CLL and Exfoliating Lymphoma (PFC) Flashcards
What is the normal count
for peripheral blood lymphocytes and normal composition ?
- absolute levels 0.75-3.6 x 10^9/L
- T cells normally account for 80-90%
- identified by sCD3, which means that has matured beyond precursor T cell stage
- cytoplasmic CD3 expression is the gold standard marker of T cell lineage
- normal peripheral blood CD4/CD8 ratio is ~2:1
- normal in bone marrow is 1:2
What is the normal T cell maturation/
immunophenotype pattern ?
- express CD2, CD5, CD7
- co-expression of CD4/CD8 is seen in thymic maturation/migration
- can be seen in peripheral blood at low levels
IMP: should NOT have CD4 or CD8 negative lymphocytes in the peripheral blood
What is the normal amount of NK
cells within the peripheral blood ?
- NK cells : 654 x 10^9/L
- these cells express CD2 but not CD3
What is the normal proportion of B cells in
the peripheral blood ?
- 10-20% of peripheral blood lymphocytes
- cytoplasmic CD79a is the gold standard used by some to identify B cells
- CD19 is usually reliable but can be aberrantly expressed by some non-B cell malignancies
- blood B cells usually express CD22 and FMC7 as well as HLA-DR
- IMP: nomrla, non-activated T cells do not express HLA-DR
What cells are positive for
CD38, CD23, CD5 and FMC7
normally ?
- CD38
- activated B cells, plasma cells, T and NK cells
- CD23
- activated, mature B cells expressing IgM or IgD
- CD5
- small subset of normal B cells and T cells
- FMC7
- mature B cells
What cells are normally positive for
CD10, HLA-DR, Kappa and Lambda ?
- CD10
- pre B lymphocytes and germinal center B cells
- HLA-DR
- Normal B cells and activated T cells
- Kappa and Lambda
- normal polyclonal mature B cells
What cells are normally positive for
CD11c and CD103 ?
- CD11c
- granulocytes, macrophages
- NK cells
- Dendritic cells
- CD103
- intraepithelial T cells
What cells are positive for
CD25 and CD123 ?
- CD25
- activated B and T cells
- macrophages
- CD123
- plasmacytoid monocytes
- PDCs
- Basophils
Where do CLL cells likely arise from ?
- either arise from:
- Naive pre-germinal center cells (unmutated CLL)
- or
- post-germinal center memory B cell (mutated CLL)
In CLL, what do increased
prolymphocytes show by cytogenetics ?
- proportional increases in prolymphocytes are associated with cytogenetic abnormalities
- often trisomy 12 and del17p
- also have progressive disease with refractoriness to therapy
FMC7 is considered to be
an epitope of which marker ?
- CD20 molecule
- FMC7 is absent or dim in CLL
What does CD38 expression in CLL
correlate with ?
- unmutated IgVH gene or Zap70 expression
- associated with poor prognosis
IMP: CD38 expression may vary in any individual patient cells over time
What marker when positive, helps differentiate
a CLL with abnormal immunophenotype vs. Mantle cell ?
- CD200
- universally positive in CLL
- negative in Mantle cell lymphoma
Detection of what mutation
likely reflects refractoriness to Fludarabine therapy ?
- del 17p (loss of TP53 function)
- refractory to Fludarabine therapy
What marker usually is a good way to differentiate
Mantle cell lymphoma from CLL….but not always ?
- CD23
- has been reported to be positive in 25% of Mantle cell lymphoma patients
Note: rare cases of MCL have also been shown to be CD10 positive (frequently blastoid morphology)
What cytogenetic and morphologic
findings in Mantle cell are associated with
rapid disease progression ?
- rearrangements of MYC gene (8q24) and TP53 at 17p13
- often seeni n blastoid morphology and with progression
How can splenic margin present ?
- often appear in the blood in low number
- can express CD5
- mild lymphocytosis, splenomegaly and cytopenias
- cytopenias due to hypersplenism and sometimes autoimmune phenomena
- 1/3 of patients have a small paraprotein, often associated with hepatitis C infection
- bone marrow involvement is variable
- interstitial or nodular pattern
- **affinity for the sinusoids
- liver and spleen
- involves the sinusoids and red pulp
When splenic marginal zone acquires
a TP53 mutation on chromsome 17p, what
morphology is typically seen ?
- larger cells with prominent nucleoli
- voluminous cytoplasm
- must differentiate from HCL and B-PLL
What is the immunophenotype of
splenic marginal zone lymphoma ?
- positive:
- pan B cell antigens
- light chain and CD20 expression is moderate to strong
- CD5 (~20%) of cases
- often seen in cases with more peripheral blood involvement
- negative:
- CD103, CD123, CD25
- positive or negative
- CD23 and CD11c
What are the most common
cytogenetic findings in splenic marginal zone lymphoma ?
- del 7q and gain of 3q
- TP53 does occur in more aggressive disease
What is the typical presentation of
B-PLL ?
- middle aged to elderly males with significant lymphocytosis
- anemia, thrombocytopenia and splenomegaly
- lymphoadenopathy is very rare
- if present should question the diagnosis
What is the immunophenotype of
B-PLL ?
- CD5 + in 20-30% of cases
- CD23 + in 10-20% of cases
- pan-B antigens positive with CD20 and light chain strong MFI
- FMC7 and CD11c positive
- therefore should not confuse with CLL
What is the characteristic immunohenotype
of LPL ?
- variable degrees of surface and cytoplasmic light chain expression
- positive for mature pan-B cells
- associated plasma cells may be restricted but do not show a malignant phenotype
- Other markers seen:
- weak CD23 and CD5 +
- loss of FMC7
- variable expression of CD38
- CD11c and CD25 can be +
What is a feature of follicular lymphoma
by flow cytometry that can help differentiate it from
background B cells ?
- generally will have a dim CD19
What is the typical immunophenotype of
Burkitt Lymphoma cells ?
- mature precursor or early mature phenotype
- pan B cell markers are positive
- CD19, CD20, CD79a, CD22, FMC7
- early surface immunoglobulin is often weak in intensity
- express CD10
- pre-GC origin
- CD38 is usually bright
- help differentiate it from true BL
What is a marker that can be often
seen on HCL ?
- CD10
- if the rest of the immunophenotype fits and CD10 is + it can still be HCL
What immunophenotype when seen in a B cell
LPD should prompt the addition of
the hairy cell tubes?
- strong surface Ig
- strong CD20
- Negative
- CD5
- CD10
- especially if the patient has cytopenias and splenomegaly
What are the additional antibodies that should be
run to assess for HCL ?
- CD11c
- CD103
- CD123
- CD25
What markers are HCL-v
typically negative for ?
- NEG
- CD25 and CD123
- May be positive or negative
- CD11c
- CD103
