Acute leukaemia types: Difference between revisions
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!colspan="2" <span style="font-size:90%; text-align:center; background:pale gray">|'''AML DIGANOSIS:''' MARKERS CONFIRMING MYELOID ORIGIN</span><span style="font-size:90%; text-align:left; background:white"> | !colspan="2" <span style="font-size:90%; text-align:center; background:pale gray">|'''AML DIGANOSIS:''' MARKERS CONFIRMING MYELOID ORIGIN OF BLAST CELLS</span><span style="font-size:90%; text-align:left; background:white"> | ||
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Revision as of 19:14, 21 July 2023
AML DIGANOSIS: MARKERS OF PRIMITIVE NATURE
(1) Typically AML blasts have low CD45 expression and cause low side scatter. This means that they form a relatively uniform and distinctive population that is clearly separate from that of lymphocytes on CD45/SSc plots, allowing their identification. However, it is important also to be aware of other cells that may occupy that area (for further details see this section) and that some forms of AML forms may not fit this pattern - particularly APL and monocytic AML; while So morphology is essential to confirm a primitive appearance and nature (2) It is often also possible to detect markers associated with primitive nature: in AML this is most often CD34, but other markers may contribute.
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Useful markers of primitive cells | |
CD45 | Expressed leukocytes and their precursors; in AML expression is "weak" i.e. significantly less intense than normal lymphocytes or monocytes. In monocytic AML expression may be stronger. |
CD34 | Frequently expressed by AML blast cells (40-80% of cases) - most often in less differentiated forms of AML. Although expression is also frequent (and often stronger) in ALL |
Markers that may be helpful in some cases | |
TDT | Expressed in some cases of AML (5-20%) particularly in less differentiated blast cells, often on a sub-population of cells. More typically associated with ALL. |
CD7 | Predominantly seen as a T-cell antigen, CD7 tends may be expressed by AML blasts (20-40%) where it most often indicates a more primitive forms or MPAL. CD7 is most consistently a marker of T-lineage (including T-ALL). |
AML DIGANOSIS: MARKERS CONFIRMING MYELOID ORIGIN OF BLAST CELLS
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Strong myeloid restriction | |
MPO | A strong lineage marker for AML (expressed in around 80% of cases) that when detected by flow cytometry is diagnostic of myeloid differentiation (AML or MPAL) although potentially gives less confident evidence on immunocytochemistry. |
Moderate myeloid restriction | |
CD117 | An early marker of myeloid lineage seen in around 80% of AML often recognising more primitive forms, aberrant expression in up to 20% of ALL |
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 | Comment |
CD10 | One of tne of the first lineage-markers acquired in AML with good relative specificity |
CD11b | One of tne of the first lineage-markers acquired in AML with good relative specificity |
CD11c | One of tne of the first lineage-markers acquired in AML with good relative specificity |
CD14 | A good marker for AML that is often less strongly expressed in monocytic forms |
CD64 | A good lineage marker for AML aquired a little later, higher than CD13 in monocytic forms |