As blood cells mature, what happens to the expression of the CD34 marker?

CD34 is a cell surface marker commonly used to identify hematopoietic stem cells and early progenitor cells in the bone marrow and peripheral blood. As blood cells mature and differentiate into more specific lineages, the expression of CD34 decreases and is ultimately lost. This pattern is particularly observed in the transition from stem cells to lineage-committed progenitors and further into fully differentiated blood cells, such as granulocytes, erythrocytes, or platelets. The loss of CD34 is an important marker of maturation, serving as a key characteristic that enables researchers and clinicians to differentiate between immature cells and fully differentiated blood cells.

Maintaining or upregulating CD34 expression during maturation would not accurately reflect the natural developmental processes of hematopoietic cells, as these cells lose their multipotent characteristics and transition to lineage-specific functions. Thus, the understanding of CD34 expression dynamics is crucial in both clinical and research settings, especially regarding stem cell identification and manipulation in therapies.