Mast cells are widely distributed in the skin and visceral submucosacapillaryAround.Secretion of variouscell factor, participationImmunomodulation（TBCells,APCCell activation).expressionMHCB7 molecule, which has APC function and also expresses a large amount of IgEFc receptor, release allergic medium.It has weak phagocytic function.And bloodBasophilAlso has strongBasophilic granuleOfHistiocyte。
Chinese name
mast cells
Foreign name
mast cell
Distribution
Around microvessels under skin and visceral mucosa
Mast cell is an immune cell,[1]These particles in the blood containheparin, histamine5-hydroxytryptamine, particles and substances in particles released by cell disintegration can be caused in tissuesImmediate anaphylaxis(inflammation).Because of the contact between IgE antibodies bound to mast cells and antigens, most cells are collapsed.
Mast cells are round or oval,nucleusSmall, round or oval, light staining, located in the center of the cell.This cell often aggregates or distributes singly near blood vessels.cytoplasmFilled with particles of uniform size dyed blue and purple,uniform distributionAround the nucleus.
Mast cell leukemiaMast Cell Leukemia is also called tissue basophilleukemiaEfrati first proposed the diagnosis of MCL in 1957, and it has been reported since then.MCL accounts for about 15% of malignant mast cell tumors.Many cases are systematic firstMast cell hyperplasia(SMCD), later it will become leukemia, and a few will start with mast cell leukemia.
Patients generally haveanemia、Thrombocytopenia；white blood cellThe total number is (10-15) x 109/L, and mast cells account for 5%~90%.Bone marrow biopsyIt shows that the number of mast cells is significantly increased, sometimes up to 90% (26.2% - 91.8%). Leukemic mast cells are round or quasi round, with fine chromatin and clear or unclear nucleoli,CytoplasmBlue, filled with more or less dark purple red particles and covered on the nucleus, and easy to seePseudopodiaAnd phagocytosisred blood cellPhenomenon.Hypertrophy of MCLCell ultrastructure: 1 or more nuclei with occasional obvious nucleoli.The cytoplasm containsmitochondrion、Liposome, particlesContentsLacking or filled with small particles and typical scroll like characteristics.Particle A is visible,Basophil0 grains of are missing.
Immune expression: malignant mast cells express CD9CD33、CD44 and CDll7, but not expressedmonocyteRelated antigens CDl4, CDl5 and basophil related antigen CDll6CDwl7、CDl23/IL-3RCK。It also lacks 0116 (CM-CSm) and hypertrophic skinCell markersAntigen CD88.HLA- D, DR and CDl, Cm, CD4, 07, CDl0, CDl9, TdT are all negative, MCG-35 has high specificity for mast cell granules, and cultured mast cells are strongly positive.
Travis et al. put forward the diagnostic criteria for MCL in 1986: ① mast cells in peripheral blood are greater than or equal to 10%; ②Leukemia cells are characterized by atypical mast cells (immature mast cells); ③Leukemia cells have the histochemical characteristics of mast cells (appearingMetachromatic granule, specific esterase positive, Pox negative, etc.).Clinically hypertrophicCell proliferationAnd leukemia.Differential diagnosis: mainly systematicMast cell hyperplasiaDifferentiation of malignant mast cell hyperplasia.
Treatment: there is no successful treatment plan, and the survival period is very short（Median survival5 months).SplenectomyIt can temporarily relieve symptoms,HemogramIt can recover temporarily, but the survival period of patients is significantly shortened (average 2 months).
Cell development
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Mast cells are derived fromHematopoietic stem cellsBut actually, the bone marrow has just entered the peripheryThe blood circulatory systemThe mast cells ofPrecursor cellMove to the final settlement, i.eVascular tissueorSerosal cavityThe differentiation and (or) maturity can be completed in the middle.stayMammalsAnd othersvertebrateMast cells are widely distributed in the whole vascular tissue, especially in the subcutaneous or skin, and close to blood vessels, nervessmooth muscleMucus secreting glands and hair follicles.Mast cells are mainly distributed in places where the body communicates with the external environment, such as the skin, airway and digestive tract, which are often accessiblepathogen、allergenAnd other substances in the environment.Therefore, the distribution characteristics of mast cells in vivo make them become hematopoietic together with DC-immune systemWhich first interacts with allergens, other antigens and invasive pathogens in the environmentCell population。
Mast cells have a long survival period and can enter again under appropriate stimulation conditionscell cycleAnd proliferation;Mast cell precursors can also be massively recruited, stayed, and locally matured, so that the mast cell population can be expanded.Under the following circumstances, the number, local tissue distribution and phenotypic characteristics of mast cells may change, for example, for various infections, especially forparasiteWorm infectionIn case of responseAdaptive immune responseEspecially in the process of chronic response, and in the state of persistent inflammation and tissue reconstruction.
Mast cells in the whole body or local tissues are well regulated in terms of their survival, proliferation and important phenotypic characteristics, includingInnate immunityAnd adaptive immune response to various stimulisusceptibility, the ability of cells to store and produce secretory substances, and the ability toSpecificityThe intensity of stimulating secretory response.The main factors affecting the number and phenotype of mast cells include c-Kit'sligandI.eStem cell factor(SCF), mast cell survival andDevelopmental factorIL-3[2], and Th2 relatedcell factorIL-4 and IL-9: other cytokinesgrowth factorandChemotactic factorParticipation of.
4. IgE dependent or IgE independent immunological mechanism.
Specific allergens determine the IgE aggregation process.In physiological state, the components of IgE independent pathway that have important influence on mast cell activation include:adenosine、complementSegment C3aChemotactic factor、cell factor、Pathogen related molecular model(PAMP), sphingosine 1-phosphate (SiP), and stem cell factor.Inflammatory mediators released by mast cell activation initiate signal transductionCascade reactionAlthough there are different mechanisms, these cascade reactions eventually cause degranulationArachidonic acidClass release and inducible expression of chemokines and cytokines.
Related diseases
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Mastocytosis is a kind of skin, bonelymph gland, viscera and monocyte-Macrophage systemIntermediate mast cellDysplasiaA relatively rare disease characterized by.According to the different types of mast cells that focus on invading organs, they can be clinically divided into the following types: (1) skin involvement type (2) skin and bone involvement type (3) bone marrow, liver, spleen and lymph node involvement type (4) mastocytosis complicatedMast cell leukemia。
systematicnessMast cell hyperplasiaSystematic mastocytosis (SM) is a rare disease characterized by abnormal proliferation of mast cells in skin, bone, lymph nodes, viscera and monocyte macrophage system.Mast cells are also called tissuesBasophil, normal personPeripheral bloodNone, only 0.03% of the nuclear cells are in the bone marrow, and mast cells are distributed throughout the bodyLoose connective tissue, such as around blood vessels, skin, respiration, digestion, urogenital system, liver, spleen, lymph nodes, thymus, etc.The granules of mast cells contain histamineheparin、EosinophilsChemokines.Slow reaction substances5-hydroxytryptamineThe content of histamine is the highest.WhenMast cell degranulationOr after the destruction of cytoplasm and the release of histamine, skin flushingTachycardia、hypotension、skin ItchandSkin scratch(+).This disease is widely distributed, but it is more common inIsraelandwhite race。Several cases have been reported in China, both men and women can suffer from it, and the cause is unknown.
clinical manifestation
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Skin involvement type
Also called pigmentationurticariaThis type is the most common, accounting for more than 90% of this disease.It is characterized by pigmentation of part of the skin (easily seen on the face, scalp, back, etc.)acupunctureMeasles often appears, usually round or oval, light or dark brownMacular rashThere were a lot of mast cells in the dermis during skin biopsy.Pigmented measles is usually seen after birth, but about 25% of it occurs in adolescence and adulthood.
Skin and bone involvement type
Some SM cases are accompanied by bone damage in addition to skin.Bone biopsy showsBone cortexHyperplasia, with considerable fibrosis and osteogenic changes.May be associated with hypertrophyCell secretionOfHyaluronidase、serotoninAnd mast cellsReticular fibreForming ability.Osteolytic lesion can also be seen, which is related to long-term infiltration and compression of mast cells. This osteolytic lesion can be misdiagnosed asMetastatic carcinoma of bone。
Bone marrow, liver, spleenlymph glandAffected type
I.e. systematicMast cell hyperplasia, massive hypertrophy can be seen in bone marrowcell proliferationThe liver, spleen and lymph nodes were enlarged to varying degrees due to mast cell infiltration.
(2) Granulocytepercentage It is normal or decreased, and eosinophils are commonly increased.
(3) The number of mast cells with abnormal morphology, often more than 20%, is distributed in piles, including immature, mature and broken mast cells.SomaThe size is mostly between 18~20nm, but it can also be seen at 30~40nm. Most of them are round, oval, a few irregular, blunt prismatic and fishhook shaped. It is easier to see if the cell membrane is torn.The cytoplasm is light pink orLight blue, most of which are dark purplish red and thickerBasophilic granule, phagocytosis of red blood cellswhite blood cellPhenomenon.The nucleus is relatively small, round, oval, dumbbell shaped, and can be seen in double nuclei or even three nuclei or lobulated nuclei,ChromatinSlim, some visiblenucleolus。
(4) Megakaryocytes often decrease.
(5) The morphology of mature red blood cells is generally normal.
On the basis of SM,Peripheral bloodMast cells were found in more than 30%.It causes the total number of white blood cells to increase and becomes mast cell leukemia.The percentage of mast cells in bone marrow is often more than 50%, and the number of granulocytes, erythrocytes and megakaryocytes is significantly reduced.About 4%~5% of SM patients develop into mast cell leukemia,prognosisPoor, the survival period is about 3~9 months.
Diagnosis
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morphologyThe diagnosis is mainly to find mast cells through the bone marrow slice stained by Ray Giemsa.usetoluidine blueStaining can further confirm mast cells, which are characterized byCytoplasmIt is filled with rose red particles with positive toluidine blue staining.It is especially helpful for the diagnosis of atypical mast cells.
Biochemical diagnosis in blood and urinehistamineThe obvious increase of the content is the evidence for the diagnosis of this disease.
