Marker patterns erythroid or megakaryocyte differentiation
From haematologyetc.co.uk
Acute erythroid leukaemia (AEL)
This may be a difficult diagnosis since markers will often not allow cells to be distinguished from a reactive erythroid expansion, and the overlap with cases of myelodysplasia-related AML may have a marked erythroid expansion. In such cases the diagnosis of AEL requires careful exclusion of other disorders by correlation with morphology and other tests.
| Markers associated with erythroid differentiation in myeloid precursor neoplams | |
|---|---|
| General: General markers may vary, but typically patterns are given below: | |
| There is very weak expression of CD45 and HLA-DR. In contrast CD34 and often CD117 will be detected. | |
| Specific: Markers of erythroid differentiation are helpful, but require careful interpretation to discriminate from other causes (described below). | |
| CD36 | Expression is expected, but is not fully lineage specific as it may be seen in other AML forms including cases with monocytic or megakaryocytic differentiation. |
| CD71 | A good marker of early erythroid differentiation that is expected to be expressed, although again not fully lineage specific and also found on reactive erythroid precursors. |
| CD235 | A good marker of erythroid differentiation; however like CD72 does not distinguish neoplastic and reactive cells. It is acquired later in erythroid differentiation and therefore may not be expressed or be confined to a sub-population in AEL. |
| Abberant phenotypic features: Some markers are frequently found: | |
| Expression of CD13, CD38 or CD4 may be encountered in some cases.
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| Markers associated with megakaryocytic differentiation in AML | |
|---|---|
| This can be tricky initially since CD34, CD45 and HLA-DR are most often very weak or negative. CD13 and CD33 may be expressed but are not always present. Look for: | |
| CD41 | Platelet glycoprotein IIbIIIa |
| CD61 | Platelet glycoprotein IIIa |
| CD36 | Relatively non-specific (seen in erythroid and monocytic leukaemias) but often strongly expressed
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