Morphology Of Mast Cells Research Articles

Electroacupuncture preconditioning prevents urticaria by regulating inflammatory response in rats with urticaria

To observe the effect of electroacupuncture (EA) preconditioning at "Quchi" (LI11) and "Xuehai" (SP10) in prevention of urticaria. Twenty-four male SD rats were randomly divided into control, model and preconditioning of EA (Pre-EA) groups (8 rats/group). The urticaria model was established by intradermal injection of dilute allogeneic antioalbumin serum at the spots of the bilateral symmetry of the spine on the back, and followed by tail venous injection of mixture solution of egg albumin diluent, plus 0.5% Evans blue and normal saline. Ten days before the end of modeling, rats of the pre-EA group received EA stimulation of LI11 and SP10 for 20 min, once a day for 10 consecutive days. The times of rat's scratching the sensitized skin were recorded. HE staining method was used to observe the pathological changes of skin tissue, and toluidine blue staining method was used to observe the morphology of mast cells (MCs) in the skin, blood, mesentery, and peritoneal fluid, and calculate the degranulation rate. Immunohistochemical stainning was used to detect immunoglobulin E (IgE), histamine (HIS), and 5-hydroxytryptamine (5-HT) expressions in subcutaneous tissue. NOD like receptor thermal domain associated protein 3 (NLRP3) inflammasome, apoptosis related granule protein (ASC), and cysteine aspartate aminotransferase 1 (Caspase-1) protein expression levels in skin tissue were detected by Western blot. The contents of serum interleukin(IL)-1β and IL-18 were detected using ELISA method. Compared with the control group, the scratching times, amount of Evans blue exudation of the sensitized blue spots, degranulation rate of MCs in skin, blood, mesentery and peritoneal fluid, the expression levels of IgE, HIS, 5-HT in subcutaneous tissue, protein expression levels of NLRP3, ASC, Caspase-1 in skin tissue, and the contents of serum IL-1β and IL-18 were significantly increased (P<0.01, P<0.05) in the model group. In comparison with the model group, the scratching times, amount of Evans blue exudation of the sensitized blue spots, degranulation rate of MCs, the expression levels of IgE, HIS, 5-HT in subcutaneous tissue, protein expression levels of NLRP3, ASC, Caspase-1 in skin tissue, and the contents of serum IL-1β and IL-18 in EA group were significantly decreased (P<0.01, P<0.05). EA preconditioning at LI11 and SP10 can prevent and treat UR by inhibiting inflammatory response, which is related to the regulation of pyroptosis.

The effects of age, origin, and biological sex on rodent mast cell (BMMC and MC/9) and basophil (RBL-2H3) phenotype and function

Mast cells initiate allergic inflammatory immune responses and play a role in disease by releasing various inflammatory and immunomodulatory mediators. Several mast cell-lines and primary cultured cells have been used as mast cell models with inconsistent results among research groups. Bone marrow-derived mast cells (BMMC) cultured from mouse bone marrow progenitor cells are often used as a representative model of mucosal mast cell behaviour, however their reported phenotype is variable due to inconsistent culture protocols. RBL-2H3 is a rat basophilic histamine-releasing cell line that has some characteristics of both mast cells and basophils but is not a true representation of either cell type. The murine mast cell line MC/9 is an IL-3-dependent mucosal mast cell model but has limited mast cell characteristics. In this study, we have compared the response of BMMC (derived from C57BL/6 male or female mice), two sources of RBL-2H3 (purchased directly from ATCC and a lab curated culture), and MC/9 (ATCC) at several critical stages to some common stimuli (IgE/Ag, A23187) and analyzed mast cell morphology, expression level of common mast cell surface markers (CD117 and FcεRI), protease expression, and function (growth kinetics, viability, ROS production, degranulation, cytokine release and FcεRI signaling). The objective of this study was to provide insight into the effects of culture conditions, biological sex, and age of the cells on variability among reported phenotypes and, to determine optimal conditions for activation of these cells. Our data show that factors that are often overlooked such as source, age and biological sex of mast cells play an integral role in phenotypic outcomes and may account for the reported variability in their function.

Cutaneous Lesions of Mastocytosis: Mast Cell Count, Morphology, and Immunomolecular Phenotype.

Mastocytosis is a condition characterized by accumulation of clonal mast cells (MCs) that often involves the skin. Pathologists are often challenged with skin biopsies with a question of cutaneous lesions of mastocytosis (CLM) including cutaneous mastocytosis, mastocytosis in the skin, or systemic mastocytosis. The histopathological criteria for CLM remain poorly defined due to heterogeneity of the published literature and the lack of comparative prospective studies. MC count is greatly influenced by detection and counting techniques, criteria for viable MCs used, anatomical location biopsied, and the dermal level that is analyzed. Although MC numbers in CLM can be significantly higher compared with healthy controls and a patient with other inflammatory skin diseases, in some instances, considerable overlap exists. Based on the largest studies published, it is suggested that a number of MCs between 75 and 250 MCs/mm 2 are a range in which CLM should be considered and, above 250 MC/mm 2 , a diagnosis of CLM can be made. A recent study showed a high specificity of >95% of a MC count >139 MC/mm 2 compared with patients with other inflammatory skin diseases. Noteworthy, the total number and percentage of MCs is significantly higher in children compared with adults, particularly in polymorphic maculopapular cutaneous mastocytosis. In difficult cases, ancillary techniques such as D816V mutation analysis on formalin-fixed paraffin-embedded tissue have a high sensitivity and specificity. There is no enough evidence that immunohistochemistry of CD25, CD2, or CD30 has any additional value in the diagnosis, subtyping, or clinical course of mastocytosis.

Age and sex influence cultured rodent mast cell and basophil responses to antigen

Abstract Mast cells initiate allergic inflammatory immune responses and play a role in disease by releasing various inflammatory and immunomodulatory mediators. Several mast cell-lines and primary cultured cells have been used as mast cell models with inconsistent results among research groups. Bone marrow-derived mast cells (BMMC) cultured from mouse bone marrow progenitor cells are often used as a representative model of mucosal mast cell behaviour, however their reported phenotype is variable due to inconsistent culture protocols. RBL-2H3 is a rat basophilic histamine-releasing cell line that has some characteristics of both mast cells and basophils but is not a true representation of either cell type. The murine mast cell line MC/9 is an IL-3-dependent mucosal mast cell model but has limited mast cell characteristics. In this study, we have compared the response of BMMC (derived from C57BL/6 male or female mice), two sources of RBL-2H3 (purchased directly from ATCC and a lab curated culture), and MC/9 (ATCC) at several critical stages to some common stimuli (IgE/Ag, A23187) and analyzed mast cell morphology, expression level of common mast cell surface markers (CD117 and FcɛRI), protease expression, and function (growth kinetics, viability, ROS production, degranulation, cytokine release and FcɛRI signaling). The objective of this study was to provide insight into the effects of culture conditions, biological sex, and age of the cells on variability among reported phenotypes and, to determine optimal conditions for activation of these cells. Factors that are often overlooked such as source, age and biological sex of mast cells play an integral role in phenotypic outcomes and may account for the reported variability in their function. National Research Council Canada

Study of mast cell density, distribution and morphology in skin lesions of leprosy

Background: Mast cells are found at all levels of dermis, grouped around blood vessels, nerves and appendages. An increase in the mast cell number has been reported in various cutaneous diseases. Mast cells respond to diverse range of stimuli like neuronal impulses, allergens, antigens, hormones, cytokines from T cells and keratinocytes and thus play a role in manifestation of dermatological disorders. The objective was to study mast cell density in various subsets of Hansen’s disease and analyse whether the distribution and density vary amongst the subsets. Methods: A total of 60 skin biopsies diagnosed as leprosy were included in this study. 10 control slides were also studied for mast cell density and distribution. Histopathological diagnosis was made on the biopsy and mast cell density and distribution was assessed on toluidine blue stained sections and compared with those of controls. Results: All the subsets of Hansen’s disease studied showed an increase in the number of mast cells. The highest mean mast cell count was noted in lepromatous leprosy (66/mm2), followed by erythema nodosum leprosum (42.6/mm2) and borderline lepromatous leprosy (40.8/mm2). The mean mast cell count showed progressive increase over the immunological spectrum of tuberculoid leprosy to lepromatous leprosy. The mast cells showed spindle and ovoid morphology in all the lesions (active) while round morphology was seen in controls. Conclusion: Tissue mast cell number, distribution and morphology vary depending on the degree of activation in different leprosy lesions. This may have a bearing on the diagnosis and management. Keywords: mast cells; lepromatous leprosy; tuberculoid leprosy; borderline tuberculoid; indeterminate leprosy

Reappraisal of Mast Cell Leukemia Based on a Single Institution Review of 16 Cases: Role of Mast Cell Morphology in Determining Clinical Outcome

Background: Mast cell leukemia (MCL) is the leukemic variant of systemic mastocytosis (SM); in addition to meeting conventional diagnostic criteria for SM, it is defined by presence of ≥20% mast cells (MC) in the bone marrow (BM) aspirate smear. Presence of circulating MC is not mandatory; MCL is subclassified into leukemic and aleukemic variants based on whether MC comprise ≥10% or <10% of circulating leukocytes, respectively. Given the rarity of MCL, important disease aspects remain incompletely defined, including frequency of evolution from antecedent SM, frequency of associated hematological neoplasm (AHN), prevalence of KITD816V/other mutations, and the prognostic relevance/reproducibility of MC morphology. Furthermore, MCL (as currently defined) has a variable clinical course, with acute and chronic disease variants being recognized; one pitfall is that the latter group may be clinically indistinguishable from other SM subtypes with high BM MC burden. The aim of the current project is to identify clinical, laboratory and pathology features that determine prognosis/survival outcome in MCL patients. Methods: The Mayo Clinic clinical and hematopathology databases were interrogated to identify MCL cases. Patients were retrospectively recruited after confirming research authorization and institutional review board approval. The diagnosis of MCL was per conventional diagnostic criteria. Clinical and laboratory data were collected at the time of MCL diagnosis. BM slides were reviewed by 3 hematopathologists (KKR, KK, and DC), with each slide set being independently reviewed by at least 2 pathologists, using prespecified criteria. MC were classified as either mature (atypical MC type I) or immature (atypical MC type II [promastocytes] and metachromatic blasts) based on the predominant MC population identified. (Valent et al., Ann Oncol. 2014 Sep;25(9):1691-1700). Patient follow up was updated in July 2022; data were censored at last follow up or death. Results: A total of 16 MCL patients were identified (8 females, median age 65 years, range 41-75). Six patients (37%) had de novo MCL; the remaining had antecedent mast cell disease (smoldering SM=4, aggressive SM=3, SM+AHN=2, cutaneous mastocytosis=1). The AHN in 2 patients was CMML and MDS/MPN-unclassifiable, respectively. Four patients (25%) had biopsy confirmed cutaneous involvement. Ten (63%) and 9 (64%) patients had hepatomegaly and splenomegaly, respectively. Median (range) hemoglobin was 9.7 g/dL (7.2-11.9), leukocytes 8.7 x 109/L (0.7-43.9), platelets 123 x 109/L (14-633), serum tryptase 614 ng/mL (69-1684), and serum albumin 3.7 g/dL (2.6-4.7). B- and C-findings were present in 15 (94%) and 12 (75%) patients, respectively. Seven (44%) and 5 (31%) patients had circulating MC and blood eosinophil count >500/µL, respectively. Nine of 13 (69%) and 3 of 14 (19%) evaluable patients harbored KITD816V and abnormal karyotype, respectively. Seven (44%) patients displayed a predominantly 'immature’ MC morphology. After a median follow up of 3.9 months, 12 deaths were recorded. The median OS was 15 months; 2 patients underwent allogeneic stem cell transplant (ASCT). Factors associated with significantly inferior overall survival (OS) on univariate analysis were: immature MC morphology (median OS 0.5 vs 20 months; p<0.01), peripheral blood eosinophilia (p<0.01), and absence of KITD816V (p=0.03). No survival difference was seen in 4 patients treated with midostaurin and/or avapritinib. On multivariable analysis, immature MC morphology retained significance for OS (Figure); among 7 patients with immature MC morphology, 5 had died within a month of their diagnosis, while 2 remain alive at 0.2- and 1-months follow-up. By contrast, among 9 patients with mature MC morphology, 7 had died after a follow-up period of 2.5-59 months, including one receiving ASCT and died at 16 months follow-up, while 2 remain alive at 5.6- and 164.2-months follow-up, the latter post-ASCT. Treatment details and NGS data (7 patients) will be presented at the meeting. Conclusions: The current study identifies immature MC morphology as the most important predictor of inferior survival in MCL. Our observations suggest the need to refine current diagnostic criteria for MCL, in order to distinguish a biologically distinct patient population with a uniformly poor clinical outcome (i.e., 'true’ MCL) from those with more favorable outcome, despite high MC burden. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Histopathological characteristics are instrumental to distinguish monomorphic from polymorphic maculopapular cutaneous mastocytosis in children.

BackgroundMastocytosis is characterized by the accumulation of mast cells (MCs) in the skin or other organs, and can manifest at any age. A significant number of paediatric mastocytosis cases persist after puberty. In particular, monomorphic maculopapular cutaneous mastocytosis (mMPCM) is often persistent and associated with systemic mastocytosis. However, clinical differentiation of MPCM from polymorphic (p)MPCM can be difficult.AimTo identify histopathological features that can help to distinguish mMPCM from other subtypes of paediatric mastocytosis.MethodsThis was a retrospective study using skin biopsies from patients with any subtype of mastocytosis. The localization and density of the MC infiltrate, MC morphology and expression of aberrant markers were evaluated and correlated with clinical characteristics.ResultsIn total, 33 biopsies were available for evaluation from 26 children [(10 with mMPCM, 5 with mastocytoma, 3 with diffuse cutaneous mastocytosis (DCM), 8 with pMPCM)] and 7 adults with MPCM. The MC number was increased in all patients, but was higher in children than adults (P < 0.01). The presence of mMPCM was associated with sparing of the papillary dermis from MC infiltration, whereas MC density in the papillary dermis was highest in pMPCM and DCM (P < 0.01). The positive predictive value of the presence of a reticular MC infiltrate for mMPCM was 72.7% (95% CI 51.4–87.0), and the negative predictive value was 83.3% (95% CI 42.2–97.2). There were no relevant differences in the expression of CD2, CD25 or CD30 between the different subtypes.ConclusionSkin histopathology might enhance the phenotypical differentiation of mMPCM from other subtypes in children, thereby increasing the accuracy of one's prognosis.

P1027: RESPONSES TO AVAPRITINIB IN PATIENTS WITH ADVANCED SYSTEMIC MASTOCYTOSIS: HISTOPATHOLOGIC ANALYSES FROM EXPLORER AND PATHFINDER CLINICAL STUDIES

Background: Systemic mastocytosis (SM) is a mast cell (MC) neoplasm driven by the KIT D816V mutation in ~95% of cases. Diagnosis includes evaluation of MC aggregates in extracutaneous organs, atypical MC morphology, and MC immunophenotype. Avapritinib, a potent and selective KIT D816V inhibitor, has been approved in the US for patients with advanced SM (AdvSM) based on the phase 1 EXPLORER and phase 2 PATHFINDER studies. Aims: Here, we describe a comprehensive evaluation of the effect of avapritinib on bone marrow (BM) pathology in patients treated in these studies. Methods: Patients aged ≥18 years with diagnoses of AdvSM per local investigator were treated with once-daily avapritinib <200 mg (n=17), 200 mg (n=126), and ≥300 mg (n=50). Bone marrow biopsies (BMBs), aspirates (BMAs), and peripheral blood (PB) smears were obtained at screening, and after 8 and 24 weeks of treatment with avapritinib. Evaluations were performed using standard Wright-Giemsa and H&E staining, and IHC was performed on formalin-fixed EDTA-decalcified BMBs using standard techniques for CD25 and CD30. Changes in fibrosis were assessed by the European Consensus on grading of BM fibrosis (MF score). Results: As of April 2021, 193 patients enrolled in EXPLORER (n=86) and PATHFINDER (n=107) were included in analyses with centrally confirmed diagnoses of aggressive SM (n=29), SM with an associated hematologic neoplasm (n=119), mast cell leukemia (n=28), indolent SM (n=14), smoldering SM (n = 2) or CMML (n=1). Median (range) age was 67 years (31–88), 56% were male and 88% had a KIT D816V mutation. Following treatment with avapritinib, a decrease in the proportion of patients with multifocal dense aggregates of MCs in BMBs was observed from 93% at screening to 50% by Week 8 (Table). Avapritinib treatment reduced the proportion of aberrant CD25+ and CD30+ MCs in BMBs by Week 8 and Week 24 (Table). In BMAs, avapritinib reduced the mean MC burden from 11% of total nucleated cells at screening to 2% at Week 8 and by Week 24, with reduced proportions of immature and spindle-shaped MCs (Table). Of 9 patients with circulating MCs at screening and post-screening sample measurements (6 with SM with associated hematologic neoplasm diagnoses and 3 with MCL), 8 had no detectable MCs in PB by Week 8. The proportion of patients with fibrosis in BMBs decreased from 96% (178/186) at screening to 90% (142/158) at Week 8 to 84% (103/123) through week 24, and MF scores were reduced during avapritinib treatment in those patients presenting with increased fibrosis at screening (Table). Image:Summary/Conclusion: Patients treated with avapritinib were observed to have rapid (Week 8) and marked (Week 24) reductions in neoplastic BM MCs with a return to a normal morphologic appearance and immunophenotype. This was accompanied by an improvement of fibrosis and a decrease in circulating MCs. These improvements in disease histopathology provide further support that treatment with this highly selective and potent KIT D816V inhibitor is disease modifying in AdvSM.

Standards of Pathology in the Diagnosis of Systemic Mastocytosis: Recommendations of the EU-US Cooperative Group

Pathology plays a central role in the diagnosis of systemic mastocytosis (SM), its delineation from other neoplasms and reactive conditions, and in monitoring of SM under therapy. The morphologic hallmark of SM is the accumulation of spindle-shaped, hypogranulated mast cells (MCs) in bone marrow (BM) and other extracutaneous tissues. Four of the 5 World Health Organization-defined diagnostic criteria (ie, compact MC aggregates [=major criterion]; atypical MC morphology; activating KIT point mutations; aberrant expression of CD25 and/or CD2 and/or CD30 in MCs [=minor criteria]) can be addressed by the pathologist. The final classification of SM variants as either BM mastocytosis, indolent SM, smoldering SM, aggressive SM (ASM), SM with an associated hematologic neoplasm (SM-AHN), or MC leukemia (MCL) has important prognostic significance and requires the integration of certain morphological, clinical, radiological, and biochemical data, referred to as B- and C-findings. Substantial diagnostic challenges may be posed to the pathologist and clinician especially in the so-called advanced SM variants, that is, ASM, MCL, and SM-AHN. In this article, updated recommendations of the EU-US Cooperative Group regarding standards of pathology in the diagnosis of SM, presented during the year 2020 Working Conference held in September in Vienna, are reported.

Effects of Nitric Oxide on the Electrical Activity of the Rat Trigeminal Nerve and Mast Cell Morphology

Effects of Nitric Oxide on the Electrical Activity of the Rat Trigeminal Nerve and Mast Cell Morphology

The presence of mast cells in lichen planopilaris and discoid lupus erythematosus of the scalp: A quantitative study.

Histopathologic differentiation of lichen planopilaris (LPP) and discoid lupus erythematosus (DLE) as two common causes of primary cicatricial alopecias remains challenging. We performed a histopathologic study on a case series of LPP and DLE specimens to investigate the number, distribution, and morphology of mast cells as indices for differentiation of these two entities. H&E investigation and Giemsa staining for the detection of mast cells was performed. A total of 74 cases comprising 50 cases of LPP and 24 cases of DLE were assessed. The mean mast cell count and percentage were significantly higher in LPP group (p < 0.001). Mean degranulated mast cell count and the mean intact mast cell count were also significantly higher in LPP patients (p < 0.001). Most of the specimens, 58 (78.4%), showed both perifollicular and perivascular distribution of mast cells without significant difference between two groups. The morphology of mast cells was predominantly round-oval in 85.5%, predominantly fusiform in 13.5% with more frequent fusiform morphology in DLE group. The mast cell count detected by Giemsa staining could assist pathologists in distinguishing between LPP and DLE.

Quantity (Number) and Quality (Morphology) Comparison of Mast Cells in Healthy and Diseased Gingiva

Introduction: Comprehending the pathogenesis of chronic periodontitis is helpful in the prevention of this disease. Since there are conflicting results regarding the role of mast cells in periodontitis, the aim of this study was to compare mast cell counts and morphology in periodontitis with clinically healthy gingiva.&#x0D; Materials and Methods: This cross sectional case-control study was performed on 36 gingival samples (obtained from 14 patients with chronic periodontitis and 22 cases with clinically healthy gingiva among those referred to a specialized medical center in 2013. Toluidine blue and hematoxylin -eosin staining was used to identify mast cells. The total number of mast cells (intact and degranulated) was counted under the light microscope in 5 consecutive high power fields (10×40) with no overlap. Data were recorded and analyzed statistically by SPSS 22 and Independent T-test. All of the data with a statistical significance (p value &lt; 0.05) were analyzed.&#x0D; Results: According to Independent t-test, mean number of degranulated mast cells in periodontitis group was 17.78 and in healthy gingiva group was 29.72 which was not statistically significant(p value = 0.071). Mean number of mast cells in periodontitis group was 20.57 and in healthy gingiva was 36.54 and was statistically significant (p value = 0.042). Mast cell degranulation proportion in periodontitis group was 0.857 and in healthy gingiva group was 0.866, not statistically significant (p value = 0.891).&#x0D; Conclusion: According to results of present study it can be concluded that total number of mast cells and proportion of degranulated mast cell to the total number showed no significant relationship but the total number of mast cell was significantly increased in healthy group.

Efficacy of Avapritinib in Patients with Advanced Systemic Mastocytosis: Hematologic and Bone Marrow Responses from the Phase 2 Open-Label, Single-Arm, Pathfinder Study

Efficacy of Avapritinib in Patients with Advanced Systemic Mastocytosis: Hematologic and Bone Marrow Responses from the Phase 2 Open-Label, Single-Arm, Pathfinder Study

Distinct Diagnostic and Clinical Features of Bone Marrow Mastocytosis: A Study of the Registry of the European Competence Network on Mastocytosis (ECNM)

Abstract Background. Bone marrow mastocytosis (BMM) is characterized by accumulation of neoplastic mast cells (MC) in the bone marrow (BM), absence of skin lesions and lack of overt infiltration of other extra-cutaneous organs by neoplastic MC. Although clinically relevant due to its association with life-threatening anaphylaxis, BMM is considered a provisional sub-entity of indolent systemic mastocytosis (ISM) in the 2016 WHO classification. Aims and methods. To define clinical and biological features of BMM we evaluated 1,343 adult patients (pts) with non-advanced systemic mastocytosis (SM) enrolled in the European Competence Network on Mastocytosis (ECNM) registry. The following characteristics were compared between pts with BMM (n=260), ISM (n=1,027) and smouldering SM (SSM, n=56): age, gender, diagnostic criteria, biochemical parameters at diagnosis [blood counts, albumin, alkaline phosphatase (AP), lactate dehydrogenase, tryptase], presence of mediator-related symptoms (diarrhea, flushing, headache, pruritus, hypotension, blistering, cramping, bone pain) and their severity (classified according to Valent P. et al. Eur J Clin Invest. 2007;37:435-53), constitutional symptoms, osteoporosis/osteopenia and allergy. The Student- t and the χ2 tests were used to assess the statistical significance of differences for continuous and categorical variables, respectively. Event-free survival (EFS) was calculated from diagnosis to progression into more severe SM (i.e. SSM, aggressive SM, SM associated with another hematological neoplasm or mast cell leukemia) or death. Results. Median age at diagnosis was 53 years (yrs) (range 19-83) for BMM vs 46 yrs (range 19-82) for ISM vs 52 yrs (range 25-79) for SSM (p 20 ng/mL at diagnosis, while 77% of ISM and 100% of SSM pts fulfilled this criterion. If performed, atypical MC morphology in BM smears, aberrant MC immunophenotype (i.e. CD25 and/or CD2 expression) and KIT D816V mutation were demonstrable in the majority of pts (CD25 and/or CD2-positive BM MC: n=918, 95%; KIT D816V positive: n=910, 86%), without differences between the three groups. As a consequence, in 31% of BMM and 11% of ISM cases the diagnosis was made on the basis of minor criteria only. BMM pts had significantly higher hemoglobin levels compared to pts with ISM/SSM (median 14.5 vs 13.9 g/dL, respectively, p BMM pts had less frequent and less severe (grade 0-2) mediator-related symptoms as compared to ISM/SSM, except for hypotension, mainly due to the association of BMM with severe allergic reactions. Indeed, 76% of the BMM pts had a history of anaphylaxis, a significant difference compared to ISM or SSM pts (34% and 31%, respectively; p Long-term prognosis was similar for all groups, even though SSM tended to a less favourable course: EFS at 10 years was 88.9% (95%CI: 73.6-95.6) for BMM, 88.1% (95%CI: 83.4-91.6) for ISM and 78.8% (95%CI:55.7-90.8) for SSM (p=0.2). Conclusions. BMM is a distinct subgroup of non-advanced SM characterized by male predominance, low burden of neoplastic MC, low level of serum tryptase and AP, limited frequency and severity of mediator-related symptoms, except hypotension, and a striking association with anaphylaxis, mainly triggered by hymenoptera. These data support the proposal of considering BMM as a distinct variant of mastocytosis. Disclosures Bonifacio: Pfizer: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees. Hadzijusufovic: Novartis: Honoraria. Gotlib: Promedior: Research Funding; Blueprint Medicines: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding; CTI Biopharma: Membership on an entity's Board of Directors or advisory committees, Research Funding; Blueprint Medicines: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Seattle Genetics: Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Promedior: Research Funding; CTI Biopharma: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Deciphera: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Deciphera: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmacyclics: Research Funding. Sperr: Meda: Research Funding; Phadia: Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria; Novartis: Other: Register; Teva: Honoraria. Valent: Teva: Honoraria; BMS: Honoraria; Deciphera: Honoraria, Research Funding; Ariad: Honoraria, Research Funding; Blueprint: Research Funding; Pfizer: Honoraria; Celgene: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Incyte: Honoraria. Zanotti: Deciphera: Consultancy.

Effect of a Cytoprotective Dose of Dehydroleucodine, Xanthatin, and 3-Benzyloxymethyl-5H-furan-2-one on Gastric Mucosal Lesions Induced by Mast Cell Activation.

The aim of this study was to determine whether the lactones dehydroleucodine, xanthatin and 3-benzyloxymethyl-5H-furan-2-one, would be effective in an animal model of gastric ulcer induced by mast cell activation. Rats were divided into ten groups. Treatments were repeated for four days. The degree of gastric erosion was assessed with a scoring system and histological preparations. Gastric mast cell morphology was analyzed by histological procedures. Serum serotonin levels were determined as markers of mast cell activation. Statistical analyses were done using ANOVA and Tukey–Kramer test. We demonstrated that the repeated administration of compound 48/80 results in extensive mucosal lesions in the gastric mucosa and that such lesions occurred in association with mast cell degranulation and a significant increase of serum serotonin. We showed that these lesions were prevented by dehydroleucodine, xanthatin, and 3-benzyloxymethyl-5H-furan-2-one and that this effect was similar to that obtained with sodium cromoglycate. In conclusion, the results of the present study indicate that the optimal gastric cytoprotective dose of dehydroleucodine, xanthatin, and 3-benzyloxymethyl-5H-furan-2-one is efficacious in an animal model of gastric ulcer induced by mast cell activation. Our findings suggest that these lactones could be valuable tools for designing novel therapeutic agents for digestive disorders associated with inappropriate mast cell activation.

Comparative Analysis of Mast Cell Density in Oral Epithelial Dysplasia and Oral Squamous Cell Carcinoma

Introduction: Oral squamous cell carcinoma (OSCC) is one of the most common malignancies of the oral cavity. One of the foremost cells recruited near the tumor front is the mast cells. Mast cells produce angiogenic mediators such as fibroblast growth factor (FGF), transforming growth factor (TGF), tumor necrosis factor, (TNF), and the vascular endothelial growth factor (VEGF) 1. which are increased in precancerous lesions and found in more abundance in OSCC.Accumulation of mast cells around the tumor margins and their release of potent pro-angiogenic and angiogenic factors may represent a tumor-host interaction which probably favors tumor progression. The progression of oral lesions from dysplasia to oral squamous cell carcinoma is characterized by an “angiogenic switch” that is associated with an increase in the neovascularization of the subepithelial lamina propria, which may be considered an indicator of malignant transformation. 2MCs also represent a rich source of proteases, especially ofmast cell tryptase and chymase, which directly degrade the extracellularmatrix through their proteolytic activity and thus indirectly stimulate angiogenesis and facilitate invasion and metastasis. Theliterature has proven that mast cells can be an indicator of increased angiogenesis and hence can help in the prediction of carcinogenesis, its progression, and also the prognosis of the malignant lesions.Aim of the Study: To compare the number, morphology, and distribution of mast cells in different grades of oral epithelial dysplasia (OED) and oral squamous cell carcinoma (OSCC) and to study their role in tumor growth and pathogenesisMaterials and Methods: A total of 39 cases, which included 13 cases of dysplasia and 26 of OSCC were included in the study. Tissue sections were stained with H&amp;E and 1% toluidine blue was used to evaluate mast cells. Mast cells were counted manually using an ocular grid throughout the tissue sections in 10 representative grid fields in a stepladder fashion. (40x magnification).The mean mast cell density (MCD) of 10 fields was calculated and was expressed as mean (standard deviation) per mm3,4. Mast cells were then categorized as typical, atypical, or granular mast cells and statistically analyzed.5Result: In the present study, there is a decrease in the number of mast cells with severe grades of dysplasia and poorer grades of oral squamous cell carcinoma.&#x0D; ConclusionMast cells may induce the tumor progression by providing a mitogenic stimulation or angiogenesis-the hallmark of the tumor growth and metastasis through the release of various mediators.

Early oral nutrition improves postoperative ileus through the TRPA1/CCK1-R-mediated mast cell-nerve axis.

BackgroundThe mechanism of early oral nutrition that regulates the mast cell-nerve axis to improve postoperative ileus (POI) remains unclear. This study aims to investigate whether early oral nutrition can improve POI through Transient receptor potential ankyrin-1 (TRPA1)/cholecystokinin 1 receptor (CCK1-R) in the mast cell-nerve axis.MethodsExperiment 1: Male Sprague-Dawley (SD) rats were randomly divided into the TRPA1 inhibitor + oral nutrition group (TI + ON + POI), oral nutrition group (ON + POI), POI group (POI) and sham surgery group (Sham). Nine rats in each group were treated. Experiment 2: Primary cultures of mast cells and dorsal root ganglion cells were created, and a non-contact co-culture system was established. The cells were divided into the dorsal root ganglion (DRG) group, mast cell group, DRG + mast cell group, TRPA1 inhibitor or enhancer group, mast cell stabilizer or enhancer group, CCK1-R inhibitor or enhancer group. The results of expression of TRPA1, CCK1-R and histamine in colon tissue, portal vein blood, supernatant or dorsal root ganglia, intestinal transport test and mast cell morphology were analysed.ResultsIn experiment 1, Early oral nutrition could alleviate the degranulation and activation of mast cells and alleviate the inflammatory reaction of intestinal wall muscles (P<0.05). Early oral nutrition improved POI by stabilizing mast cells with TRPA1. TRPA1 inhibitor decreased CCK1-R concentrations in portal vein blood and CCK1-R expression in colonic smooth muscle (P<0.05). In experiment 2, the change in mast cell function regulated the secretion of CCK1-R by neurons, CCK1-R negatively regulated the degranulation and activation of mast cells (P<0.05), and mast cells positively regulated the expression of TRPA1 protein in DRG (P<0.05).ConclusionsEarly enteral nutrition can improve POI through the TRPA1/CCK1-R-mediated mast cell-nerve axis. TRPA1 positively regulates CCK1-R to stabilize mast cells, but TRPA1 is not the target of the downstream CCK1-R pathway.

Human Mast Cell Development from Hematopoietic Stem Cells in a Connective Tissue-Equivalent Model.

Mast cells (MCs) play critical roles in the pathogenesis of IgE- and non-IgE-mediated immune responses, as well as host defense against parasites, bacteria, and viruses. Due to the effect of extracellular matrix components on tissue morphogenesis and cell behavior, utilizing a tissue model that mimics MC microenvironmental conditions in vivo has greater relevance for in vitro studies. For this work, MCs were developed within a connective tissue-equivalent model and cell function was examined in response to an allergen. MCs are located in proximity to fibroblasts and endothelial cells (ECs) that play a role in MC development and maturity. Accordingly, MC progenitors isolated from human peripheral blood were co-cultured with human primary fibroblasts in a 3D collagen matrix to represent the connective tissue. The matrix was coated with type IV collagen and fibronectin before seeding with primary human ECs, representing the capillary wall. The stem cell-derived cells demonstrated MC characteristics, including typical MC morphology, and the expression of cytoplasmic granules and phenotypic markers. Also, the generated cells released histamine in IgE-mediated reactions, showing typical MC functional phenotype in an immediate-type allergenic response. The created tissue model is applicable to a variety of research studies and allergy testing. Impact Statement Mast cells (MCs) are key effector and immunoregulatory cells in immune disorders; however, their role is not fully understood. Few studies have investigated human ex vivo MCs in culture, due to the difficulties in isolating large numbers. Our study demonstrates, for the first time, the generation of cells exhibiting MC phenotypic and functional characteristics from hematopoietic stem cells within a connective tissue-equivalent model with ancillary cells. Utilizing the 3D matrix-embedded cells can advance our understanding of MC biological profile and immunoregulatory roles. The tissue model can also be used for studying the mechanism of allergic diseases and other inflammatory disorders.

The distribution and heterogeneity of mast cells in tongue from five different avian species.

This study was conducted with the aim of determining the morphology, distribution and heterogeneity of mast cells in the tongues of seagull (Larus fuscus), common buzzard (Buteo buteo), goose (Anser anser), white stork (Ciconia ciconia) and Gerze rooster. The study used five samples of tongue material from each of the healthy adult avian species. The samples were fixed in 10% neutral-buffered formalin (NBF) solution, then, after routine tissue follow-up, the samples blocked with paraplast. Cross-sections with 5-6μm of thickness were stained with the 0.5% toluidine blue and alcian blue/safranin O (AB/SO). In all five avian species, it was found that the mast cells were in different sizes and round, oval or spindle-shaped based on their place of distribution. Mast cell numbers were determined in stained with toluidine blue, examined ×40 objectives in a 1mm2 area. It was observed that mast cell density in subepithelial lamina propria and microscopic papilla was higher in the tongues of all species. Mast cell distribution and heterogeneity varied through the tongue, and there were more mast cells in the dorsal side of the tongue than the ventral side. The highest amount of mast cells was found in the tongue of the Gerze rooster among all five species. In the tongue cross-sections stained with the combined method of alcian blue/safranin O (AB/SO), the mast cells were stained as AB (+), SO (+) and AB/SO (+) (mixed).

Imaging of mast cells.

Mast cells are a part of the innate immune system implicated in allergic reactions and the regulation of host-pathogen interactions. The distribution, morphology and biochemical composition of mast cells has been studied in detail in vitro and on tissue sections both at the light microscopic and ultrastructural level. More recently, the development of fluorescent reporter strains and intravital imaging modalities has enabled first glimpses of the real-time behavior of mast cells in situ. In this review, we describe commonly used imaging approaches to study mast cells in cell culture as well as within normal and diseased tissues. We further describe the interrogation of mast cell function via imaging by providing a detailed description of mast cell-nerve plexus interactions in the intestinal tract. Together, visualizing mast cells has expanded our view of these cells in health and disease.