Acute leukaemia types
From haematologyetc.co.uk
Acute Myeloid Leukaemia | |
---|---|
Markers with value in confirming primitive phenotype
(1) Typically AML blasts have low CD45 expression together with low side scatter, so that they form a relatively uniform and distinctive population that is clearly separate from that of lymphocytes on CD45/SSc plots allowing their identification and "gating" for analysis (for further details see this section). please note some AML forms may not fit these typical patterns particularly APL and monocytic AML; while lymphoblasts and regenerating lymphocytes haematogones or basophils also lie in this area. So morphology is essentail to confirm a primitive nature (2) Other markers of early differentiation: particularly CD34, but also TdT and CD7 may be expressed by AML cells and can help increase diagnostic confidence that blast cells are present (3) While not fully specific, in some cases particular primitive markers are more frequently associated with a particular lineages so may contribute to lineage assignment in difficult cases (see comments).
| |
Strong role in AML | |
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 |
Less strong role in AML | |
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 | Similar to TdT, although more frequently expressed (20-40%) CD7 tends to be expressed by AML blasts in the more primitive forms. CD7 is most consistently a marker of T-lineage (including T-ALL). |
Markers with value in confirming myeloid differentiation
| |
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 |