Promyelocyte (or progranulocyte ) is a myeloid cell, the precursor of granulocytes in the process of granulopoiesis, which develops from a myeloblast into a myelocyte .
| Promyelocyte | |
|---|---|
| Cell differentiation history | Zygote → Blastomer → Embryoblast → Epiblast → ... → Myeloblast |
| Opportunities for further differentiation | granulocytes |
Content
Morphological characteristics
Promyelocyte is somewhat larger than myeloblast, and has a size of 10-20 microns. Its nucleus is similar to the myeloblast nucleus, but in it there is some condensation of chromatin , and the nucleolus is less pronounced. The cytoplasm of promyelocyte contains pronounced azurophilic granules, the so-called "primary granules." These granules contain the enzymes myeloperoxidase , acid phosphatase and esterase . Normally, promyelocytes should not be in the peripheral blood .
Diseases
Excess reproduction of promyelocytes as a result of a malfunction in the process of their maturation and differentiation caused by the disruption of the functioning of the RARalpha gene and the disruption of the activation of the genes necessary for maturation leads to the development of acute promyelocytic leukemia (a type of acute myeloid leukemia classified as M3 by FAB classification).
Images
Promyelocyte in a bone marrow smear
Hematopoiesis process schematically
- Types of Promyelocytes
Basophilic promyelocyte
Eosinophilic promyelocyte
Neutrophilic promyelocyte
Links
- Promyelocyte at eMedicine Dictionary
- Maturation of white blood cells (University of Virginia course)
- Mesh promyelocyte