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29 Cards in this Set
- Front
- Back
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Immature mast cells circulate in the peripheral blood and express:
Mature mast cells develop in the presence of stem cell factor and express: |
Immature mast cells: CD34, KIT (CD117), IgG receptor FcyRII
Mature mast cells: KIT (CD117), FcER1, loss of CD34 and FcyRII |
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What stimulated mast cell maturation?
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Stem cell factor (bone marrow, fibroblasts, keratinocytes, endothelial cells)
IL-3 > 4, 6, 9 |
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Cytokine mileu of mast cell secretion?
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TH2!
IL1, IL3, IL4, IL5, IL6, GM-CSF, TGFB, TNFa |
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Mast cells can be degranulated via immunologic and non immunologic stimuli...
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Immunologic caused by antigen/autoantibodies binding to IgE or FcERI receptors --> crosslinking --> degranulation (can be a drug like PCN)
Non immunologic caused by direct binding of substance P, stem cell factor, C5a*, drugs (PIANOS) |
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Which drugs cause mast cell degranulation?
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Immunologic: d/t antigen/autoantibodies, drug like PCN
Non immunologic: d/t direct binding, PIANOS, polymixin, IV contrast, ASA, etoh, amphotericin B, NSAIDS, opiates, systemic anesthetics, scopalamine |
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Preformed mediators?
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Preformed and easy!
histamine, heparin, tryptase, neutrophil chemotactic factor, eosinophil chemotactic factor |
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Newly formed mediators?
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Prostaglandin D2, leukotrienes C4, D4, E4, platelet activating factors
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What is the ligand for KIT on mast cells?
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stem cell factor --> activation leads to cellular growth and prevents apoptosis
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Activating mutation of KIT? Inactivating mutation?
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Activating: mastocytosis, GIST, testicular seminoma, melanoma, AML
Inactivating: piebaldism |
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What chromosome is KIT on? Most common mutation for mastocytosis?
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Chromosome 4
D816V (intracellular region) |
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Children are more likely to have cutaneous mastocytosis with a limited course, while adults are more likely to have systemic symptoms and evidence of extracutaneous involvement.
What are the common cutaneous mastocytoses in children? |
Urticaria pigmentosa
Solitary mastocytoma Diffuse cutaneous mastocytosis |
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Prognosis?
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Urticaria pigmentosa: most common form of cutaneous mastocytosis in children, variable numbers of tan/brown macules and apules beginning in first weeks of life
Most resolve before adolescence |
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Most common site of a solitary mastocytoma?
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dorsal hand
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prognosis?
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Solitary mastocytoma: 10-35% of childhood cases, may be present at birth or first few weeks of life, most common site dorsal hand, usually involutes before age 10
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Which entities can exhibit a pseudo Dariers sign?
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JXG, piloleiomyoma
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dx?
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diffuse cutaneous mastocytosis
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Mastocytosis of the skin is almost always indicative of systemic disease in adults. What systemic symtpoms associated?
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CNS: headache, cognitive disorganization, fatigue, mixed organic brain syndrome
GI: cramping, diarrhea, epigastric pain, NVD, HSM CV: CP, dizziness, palpitations, syncope MSK: bone pain |
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You can see manifestation so mast cell disease on radiographs, why?
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due to increased numbers of mast cells and effect of mediators on bones --> heparin induced osteoporosis, KIT on osteoclasts, histamine promotes bone sclerosis, IL6 promotes resorptive activity
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Survival rate of aggressive systemic mastocytosis? Mast cell leukemia?
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Aggressive systemic mastocytosis: 3.5 years
Mast cell leukemia: less than 1 year |
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Mast cell stains?
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Leder, Giemsa, Toluidine blue, KIT (CD117)
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Major criteria for systemic mastocytosis?
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more than 15 mast cells in bone marrow or extracutaneous tissue
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Total serum tryptase must remain elevated above X for diagnosis of systemic mastocytosis?
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>20ng/ml
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Types of tryptase?
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Alpha tryptase useful to assess total mast cell burden
Beta tryptase is only increased during acute episodes Normal tryptase is <20ng/ml |
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Which urinary metabolite is directly proportional to the extent of mast cell disease?
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Urinary histamine and its metabolite 1,4 methylimidazole acetic acid
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Tx of GI symptoms in systemic mastocytosis?
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oral cromolyn
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Systemic mastocytosis with associated hematological non mast cell lineage disease (SM-AHNMD) is associated with what?
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underlying malignancy
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What systemic anesthetic can be used safely in mastocytosis?
lidocaine succinylcholine tubocurarine thiopental propofol |
propofol also: non-depolarizing muscle relaxants are less likely to cause an anaphylactic reaction than depolarizing |
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Mastocytosis can be diagnosed via measurement of:
tryptase kinase bile acids histamine IgE |
tryptase
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Which organ system is least likely to be involved in systemic mastocytosis?
liver spleen GI GU bone marrow |
GU
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