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Query: UNIPROT:P15088 (mast cell)
 14,925 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The term mastocytosis denotes a heterogeneous group of rare hematological disorders characterized by abnormal accumulation of mast cells. While cutaneous mastocytosis is relatively frequent mast cell leukemia belongs to the rarest forms of human leukemia. In the following we present the case of an aleukemic mast cell leukemia and shall discuss the revised classification of mastocytosis based on the "Year 2000 Working Conference on Mastocytosis" held in Vienna, Austria. A 48 year-old caucasian man presented with a four-week history of diarrhea, obstipation, vomiting, rash, and mild fever. Clinical inspection revealed a disseminated itching rash and a mild hepatomegaly. Red and white blood cell counts were within the normal range. Levels of the alkaline phosphatase and serum histamine were significantly increased. There was no splenomegaly or lymphadenopathy. Cytologic and histologic investigation of the bone marrow revealed a marked increase in atypical mast cells. Since only a few circulating mast cells could be detected in a cytospin preparation of the blood, the diagnosis of an aleukemic mast cell leukemia was established. About four weeks after the diagnosis had been established, the patient died with signs of a hemorrhagic shock due to a massive gastrointestinal bleeding. Autopsy revealed widespread mast cell infiltration of bone marrow, spleen, liver and lungs, but also a small, deeply penetrating, non-specific duodenal ulcer. In conclusion, despite of presentation with signs of a primary gastrointestinal disorder, the patient was found to suffer from an exceedingly rare aleukemic mast cell leukemia ("malignant mastocytosis") and died after a total duration of the disease of only about three months.
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PMID:[Aleukemic mast cell leukemia (formerly: "malignant mastocytosis"): an extremely rare form of leukemia. A case report and simultaneously a contribution to revised classification of mastocytosis]. 1223 4

Human mast cells are often found perivascularly and at mucosal sites and may play crucial roles in the inflammatory response. Recent studies have suggested a prominent role for mast cells in host defense. In this study, we analyzed the effects of a common airway pathogen, Moraxella catarrhalis and a commensal bacterium, Neiserria cinerea, on activation of human mast cells. Human mast cell leukemia cells (HMC-1) were activated with either phorbol myristate acetate (PMA) and calcium ionophore or with varying concentrations of heat-killed suspensions of bacteria. Supernatants were assayed for the cytokines interleukin-4 (IL-4), granulocyte macrophage colony stimulating factor (GM-CSF), IL-6, IL-8, IL-13 and monocyte chemotactic protein-1 (MCP-1). Nuclear proteins were isolated and assayed by electrophoretic mobility shift assay (EMSA) for nuclear factor kappaB (NF-kappaB) nuclear binding activity. In some experiments, NF-kappaB inhibitor, Bay-11 was added to determine functional significance. Both M. catarrhalis and N. cinerea induced mast cell activation and selective secretion of two key inflammatory cytokines, IL-6 and MCP-1. This was accompanied by NF-kappaB activation. Neither spun bacterial supernatants nor bacterial lipopolysaccharide induced cytokine secretion, suggesting need for direct bacterial contact with mast cells. Scanning electron microscopy revealed active aggregation of bacteria over mast cell surfaces. The NF-kappaB inhibitor, Bay-11, inhibited expression of MCP-1. These findings suggest the possibility of direct interactions between human mast cells and common bacteria and provide evidence for a novel role for human mast cells in innate immunity.
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PMID:Moraxella catarrhalis induces mast cell activation and nuclear factor kappa B-dependent cytokine synthesis. 1245 64

Mastocytosis comprises a heterogeneous group of hematological disorders which are morphologically defined by proliferation and accumulation of tissue mast cells in one or more organs. Clinical manifestations of mastocytosis range from disseminated maculopapular skin lesions (= urticaria pigmentosa [UP]) that may spontaneously regress to highly aggressive neoplasms like mast cell leukemia or mast cell sarcoma. Recently, it could be shown that systemic mastocytosis (SM) is a clonal disorder often exhibiting mutations of c-kit, a protooncogene encoding the tyrosine kinase receptor for stem cell factor (SCF). Mutations of c-kit are considered to play a key role in the pathogenesis of mastocytosis. Therefore, we investigated the unique case of a 36 year-old male patient with indolent systemic mastocytosis (ISM) evolving from UP (cutaneous mastocytosis) by means of histology, immunophenotyping and molecular biology. At the time of initial diagnosis the bone marrow showed only a mild diffuse increase in mast cells but compact infiltrates were missing. The serum tryptase levels were normal. Five years later, however, the bone marrow histology displayed patchycompact mast cell infiltrates, which now allowed to establish the diagnosis of an ISM. The serum tryptase levels at this time were markedly elevated. At both time points, mast cells were analyzed by immunohistochemistry using anti-tryptase antibody AA1, by flow cytometry using antibodies against CD2 and CD25, and nested polymerase chain reaction (PCR) on laser-microdissected, single pooled mast cells. Immunohistochemistry revealed strong tryptase-positivity of mast cells in both cutaneous and bone marrow infiltrates. Flow cytometry yielded an aberrant expression of CD2 and CD25 on bone marrow mast cells. However, repeated thorough PCR analysis failed to unveil c-kit mutation in atypical mast cells of skin and bone marrow samples of both dates. These findings clearly show that ISM can evolve from UP. Moreover, our study provides further evidence that the c-kit mutation Asp-816-Val is not invariably present in ISM.
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PMID:Evolution of urticaria pigmentosa into indolent systemic mastocytosis: abnormal immunophenotype of mast cells without evidence of c-kit mutation ASP-816-VAL. 1268 51

Mastocytosis is a rare disease characterized by an abnormal increase of mast cells in tissues. We report a case of acute myeloid leukemia (AML) with t(8;21) and mast cell leukemia (MCL) in which the mastocytosis persisted after standard chemotherapy and allogeneic stem cell transplantation, although the myeloid leukemia achieved molecular complete remission soon after induction chemotherapy. Donor-type mast cells were noted on d31 after transplant. No c-kit mutation was found before or after the transplant. This represents the first reported case in which rapid engraftment of mast cells of donor origin was documented. Thus, the possibility that the mast cell originates from a common myeloid precursor cell may be questioned and a reactive process should be considered in some cases of systemic mastocytosis.
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PMID:Rapid engraftment of mast cells of donor origin in a case of acute myeloid leukemia with mast cell leukemia after allogeneic stem cell transplantation. 1281 87

Mutations in the proto-oncogene c-kit cause constitutive kinase activity of its product, KIT protein, and are associated with human mastocytosis and gastrointestinal stromal tumors (GISTs). Although currently available tyrosine kinase inhibitors are effective in the treatment of GISTs, there has been limited success in the treatment of mastocytosis. 17-Allylamino-17-demethoxygeldanamycin (17-AAG), a benzoquinoid ansamycin antibiotic, which binds to heat shock protein 90 (hsp90) causes destabilization of various hsp90-dependent kinases important in oncogenesis. Treatment with 17-AAG of the mast cell line HMC-1.2, harboring the Asp816Val and Val560Gly KIT mutations, and the cell line HMC-1.1, harboring a single Val560Gly mutation, causes both the level and activity of KIT and downstream signaling molecules AKT and STAT3 to be down-regulated following drug exposure. These data were validated using Cos-7 cells transfected with wild-type and mutated KIT. 17-AAG promotes cell death of both HMC mast cell lines. In addition, neoplastic mast cells isolated from patients with mastocytosis, incubated with 17-AAG ex vivo, are selectively sensitive to the drug compared to the mononuclear fraction. These data provide compelling evidence that 17-AAG may be effective in the treatment of c-kit-related diseases including mastocytosis, GISTs, mast cell leukemia, subtypes of acute myelogenous leukemia, and testicular cancer.
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PMID:17-Allylamino-17-demethoxygeldanamycin (17-AAG) is effective in down-regulating mutated, constitutively activated KIT protein in human mast cells. 1455 Nov 38

Mast cells are involved in allergic inflammation and some rare disorders such as systemic mastocytosis and mast cell leukemia. Certain naturally occurring flavonoids have been shown to inhibit mast cell activation and promote maturation of secretory granules. Here, we report that the isoflavone genistein inhibited the growth of human leukemic mast cells (HMC-1) by 68.8, 51.6, and 30.2% at 10(-4), 10(-5), and 10(-6) M, respectively, at day 3 (p < 0.001). Genistein at 10(-4) M increased the histamine content per 2 x 10(5) cells at day 3 from 5.9 +/- 1.2 micrograms/mL to 11.1 +/- 1.3 micrograms/mL (n = 6; p < 0.0001). These results indicate that genistein can inhibit proliferation and induce maturation of HMC-1 cells.
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PMID:The isoflavone genistein inhibits proliferation and increases histamine content in human leukemic mast cells. 1461 39

Systemic mastocytosis (SM), as opposed to cutaneous-only mastocytosis, implies the presence of neoplastic mast cell infiltration in extracutaneous tissue. Mast cell disease in adults is often systemic and often involves the bone marrow. Typical clinical and laboratory features of SM include urticaria pigmentosa, mast cell mediator symptoms (eg, headache, flushing, lightheadedness, urticaria and pruritus, nausea, diarrhea, abdominal pain, and vasodilatory shock), bone pain (eg, osteoporosis, lytic bone lesions, and fractures), hepatosplenomegaly, cytopenia, eosinophilia, elevated serum tryptase and histamine, and bone marrow fibrosis and angiogenesis. SM may be indolent (no evidence of organ dysfunction), aggressive (presence of organ dysfunction), associated with another often chronic myeloid hematologic disease (SM-AHD), or present as mast cell leukemia or sarcoma. Mast cell-mediator symptoms are treated with histamine antagonists and cromolyn sodium. Indolent SM does not require cytoreductive therapy. Aggressive SM and SM-AHD are managed based on their molecular profile. Recent information suggests that FIP1-like-1-platelet-derived growth factor receptor-alpha(+) SM responds well to imatinib mesylate, whereas interferon-alpha should be considered as a first-line treatment in all of the other cases, including patients with Asp816Val(+) SM. Cladribine has been shown to be effective in patients who develop resistance to interferon treatment.
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PMID:Systemic mastocytosis: current concepts and treatment advances. 1508 68

The aberrant co-expression of CD2 and CD25 antigens is the immunophenotypic hallmark of neoplastic mast cells, and has been consistently identified on bone marrow mast cells from patients with indolent mast cell disease (MCD). We prospectively analyzed the bone marrow mast cell immunophenotype by multiparametric flow cytometry (FC) for 33 MCD cases, to examine the role of CD2 and CD25 expression in establishing diagnosis, detecting histologically occult bone marrow mast cell infiltration, and assessing treatment response. While CD25 was almost uniformly expressed, only 6 of 13 patients with indolent MCD, 1 of 8 with aggressive MCD, 2 of 7 with MCD and an associated hematological disorder, and none of the 2 patients with either mast cell leukemia or smoldering systemic mastocytosis, expressed CD2. One of three patients with cutaneous mastocytosis had an aberrant CD2+/CD25+ mast cell population suggesting histologically occult bone marrow involvement. CD25 expression was lost in one patient who achieved complete histologic remission with therapy, but not in two patients who achieved a partial remission. In conclusion, CD25, but not CD2, is a reliable marker for neoplastic mast cells, and CD25 expression indicates histologically occult bone marrow infiltration and residual disease after therapy.
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PMID:Bone marrow mast cell immunophenotyping in adults with mast cell disease: a prospective study of 33 patients. 1520 75

Mastocytoses are a heterogenous group of diseases characterized by proliferation and accumulation of mast cells in the skin and other organs. They are subdivided into cutaneous mastocytoses; systemic forms, which may appear with or without skin lesions; mast cell sarcomas and extracutaneous, localized, benign mastocytomas. Systemic mastocytoses apart from the skin mainly involve bone marrow, gastrointestinal tract, bones, lymph nodes, spleen and liver. Whereas indolent forms of systemic mastocytosis are mainly treated with antihistamines, glucocorticosteroids and PUVA therapy, the more aggressive forms, including mast cell leukemia, often require cytostatic chemotherapy. A 53-year old patient with beginning "smoldering systemic mastocytosis" failed to respond to high-dose systemic glucocorticosteroids and interferon-alpha. Treatment with cladribine led to an impressive improvement of skin lesions, a significant decrease in tryptase serum levels and stabilization of bone marrow infiltrates.
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PMID:["Smoldering systemic mastocytosis. "Successful therapy with cladribine]. 1524 20

Mast cell leukemia (MCL) is a rare form of aggressive mastocytosis with a reported median survival below 6 months. Casuistic reports suggest the effectiveness of allogeneic bone marrow transplantation (BMT) for MCL. However, these reports lack clear evidence for a graft-versus-mast-cell (GvMC) effect. We prospectively investigated the GvMC at different time points after allogeneic BMT and donor-lymphocyte infusions (DLI). Samples were gathered from a patient with MCL treated with allogeneic BMT from an unrelated HLA identical donor. Parameters for detection of a GvMC effect included flow cytometrical analysis of mast cell (MC) populations in peripheral blood and BM, BM smear and histology, chimerism analysis of flow cytometrically sorted BM CD117+/CD34- MC and testing for anti-mast cell reactivity of donor lymphocytes by interferon (IFN)-gamma ELISPOT. DLIs reduced MC from 5 to 0.5%. MC chimerism analysis demonstrated a complete recipient genotype after BMT, suggesting that the persistent mastocytosis was part of residual neoplastic disease. At 3.7 years after BMT, there is some evidence for relapse. In summary, BMT and DLIs attenuated the mastocytosis from an aggressive to an indolent form and may have improved the patients' prognosis. The in vitro data of our study indicate for the first time the existence of a GvMC effect.
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PMID:Evidence for a graft-versus-mast-cell effect after allogeneic bone marrow transplantation. 1527 11


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