Precursor cells:

CD34+ precursors.

In normal conditions, CD34+ precursors mostly comprise myeloid (red) and B-cell precursors (blue), with small numbers of erythroid and other precursors

  • The term myeloid precursors can encompass granulocytic, monocytic, erythroid, mast cell, basophil precursors and plasmacytoid dendritic cells (see topic on identification of cells in the blast gate).

Myeloid precursors have slightly higher SSC compared to B-cell precursors.

Precursor cells 1
Precursor cells 2

For the following 3 figures:

Granulocytic precursors (Red)

  • Express CD117 and HLA-DR, which are lost throughout differentiation
  • Express CD13 and CD33 (not shown here)
  • Do not express CD10

B-cell precursors (Blue)

  • Do not express CD117 and maintain HLA-DR expression during differentiation
  • Do not express CD13
  • Express CD10
Precursor cells 3
Precursor cells 4
Precursor cells 5

For the following 4 figures:

This example of a regenerating marrow post-chemotherapy shows higher numbers of CD34+ myeloid cells that better highlight the normal pattern of expression.

Precursor cells 6
Precursor cells 7
Precursor cells 8
Precursor cells 9

For the following 2 figures:

Erythroid precursors

  • Express CD117 and HLA-DR, which are lost throughout differentiation
  • Do not express CD13 and CD33
  • Do not express CD10

Monocytic precursors

  • Express CD117 and maintain HLA-DR expression during differentiation
  • Express CD13 and gain CD11b
  • Do not express CD10
Precursor cells 10
Precursor cells 5

Next page: Granulocytic maturation

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