Types of Leukemia
The classification of different types of leukemia are based on the type of the blood cells involved and the speed of onset. The onset may be gradual, giving rise to chronic leukemia or sudden, giving rise to acute anemia.
The chronic type of leukemia gradually escalates since abnormal cells are present but are more mature than in the acute type of leukemia and can partially function. However, their ability to fight infections is marginal and they tend to accumulate since their lives are very extended.
Types of Leukemia
The acute type of leukemia develops from early, undifferentiated cells called blasts. The blasts are very young cells that divide frequently like normal cells but the difference in acute leukemia is that they do not stop dividing when they should.
The blood cells involved may be the lymphocytes which are the white blood cells that find and destroy foreign substances like viruses (causing lymphocytic leukemia) or myelocytes which are a type of blood cells in the marrow which protect the body from bacteria and infections (causing myelocytic leukemia). These two sets of classes give the following types of leukemia:
(a) Acute Lymphocytic Leukemia (ALL): This is the most common type of leukemia in young children and 80 percent of all childhood leukemias fall into this category.
(b) Chronic Lymphocytic Leukemia (CLL): CLL is most common in Jewish people especially of Russian or East European origin. and is almost never found in children. It may be asymptomatic till a very advanced stage.
(c) Acute Myeleocytic Leukemia (AML): This is the most common type of leukemia found equally in children and adults and is als o known as acute non-lymphocytic leukemia
(d) Chronic Myeleocytic Leukemia (CML) This type of leukemia is found mostly in adults and is thought to be closely associated with the Philadelphia chromosome abnormality. The abnormal gene produces a rogue protein, tyrosine kinase, that causes leukemia cells grow without bounds. This type of leukemia may be totally asymptomatic till the growth of the leukemia cells accelerates.
A rare type of leukemia is the so-called hairy cell leukemia which is a chronic manifestation of leukemia in which lymphocytic cells develop a hairy look due to tiny, hair-like projections that appear on the cells.