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<span style="color: navy>'''Background'''</span>


Typical CLL can be diagnosed with some confidence using flow cytometry. CLL cells express low levels of B-cell receptor associated molecules (e.g. CD19, CD79B and sIg) together with CD5 and CD23 in typical cases. However, atypical cases are regularly encoutered and can cause diagnosic difficulty.  
<span style="color: navy>'''Background to flow cytometric diagnosis'''</span>
 
Differentiation to plasma cells involves (in mast cases) the loss of typical pan B-cell markers and surface light chains. The expression of CD45 also differs both within and between cases making standard gating strategies difficult to apply. Cells are most often identified through their co-expression of CD138 with a relatively high expression of CD38, together with the absence of typical B-cell features.




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<div style="width: 95%; overflow: auto; border: 1px solid navy; font-size:100%">
{| class="wikitable" style="color:black; background-color:#ffffff;" cellpadding="5"
{| class="wikitable" style="color:black; background-color:#ffffff;" cellpadding="5"
!colspan="3" style = "font-size:110%; color: navy; text-align:center; background:#DEE0DE;"|'''Immunophenotype of CLL'''
!colspan="4" style = "font-size:110%; color: navy; text-align:center; background:#DEE0DE;"|'''Immunophenotype of plasma cells'''
|-
!colspan="4" style = "font-size:90%; background:#DAE8F2"|'''CD45''' expression
|-
|colspan="4" style = "font-size:90%; color:black;" |There is no consistent pattern of expression of CD45 although it is most often weak, but may be variable and is occasionally strong.
|-
!colspan="4" style = "font-size:90%; background:#DAE8F2"|Major markers useful in plasma cell identification
|-
|colspan="1" style = "font-size:80%; width: 4%; |'''Marker'''
|colspan="1" style = "font-size:80%; width: 8%; |'''Freq'''
|colspan="1" style = "font-size:80%; width: 8%; |'''Level'''
|colspan="1" style = "font-size:80%; width: 80%; |'''Comment'''
|-
|colspan="1" style = "font-size:90%; color:black;" |CD38
|colspan="1" style = "background:#004466;"|
|colspan="1" style = "font-size:80%;"|-
|colspan="1" style = "font-size:84%;"|The relatively strong expression of CD38 is typical of plasma cells
|-
|colspan="1" style = "font-size:90%;" |CD138
|colspan="1" style = "background:#004466;"|
|colspan="1" style = "font-size:80%;"|var
|colspan="1" style = "font-size:84%;"|Expression is expected although the intensity can vary
|-
|-
!colspan="4" style = "font-size:90%; background:#DAE8F2"|'''Major markers useful in CLL diagnosis'''
|colspan="1" style = "width: 4%; font-size:90%; color:black;" |κ/λ
|colspan="1" style = "width: 8%; background:#E6FAFF;"|
|colspan="1" style = "font-size:80%; width: 8%; |
|colspan="1" style = "font-size:80%;"|Surface light chain expression is lost (internal will be detected in permeabilised cells)
|-
|-
|colspan="1" style = "width: 8%; font-size:90%;" |'''κ/λ'''
|colspan="1" style = "font-size:90%; color:black;" |CD19
|colspan="1" style = "width: 4%; background:#00b8e6;"|
|colspan="1" style = "background:#66e0ff;"|
|colspan="1" style = "width: 4%; |wk
|colspan="1" style = "font-size:80%;"|-
|colspan="1" style = "font-size:85%;"|Either weak restricted κ or λ or undetectable expression
|colspan="1" style = "font-size:84%;"|Expression of CD19 may persist in some cases
|-
|-
|colspan="1" style = "width: 10%; font-size:90%;" |'''CD19'''
!colspan="4" style = "font-size:90%; background:#DAE8F2"|Other relevant markers
|colspan="1" style = "width: 7%; background:#004466; font-size:80%; color:white;" |Wk/mod
|colspan="1" style = "font-size:85%;"|Expression is expected, but less strong than normal B cells
|-
|-
|colspan="1" style = "width: 7%; font-size:90%;" |'''CD20'''
|colspan="1" style = "font-size:90%; color:black;" |CD5
|colspan="1" style = "width: 7%; background:#004466; font-size:80%; color:white;" |Wk
|colspan="1" style = "background:#E6FAFF;"|
|colspan="1" style = "font-size:85%;"|Expression is expected, but characteristically weak
|colspan="1" style = "font-size:80%;"|-
|colspan="1" style = "font-size:80%;"|Not detected on plasma cells
|-
|-
|colspan="1" style = "width: 7%; font-size:90%;" |'''CD79A'''
|colspan="1" style = "font-size:90%;" |CD10
|colspan="1" style = "width: 7%; background:#004466; font-size:80%; color:white;" |Wk
|colspan="1" style = "background:#E6FAFF;"|
|colspan="1" style = "font-size:85%;"|Expression is expected, but characteristically weak
|colspan="1" style = "font-size:80%;"|-
|colspan="1" style = "font-size:84%;"|
|-
|-
|colspan="1" style = "width: 7%; font-size:90%;" |'''FMC7'''
|colspan="1" style = "font-size:90%;" |CD11C
|colspan="1" style = "width: 7%; background:#66e0ff; font-size:80%; color:black;" |Wk
|colspan="1" style = "background:#E6FAFF;"|
|colspan="1" style = "font-size:85%;"|May be expressed by atypical cases, generally absent
|colspan="1" style = "font-size:80%;"|-
|colspan="1" style = "font-size:84%;"|
|-
|-
|colspan="1" style = "width: 7%; font-size:90%;" |'''CD200'''
|colspan="1" style = "font-size:90%;" |CD20
|colspan="1" style = "width: 7%; background:#004466; font-size:80%; color:white;" |Mod
|colspan="1" style = "background:#66e0ff;"|
|colspan="1" style = "font-size:85%;"|Characteristically positive in CLL and negative in MCL
|colspan="1" style = "font-size:80%;"|-
|colspan="1" style = "font-size:84%;"|Expression retained in some cases
|-
|-
|colspan="1" style = "width: 7%; font-size:90%;" |'''CD5'''
|colspan="1" style = "font-size:90%; color:black;" |CD23
|colspan="1" style = "width: 7%; background:#004466; font-size:80%; color:white;" |Mod
|colspan="1" style = "background:#E6FAFF;"|
|colspan="1" style = "font-size:85%;"|Characteristic of CLL, usually less strong than on T cells
|colspan="1" style = "font-size:80%;"|-
|colspan="1" style = "font-size:84%;"|
|-
|-
|colspan="1" style = "width: 7%; font-size:90%;" |'''CD23'''
|colspan="1" style = "font-size:90%; color:black;" |CD25
|colspan="1" style = "width: 7%; background:#004466; font-size:80%; color:white;" |Mod
|colspan="1" style = "background:#E6FAFF;"|
|colspan="1" style = "font-size:85%;"|Characteristic of CLL, although can rarely be weak or absent
|colspan="1" style = "font-size:80%;"|-
|colspan="1" style = "font-size:84%;"|
|-
|-
|colspan="1" style = "width: 7%; font-size:90%;" |'''CD43'''
|colspan="1" style = "font-size:90%;" |CD43
|colspan="1" style = "width: 7%; background:#004466; font-size:80%; color:white;" |Mod
|colspan="1" style = "background:#006699;"|
|colspan="1" style = "font-size:85%;"|Similar to CD200, may be helpful in some cases
|colspan="1" style = "font-size:80%;"|-
|colspan="1" style = "font-size:84%;"|Generally not expressed by LPL
|-
|-
!colspan="3" style = "font-size:90%; background:#DAE8F2"|'''Other markers with diagnostic relevance'''
|colspan="1" style = "font-size:90%; color:black;" |CD79b
|colspan="1" style = "background:#66e0ff;"|
|colspan="1" style = "font-size:80%;"|-
|colspan="1" style = "font-size:84%;"|Expressed in some cases
|-
|-
|colspan="1" style = "width: 7%; font-size:90%;" |'''CD11c'''
|colspan="1" style = "font-size:90%;" |CD103
|colspan="1" style = "width: 7%; background:#00b8e6; font-size:80%; color:black;" |Wk
|colspan="1" style = "background:#E6FAFF;"|
|colspan="1" style = "font-size:85%;"|Expressed in some cases, but tends to be wk
|colspan="1" style = "font-size:80%;"|-
|colspan="1" style = "font-size:84%;"|
|-
|-
|colspan="1" style = "width: 7%; font-size:90%;" |'''CD103'''
|colspan="1" style = "font-size:90%; color:black;" |CD200
|colspan="1" style = "width: 7%; background:#E6FAFF; font-size:80%; color:black;" |-
|colspan="1" style = "background:#006699;"|
|colspan="1" style = "font-size:85%;"|Not expressed by CLL, consider HCL if found
|colspan="1" style = "font-size:80%;"|-
|colspan="1" style = "font-size:84%;"|Detected frequently|-|}
|-
|-
|colspan="1" style = "width: 7%; font-size:90%;" |'''CD10'''
|colspan="1" style = "font-size:90%; color:black;" |FMC7
|colspan="1" style = "width: 7%; background:#00b8e6; font-size:80%; color:black;" |Wk
|colspan="1" style = "background:#E6FAFF;"|
|colspan="1" style = "font-size:85%;"|Rare in CLL, consider FL if detected
|colspan="1" style = "font-size:80%;"|
|colspan="1" style = "font-size:80%;"|Not expressed
|-
|-
|}
|}
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<span style="color: navy>'''Pitfalls and atypical cases'''</span>
<span style="color:navy;font-size:80% ">'''Key to table: '''</span>
 
<span style="font-size:80% ">Key to colour code for expression frequency [[Key_to_marker_expression_table|Click for link]]</span>
 
<span style="font-size:80% ">Key to expression strength code and use [[Expression strength key|Click for link]]</span>
 
 
 
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Latest revision as of 18:09, 14 July 2023




Background to flow cytometric diagnosis

Differentiation to plasma cells involves (in mast cases) the loss of typical pan B-cell markers and surface light chains. The expression of CD45 also differs both within and between cases making standard gating strategies difficult to apply. Cells are most often identified through their co-expression of CD138 with a relatively high expression of CD38, together with the absence of typical B-cell features.


Immunophenotype of plasma cells
CD45 expression
There is no consistent pattern of expression of CD45 although it is most often weak, but may be variable and is occasionally strong.
Major markers useful in plasma cell identification
Marker Freq Level Comment
CD38 - The relatively strong expression of CD38 is typical of plasma cells
CD138 var Expression is expected although the intensity can vary
κ/λ Surface light chain expression is lost (internal will be detected in permeabilised cells)
CD19 - Expression of CD19 may persist in some cases
Other relevant markers
CD5 - Not detected on plasma cells
CD10 -
CD11C -
CD20 - Expression retained in some cases
CD23 -
CD25 -
CD43 - Generally not expressed by LPL
CD79b - Expressed in some cases
CD103 -
CD200 - Detected frequently|-|}
FMC7 Not expressed


Key to table:

Key to colour code for expression frequency Click for link

Key to expression strength code and use Click for link