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Updated: Aug 8, 2026
Fast and Specific Assessment of the Halogenating Peroxidase Activity in Leukocyte-enriched Blood Samples
Published on: July 28, 2016
Peroxidase expression in acute unclassified leukemias: ultrastructural studies in combination with immunophenotyping
G Heil1, E Gunsilius, D Hoelzer
1Dept. of Internal Medicine III, University of Ulm, Germany.
Insights
Ultrastructural analysis of peroxidase expression (POEM) reclassified acute unclassified leukemias (AUL). Many AUL cases showed myeloid or megakaryoblastic lineage, while others originated from early lymphoid progenitors.
Area of Science:
- Hematology
- Oncology
- Cell Biology
Background:
- Acute unclassified leukemias (AUL) present a diagnostic challenge.
- Accurate lineage determination is crucial for prognosis and treatment.
Purpose of the Study:
- To reevaluate the lineage affinity of AUL cases.
- To investigate the utility of ultrastructural analysis of peroxidase expression (POEM) in conjunction with immunophenotyping for AUL classification.
Main Methods:
- Ultrastructural analysis of peroxidase expression (POEM) was performed on 61 AUL cases.
- Immunophenotyping, including myeloid and lymphoid markers (CD19, CD24), was utilized.
- Immunoelectron microscopy (IEM) was employed in select cases.
Main Results:
- POEM positivity, indicating myeloid or megakablastic lineage, was detected in 27 cases (24 with UMPO, 3 with UPPO).
- No significant correlation was found between myeloid markers and POEM positivity.
- CD19 or CD24 antigen presence correlated with POEM negativity.
- Lymphoid markers on POEM+ blasts suggest bipotential progenitors.
- One case of bilineage leukemia was identified.
- 34 cases were POEM negative, likely originating from early lymphoid progenitors.
Conclusions:
- AUL is a heterogeneous group with diverse cellular origins.
- Ultrastructural analysis of peroxidase expression (POEM) is valuable for identifying myeloid differentiation in AUL.
- Some AUL cases may arise from bipotential progenitors with retained lymphoid antigens.
- POEM-negative AUL cases likely originate from early lymphoid progenitors.
Abstract:
The lineage affinity of 61 cases of acute unclassified leukemias (AUL) was reevaluated by ultrastructural analysis of peroxidase expression (POEM) in combination with immunophenotyping. In 24 cases a significant proportion of the blasts displayed ultrastructural myeloperoxidase (UMPO) and in another 3 cases platelet peroxidase (UPPO) suggesting the allocation of these leukemias to the myeloid or megakaryoblastic lineage. No significant correlation between myeloid surface marker expression and POEM positivity could be detected, while the presence of the CD 19 or CD 24 antigen significantly correlated with POEM negativity. The detection of lymphoid markers on POEM+ blasts indicates, that these leukemias might be derived from bipotential progenitors, which have retained their lymphoid antigens during myeloid differentiation. In one case a bilineage leukemia with a POEM+/CD 19- and a POEM-/CD 19+ population could be identified by immunoelectron microscopical studies (IEM). The remaining 34 AUL cases were POEM negative. Combined data suggest that these cases probably derive from early lymphoid progenitors. Taken together, AUL are heterogenous in presentation and in their cellular origin including a major portion of cases with an unequivocal myeloid differentiation detectable by ultrastructural analysis of myeloperoxidase expression.
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