Acute leukaemia types: Difference between revisions
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</br>AML cells often have markers that reflect thier primitive nature. | </br>AML cells often have markers that reflect thier primitive nature. Although they are not required to identify blast cells if other features fit (weak CD45 and/or blast cell morphology), detecting them can increase diagnostic confidence. In AML these markers are most frequently expressed by less differentiated types.</span></br> | ||
<span style="font-size:90%;>*Note while not fully specific for any given lineage, some are more frequently associated with particular lineages so may contribute to lineage assignment in difficult cases (see comments). | <span style="font-size:90%;>*Note while not fully specific for any given lineage, some are more frequently associated with particular lineages so may contribute to lineage assignment in difficult cases (see comments). | ||
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|colspan="1" style = "width: 4%; font-size:90%; color:black;" |'''[[TDT]]''' | |colspan="1" style = "width: 4%; font-size:90%; color:black;" |'''[[TDT]]''' | ||
|colspan="1" style = "width: 8%; background:#66e0ff;"| | |colspan="1" style = "width: 8%; background:#66e0ff; color:black; font-size:80%;"|5-20% of cases | ||
|colspan="1" style = "font-size:80%;"|Expressed particularly in less differentiated forms of AML. Often on a sub-population of cells; expression '''usually less intense than in lymphoid leukaemias.''' | |colspan="1" style = "font-size:80%;"|Expressed particularly in less differentiated forms of AML. Often on a sub-population of cells; expression '''usually less intense than in lymphoid leukaemias.''' | ||
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|colspan="1" style = "font-size:90%; color:black;" |'''[[CD7]]''' | |colspan="1" style = "font-size:90%; color:black;" |'''[[CD7]]''' | ||
|colspan="1" style = "background:#00b8e6;"| | |colspan="1" style = "background:#00b8e6; color:black; font-size:80%;"|20-40% of cases | ||
|colspan="1" style = "font-size:80%;"|Similar to TdT, CD7 expression is recognised on a proportion of AML, usually those with less differentiated phenotype. '''Most consistently expressed in T-ALL'''. | |colspan="1" style = "font-size:80%;"|Similar to TdT, CD7 expression is recognised on a proportion of AML, usually those with less differentiated phenotype. '''Most consistently expressed in T-ALL'''. | ||
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Revision as of 12:39, 18 July 2023
Expression guide: acute myeloid leukaemia | |||
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Expected expression of CD45 in AML | |||
CD45 expression in AML is "weak" i.e. significantly less intense than normal T cells, B cells or monocytes. The typically low side scatter of most blast cells means that myeloid blast cells tend to form a relatively uniform population that is clearly separated from that of lymphocytes on CD45/SSc plots.
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Markers of primitive cell type frequently expressed in AML
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Marker | Expectation | Comment | |
CD34 | >70% of cases | Frequently expressed, most often in less differentiated forms of AML. Expression often less intense than in lymphoid leukaemias | |
TDT | 5-20% of cases | Expressed particularly in less differentiated forms of AML. Often on a sub-population of cells; expression usually less intense than in lymphoid leukaemias. | |
CD7 | 20-40% of cases | Similar to TdT, CD7 expression is recognised on a proportion of AML, usually those with less differentiated phenotype. Most consistently expressed in T-ALL. | |
Markers with very strong lineage specificity in AML | |||
While not expressed by all cases, when detected by flow cytomwtry MPO can be considered to be lineage-defining marker in AML (or establishing myeloid lineage in MPAL). | |||
Marker | Expectation | Comment | |
MPO | A strong lineage marker for AML when detected by flow cytometry (though potentially less so by immunocytochemistry) | ||
Lineage markers in AML that with relatively high speificity | |||
These markers are each expressed by many cases (around 80% for each marker), they have high specificity although abberrent expression in ALL is feequent (overall 10-20% for any individual marker)). | |||
Marker | Expectation | Comment | |
CD117 | One of tne of the first lineage-markers acquired in AML with good relative specificity | ||
CD33 | A good marker for AML that is often less strongly expressed in monocytic forms | ||
CD13 | A good lineage marker for AML aquired a little later, higher than CD13 in monocytic forms | ||
Other markers helpful in detecting myeloid lineage (often in AML subtypes) | |||
These markers have less general value in diagnosis, but can be useful in subtype selection or in cases whwere lineage is ambiguous. | |||
Marker | Expectation | Comment | |
CD10 | Gran | One of tne of the first lineage-markers acquired in AML with good relative specificity | |
CD11b | Gran | One of tne of the first lineage-markers acquired in AML with good relative specificity | |
CD11c | Mono | One of tne of the first lineage-markers acquired in AML with good relative specificity | |
CD14 | Mono | A good marker for AML that is often less strongly expressed in monocytic forms | |
CD64 | Mono | A good lineage marker for AML aquired a little later, higher than CD13 in monocytic forms |