Phenotypic Markers Flashcards
1
Q
What diagnosese can
TdT be positive in ?
A
- B-ALL
- T-ALL
- Thymocytes
- thymic hyperplasia
- thymoma
- AML
- Blastic plasmacytoid dendritic cell neoplasm (BPDCN)
- Hematogones
2
Q
What type of molecule is TdT ?
A
- it is a unique intranuclear DNA polymerase
- in AMLs usually seen in
- minimally differentiated
- or rarely monoblastic leukemias
3
Q
What diseases is MPO positive in ?
A
- AML
- Mixed phenotypic acute leukemia (MPAL)
4
Q
What is the threshold for MPO positivity ?
A
- 3% threshold has been used historically for cytochemistry
- 10% threshold has been recommended for flow cytometry
- recent proposal for 13-28% positivity
5
Q
Is there MPO positivity in B-ALL ?
A
- yes there can be without it being classified as an MPAL
- if there is homogeneous expression of lymphoid markers on the single blast population and there is no evidence of other myeloid marker expression othere than MPO
- B-ALL has been known to show low levels of MPO expression
6
Q
What populations is HLA-DR positive in?
A
- expressed on B cells at different stages of maturation
- except in plasma cells where it is lost
7
Q
What is HLA-DR negative in ?
A
- hematopoietic progenitor cells
- myeloid
- erythroid
- megakaryocytic
- monocytic/macrophage
- Hypo and hypergranular APL
- Plasma cell neoplasms
- Majority of T cell lymphoma/leukemias
8
Q
What malignancies are typically
HLA-DR positive ?
A
- HLA-DR is positive on precursors and mature B cell lymphoproliferations
- majority of AML
9
Q
CD235a (glycophorin A) is positive
in which cell populations?
A
- expressed on RBCs and their precursors
- very early precursors are usually negative or only dimly positive
- IMP:
- this is in contrast to CD71
- CD71 is strongly expressed by even the early precursors
- IMP:
10
Q
CD138 is positive in what situations ?
A
- majority of plasma cell neoplasms
- subsets of mature B cell lymphoproliferations
- Plasmablastic lymphoma
- DLBCL with activated B cell like phenotype
11
Q
What malignancies is CD123
positive in ?
A
- Blastic plasmacytoid dendritic cell neoplasm (BPDCN)
- Benign plasmacytoid dendritic cells
- AML (subsets)
- APL (subset)
- CMML
- B-ALL (subset)
- Hairy cell leukemia (bright)
- Hairy cell leukemia variant (subset)/lower intensity of expression
- NK-cell malignancies
- Dendritic cell malignancies
- MDS blasts may be CD123+
12
Q
What is the normal role of CD123 ?
A
- CD123 binds to the alpha subunit of the interleukin-3 receptor
13
Q
When CD123 is positive in AML
what should you suspect is present ?
A
- usually NPM1 positive
- also positive in monoblastic leukemias
- the leukemias are also positive for FLT3-ITD mutations and show low expression of CD34
- positive for CD11b and CD14
Note: CD123 is positive in a subset of APL
14
Q
What is the expected expression
of CD123 in HCL?
A
- expression of CD123 is bright
- Other rare cases of mature B cell lymphomas with CD123 (but expression is usually partial or dim)
- HCLv (~40% of cases)
- splenic marginal zone
- CLL
- MCL
- FL
15
Q
What disease processes can have
CD123+ associated plasmacytoid dendritic cells?
A
- seen in the bone marrows of patients with CMML
- lymph nodes with Kikuchi-fujimoto lymphadenopathy
16
Q
What type of B-ALL can you
see expression of CD123 ?
A
- usually hypodiploid B-ALL
- IMP
- normal bone marrow hematogones are negative for CD123
17
Q
What benign cells are positive for CD117?
A
- Myeloblasts
- Promyelocytes
- Mast cells
18
Q
Which leukemias are typically
positive for CD117?
A
- most AMLs are CD117 positive
- even AML without maturation
- AMML
- pure erythroid leukemias
- acute megakaryoblastic leukemia
19
Q
What leukemias are typically
negative for CD117 ?
A
- acute monoblastic leukemia
20
Q
What other hematopoietic tumors are
positive for CD117 ?
A
- Mast cell proliferations
- plasma cell neoplasms
- subsets of T-ALL
- especially ETP-ALL
- rare cases of mature CD8+ peripheral T cell proliferations
- notably T-PLL
21
Q
What non-hematopoietic things
are positive for CD117 ?
A
- GIST
- occasionally malignant melanomas
- poorly differentiated caricnomas/neuroendocrine tumors
22
Q
What are the 3 maturational stages of dendritic cells based on the expression of CD34 and CD117?
A
- immature cell (CD34+)
- intermediate cell (CD117+/CD34-)
- mature cells (CD117-/CD34-)
Note: these maturational stages explain the different presentations of BPDCN
23
Q
What benign cells are positive for CD103?
A
- minor subset of T-cells in the GI tract and liver
- dendritic cells, subset
- rare circulating B cells
24
Q
What neoplasms is CD103 expressed in ?
A
- HCL
- may be dim and or partial
- HCL(v)
- may be dim and or partial
- Enteropathy associated T-cell lymphoma (EATL)
- MEITL
- Diffuse large B cell lymphoma (rare cases)
- Marginal zone lymphoma (occasional cases)
- rare cases of PTCL, ATLL, and T-PLL
25
What other tumors may express CD103?
- BPDCN, subset
26
What neoplasms are negative for
CD103 ?
* MCL
* FL
* CLL
* MZL
* including splenic marginal zone lymphoma
27
What normal cells express CD79a ?
* benign, B cells
* this includes plasma cells which are essentially terminally differentiated B cells
28
What can pick up CD79a staining in a
non-specific manner in the BM ?
* megakaryocytes
29
What neoplaasms are often positive for CD81 ?
* mature B cell proliferations
30
What normal cells and neoplasms
is CD71 positive in?
* early erythroid precursors
* pure erythroid leukemia
* AML
* B-ALL subset
* T-ALL subset
* High grade B and T cell lymphomas
31
What benign cells express CD71 (transferrin receptor)?
- B and T cell precursors
- Myeloblasts
- Activated B and T/NK cells
- Erythroblasts/Pronormoblasts
- Germinal center B-cells (centroblasts)
- Reactive follicular hyperplasia (CD10+ B cells are CD71+)
32
What is the normal function of CD71 ?
* it is the transferrin receptor
* it mediates the uptake of transferrin-iron complexes
33
What normal cells express CD71 ?
* strongly positive in erythroid precursors
* myocytes
* hepatocytes
* endocrine pancreas cells
* spermatocytes
* basal keratinocytes
* placental syncitiotropholblasts
34
How is the expression of CD71 compared to glycophorin A?-
- CD71 is positive in early precursors while negative on mature red blood cells
35
What is the expression pattern of CD71
in erythroid precursors ?
* strongly positive in early precursors
* level of expression decreases gradually through the reticulocyte stage
* this is contrast to glycophorin (CD235a), CD71 is negative in mature erythrocytes
* CD71 has a similar expression pattern to E-cadherin
36
How does the intensity of CD71 vary
amongst lymphomas?
* CD71 is low intensity in low-grade lymphomas
* while it is high intensity in high grade lymphomas
* Note: expression is higher in DLBCL as compared to Burkitt lymphoma
37
What is the expression of CD71
in the BM and why ?
* CD71 is expressed at a higher level on cells that have a high proliferation rate (due to high iron demand)
* myeloblasts, promyelocytes, and erythroblasts are CD71+
* more mature forms are negative
38
CD71 is expressed more inT-ALL or B-ALL?
* usually more common in T-ALL
* also IMP
* ATLL shows some expression
39
What can CD71 be a surrogate marker
for by flow cytometry ?
* it can be a surrogate for Ki67
* or a proliferation marker
40
How is CD71 expression affected in dysplasia?
- The expression of CD71 is decreased in dysplastic erythroid precursors
41
In bone marrow specimens how is CD71 expressed?
- CD71 expression is restricted to the erythroid lineage
Note: myeloblasts, neoplastic plasma cells and metastatic carcinoma cells are usually negative.
42
What is CD64 expressed in ?
* monocytes (classical, CD14 bright +/CD16 -)
* acute monoblastic leukemia
* CMML
* monocytic components of AMML
* blasts in subsets of AML
* APL, subset dim partial
* Acute megakaryoblastic leukemia
43
What is different about the expression of
CD64 in acute monocytic leukemias vs. others ?
* CD64 is brighter
* in other AMLs the expression is dim or partial
44
What is CD61 expression seen in?
* megakaryocytes
* Acute megakaryoblastic leukemia
45
What is CD57 expression seen in?
* NK cells and a subset of T cells
* Positive in:
* T-LGL leukemia
* subset of NK-cell neoplasms
* rare T cell lymphoblastic tumors
* T-PLL, rare (mostly dim and partial)
* Chronic LPD of NK cells
46
Where are the CD57+ T cells
in NLPHL ?
* they form characteristic rosettes around the large neoplastic cells
47
What non-hematopoietic tumors can express CD57?
- Primitive Neuroectodermal Tumor (PNET)
- Rhabdomyosarcoma
- Small cell carcinoma
48
What is CD56 and what cells typically express it ?
* neural cell adhesion molecule (N-CAM)
* expressed by natural killer cells, subsets of T cells, and monocytes
49
When can CD56 expression be unregulated?
- subsets of granulocytes and monocytes from patients with MDS, MPNs and mixed MDS/MPN (such as CMML)
50
What non-leukemic, hematolymphoid
neoplasms express CD56?
* Extranodal NK/T cell lymphoma, nasal type
* Peripheral T cell lymphoma, NOS (subset)
* T-LGL leukemia (subset)
* NK-cell proliferations
*Chronic lymphoproliferative disorder of NK cells
* ALCL (subset)
* Subcutaneous panniculitis-like T cell lymphoma (subset)
*Primary cutaneous gamma delta T cell lymphoma
*HSTL
* MEITL
* EITL, subset
* Lymphomatoid papulosis (LyP)
* DLBCL (rare cases)
* Plasma cell myeloma
51
What leukemia's often express CD56 ?
* acute monoblastic leukemia
* acute myeloid leukemia with t(8;21)
* usually with co-expression of CD19 by myeloblasts
* APL (rare cases)
* AML (rare cases)
Also, cutaneous gamma-delta T cell lymphoma and BPDCN
52
In what neoplasms is CD56 been associated
with a poor risk factor ?
* AML with t(8;21) and t(15;17)
* in t(8;21) associated with significantly shorter complete remission duration and survival
53
What non-hematopoietic neoplasms can express CD56?
- Small cell carcinoma
- Carcinoma with NE differentiation
- Malignant melanoma
- Neuroblastoma
- Wilms Tumor
- Rhabdomyosarcoma
54
What benign cells express CD19?
- Hematogones
- B- cells
- Plasma cells (variable, often dim or partial expression)
55
What neoplastic B cell lymphoproliferations express CD19?
- Majority of mature B cell LPDs
- PCM, rare cases
56
What neoplastic B cell lymphoproliferations are often negative for CD19?
- PEL
- ALK + Large B cell lymphoma
- Plasmablast lymphoma
- Subset of PTLD
57
What other tumors are positive for CD19?
- B-ALL/LBL
- AML, subset (AML with t(8;21)(RUNX1-RUNX1T1)
- MPAL; AML/B-ALL
- CML in lymphoid blast crisis
- Nodular lymphocyte predominant Hodgkin lymphoma
58
What type of molecule is CD19?
- integral membrane protein
- expression is limited to B cells and follicular dendritic cells
59
What is the possible function of CD20?
- poorly understood
- been implicated in B cell activation, regulation of B cell growth and regulation of transmembrane calcium flux
60
What cells is CD20 typically expressed on normally?
- B cells
- Germinal center cells show brighter expression than mantle zone cells
61
What B cell lymphoproliferative disorders often show CD20 expression?
- CLL, dim expression
- HCL and HCL-v
- Majority of B cell lymphomas
- PCM, minor subset
62
What T cell lymphoproliferations have been known to show CD20 expression?
- Aberrant expression has been documented in many cases
- Usually seen only in a subset of the neoplastic cells
- PTCL, NOS
- ALCL, T-PLL, follicular T cell lymphoma, and AITL
63
What other neoplastic conditions have shown aberrant CD20 expression?
- B-ALL/LBL (rare cases, usually dim and or partial expression)
- NLPHL
- Hodgkin Lymphoma, minor subset
- Thymoma, Type A (spindle, medullary subset)
64
What B cell lymphomas are notably negative for CD20?
- PBL
- PEL
- DLBCL associated with chronic inflammation
- ALK positive large B cell lymphoma
- DLBCL, rare cases
65
What is CD22 positive in ?
- CD22 is a B cell specific marker
- Plasma cells are CD22 negative
66
What cells is CD22 positive in ?
- B-cells
- Basophils, subset
67
What B cell lymphoproliferatie disorders is CD22 positive in ?
-Majority of mature B cell LPDs (somewhat dim)
**IMP: CLL is negative
-PCM, very rare cases
- CD22 is bright in HCL and splenic MZL
-Clonal plasma cell components of LPL may be CD22+
68
What acute leukemia's can express CD22 ?
- B-ALL/LBL - cytoplasmic expression of CD22
- MPAL; AML and B-ALL
- Acute basophilic leukemia, subset
69
What other tumors can express CD22 ?
- Basophils in CML and AMLs with basophilic differentiation, they may also show CD13 and CD25 expression
- Mast cell neoplasms
70
What neoplasms are notably negative for CD22 ?
- CLL
- Plasma cell neoplasms
* BUT clonal plasma cell components of LPL may be CD22+
71
What cells is CD23 normally positive in?
- benign B cells of the blood, mantle zone and germinal centers of lymph node and tonsil
- subset of plasma cells
- follicular dendritic cells
- subset of activated T cells
- subset of activated monocytes
72
What B cell lymphoproliferations are positive for CD23 ?
- CLL, strong expression
- Follicular lymphoma, minor subset but particularly seen in the diffuse variant
- MZL, very rare cases
- B-PLL, rare cases
- LPL, rare cases
- HCL, rare cases
- DLBCL, rare cases
- PMBL, subset of cells
- MCL, very rare cases
- PCM, very rare cases
73
What acute leukemias may show CD23 expression ?
- Acute monoblastic leukemia, subset
74
What myeloid tumors may show CD23 expression ?
- CMML, minor subset
75
What other tumors may show CD23 expression?
- Follicular dendritic cell tumors
76
Can MCL express CD23?
- most are CD23 negative
- subset of MCL may be dim for CD23
77
What B cell lymphoproliferations are negative for CD23 ?
- MCL
- BL
- HCL
- majority of DLBCL
- majority of nodal and splenic MZL
78
What other cells may express CD23 ?
- benign plasma cells
- subset of plasma cells
79
What type of protein is CD24?
- it is a GPI linked protein also known as heat stable antigen (HSA)
80
What cells normally express CD24?
- surface of B cells (but not plasma cells)
- granulocytes
- follicular dendritic cells
- epithelial cells
81
What diagnosis is CD24 typically used in a flow cytometry panel for?
- diagnosis of PNH
82
What lymphoproliferations can express CD24?
- B-ALL
- majority of mature B cell LPDs
* HCL, MZL
* subset of DLBCL are usually negative or show dim expression
83
What type of protein is CD25 ?
-interleukin 2 receptor
84
What neoplasms are negative for CD25?
- AITL
- HSTL
- T-PLL
- T-LGLL
- HCL-v
85
The presence of CD25 expression by an AML is generally associated with what molecular findings?
- FLT3-ITD
- DNMT3A
- NPM1
86
What benign cells often express CD25 ?
- T-cells, subset
- NK cells
- B-cells, minor subset (dim expression)
- Basophils
87
What B cell lymphoproliferations express CD25?
- HCL (not HCL-v)
- CLL, rare cases
- B-ALL, subset
- Follicular lymphoma, rare cases
- Splenic marginal zone lymphoma, subset
-B- cell lymphoma subsets (MCLs and splenic red pulp B cell lymphoma are CD25 (-))
88
What T cell lymphoproliferations are positive for CD25?
- ATLL, strong expression (100% of cases)
- ALCL, subset
- MF, subset
- PTCL, subset
- Follicular T cell lymphoma, subset
- ENKTL, majority of cases
89
Which acute leukemias can express CD25 ?
- AML, minor subset
- B-ALL, subset
- T-ALL, rare cases
90
What myeloid tumors can express CD25?
- Chronic eosinophilic leukemia, subset
- CML in blast crisis, subset
91
What other tumors can express CD25?
- systemic mastocytosis (benign mast cells should be CD25-)
- langerhans cell histiocytosis (LCH)
92
What type of protein is CD26?
- type II membrane protein, which is expressed on the membrane of mature thymocytes
93
What other normal cells can express CD26?
- T lymphocytes (upregulated upon activation)
- B cells
- NK cells
- MacrophagesI
94
In what situations is the evaluation of CD26 particularly useful?
- patient's with MF
- there is a loss of CD26 in ~92% of cases of transformed MF
95
In what neoplasms is CD26 negative?
- circulating neoplastic T cells from patient's with MF (Sezary Syndrome)
- ATLL
96
What benign cells show expression of CD27?
- T-cells, subset
- NK cells
- B-cells (memory)
- Thymocytes
- Plasma cells
97
What B cell lymphoproliferations express CD27?
- CLL
- B-APLL
- FL
- LPL
- SMZL
- Nodal marginal zone lymphoma
- DLBCL
- BL
- MGUS ( CD27 is positive only in rare PCMs)
98
What T cell lymphoproliferations express CD27?
- Sezary syndrome (SS), subset (MF is negative!)
- PTCL, minor subset
- Follicular T cell lymphoma, subset
- AITL, subset
99
What benign cells express CD30?
- activated B and T cells with immunoblast morphology
- Atypical cells (immunoblasts) in EBV lymphadenitis or Kikuchi lymphadenopathy
100
What B cell lymphoproliferations can express CD30 ?
- DLBCL, subset
- PEL - most cases
- FL, rare cases
- Primary mediastinal large B cell lymphoma (PMBL)
- Lymphomatoid granulomatosis (LyG)
- PCM, rare cases
101
What neoplasms generally have 100% expression of CD30?
-CHL
- ALCL
- PEL
- Pagetoid reticulosis (variant of MF)
- MF with large cell transformation
102
CD30 expression can help classify T cell lymphomas. What T cell lymphomas in general have strong and uniform expression of CD30?
- ALCL (ALK + and - )
- ATLL (large cells, subset of cells in acute form of ATLL)
- Primary cutaneous ALCL
- Breast-implant associated ALCL
- MF with large cell transformation
- rare cases of PTCL, NOS
- ENKTL
103
What T cell lymphomas have focal, variable and weak expression of CD30?
- AITL
- subset of PTCL, EATL, ENKTL, and MEITL
104
What other tumors can express CD30?
- subset of AML
*often associated with FLT3-ITD, high leukocytosis and high risk disease
- CHL
- Aggressive systemic mastocytosis (benign mast cells are CD30 negative)
105
Approximately what percentage of DLBCL express CD30?
- 14-21% express CD30
- often associated with a unique gene expression profile
- generally non-GC subtype
- have a favorable prognosis
106
What is the recommendation for reporting of CD30 ?
- intensity of staining(1-3+)
- percentage of tumor cells with membranous or Golgi staining (>1% or <1%)
- this is due to the availability of anti-CD30 medications
107
What normal cells are positive for CD34?
- it is a marker of immaturity (myeloid and lymphoid)
- hematogones
- myeloblasts
- immature megakaryocytes
- mast cell progenitors
108
What types of AML's are typically negative for CD34?
- classic hyper granular APL
- monocytic leukemias
- AML's with NPM1 mutation
Note: hypo granular APL is often CD34 positive
109
What other leukemias are CD34 positive ?
- B-ALL
- T-ALL
- MPAL
Note: BPDCN's are negative for CD34
110
What other marker is positive in leukemias that are NPM1 negative but FLT3-ITD positive?
- CD34+
- also TdT+
111
What is the normal number and distribution of CD34+ blasts in the bone marrow?
- normal bone marrow has < 2% blasts
- they are typically scattered individually without forming significant clusters
112
In myeloid neoplasms, what abnormal marker expression of CD34+ blasts can be helpful in diagnosing an abnormality by flow cytometry?
- CD117 (-)
- CD123 +
- down regulation of CD13, CD33, or CD45
- aberrant expression of CD7 or CD56
113
What markers may be helpful in fibrotic marrows to differentiate myeloblasts, hematogones, mast cells, immature basophils, immature erythroid cells and plasma cells?
- CD34, CD117, Pax5, MUM1, CD71, and tryptase
- Myeloblasts: CD34 +, CD117 +
- Hematogones: CD34+, Pax5+
- Mast cells: CD117+, Tryptase +
- Immature basophils: Tryptase +, CD34 (-), CD117 (-)
- Immature erythroid precursors: CD117+, CD71+, CD34(-)
- Plasma cells: CD117+, MUM1+
114
What are some non-hematopoietic tumors that are CD34 positive?
- vascular tumors
- Kaposi's sarcoma
- DFSP
- GIST
- other soft tissue tumors
115
What type of marker is CD36?
- glycoprotein IV
- monocytic marker similar to CD14
- expressed in mature monocytes
116
What disease processes can CD36 be positive in?
- BPDCN
- Monocytic leukemias
Note: in acute monoblastic leukemia, CD36 is more often positive than CD14
- only a minor subset of AMLs with/or without maturation may show aberrant CD36 expression
117
What is the expression of CD36 in APL and Acute megakaryoblastic leukemia ?
- APL: negative
- Megakaryoblastic: usually positive and seen in cases associated with Trisomy 21
118
What benign cells express CD38?
- plasma cells
- activated (stimulated ) B and T cells
- Thymocytes
- Hematogones
- Neutrophils and maturing myeloid precursors
- Eosinophils
- Basophils
- NK cells
- classic monocytes (CD14 bright/ CD16 -)
119
What normal cells show bright/strong CD38 expression?
- high in B cell precursors and terminally differentiated plasma cells
Note: expression is low to absent in mature B cells
120
What is the typical expression of CD38 in AML's?
- often positive (dim to moderate)
121
What mature neoplasms have bright CD38 expression?
- T cell neoplasms, esp ALCL or PTCL
- High grade B cell lymphomas
*Double hit, NOS, etc
-Burkitt Lymphoma
- subset of Hairy cell leukemia
Note: generally MYC translocated B cell lymphomas have bright CD38
122
Why is CD38 evaluated in CLL and what is it's significance?
- based on the number of clonal cells expressing CD38 CLL can be divided into two categories
- CLL >30% positive CD38
- CLL <30% positive CD38
- >30% CD38 positive = unmutated IGHV
- <30% CD38 positive = mutated IGHV
123
The level of expression of CD38 in CLL correlates with clinical stage, response to treatment and overall survival. What does higher CD38 expression typically indicate/morphologically show?
- >30% = unmutated IGHV
- more advanced stage
- diffuse bone marrow involvement
- atypical morphology
- deletion 11q
- trisomy 12
- poorer chemosensitivity
- significantly shorter overall survival
124
What is important to remember about CD38 expression in patient's with CLL?
- in ~30% of patients the levels of CD38 expression and IGHV mutational status are discordant.
125
What is important to remember regarding CD38 treatment in plasma cell myeloma?
- anti-CD38 (Daratumumab) may cause a loss of CD38 expression plasma cells
- other markers should be used to evaluate neoplastic plasma cells
126
What B cell lymphoproliferations express CD38?
- PCM, bright expression
- CLL, subset
- MCL, major subset
- DLBCL, subset
- FL, subset
- HCL, minor subset
- PEL
- DLBCL, associated with chronic inflammation
- PBL
- ALK+ Large B cell lymphoma
- BL
- LPL
- HGBCL
- MZL, subset
127
What T cell lymphoproliferations are positive for CD38?
- ALCL, subset [ALK+ is ofte negative]
- PTCL
- ATLL, acute variant [chronic variant is negative]
- T-PLL, subset
-HTSL, subset
-T-LGLL, majority
- AITL, majority
- ENKTL, majority
128
What acute leukemias can express CD38?
- AML, majority
- B-ALL, majority
- T-ALL, all cases
129
What other myeloid tumors may express CD38?
- Blasts and myeloid cells in MDS, MPN and mixed MDS/MPN
130
What other tumors can express CD38?
- BPDCN, subset
131
In what setting is the expression of CD43 useful?
- CD43 is NOT a lineage specific marker
- it is present on a wide range of both benign and neoplastic hematopoietic cells
- BUT it can be useful in cases of poorly differentiated or anaplastic neoplasms in demonstrating whether they are hematopoietic or non-hematopoietic in origin
*rarely expressed by non-heme tumors
132
Most benign B cells are NEGATIVE for CD43 except in what location in the body?
- Benign B cells in the terminal ileum may show expression of CD43
133
In what subset of ALCL can CD43 be helpful?
- ALCL (null cell type)
- CD43 may be the only expressed marker aside from CD30 and ALK
134
What benign cells may express CD43?
- T cells
- NK cells
- Neutrophils
- Eosinophils
- Basophils
- Mast cells
- Monocytes
- Hematogones
- Erythroblasts/Pronormoblasts
- B cells, minor subset (<10%)
135
What B cell lymphoproliferations are POSITIVE for CD43?
- BL
- MCL
- CLL
- MZL, subset
- DLBCL, minor subset
- Primary cutaneous DLBCL, leg type
- ALK+ large B cell lymphoma, rare cases
- PCM
- LPL, rare cases
- HCL, subset BUT HCL-v is CD43 negative
136
What T/NK cell lymphoproliferations are positive for CD43?
- Mature (peripheral) T-cell and NK-cell lymphomas
137
What acute leukemias may be positive for CD43?
- AML
- B-ALL
- T-ALL
138
What myeloid tumors may be positive for CD43?
- Blasts and myeloid cells in MDS, MPN and mixed MDS/MPN
139
What other hematopoietic tumors may be positive for CD43?
- BPDCN, subset
- Langerhans cell sarcoma
140
CD45 is known as the leukocyte common antigen and is expressed on the majority of hematopoietic cells with the exception of which two?
- maturing megakaryocytes
- erythroid cells
141
Which cells have the lowest expression of CD45?
- lower on blasts and immature forms
142
Which cells have the highest expression of CD45?
- maturę myelomonocytic cells and lymphocytes
143
What neoplasms are notably NEGATIVE for CD45?
- PCM
- Classic HL (R-S and H-S cells)
- Acute erythroid leukemia
- B-ALL/LBL, subset
- PBL
- Rare cases of ALCL and other mature T cell neoplasms
- AML, rare cases
- DLBCL, rare cases
- T-PLL, subset
- Dendritic cell sarcoma
144
What normal cells express CD49d?
- B and T cells
- thymocytes
- langerhan cells
- eosinophils
- monocytes
145
In what neoplasm is CD49d emerging as a prognostic marker?
- one of the most valuable markers in CLL/SLL for prognostics
- Considered positive if >30% of cells express it
- ~40-60% of CLL cases express this marker
- Detection of CD49d is superior to CD38 and ZAP-70 in predicting overall and treatment-free survival
146
What are high levels of expression of CD49d associated with in CLL?
- shorter time from diagnosis to treatment and overall survival
- prognostic value of CD49d is independent of other prognostic parameters including FISH and IGVH, positive CD38, and ZAP70 expression
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In what setting would you see lower expression of CD49d in CLL?
- patients with a deletion of 11q
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In what setting would you see higher expression of CD49d in CLL?
- patients with trisomy 12
149
What is the medication name for Alemtuzumab and what antibody does it target?
- Campath
- targets CD52
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What is the mechanism of action of Campath?
- antibody-dependent cell mediated cellular toxicity leading to complement activation and apoptosis
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What cells express CD52?
- normal and malignant T cells
- majority of B lymphoproliferations
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In what setting has Campath been used for treatment?
- CLL
- T-PLL
- low-grade Non- Hodgkin Lymphomas
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What normal cells typically express CD65?
- Neutrophils
- Eosinophils
- Basophils
- Monocytes, subset
- NK cells, minor subset
154
What acute leukemias are known to express CD65?
- AML, subset
- Early T-cell precursor acute lymphoblastic leukemia (ETP-ALL), subset
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What type of marker is CD79?
- it is a B cell marker which can be detected on the B cell surface or intracytoplasmic
156
What benign cells express CD79?
- B cells
- Hematogones
157
What B cell proliferations are positive for CD79?
- Majority of mature B cell lymphoproliferative disorders (CLL, PEL, and PBL)
*for both CD79a and CD79b
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B-ALL typically expresses which isoform of CD79?
- CD79a
- CD79b is variably expressed with a subset of cases being negative
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What is the difference in CD79 expression in CLL and MCL?
- CLL: CD79b negative
- MCL: CD79b positive
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What benign cells express CD81 ?
- Hematogones (bright expression)
- Plasma cells
- Myeloblasts
- B-cells
- T-cells
- NK cells
- Mast cells
- Dendritic cells
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What role does CD81 play ?
- CD81 is critical for B cell development and the humoral response
- interacts with CD19 in B cell development
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How is CD81 helpful in the evaluation of B-ALL?
- CD81 is usually dimly expressed in B-ALL, which helps with the differential diagnosis with hematogones (brightly positive for CD81)
163
How is CD81 helpful in the evaluation of plasma cell myeloma?
- benign plasma cells show bright expression of CD81
- most malignant plasma cells show either dim or negative CD81
IMP: expression of CD81 by PCM is a poor prognostic indicator
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What is CD81 expression in BL?
- BL shows bright positive expression of CD81
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What is CD81 expression in FL and DLBCL?
- dimmer expression of CD81 as compared to BL
166
What is the expression of CD81 in CLL and MCL?
- CLL is negative to partially dim
- MCL is positive
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What is the expression of CD81 in HCL and HCL-v?
- Both HCL and HCL-v are CD81 positive
- BUT
*HCL-v has brighter CD81 expression
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What is unique about CD133?
- it is a primitive cell antigen that has been shown to be a more specific marker of hematopoietic stem cells as compared to CD34
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What benign cells express CD133?
- Myeloblasts
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What malignancies express CD133?
- AML, subset
- Blasts in MDS and CMML may be CD133+
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In AML the expression of CD133 has been also shown to be correlated with the expression of what other markers?
- HLA-DR
- CD3
- CD7
- TDT
- CD13
- CD34
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What is the expression of CD138 in plasma cell neoplasms compared to normal plasma cells?
- the expression of CD138 in plasma cell neoplasms is often dimmer than in benign plasma cells when analyzed by FC
173
What B cell lymphoproliferations can express CD138?
- PCM
- ALK+ large B cell lymphoma
- PBL
- DLBCL, subset
- PEL
174
What is CD157 a marker of and what disease process can it be seen in?
- GPI-linked protein expressed on neutrophils and monocytes
- used in panels to evaluate for PNH
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