Search the Health Library
Get the facts on diseases, conditions, tests and procedures.
I Want To...
I Want To...
Find Research Faculty
Enter the last name, specialty or keyword for your search below.
School of Medicine
Leukemia is a cancer of the blood cells, which are produced in the bone marrow -- the spongy interior of the bones. Normally, blood cells are made in an orderly, controlled way. When leukemia develops, the bone marrow produces abnormal cells; therefore, the cells that are responsible for fighting infections and preventing bleeding are not made correctly.
Johns Hopkins is home to one of the largest leukemia programs worldwide. Our researchers are covering groundbreaking treatments in all types of leukemias and blood disorders. Our expert staff at Johns Hopkins are world renowned experts, nationally and internationally known, in the treatment and management of leukemia and blood disorders.
Four Primary Types of Leukemia:
More on Leukemia:
- Leukemia Experts
- Risk Factors
- Diagnosis and Screening
- Treatment Options
- Current Clinical Trials
- Support Resources
In acute myelogenous leukemia (AML) and acute lymphocytic leukemia (ALL), the original acute leukemia cell goes on to form about a trillion more leukemia cells. These cells are described as "nonfunctional" because they do not work like normal cells. They also crowd out the normal cells in the marrow, causing a decrease in the number of new normal cells made in the marrow and resulting in a low red cell count (anemia). The lack of normal white cells impairs the body's ability to fight infections. A shortage of platelets results in bruising and easy bleeding.
In chronic lymphocytic leukemia (CLL), the leukemia cell that starts the disease makes too many lymphocytes that do not function. These cells replace normal cells in the marrow and lymph nodes. They interfere with the work of normal lymphocytes, which weakens the patient's immune response. The high number of leukemia cells in the marrow may crowd out normal blood-forming cells and lead to a low red cell count (anemia). A very high number of leukemia cells building up in the marrow also can lead to low neutrophil and platelet counts.
Unlike the other three types of leukemia, some patients with CLL may have disease that does not progress for a long time. Some people with CLL have such slight changes that they remain in good health and do not need treatment for long periods of time, though most patients require treatment.
In chronic myelogenous leukemia (CML), the leukemia cell that starts the disease makes blood cells (red cells, white cells and platelets) that function almost like normal cells. The number of red cells is usually less than normal, resulting in anemia. But many white cells and sometimes many platelets are still made. Even though the white cells are nearly normal in how they work, their counts are high and continue to rise. This can cause serious problems if the patient does not get treatment. If untreated, the white cell count can rise so high that blood flow slows down and anemia becomes severe.
In addition, there are other forms of leukemia that are rarer but can be highly treatable.