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Myeloperoxidase expression in CD34+ normal human hematopoietic cells
H Strobl1, M Takimoto, O Majdic
1Institute of Immunology, University of Vienna, Austria.
Blood
|October 1, 1993
Summary
Myeloperoxidase (MPO) is expressed in 35% of CD34+ bone marrow cells, indicating early granulomonocytic differentiation. Umbilical cord and peripheral blood CD34+ cells generally lack MPO expression.
Area of Science:
- Hematopoiesis
- Cell Biology
- Immunology
Background:
- Hematopoietic progenitor cells, found in bone marrow (BM), adult peripheral blood (aPB), and umbilical cord blood (CB), are characterized by CD34+ expression.
- Myeloperoxidase (MPO) is a key enzyme in granulomonocytic differentiation.
Purpose of the Study:
- To investigate the expression stage of MPO in CD34+ cells during normal hematopoietic differentiation.
- To compare MPO expression in CD34+ cells across different blood sources (BM, aPB, CB).
Main Methods:
- Flow cytometry analysis using an antibody against MPO.
- Phenotypic characterization of MPO+ CD34+ cells (HLA-DR, CD71, CD45RA, CD45RO).
- In vitro clonogenic assays on MPO-enriched and MPO-depleted CD34+ BM cell fractions.
Main Results:
- Approximately 35% of CD34+ BM cells express MPO, co-expressing CD33 and exhibiting a distinct phenotype (high HLA-DR, weak CD71, CD45RA+, CD45RO-).
- MPO+ CD34+ cells are larger than MPO- CD34+ cells and show characteristics of in vitro granulomonocytic progenitors.
- CD34+ cells from CB and aPB largely lack MPO expression but frequently coexpress CD45RO.
Conclusions:
- MPO expression in CD34+ cells signifies commitment to granulomonocytic differentiation in bone marrow.
- MPO expression is a useful marker for identifying early granulomonocytic progenitors within the CD34+ population.
- Significant differences in MPO expression exist between bone marrow and peripheral/cord blood CD34+ cells.