Monoblast

Monoblasts are immature cells that develop into monocytes and macrophages in the bone marrow. They are part of the myeloid lineage of cells in the immune system. Monoblasts are characterized by a large nucleus and a small amount of cytoplasm. They are typically found in the bone marrow, but can also be found in the blood in certain diseases, such as leukemia.

Structure and Function

Monoblasts are the earliest identifiable cells in the monocyte-macrophage lineage. They are large cells, with a diameter of 12-20 micrometers. The nucleus is large and round, and takes up most of the cell. The cytoplasm is sparse and basophilic. Monoblasts have a high nuclear-to-cytoplasmic ratio.

Monoblasts differentiate into promonocytes, which then differentiate into monocytes. Monocytes can leave the bone marrow and enter the blood, where they can travel to tissues and differentiate into macrophages. Macrophages are important cells in the immune system, as they can phagocytose (engulf and destroy) pathogens and dead cells.

Clinical Significance

An increase in the number of monoblasts in the blood can be a sign of a disease, such as monocytic leukemia. This is a type of leukemia in which the body produces too many monocytes or their precursors. Monoblasts can also be found in the blood in other types of leukemia, such as acute myeloid leukemia.

A decrease in the number of monoblasts can be a sign of aplastic anemia, a condition in which the bone marrow does not produce enough new blood cells.

See Also

• Monocyte
• Macrophage
• Myeloid cell
• Leukemia
• Aplastic anemia

Monoblast Resources
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