Leukemia produces a large number of abnormal blood cells that look different and function differently from normal blood cells. The types of leukemia are grouped in two ways. The first way is by the rate at which the disease progresses. The second is by the specific type of white blood cell affected. In acute leukemia, the disease progresses very rapidly and needs to be treated quickly.
Acute leukemia occurs in two main types of white blood cells.
These are the lymphoid and myeloid cells. When leukemia affects the lymphoid cells it is called lymphocytic leukemia. Acute lymphocytic leukemia , or ALL, is the most common type of leukemia in young children. This disease also affects adults, especially those age 65 and older. When myeloid cells are affected, the leukemia is called myelogenous.