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!colspan="3" style = "font-size:90%;"|'''Markers predominantly associated with B-cell lineage''' | !colspan="3" style = "font-size:90%;"|'''Markers predominantly associated with B-cell lineage''' | ||
|+<span style="color: navy; height: 120% | |+<span style="color: navy; height: 120%;">'''Immunophenotype of CLL'''</span> | ||
|- | |- | ||
|colspan="1" style = "width: 10%; font-size:90%;" |'''Light chains''' | |colspan="1" style = "width: 10%; font-size:90%;" |'''Light chains''' |
Revision as of 12:47, 15 June 2023
Background
Typical CLL can be diagnosed with some confidence using flow cytometry. However, atypical cases are regularly encoutered and can cause diagnosic difficulty.
This image shows a typical CLL cells and a dot plot of CD45/SSc. Note that although the CLL cells (shown in blue) generally lie close to the position of normal lymphocytes, consistent with their "anergic nature" CLL cells express low levels of B-cell receptor associated molecules and generally have lower expression of CD45 than normal typical T cells (shown in red) or NK cells (shown in green). They also have wider range of CD45 expression causing them to have a "sausage like" shape. This is a fairly typical appearance of CLL though not in itself diagnostic.
file CLL image file CD45CLL.jpg left 250px
Markers predominantly associated with B-cell lineage | ||
---|---|---|
Light chains | Wk | Either weak resticted κ or λ or undetectable expression |
CD19 | Wk/mod | Expression is expected, but less strong than normal B cells |
CD20 | Wk | Expression is expected, but characteristically weak |
CD79A | Wk | Expression is expected, but characteristically weak |
FMC7 | Wk | May be expressed by atypical cases, generally absent |
Immunophenotype:
Markers of B-lineage
- Immunoglobulin light chains: expect either light chain restriction with low intensity, or undetectable expression
- CD19 should be detected, but intensity is generally weak in CLL
- CD20 has expected expression in CLL, but intensity is generally weak
- CD79b expression is characteristically weak in CLL
Markers allowing diagnostic distinction
- FMC7 will have low or absent expression, high expression is particularly may suggest alternative disorders such as MCL or MZL
- CD5 should be expressed at moderate intensity in CLL (note also on expressed on mcl and occasionally on other lpd)
- CD23 has expected expression in CLL often at low intensity, generally absent in mcl but variably present on other lpd
- CD200 expressed on most CLL cases as well as other b-lpd but is most frequently absent in mcl optional markers extended panel for atypical cases
- CD43 a pan b-cell marker with expected expression in CLL; frequently but not always absent in mcl
Pitfalls