Red Blood Cells

• Red blood cells, or erythrocytes, are the most prevalent blood cell in the body. For every white blood cell, a healthy person has approximately 600 red blood cells. Hemoglobin is found in these red blood cells, which is what brings oxygen from the lungs to the rest of the body. If a person has anemia and lacks healthy red blood cells, then myelodysplastic syndrome symptoms can occur. These symptoms include weakness, fatigue, very pale skin and shortness of breath.
  
  

White Blood Cells

• White blood cells, or leukocytes, work with the body's immune system to fight off infections, such as colds, and act as a protector against invaders, such as viruses and bacteria. There are five major kinds of white blood cells: lymphocytes, monocytes, basophils, neutrophils and eosinophils. Eosinophils, neutrophils and basophils, which together are called granulocytes, help to kill bacteria. When a person lacks enough granulocytes, myelodysplastic syndrome can develop and infections can occur. Infections are a beginning sign of myelodysplastic syndrome.
  
  

Platelets

• Platelets are a type of blood cell produced in the bone marrow by megakaryocytes. Platelets regulate bleeding by helping to form clots in the blood and also aid in the repair of damaged blood vessels. If a person lacks enough platelets, myelodysplastic syndrome can occur, along with bruising or abnormal bleeding. This is called thomocytopenia, which is also a symptom of myelodysplastic syndrome.
  
  

All Blood Cells

• In a healthy person, bone marrow creates millions of red blood cells, white blood cells and platelets on a daily basis. Millions of cells also die each day. The body performs a balancing act between the new and dying cells, which are partially aided by growth factors in the bone marrow. If a person has myelodysplastic syndrome, the cells die prematurely, either after they enter the blood or in the bone marrow. It appears that the abnormal cells originate from one unhealthy cell. The one unhealthy cell then creates more unhealthy cells. After a while, there are more unhealthy cells than healthy ones. This can cause myelodysplastic syndrome, which includes symptoms such as abnormal bleeding, infections and anemia.
  
  

Genetic Defect

• A genetic defect can also cause myelodysplastic syndrome. Surprisingly, the prognosis is better if the myelodysplastic syndrome is causes by a genetic defect. With this defect, the body produces enough or even a high number of platelets, but a lower number of red blood cells.
  
  

Cancer Treatment

• Some chemotherapy drugs, such as chlorambucil, mechlorethamine and procarbazine, can cause myelodysplastic syndrome. This occurs because chemotherapy drugs and/or radiation therapy become toxic in the bone marrow.
  
  

Hodgkin's Treatment & Environmental Toxis

• Myelodysplastic syndrome may also develop after treatment for Hodkin's disease, non-Hodgkin's lymphoma or actute lymphocytic leukemia, all of which affect the blood cell levels.
  
  Chemicals and toxins in the environment can cause myelodysplastic syndrome. Such toxins include pesticides, herbicides, heavy metals and chemical fertilizers.