Acute Promyelocytic Leukemia - Signs and Symptoms

Signs and Symptoms

Normal differentiation of the white blood cells in the marrow starts with the multi-potent hematopoietic stem cells (HSC). Several transcription factors such as PU.1 and CCAAT/enhancer binding protein, alpha (CEBPA) have been identified to be important in the white blood cell differentiation process. The HSC generates the lymphoid (B cells and T cells of our immune system) cell line and the myeloid cell lines. The myeloid cell lines have granules in their cytoplasm called granulocytes which are important in fighting infections.

The accumulation of promyelocytes in the bone marrow results in a reduction in the production of normal red blood cells and platelets, resulting in anemia and thrombocytopenia. The bone marrow is unable to produce healthy red blood cells. Either leukopenia (low white cell count) or leukocytosis (high white cell count) may be observed in the peripheral blood.

Symptoms include:

• Fatigue, weakness, shortness of breath (from anemia, the decrease of normal red blood cell production or lack thereof)
• Easy bruising and bleeding (from thrombocytopenia and coagulopathy, which prevents blood clotting)
• Fever and infection (from lack of normal white blood cells)
• Minor abdominal discomfort (from enlargement of the spleen)

In addition, in 85% of cases acute promyelocytic leukemia is associated with bleeding caused by disseminated intravascular coagulation (DIC). It is characterized by rapid increase in the number of immature white blood cells, resulting in rapid progression of malignant cell counts and crowding of the bone marrow. This results in very low red blood cells (anemia) and platelet counts, which can cause serious bleeding.