. Similarly, MCs accumulated in the motor neuron-vascular niche of ALS murine models, in the vicinity of astrocytes and motor neurons expressing the c-Kit ligand stem cell factor (SCF), suggesting an SCF/c-Kit-dependent mechanism of MC differentiation from precursors. Mechanistically, we provide evidence that fully differentiated MCs in cell cultures can be generated from the murine ALS spinal cord tissue, further supporting the presence of c-Kit+ MC precursors. Moreover, intravenous administration of bone marrow-derived c-Kit+ MC precursors infiltrated the spinal cord in ALS mice but not in controls, consistent with aberrant trafficking through a defective microvasculature. Pharmacological inhibition of c-Kit with masitinib in ALS mice reduced the MC number and the influx of MC precursors from the periphery. Our results suggest a previously unknown pathogenic mechanism triggered by MCs in the ALS motor neuron-vascular niche that might be targeted pharmacologically. Supplementary Information The online version contains supplementary material available at 10.1186/s40478-021-01241-3.

Paired acute and baseline serum or plasma tryptase sampling and determination have recently been included as a mechanistic approach in the diagnostic and management guidelines of perioperative immediate hypersensitivity and anaphylaxis. The timing of this paired sampling is clearly defined in international consensus statements, with the optimal window for acute tryptase sampling between 30 minutes and 2 hours after the initiation of symptoms, whereas baseline tryptase should be measured in a sample collected before the event (preop) or at least 24 hours after all signs and symptoms have resolved. A transient elevation of the acute tryptase level greater than [2 D (1.2 3 baseline tryptase level)] supports the involvement and activation of mast cells. Here, we provide the clinical, pathophysiological, and technical rationale for the procedure and interpretation of paired acute and baseline tryptase. Clinical examples, upto-date knowledge of hereditary alpha-tryptasemia as a frequent cause of baseline tryptase of 7 mg/L and higher, mastocytosis, other clonal myeloid disorders, cardiovascular or renal failure, and technical improvements resulting in continued lowering of the 95th percentile value are discussed. Clues for improved management of perioperative immediate hypersensitivity and anaphylaxis include (1) sustained dissemination and implementation of updated guidelines; (2) preoperative sample storage for deferred analysis; (3) referral for thorough allergy investigation, screening for mast cellerelated disorders, and recommendations for future anesthetic procedures; and (4) sustained collaboration between anesthesiologists, immunologists, and allergists. (C) 2021 American Academy of Allergy, Asthma & Immunology

Introduction. Mastocytosis occurs due to clonal mast cells proliferation and may have different clinical course. As the disease only rarely occurs in pediatric population there are very few clinical observations describing its symptoms, prognosis and therapy response in pediatric cohorts.Aim of the study — characterization of gender, sympthoms, prognosis and therapy in children with mastocytosis using data obtained by electronic parent survey.Methods. The study data was collected from November 2014 till August 2020 from parents referring for consultation of hematologist via “Vkontakte” social network. All parents completed two surveys. The first one was performed right after the referral, the second one was performed from May 2020 to August 2020. The data on age at symptoms onset, family history, symptoms, rash distribution, serum tryptase concentrations, sunlight sensitivity and clinical course was obtained and analyzed.Results. The data on 163 children was obtained, 86 (52.7 %) of them were boys and 77(47.3 %) were girls. The median age was 6 (0.5—22) years. At the end of survey the median observation time was 61.5 (2—276) months. The most common mastocytosis clinical variant was urticaria pigmentosa (n = 129; 79.1 %), mastocytoma in 18 (11 %) and in 15 (9.9 %) an unknown variant was observed. The diagnosis was based on skin biopsy in 19 patients (11.6 %). Characteristic symptoms were seen in 123 (75.4 %) children. The main complaints were skin reaction triggered by various factors (n = 89; 72.3 %) and itching (n = 78; 63.4 %). Most patients took antihistamines (n = 64; 61 %) and ketotifen (n = 22; 21 %). The second survey was conducted in 139 (85.2 %) pts. At the time of survey symptoms progression was seen in 4 (2.9 %) patients, while in 42 (30.2 %) cases stabilization, and in 93 (66.9 %) cases improvement were observed.Conclusion. The symptoms onset mostly occurs in the first year of life. Most frequents symptoms are itching and rash in response to various triggers. Antihistamine drugs led to symptoms mitigation. The clinical course is benign in most children.

The primary care literature lacks information on mast cell activation disease (MCAD) and, more specifically, mast cell activation syndrome, yet it affects approximately 17% of the population. Because many providers remain unaware of MCAD, this article provides a primer on mast cell diseases, including triggers, signs and symptoms, diagnosis, treatment, and resources for patients and providers. Primary care nurse practitioners are uniquely positioned and qualified to identify patients with multiple, diffuse complaints and chronic, multisystem symptoms—the hallmark of MCAD—and refer them for further diagnosis and treatment to reduce debilitating symptoms.

Background Anaphylaxis caused by a catheter itself used for endovascular surgery is rare, and a method for detection of a causative catheter has not been established. We report a case of catheter-induced anaphylaxis in which the causative catheter was successfully detected. Case presentation A 47-year-old male underwent neuroendovascular surgery. During surgery, blood pressure suddenly dropped and the level of tryptase indicated the occurrence of anaphylaxis. There were 24 candidate agents for the cause of anaphylaxis including 8 catheters. We performed the basophil activation test by directly mixing the catheter with blood. One catheter coated with a hyaluronic acid product showed a positive reaction, and we confirmed the result by a modified skin test using an elution solution of the catheter. Later, we successfully completed the neuroendovascular surgery without the catheter. Conclusions The methods used in this case can be useful for the detection of the causative agent in catheter-induced anaphylaxis.

Typical murine models of allergic inflammation are induced by the combination of ovalbumin and aluminum hydroxide. However, accumulating evidence indicates that, in models of asthma and atopic dermatitis, allergic inflammation can be generated in the absence of aluminum hydroxide. Moreover, co-administration of Staphylococcus aureus enterotoxin B with ovalbumin can enhance inflammation. The objective of this study was to establish a rapid and mast cell-dependent murine model of allergic inflammation by inducing allergic peritonitis using ovalbumin and S. aureus enterotoxin B. Allergic peritonitis was induced in C57BL/6 mice by subcutaneous sensitization and intraperitoneal challenge with ovalbumin and S. aureus enterotoxin B. Disease characteristics were assessed by flow cytometry, enzyme-linked immunosorbent assay (ELISA), trypan blue exclusion and colorimetric assays. The time–course of the allergic peritonitis revealed a peak of peritoneal inflammation 48 h after challenge, as assessed by total cells and eosinophil counts. The decrease of cell numbers started 96 h post-challenge, with complete clearance within 168 h. Moreover, significantly higher levels of tryptase and increased vascular permeability were found 30 min following challenge. Allergic inflammation induction by ovalbumin and S. aureus enterotoxin B was impaired in mast cell-deficient mice and partially restored by mice reconstitution with bone marrow-derived mast cells, indicating the mast cell role in this model. We present a novel model of allergic peritonitis that is mast cell-dependent, simple and robust. Moreover, the use of S. aureus enterotoxin B better resembles human allergic inflammation, which is known to be characterized by the colonization of S. aureus.

Hereditary alpha-tryptasemia (HαT) is an autosomal dominant genetic trait found in 4% to 6% of the general population and defined by excess copies of alpha-tryptase at TPSAB1. Elevated basal serum tryptase (sBT >8 ng/mL) is a defining feature of HαT and appears to result from increased pro-alpha-tryptase synthesis and secretion rather than mast cell activation. It is estimated that approximately one-third of individuals with HαT have associated symptoms, including cutaneous, gastrointestinal, atopic, musculoskeletal, autonomic, and neuropsychiatric manifestations. HαT is found at a disproportionately high rate in systemic mastocytosis and idiopathic anaphylaxis, and is a modifying factor that independently increases the incidence and severity of anaphylaxis. The varied phenotypes associated with HαT may, in part, result from coinheritance of other genetic variants, increased expression of α-/s-tryptase heterotetramers, and/or overexpression of pro-alpha-tryptase, although further studies are needed. There is an accurate diagnostic test available to confirm HαT in patients that can be used in combination with sBT to help risk-stratify individuals in whom bone marrow biopsy is being considered. There is no specific treatment for symptoms associated with HαT, and management is focused on controlling clinical manifestations with mast cell mediator antagonists, aspirin, inhalers, epinephrine, omalizumab, and involvement of other specialists.

Background Mast cells (MCs) are known to contribute to both acute and chronic inflammation. Bronchial epithelial cells are the first line of defence against pathogens and a deficient anti-viral response has been suggested to play a role in the pathogenesis of asthma exacerbations. However, effects of MC mediators on bronchial epithelial immune response have been less studied. The aim of this study is to investigate the direct effects of stimulation with MC proteases, tryptase and chymase, on inflammatory and anti-viral responses in human bronchial epithelial cells (HBECs). Method Cultured BEAS-2b cells and primary HBECs from 3 asthmatic patients were stimulated with tryptase or chymase (0.1 to 0.5 μg/ml) for 1, 3, 6 and 24 h. To study the effects of MC mediators on the anti-viral response, cells were stimulated with 10 μg/ml of viral mimic Poly (I:C) for 3 and 24 h following pre-treatment with 0.5 μg/ml tryptase or chymase for 3 h. Samples were analysed for changes in pro-inflammatory and anti-viral mediators and receptors using RT-qPCR, western blot and Luminex. Results Tryptase and chymase induced release of the alarmin ATP and pro-inflammatory mediators IL-8, IL-6, IL-22 and MCP-1 from HBECs. Moreover, tryptase and chymase decreased the expression of E-cadherin and zonula occludens-1 expression from HBECs. Pre-treatment of HBECs with tryptase and chymase further increased Poly (I:C) induced IL-8 release at 3 h. Furthermore, tryptase significantly reduced type-I and III interferons (IFNs) and pattern recognition receptor (PRR) expression in HBECs. Tryptase impaired Poly (I:C) induced IFN and PRR expression which was restored by treatment of a serine protease inhibitor. Similar effects of tryptase on inflammation and anti-viral responses were also confirmed in primary HBECs from asthmatic patients. Conclusion MC localization within the epithelium and the release of their proteases may play a critical role in asthma pathology by provoking pro-inflammatory and alarmin responses and downregulating IFNs. Furthermore, MC proteases induce downregulation of epithelial junction proteins which may lead to barrier dysfunction. In summary, our data suggests that mast cells may contribute towards impaired anti-viral epithelial responses during asthma exacerbations mediated by the protease activity of tryptase.

Fish as an important food source, with the increase of consumption rate, the resulting allergic phenomenon increased year by year. Food allergen in aquatic products was an important allergy-inducing factor, which had a great impact on the body’s tissue, inflammatory factors, immunoglobulin and intestinal flora. The research objective of this study was to evaluate the allergenic risk of turbot parvalbumin (PV) and provided effective biological reference markers for the safety assessment of aquatic products. Results showed PV has high purity, high binding capacity with IgE and IgG, influenced release of inflammatory factors in DCs (IL-6/10/12p70), induced allergic response in mice. PV increased the levels of PV-specific IgE, total IgE, IgG1, monocyte chemotactic protein 1(MCP-1), histamine, tryptase significantly. PV obviously mutagenic effect on spleen, intestinal tissue. Sequencing of microbial diversity showed that microorganism Ruminiclostridium and Alistipes in PV group changed significantly, which proved that the structure of intestinal microorganism has changed. In summary, Turbot parvalbumin triggered fish allergic responses by induced imbalance of inflammatory factors and microbial composition of IL-6/10/12p70, IgE/IgG and Ruminiclostridium, Alistipes. These results indicated that PV had high-risk allergy inducing ability, and the changes of the above indicators provided biological reference markers for risk assessment of the safety of aquatic products intake.

Diffuse Large B-Cell Lymphoma (DLBCL) presents a high clinical and biological heterogeneity, and the tumor microenvironment chracteristics are important in its progression. The aim of this study was to evaluate tumor T, B cells, macrophages and mast cells distribution in GBC and ABC DLBCL subgroups through a set of morphometric parameters allowing to provide a quantitative evaluation of the morphological features of the spatial patterns generated by these inflammatory cells. Histological ABC and GCB samples were immunostained for CD4, CD8, CD68, CD 163, and tryptase in order to determine both percentage and position of positive cells in the tissue characterizing their spatial distribution. The results evidenced that cell patterns generated by CD4-, CD8-, CD68-, CD163- and tryptase-positive cell profiles exhibited a significantly higher uniformity index in ABC than in GCB subgroup. The positive-cell distributions appeared clustered in tissues from GCB, while in tissues from ABC such a feature was lower or absent. The combinations of spatial statistics-derived parameters can lead to better predictions of tumor cell infiltration than any classical morphometric method providing a more accurate description of the functional status of the tumor, useful for patient prognosis.

Tuberculosis (TB) is still a major worldwide health threat and primarily a lung disease. The innate immune response against Mycobacterium tuberculosis (Mtb) is orchestrated by dendritic cells, macrophages, neutrophils, natural killer cells and apparently mast cells (MCs). MCs are located at mucosal sites including the lungs and contribute in host-defence against pathogens, but little is known about their role during Mtb infection. This study investigates the location and characteristics of MCs in TB lesions to assess their contribution to TB pathology. To this purpose, number, location and phenotype of MCs was studied in 11 necropsies of pulmonary TB and 3 necropsies of non-TB infected lungs that were used as controls. MCs were localised at pneumonic areas, in the granuloma periphery and particularly abundant in fibrotic tissue. Furthermore, MCs displayed intracellular Mtb and IL-17A and TGF-β immunostaining. These findings were validated by analysing, post-mortem lung tissue microarrays from 44 individuals with pulmonary TB and 25 control subjects. In affected lungs, increased numbers of MCs expressing intracellularly both tryptase and chymase were found at fibrotic sites. Altogether, our data suggest that MCs are recruited at the inflammatory site and that actively produce immune mediators such as proteases and TGF-β that may be contributing to late fibrosis in TB lesions.

Background Evidence-based guidelines are needed in the United States to improve evaluation of perioperative allergic reactions including recommendations for subsequent anesthesia. Objective To identify causative agent(s) and evaluate patients' tolerability of subsequent anesthesia in patients evaluated by Allergy/Immunology (A/I) at Massachusetts General Hospital. Methods We performed a retrospective review of patients referred to the outpatient A/I clinic for perioperative allergic reactions between October 2003 and May 2017. Patient demographics, atopic history, and prior adverse drug reactions were reviewed. Patients underwent a comprehensive evaluation with testing including skin testing (ST), drug challenges (when appropriate), tryptase level measurement, and specific IgE to latex measurement. Tolerance of subsequent procedures requiring anesthesia was assessed. Results Of 123 patients referred, 74 (60%) were female and the mean age was 46 (±18) years. At least 1 causative agent was identified in 28 patients (24%, n = 28 of 118). Seventeen of 28 (61%) patients were ST positive to an antibiotic, including 13 (46%) positive to cefazolin; 3 patients (11%) had a positive latex specific IgE. Of 85 patients who had subsequent anesthesia with a known outcome, 78 (91%) did not have another perioperative allergic reaction. Two of 5 patients with an elevated baseline tryptase level did not tolerate subsequent anesthesia. Conclusion The majority of patients safely received subsequent anesthesia after comprehensive A/I evaluation for their perioperative allergic reactions; however, improved algorithmic care is needed in the United States. Among ST-positive patients (24%), antibiotics (especially cefazolin) were the most common culprits. An elevated baseline tryptase level was associated with an increased risk of recurrent perioperative allergic reactions.

Suicidal ingestion of food which the victim is aware they are allergic to is an exceptional occurrence in the forensic field. To the best of our knowledge, no cases of suicidal food anaphylaxis have been reported to date. Therefore we present the first case described in the literature. A 30-year-old prisoner was found dead inside his cell with the remains of a peach remains next to his body, and a handwritten farewell note in his pocket. The autopsy revealed only non-specific findings, while laboratory investigations (serological, toxicological, histological, and immunohistochemical) played a pivotal role in determing the cause and manner of death. In particular, a high titer of both total and specific IgE antibodies was detected, as well as an increase of the tryptase level in cadaveric blood. Moreover, a massive concentration of salicylates was measured in the gastric contents. Microscopically, cellular residues characterized by a vegetal structure were observed in the gastric contents and elements suggestive of mast cells were detected in the glottis, lungs, and myocardium. The immunohistochemical investigation with anti-CD117 and anti-tryptase antibodies showed positivity for mast cells, some of which appeared degranulated. Such findings were entirely consistent with an acute systemic anaphylactic reaction triggered by allergy. Therefore, the prisoner’s death was attributed to self-induced food anaphylaxis caused by the ingestion of peaches. This conclusion was achieved based only on circumstantial data, anamnestic information, autopsy findings, and multiple laboratory results. This integrated approach should be used to pursue a post-mortem diagnosis of anaphylaxis.

Ovarian ectopic pregnancy (OEP) represents the rarest type of ectopic pregnancy, accounting for 1-3% of this pathology. The diagnosis of this pathology is challenging due to the non-specific clinical aspects and the ultrasound examination hampered by the lack of visible gestational sac in the presence of hematocele and hemoperitoneum. The purpose of the extended histopathological (HP) examination was to identify particular aspects of the OEP trophoblast and to highlight potential local ovarian modifications which can determine pregnancy fixation at this level. The patient presented local favorable conditions for intraovarian nidation, conditions confirmed by the HP classical examination and by the immunohistochemical evaluation. We identified, using classical Hematoxylin-Eosin, Masson's trichrome and Periodic Acid-Schiff (PAS)-Hematoxylin, necrotic hemorrhage, accentuated vascular thrombosis and high density lymphoplasmocytary infiltrate. These modifications increased local adhesivity and cell destruction through hypoperfusion. Anti-cluster of differentiation antibodies (CD34, CD38, tryptase) revealed the low number of intravillous vessels and the high number of macrophages and mastocytes involved in the local inflammatory process heighten. We identified the presence of trophoblast tissue in the ovarian structure using anti-cytokeratin AE1∕AE3 (CK AE1∕AE3)/anti-cytokeratin 7 (CK7) antibodies. The anti-alpha-smooth muscle actin (α-SMA) and anti-vimentin (VIM) antibodies displayed the density of myofibroblasts and intravillous stromal cells and with the aid of anti-progesterone receptor (PR) antibody, we identified the corpus luteum hormonal response in the OEP. The placental villosities present a blocked multiplication process at the anti-apoptotic B-cell lymphoma 2 (BCL2) protein, confirmed by the Ki67 cell proliferation and tumor protein 63 (p63) immunomarkers. Anti-neuron specific enolase (NSE), anti-calretinin and anti-inhibin A antibodies showed the particular aspects of the granulosa and internal theca cells, which may be involved in oocyte release blockage, intraluteal and extraluteal fecundation of the OEP.

Objective. To study the cellular composition of the human epiphysis. Materials and methods. An immunohistochemical method using cell-specific markers selectively detecting astroglial, endothelial, nerve, and mast cells was employed to study the epiphysis in seven males aged 16–68 years. Antibodies to glial fibrillary acidic protein (GFAP), vimentin, low molecular weight neurofilament proteins (clone 2F11), and mast cell tryptase were used. Results. Immunohistochemical reactions for GFAP in the human epiphysis identified a large number of astroglial processes but few astroglial cell bodies. Cells had relatively small primary processes which were significantly thicker than those of stellate astrocytes in other parts of the brain. Astrocyte processes formed dense plexuses around blood vessels and many concretions. Many cell processes in the stroma and particularly the parenchyma and blood vessel endothelial cells were vimentin-immunoreactive. Coexpression of GFAP and vimentin was not seen in any of the structures studied. Low molecular weight neurofilament proteins were detected in occasional pinealocytes and their processes. Mast cells immunohistochemically labeled for tryptase were detected in all the epiphyseal formations studied (most frequently in the stroma) Conclusions: 1) GFAP-immunopositive astrocytes in the human epiphysis differed in terms of their morphological features from typical stellate astrocytes in other parts of the brain, such that pineal GFAP-immunopositive astrocytes could be placed in a separate subgroup of astrocytes; 2) human epiphyseal astrocytes did not simultaneously contain GFAP and vimentin, in contrast to pineal astrocytes in other mammals; 3) mast cells are a consistent component of the human epiphysis – obligatory in the stroma and facultative in the parenchyma; 4) human epiphyseal pinealocytes express neuron-specific neurofilament protein, which is evidence supporting their neuron-like nature; 5) the localization of neuron-like endocrine cells and significant quantities of immunocompetent mast cells in the human epiphysis define this endocrine organ as an important component of the unified neuroimmunoendocrine system of the body.

Imidazolidinyl urea (IU) is used as an antimicrobial preservative in cosmetic and pharmaceutical products. IU induces allergic contact dermatitis, however, the mechanism has not yet been elucidated. Mas-related G protein-coupled receptor-X2 (MRGPRX2) triggers drug-induced pseudo-allergic reactions. The aims of this study were to determine whether IU activated mast cells through MRGPRX2 to further trigger contact dermatitis. Wild-type (WT) and KitW-sh/HNihrJaeBsmJNju (MUT) mice were treated with IU to observe its effects on local inflammation and mast cells degranulation in vivo. Laboratory of allergic disease 2 cells were used to detect calcium mobilization and release of inflammatory mediators in vitro. WT mice showed a severe local inflammatory response and contact dermatitis, whereas only slight inflammatory infiltration was observed in MUT mice. Thus, MRGPRX2 mediated the IU-induced activation of mast cells. However, histamine, a typical allergen, was not involved in this process. Tryptase expressed by mast cells was the major non-histaminergic inflammatory mediator of contact dermatitis. IU induced anaphylactic reaction via MRGPRX2 and further triggering non-histaminergic contact dermatitis, which explained why antihistamines are clinically ineffective against some chronic dermatitis.

Salivary gland neoplasms represent an important group of cancers in the head and neck and myoepithelial cells play a key role on the development these tumors. This study evaluated the distribution of mast cells and related proteins (PAR-2, TGFβ1, IL-6) to the myofibroblastic differentiation in malignant tumors of salivary glands with and without myoepithelial differentiation. Immunohistochemical assessement for tryptase mast cells, SMA, PAR-2, TGFβ1, IL-6 was performed in 10 cases of polymorphous low-grade adenocarcinoma, 14 cases of mucoepidermoid carcinoma (MEC) and 10 cases of adenoid cystic carcinoma. When the density of mast cells were compared between tumors, their density was significantly higher in MEC (P=0.08). Tumors with high expression of PAR-2 (79.4%) exhibited a high density of mast cells. Myofibroblasts were more frequent in malignant tumors with low expression (

Mastocytosis is a rare group of disorders characterized by abnormal accumulation of mast cells in the skin, bone marrow, and internal organs. In particular, patients with systemic mastocytosis are at an increased risk of frequent and severe episodes of anaphylaxis. Hymenoptera venom allergy is the most common trigger of anaphylaxis in these patients. Immunotherapy is an effective and safe therapy recommended for patients with mastocytosis and venom allergy. Although this therapy can be administered according to different protocols, the preferred protocol for patients with mastocytosis remains unclear. Systemic side effects can occur, in particular, during the up-dosing phase of immunotherapy, making progression to the maintenance phase of therapy challenging. This case report presents the diagnosis and ultrarush immunotherapy process ended with anaphylaxis of a 33-y-old male patient with Apis mellifera allergy.

Haemolysis is reported to be an artefact that may alter post-mortem tryptase levels. However, previous studies did not sample peripheral blood using newly standardised methods. Recent studies have shown that some previously recognised peri- and post-mortem confounders can be muted by careful sample collection with first clamping and then sampling the femoral vein. This prospective study investigated the relationship between the degree of haemolysis of the blood samples and femoral vein post-mortem tryptase levels when sampled using this recommended method. Seventy consecutive post-mortem tryptase levels in non-anaphylactic deaths were compared to the degree of haemolysis of these samples, and results showed no significant correlation between them. The mean post-mortem tryptase level was 9.5 μg/L. This study demonstrated that the effects of haemolysis on femoral vein post-mortem tryptase was negligible when the blood was sampled using the recommended sampling method. Future studies on post-mortem tryptase as well as other typically used blood markers in forensics are recommended to adopt this method of blood sampling in routine practice.

Background: Chronic infection by HIV evolves with a vascular inflammatory action causing endothelial dysfunction. The action of the virus, as well as the side effects of antiretroviral drugs, contribute to the progression of cardiovascular diseases. The present study aimed to evaluate the percentage of collagen fibers and the density of mast cells, chymase and tryptase, in aortas of patients with and without HIV, and also patients with and without atherosclerosis. Methods: Aortic fragments were obtained from autopsied patients aged 22-69 years and selected regardless of the cause of death or underlying disease. The samples were divided into four groups, (1) Group with HIV and with atherosclerosis; (2) Group with HIV and without atherosclerosis; (3) Group without HIV and with atherosclerosis; (4) Group without HIV and without atherosclerosis (Control). The percentage of collagen fibers was analyzed in the intima-media layer and the density of mast cells was analyzed in all aortic layers. Graphpad Prism 5.0® software was used for statistical analysis. Results: There were more collagen fibers in HIV patients, with or without atherosclerosis. The group with HIV and atherosclerosis presented a higher density of chymase and tryptase mast cells. The correlation between collagen fibers and age was negative in the non-HIV group and with atherosclerosis. Conclusion: The inflammatory process resulting from HIV infection may be relevant in the alteration of aortic collagen fibers and in triggering or accelerating atherosclerosis. The study is important because HIV patients have increased risks for the development of cardiovascular diseases, and follow-up is necessary to prevent such diseases.

Background There is no trial to make a diagnostic tool of allergic rhinitis (AR) utilizing biomarkers from nasal fluid. Base on previous studies, we selected following five biomarkers in nasal fluids that represent the characteristics of allergic reactions: tryptase, eosinophil cationic protein (ECP), interleukin 5 (IL-5), Clara cell protein 16 (CC16) and CC16-to-albumin ratio. Objective This study aimed to identify biomarkers in nasal discharge that may be used in biosensors to diagnose AR as an additional diagnostic tool. Methods Patients showed rhinorrhea and tested positive on allergic skin and specific immunoglobulin E (IgE) tests were included in the AR group. The non-AR group included individuals no dominant nasal symptoms and tested negative on allergy tests. Nasal lavage fluid samples were collected from all participants. Biomarkers in the samples were quantified using enzyme-linked immunosorbent assay. Results Forty-five patients with AR and 28 non-AR subjects were enrolled in this study. Comparing the concentrations of biomarkers, the concentrations of tryptase and IL-5 were significantly higher in the AR group than in the NAR group. And CC16 level and CC16-to-albumin ratio were significantly lower in the AR group. In the combination of tryptase or CC16-to-albumin ratio, the sensitivity was 90.7% and the specificity was 64.3% ( p = 0.013). Conclusion The combination of “tryptase or CC16-to-albumin” could be used as a screening tool for AR. Although this diagnostic method could not replace conventional diagnostic tools, we could consider the method we proposed as an additional screening tool for patients who could not undergo allergy tests.

Yan Chen, 1, 2 Jiafei Cheng, 1 Yiling Zhang, 1 Jiande DZ Chen, 1, 3 Florin M Seralu 1 1Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; 2Division of Gastroenterology, Binzhou Medical University Hospital, Binzhou, Shandong, People’s Republic of China; 3Division of Gastroenterology and Hepatology, University of Michigan, Ann Arbor, MI, USACorrespondence: Florin M SeraluDivision of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD, USATel/Fax +1 4105023147Email fselaru1@jhmi.eduJiande DZ ChenDivision of Gastroenterology and Hepatology, University of Michigan, Ann Arbor, MI, USATel +1 7346475749Email Jiandedzchen@gmail.comPurpose: The aim of the study was to investigate the effects of electroacupuncture (EA) at ST36 on rectal hypersensitivity and compliance in DSS-treated post-inflammation rats. In addition, we explored the involvement of mast cells-triggered NGF/TrkA/TRPV1 peripheral afferent pathway.Methods: Rats were provided water with 5% dextran sulphate sodium (DSS) for 7 days. Two weeks after the DSS treatment they were subjected to initial and repetitive EA. Different sets of parameters were compared in the initial test and then EA with the selected parameters were performed for 2 weeks. Rectal compliance was assessed by colorectal distension while visceral sensitivity was evaluated by abdominal withdraw reflexes (AWR) and electromyogram (EMG). Masson’s trichrome staining was performed to stain collagen and toluidine blue staining was applied to assess the degranulation of mast cells. Nerve growth factor (NGF), tryptase, TrkA and TRPV1 were measured by Western blot or immunofluorescence staining.Results: EA at 100 Hz was more effective in improving rectal compliance and visceral hypersensitivity. Daily EA improved visceral hypersensitivity but not rectal compliance. Five weeks after DSS treatment, fibrosis was noted in both sham-EA and EA groups. The expression and activation of mast cells were significantly reduced after the 2-week EA treatment with a concurrent decrease in the expression of colonic NGF/TrkA and TRPV1 in both colon and dorsal root ganglions.Conclusion: EA at ST36 with a special set of parameters has no effect on reduced rectal compliance but relieves visceral hypersensitivity via the mast cells-triggered NGF/TrkA/TRPV1 peripheral afferent pathway in DSS-treated post-inflammation rats.Keywords: electroacupuncture, inflammation remission, ulcerative colitis, visceral hypersensitivity, mast cellsErratum for this paper has been published

Mast cells (MC) are immune cells that produce a variety of mediators, such as proteases, that are important in the body’s immune responses. MC proteases have pronounced multifunctionality and in many respects determine the biological characteristics of the organ-specific MC population. Although, increased numbers of MC are one of the objective mastocytosis signs, a detailed assessment of the proteases biogenesis and excretion mechanisms in the bone marrow (BM) has not yet been carried out. Here, we performed an analysis of the expression of proteases in patients with various forms of systemic mastocytosis. We presented data on intracellular protease co-localization in human BM MCs and discussed their implication in secretory pathways of MCs in the development of the disease. Systemic mastocytosis, depending on the course, is featured by the formation of definite profiles of specific proteases in various forms of atypical mast cells. Intragranular accumulation of tryptase, chymase and carboxypeptidases in the hypochromic phenotype of atypical mast cells is characterized. Characterization of MC proteases expression during mastocytosis can be used to refine the MC classification, help in a prognosis, and increase the effectiveness of targeted therapy.

Mast cells cyclically synthesize and excrete a wide range of biogenesis products with different biological activities into the extracellular matrix and are regulators of local homeostasis both in normal conditions and in pathology – inflammation, oncogenesis, etc. The relative specificity of classical histochemical methods for detecting mast cells in relation to chromogenic to substrates causes certain difficulties in the selective study of the components of the secretome of mast cells, for example, heparin, histamine, chymase or tryptase. Therefore, immunomorphological techniques have become very popular, which identify specific substrates and allow differentiation of the components of the mast cell secretome. Mediators produced by mast cells promote neoangiogenesis, fibrillogenesis and re-epithelialization during the repair process.The aim of our work was to study the tryptase profile of the mast cell population of rat skin during the wound processusing an original combined method of immunohistochemical staining.Material and methods. The experiment involved 12 Wistar rats divided into two groups – intact (n=6) and with the existing wound process of the skin in the withers (n=6). The tryptase profile of mast cells was assessed on the 7th day of the wound process in comparison with the control group.Results. The results obtained showed a significant increase in the number of tryptase-positive mast cells on the 7th day of the wound process in the skin against the background of a general increase in the population of mast cells. Intragranular tryptase reserve was significantly increased. In contrast to the control, where mast cells with single tryptase-positive granules dominated, during the wound process, cells of this type were practically not detected in the skin (43.69±2.9% and 8.55±0.9%). The content of tryptase-positive mast cells with complete filling of the cytoplasm in the control group and the group of animals with a wound process was 14.24±1.2% and 38.03±2.9%, respectively.Conclusion. Thus, when modeling a wound, an increase in tryptase synthesis is detected both in individual MCs and within the entire MC population. This fact indicates that mast cell proteases can become a potential therapeutic target for improving wound regeneration by correcting immunogenesis, inflammation and fiber formation.

Mastocytosis is a hematopoietic neoplasm characterized by expansion of KIT D816V-mutated clonal mast cells in various organs and severe or even life-threatening anaphylactic reactions. Recently, hereditary α-tryptasemia (HαT) has been described as a common genetic trait with increased copy numbers of the α-tryptase encoding gene, TPSAB1, and associated with an increased basal serum tryptase level and a risk of mast cell activation. The purpose of our study was to elucidate the clinical relevance of HαT in patients with mastocytosis. TPSAB1 germline copy number variants were assessed by digital polymerase chain reaction in 180 mastocytosis patients, 180 sex-matched control subjects, 720 patients with other myeloid neoplasms, and 61 additional mastocytosis patients of an independent validation cohort. α-Tryptase encoding TPSAB1 copy number gains, compatible with HαT, were identified in 17.2% of mastocytosis patients and 4.4% of the control population (P < .001). Patients with HαT exhibited higher tryptase levels than patients without HαT (median tryptase in HαT+ cases: 49.6 ng/mL vs HαT− cases: 34.5 ng/mL, P = .004) independent of the mast cell burden. Hymenoptera venom hypersensitivity reactions and severe cardiovascular mediator-related symptoms/anaphylaxis were by far more frequently observed in mastocytosis patients with HαT than in those without HαT. Results were confirmed in an independent validation cohort. The high prevalence of HαT in mastocytosis hints at a potential pathogenic role of germline α-tryptase encoding TPSAB1 copy number gains in disease evolution. Together, our data suggest that HαT is a novel emerging robust biomarker in mastocytosis that is useful for determining the individual patient´s risk of developing severe anaphylaxis.

In the present study, the influence of lipid emulsion on the allergenicity of digestion products of fish parvalbumin (PV) was investigated, which was initially subjected to simulated gastric/intestinal digestion both under emulsified and non-emulsified conditions. The release of β-hexosaminidase (β-hex), histamine (His), tryptase (TPS), interleukin 4 (IL-4), and IL-13 in RBL cells was decreased by 79.32, 26.19, 41.67, 53.95 and 54.40%, respectively, following stimulation with the gastric digestion products of PV. Whereas, lipid emulsified digestion products of PV (e-PV) significantly enhanced the release of active mediators and cytokines. The digestion products of emulsified PV at 180 min resulted in a higher release of β-hex (197.60%), His (12.18%), TPS (38.85%), IL-4 (48.19%) and IL-13 (59.40%), as compared to that of PV. However, no obvious differences in the release of active substances and cytokines were noted between intestinal digestion products of PV and intestinal digestion products of emulsified PV. In the mouse model studies, digested PV products reduced the anaphylactic scores, whereas e-PV manifested a higher level of allergic symptoms. Moreover, mice treated with 50% e-PV had significantly higher levels of specific IgE (32.56%), total IgE (16.67%) and total IgG1 (5.15%) than those treated with 50% PV. Mice treated with 50% e-PV had significantly higher levels of His (8.50%) and TPS (10.07%) compared with mice treated with 50% PV. Lipid emulsions altered the digestibility of PV in gastrointestinal digestion and enhanced the allergenicity of PV digestion products at the cellular levels, subsequently posing a higher risk of allergic reactions in susceptible individuals.

Hypoxia exposure often cause the increases of pulmonary arterial pressure (PAP). Studies reported that mast cells (MCs) participate in pulmonary vascular remodeling and promote the formation of chronic pulmonary hypertension. Current studies mainly focus on the change of MCs under chronic hypoxia, but few studies on the regulatory role and mechanism of MCs under acute hypoxia. T herefore, present study investigated the dynamic change of MCs in lung tissues under acute hypoxia and the role of MCs activation in the increasement of PAP. In our study, we established an experimental rat model of acute hypobaric hypoxia using a hypobaric chamber (simulated altitude of 7,000 m) and pretreated with MCs degranulation inhibitor sodium cromoglycate (SCG) to study the MCs changes under acute hypoxic exposure. We found that acute hypobaric hypoxia contributed to the increased quantity, activity, and degranulation of MCs and SCG pretreatment showed attenuated PAP elevation under acute hypoxia. Our findings implied that there is a possible mechanism of acute hypoxia cause rapid recruitment of MCs, activation, and explosive degranulation to release Tryptase, Chymase, IL-6, His, 5-HT, and Ang II, which further contributed to pulmonary microvascular contraction and increase in PAP. This work extends the knowledge about MCs, providing a potential profile of MCs as an alternative treatment for high-altitude pulmonary edema (HAPE)-related increased pulmonary artery pressure.

Introduction: Mast cells and their major protein, the serine proteinase tryptase, can be involved in cutaneous photodamage and carcinogenesis. The serum test of tryptase (S-tryptase) measures total tryptase protein (active tryptase and inactive protryptases), and S-tryptase is elevated in a variety of diseases, for example, in mastocytosis and α-tryptasemia. Objectives: The objective of this study is to study whether S-tryptase is a marker of cutaneous photodamage and carcinogenesis. Methods: Adult subjects (n = 399, aged 21–79) evaluated to be at risk for skin cancers were recruited at the dermatological policlinic and examined for photodamage severity, mole count, actinic keratoses (AKs), skin cancers, and immunosuppression (IS). A blood sample was analyzed for S-tryptase using the ImmunoCAP® Tryptase fluoroenzymeimmunoassay. Results: There was no difference in S-tryptase between non-IS (n = 321) and IS (n = 78) subjects or between genders. S-tryptase correlated slightly to photodamage and AKs in 321 non-IS subjects, and this association can be related, in part, to the age of subjects. In 34 subjects, S-tryptase was elevated (≥13.5 ng/mL), and in 20 males, but not in 14 females, the photodamage level was significantly (p = 0.031) more severe than in 179 males with normal S-tryptase. In contrast, there were more frequently subjects (n = 12) with past or present skin cancer (basal or squamous cell carcinoma or melanoma) in 14 females with elevated S-tryptase than in 186 female controls. So far, no explanation has been found for the elevated S-tryptase. Conclusion: There are significant associations between elevated S-tryptase and skin carcinogenesis, but the molecular mechanisms are unclear and gender differences can exist.

Epithelial damage and increase of intraepithelial mast cells (MC) are characteristics of asthma. The role of MC mediator tryptase and the protease-activated receptor-2 (PAR2) on epithelial wound healing is not fully investigated. Stimulation of bronchial epithelial cells (BECs) with tryptase promoted gap closure, migration and cellular speed compared to controls. Stimulated BECs had higher expression of migration marker CD151 compared to controls. Proliferation marker KI67 was upregulated in tryptase-stimulated BECs compared to controls. Treatment with PAR2 antagonist I-191 reduced gap closure, migration and cell speed compared to BECs stimulated with tryptase. We found that tryptase enhances epithelial wound healing by increased migration and proliferation, which is in part regulated via PAR2. Our data suggest that tryptase might be beneficial in tissue repair under baseline conditions. However, in a pathological context such as asthma with increased numbers of activated MCs, it might lead to epithelial remodeling and loss of function.