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Leukemic blasts with markers of four cell lineages in Down's syndrome ("megakaryoblastic leukemia")
S H Slørdahl1, E B Smeland, H Holte
1Department of Pediatrics, National Hospital, University of Oslo, Norway.
Insights
Acute megakaryoblastic leukemia (AMkL) in Down's syndrome (DS) may be a mixed lineage leukemia. Four out of six DS-AMkL patients achieved complete remission with standard acute myeloid leukemia (AML) protocols.
Area of Science:
- Hematology
- Oncology
- Genetics
Background:
- Down's syndrome (DS) is associated with an increased risk of leukemia.
- Acute megakaryoblastic leukemia (AMkL) is a subtype of acute myeloid leukemia (AML).
Purpose of the Study:
- To investigate the immunophenotype of AMkL in patients with DS.
- To assess treatment outcomes for AMkL in DS patients.
Main Methods:
- Retrospective analysis of 16 DS patients with acute leukemia over ten years.
- Diagnosis of AMkL based on clinical and hematologic criteria.
- Immunophenotyping using monoclonal antibodies (MoAb) for cell surface antigens.
Main Results:
- Six out of 16 DS patients were diagnosed with AMkL.
- MoAb confirmed AMkL in three patients and revealed mixed lineage markers (myeloid, lymphoid, erythroid) in four patients.
- Four of six AMkL patients treated with standard AML protocols achieved complete continuing remission (CCR) with long-term follow-up (57+ to 148+ months).
Conclusions:
- DS-associated AMkL may originate from early progenitor cells with multi-lineage potential, classifying it as a mixed lineage leukemia.
- Standard AML treatment protocols appear effective in achieving long-term remission for AMkL in DS patients.
Abstract:
Among 16 patients with Down's syndrome (DS) and acute leukemia admitted to our department during a ten year period, 6 were diagnosed as acute megakaryoblastic leukemia (AMkL). The diagnosis was based on clinical and hematologic criteria, confirmed in three patients with the use of monoclonal antibodies (MoAb) specific for megakaryocytic antigens. In these three, and in a fourth patient, the leukemic blasts were positive for other myeloid, lymphoid and erythroid markers in MoAb testing. We suggest that AMkL in DS is a mixed lineage leukemia with blasts presenting a variety of cell surface antigens, indicating origin from an early progenitor cell with the capability of megakaryocytic differentiation. Of the 6 patients with AMkL, 4 treated with standard AML protocols are in complete continuing remission (CCR) with observation periods from 57+ to 148+ months.