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Mast cells

Developed from hematopoietic stem cells in response to stem cell factor, KIT ligand, which is the ligand of CD117 transmembrane tyrosine kinase receptor, encoded by KIT.

Cells migrate from the blood to skin, lungs, mucosal interfaces where they acquire tissue specific phenotypes.

The acquisition of phenotype is related to the local microenvironment, especially blood vessel and nerve ending supply.

Effector cells in allergic disorders and immunoglobin E immune responses.

Activated cells secrete inflammatory mediators in response to pathogens.

Activated by exposure to antigens that cross-links allergen specific IgE bound to Fc epsilon receptor.

As mass cells express toll-like receptors They can be activated by bacterial and viral products, and have enhanced activation by stem cell factor and interleukin-33.

Can also be activated by anaphylatoxins C3a and C5a, aggregated IgG, some drugs, venoms, physical pressure, temperature changes, cytokines, neuropeptides, neutotensin, stem cell factor, and substance P.

Tissue cells found close to blood vessels and are numerous at sites in close proximity to the external environment such as the skin and respiratory airways.

Recognize and respond to pathogens.

Relatively resistant to ultraviolet an gamma radiation.

Allergic activation leads to degranulation And secretion of vasoactive M Pro inflammatory mediators contributing to symptomatology.

Molecules stored in secretory granules in mast cells include histamine, serotonin, proteases, and tumor necrosis factor.

Mast cells secrete mitochondrial DNA which carries out autocrine and paracrine stimulatory activity.

Following activation produce histamine, cytokines, chemokines, and lipid mediators.

Mast cells release exosomes capable of delivering DNA and micro RNAs to other cell types.

Can release leukotrienes, prostaglandins, platelet activating factor, interleukin-6, interleukin-9, interleukin-13, interleukin-17,TNF, chemokines CXCL8, CCL2, and CCL5.

Can secrete mitochondrial DNA which carries out on autocrine and paracrine stimulatory actions.

CD117 regulates growth, migration, survival and effector functions.

Can activate and recruit eosinophils, neutrophils and monocytes.

Can release exosomes capable of delivering DNA and micro-RNA is to other cell types.

Have a role in immune response to bacterial infections.

Express Toll-like receptor 3 which recognizes viral double stranded RNA.

Can produce interferons via Toll-like receptor 2.

Can be infected by HIV, dengue virus and respiratory syncytial virus and can respond to such infections.

Capable of releasing many molecules that participate in physiologic and pathologic processes including: Innate immunity, autoimmune processes, immunomodulation, and antimicrobial functions.

Disorders of mast cells can manifest with flushing, hives, urticaria, angioedema, nasal congestion, shortness of breath, itching, tachycardia, hypertension, hypotension, tightness of the chest, fatigue, osteoporosis, nausea, vomiting, musculoskeletal pain, vomiting, migraines, neurologic problems, impaired memory, impaired concentration ability, or other neuropsychiatric processes.

 

Mast cell disorders symptomatology are protean.

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