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 | |
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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: Expression of CD13, CD38 or CD4 may be encountered in some cases.
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Markers associated with megakaryocytic differentiation in AML | |
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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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