The bone marrow is the principal source of the many different types of cells that circulate in your blood stream. The term “myelodysplasia“ describes certain abnormalities in the production of these blood cells. “Myelodysplastic syndrome” (MDS) refer to at least five different entities, all of which interfere with the growth of blood cells in the bone marrow. The differences among them are found in the appearance of the cells under the microscope and are helpful primarily in determining prognosis.
MDS frequently progresses to a form of acute leukemia. Leukemia is a cancer of the blood cells. But in the case of leukemia, there is an overproduction of immature cells (blasts) circulating in the blood and an underproduction of healthy cells. In MDS, there is usually, but not always, only an underproduction of healthy cells. The progression to acute leukemia is so common that MDS used to be known as “preleukemia.”
The bone marrow contains stem cells, which have the capacity to become any of the cell types that circulate in the blood stream. These stem cells normally undergo a maturation process that results in mature cells with fixed functions:
- Red blood cells carry oxygen.
- Three types of granulocytes (a type of white blood cell) carry out immune functions.
- Two types of lymphocytes (a type of white blood cell) carry out immune functions.
- Macrophages and monocytes help us fight infection.
- Platelets provide a defense against bleeding and bruising.
Once cells have matured in the bone marrow, they are released into the blood circulation. MDS interrupts the normal maturation process of blood cells.
Who Is Affected?
Roughly 3,000 new cases of M