What does the CD33 marker indicate?

The CD33 marker is primarily expressed on myeloid cells, particularly monocytes and macrophages, as well as on some granulocyte subsets. It plays a role in cell adhesion, signal transduction, and regulation of the immune response. The presence of CD33 is especially significant in the context of hematological malignancies, such as acute myeloid leukemia (AML), where it is commonly used as a diagnostic marker. This characteristic of CD33 makes it a key identifier for monocytes compared to other cell types such as T cells, B cells, or NK cells, which have distinct surface marker profiles.

In summary, the identification of the CD33 marker indicates monocytes and their lineage, thereby providing valuable information for both diagnostic and therapeutic applications in cytometry.