Acute Lymphocytic Leukemia

Acute lymphocytic leukemia is also known as ALL, acute lymphoblastic leukemia and acute lymphoid leukemia. It progresses quickly and occurs most often in the first decade of life.

It is the most common type of leukemia in children under 15 years of age.

ALL is caused by a rapid increase of immature lymphocytes (lymphoblasts), which are a cell type in the immune system. These lymphoblasts crowd out the normal blood cells.

This first picture shows normal blood cells and the other shows leukemia cells.

* The cause is not known.

* ALL can occur at any age.

* The leukemia cells stop the production of normal blood cells which cause a deficiency of platelets (thrombocytopenia), red cells (anemia) and white cells (neutropenia).

* Click here to learn about the signs and symptoms of leukemia.

There are subtypes of leukemia that involve cell types and chromosome abnormalities.

There are two lines of leukemia cells in ALL, B cells and T cells.

B cell subtypes are identified by surface marks on the leukemic blasts cells that are the same as those that develop on normal B lymphocytes. Precurser B or B cell subtypes account for almost 90 percent of cases.

The two other subtypes are the T and NK cell subtypes. They are identified by finding markers on the cell surface that are identical to those on normal T lymphocytes. T and NK subtypes account for about 10 percent of cases.

A small percentage of children and a larger percentage of adults with acute lymphocytic leukemia are in a higher risk category when they have chromosome abnormalities. An example of this would be a change in chromosome number 22, which is called the Philadelphia or Ph chromosome.