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WILLIAM'S HEMATOLOGY > 66 Basophils and Mast Cells and Their Disorders > Flashcards

66 Basophils and Mast Cells and Their Disorders Flashcards

1
Q

Mast cells and basophils express this receptor

A

high-affinity receptor for immunoglobulin (Ig) E (FcεRI)

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2
Q

The most common form of mastocytosis and typically presents with urticaria pigmentosa involving the skin

A

Indolent Systemic Mastocytosis

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3
Q

Most adult patients with mastocytosis has this mutation

A

Gain-of-function mutations affecting KIT
(kit ligand and mast cell growth factor)

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4
Q

The least common granulocyte in human blood

A

Basophil

0.5% to 0.6% of total leukocytes
0.3% of nucleated marrow cells

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5
Q

Basophil major growth factor

A

Interleukin (IL)-3

IL-3 is not necessary for the development of normal numbers of marrow or blood basophils but is important for the marrow and blood basophilia associated with certain T-helper (Th) 2 cell–associated immunologic responses

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6
Q

TRUE OR FALSE

Unlike basophils, mast cells can be longlived.

A

TRUE

Unlike basophils, mast cells can be longlived.

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7
Q

Mast cell major growth factor

A

Stem cell factor (SCF)

Promote mast cell mediator release and, at even lower concentrations, can augment mast cell mediator release in response to stimulation by IgE and antigen.

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8
Q

Basophil or Mast Cell

Represent the source of most (if not all) of the histamine present in normal human blood

A

Basophil

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9
Q

Basophil or Mast Cell

Origin of precursor cells is the marrow AND yolk sac

A

Mast Cell

Basophil: marrow

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10
Q

Difference of mast cell from basophil

A
  • nonsegmented nucleus with moderate condensation
  • smaller, more numerous
  • more variable in appearance than in basophils
  • covered by more uniformly distributed thin surface processes
  • more cytoplasmic filaments and lacking cytoplasmic glycogen deposits
  • contain numerous cytoplasmic lipid bodies
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11
Q

Site of maturation of mast cells

A

Connective Tissue

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12
Q

MAST CELL OR BASOPHIL

Responsible for virtually all of the vascular permeability changes and leukocyte infiltration associated with IgE-dependent cutaneous late-phase reactions and that TNF can importantly contribute to these responses

A

Mast Cell

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13
Q

HIV-derived protein that can induce mast cell or basophil mediator release (histamine and, in basophils, IL-4 and IL-13) by binding to and crosslinking cell surface–bound IgE

A

glycoprotein 120 (gp120)

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14
Q

Account for much or all of the protective effects against various venoms that were attributable to mast cells

A

CPA3 or mMCP-4 (the functional counterpart in the mouse to human chymase)

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15
Q

TRUE OR FALSE

Basophilopenia occurs in conditions that also are associated with eosinophilopenia

A

TRUE

Basophilopenia occurs in conditions that also are associated with eosinophilopenia

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16
Q

TRUE OR FALSE

A slight increase in the absolute monocyte count may be a useful early sign of a myeloproliferative neoplasm

A

FALSE

A slight increase in the absolute BASOPHIL count may be a useful early sign of a myeloproliferative neoplasm

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17
Q

TRUE OR FALSE

An increased absolute basophil count occurs in virtually all patients with CML.

A

TRUE

An increased absolute basophil count occurs in virtually all patients with CML.

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18
Q

TRUE OR FALSE

Exaggerated basophilia of this type is a poor prognostic sign and may herald transformation to the accelerated phase of CML.

A

TRUE

Exaggerated basophilia of this type is a poor prognostic sign and may herald transformation to the accelerated phase of CML.

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19
Q

Immunophenotype of Acute basophilic leukemia

A

CD123-positive, CD203cpositive, and CD117-negative blast cell

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20
Q

Gene mutation in Acute basophilic leukemia

A

t(X;6)(p11.2;q23.3)

Resulting in the fusion of MYB and GATA1

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21
Q

AML with marrow basophilia

A

t(9;22), t(6;9), t(3;6), or 12p

Other types of AML that have an associated increase in basophils are more prevalent than acute basophilic leukemia

t(6;9) AML : associated with erythroid hyperplasia and dysplasia, a high frequency of FLT3 mutations, and poor prognosis

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22
Q

Hyperbasophilia is defined as a basophil count of greater than or equal to ______ × 10 9 /L in the blood

A

1 × 10 9 /L

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23
Q

Human mast cells have been classified according to their content of neutral proteases

A

MC T: contain tryptase but not detectable chymase; predominates in lung and gastrointestinal (GI) mucosal tissues

MCTC: both enzymes; predominates in dermis and submucosal tissues

MCC: chymase but little or no tryptase

24
Q

TRUE OR FALSE

No clinical disorder whose primary feature is a reduction in levels of tissue mast cells has been reported.

A

TRUE

No clinical disorder whose primary feature is a reduction in levels of tissue mast cells has been reported.

25
Q

Skin lesions containing numerous mast cells

Usual presenting lesion of mastocytosis

A

Urticaria pigmentosa (UP) OR maculopapular cutaneous mastocytosis (MPCM)

Small yellowish-tan to reddish-brown macules or slightly raised papules

26
Q

Compose the great majority of subjects with a clonal mast cell disorder

Can expect a normal lifespan

A

Indolent systemic mastocytosis (ISM)

27
Q

Expected survival time of patients with aggressive systemic mastocytosis (ASM)

A

3- to 5-years

28
Q

Most common mutation in clonal mastocytosis

A

Asp816Val
KIT, which encodes the SCF receptor

Results in ligand-independent activation of the KIT receptor
Result in the substitution of phenylalanine or tyrosine for aspartate
Believed to occur in more than 90% of adult patients with mastocytosis

29
Q

Organs most frequently involved in systemic mastocytosis

A

Skin, lymph nodes, liver, spleen, marrow, and GI tract

30
Q

Urticaria after mild friction of the skin

A

Darier sign

31
Q

Areas of the skin that are free of lesions in mastocytosis

A

Palms, soles, face, and scalp

32
Q

Lymphadenopathy is most prominent in patients with

A

SM-AHN or ASM

33
Q

Marrow finding and major criterion in the diagnosis of systemic mastocytosis

A

Foci of spindle-shaped mast cells in a fibrotic background

34
Q

Aggressive variants of mastocytosis, such as MCL, should be considered if the percentage of mast cells in the marrow aspirate film exceeds ____% of all nucleated cells.

A

20%

35
Q

TRUE OR FALSE

Mast cells with bilobed nuclei may be seen in these lesions and is a finding associated with a poor prognosis.

A

TRUE

Mast cells with bilobed nuclei may be seen in these lesions and is a finding associated with a poor prognosis.

36
Q

IHC of choice or visualizing mast cells

A

Tryptase

Others: chloracetate esterase and aminocaproate esterase

37
Q

More specific mast cell markers in paraffin sections are

A

CD117 and mast cell tryptase

Strong CD117 membrane staining is equally sensitive for mast cells as tryptase but is less specific

38
Q

Major diagnostic criteria for Systemic Mastocytosis

A

Multifocal, dense infiltrates of mast cells (≥15 mast cells in
an aggregate) detected in sections of marrow or other
extracutaneous organ(s)

39
Q

Minor diagnostic criteria for Systemic Mastocytosis

A

a. In biopsy sections of marrow or other extracutaneous organs, >25% of the mast cells in the infiltrate are spindle shaped or have atypical morphology, or of all mast cells in marrow aspirate smears, >25% are immature or atypical mast cells

b. Detection of a point mutation in KIT at codon 816 in marrow,
blood, or other extracutaneous organ

c. Mast cells in marrow, blood, or other extracutaneous organs
express CD25 with or without CD2 in addition to normal mast cell markers

d. Serum total tryptase persistently >20 ng/mL unless there is an associated myeloid neoplasm, in which case this parameter is not valid

The diagnosis of systemic mastocytosis can be made if one major and one minor criterion are present or if three minor criteria are met.

40
Q

TRUE OR FALSE

No single laboratory test showing an elevation in a mast cell mediator is diagnostic of mastocytosis; Rather, the demonstration of such mediators in blood or urine should prompt the clinician to investigate further for the presence of mastocytosis

A

TRUE

No single laboratory test showing an elevation in a mast cell mediator is diagnostic of mastocytosis; Rather, the demonstration of such mediators in blood or urine should prompt the clinician to investigate further for the presence of mastocytosis

41
Q

TRUE OR FALSE

Mastocytosis can be cured

A

FALSE

Mastocytosis currently has no cure.

42
Q

It is often considered to be a first-line drug of choice in Systemic Mastocytosis

A

Interferon-α or Cladribine

For many patients with advanced systemic mastocytosis, midostaurin may be considered the first-line therapy.

43
Q

FDA-approved treatment for adult patients with ASM who do not have the KIT D816V mutation or with unknown KIT mutational status

A

Imatinib mesylate (Gleevec)

Inhibits ABL1, KIT, and PDGFR tyrosine kinases.

It does not inhibit KIT bearing codon 816 mutations associated with most common forms of systemic mastocytosis.

44
Q

Inhibits both IgE-dependent release of histamine and the growth of neoplastic mast cells bearing various mutant forms of KIT

A

Midostaurin

FDA-approved for treatment of ASM, SM-AHN, and MCL

For many patients with advanced systemic mastocytosis, midostaurin may be considered the first-line therapy.

45
Q

Primary toxicity of Midostaurin

A

GI side effects

46
Q

Examples of KIT D816V inhibitors

A

Avapritinib
Masitinib

47
Q

Most common adverse events for Avapritinib

A

Periorbital edema and myelosuppression

48
Q

Most common adverse events for Masitinib

A

Diarrhea and rash

49
Q

Term adopted for patients who have one or two minor diagnostic criteria for mastocytosis but lack the full diagnostic criteria for systemic disease.

A

Monoclonal Mast Cell Activation Syndrome

50
Q

Patient with Monoclonal Mast Cell Activation Syndrome should e monitored every _________

A

Yearly

To determine if there is evidence of an expanding mast cell compartment

51
Q

Term applied as a diagnosis for patients with episodic allergic-like signs and symptoms, including flushing, urticaria, diarrhea, and wheezing, involving two or more organ systems, when an extensive medical evaluation has failed to identify an etiology

A

Mast Cell Activation Disorder

52
Q

Poor prognostic factors associated with mast cell disorders

A
  • Elevated serum lactate dehydrogenase levels
  • Late age of onset
  • Patients with SM-AHN
  • Presence of a significant hematologic abnormality
53
Q

A major differential diagnosis to Mast Cell Leukemia

A

Myelomastocytic leukemia (MML)

54
Q

Rare tumor characterized by nodules at various cutaneous and mucosal sites.

A

Mast Cell Sarcoma

55
Q

Chronic basophilic leukemia should be distinguished from hyperbasophilia, defined as a basophil count of greater than or equal to ________in the blood.

A

1 × 10 9 /L

Hyperbasophilia is usually associated with an underlying myeloid neoplasm and presumably reactive.

56
Q

Primary side effect of Midostaurin

A

GI side effects

WILLIAM'S HEMATOLOGY (90 decks)

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