Acute lymphoblastic leukaemia

Acute lymphoblastic leukaemia

About acute lymphoblastic leukaemia

Leukaemia is cancer of the white blood cells. Acute leukaemia means the condition progresses rapidly and aggressively and requires immediate treatment.

Acute leukaemia is classified according to the type of white blood cells affected by cancer. There are 2 main types:

• lymphocytes, which are mostly used to fight viral infections
• neutrophils, which perform several functions, such as fighting bacterial infections, defending the body against parasites and preventing the spread of tissue damage 

These pages focus on acute lymphoblastic leukaemia, which is cancer of the lymphocytes. The following other types of leukaemia are covered elsewhere:

• chronic lymphocytic leukaemia
• chronic myeloid leukaemia
• acute myeloid leukaemia

Warning signs of acute leukaemia

Symptoms of acute lymphoblastic leukaemia usually begin slowly before rapidly getting severe as the number of immature white blood cells in your blood increases. Symptoms include:

• pale skin
• tiredness
• breathlessness
• having repeated infections over a short space of time
• unusual and frequent bleeding

Read more about the symptoms of acute lymphoblastic leukaemia

What happens in acute leukaemia

All of the blood cells in the body are produced by bone marrow – a spongy material found inside bones.

Bone marrow produces specialised cells called stem cells which have the ability to develop into three important types of blood cells:

• red blood cells, which carry oxygen around the body
• white blood cells, which help fight infection
• platelets, which help stop bleeding

The bone marrow usually produces stem cells which are allowed to fully develop before being released into the blood. But in acute leukaemia, bone marrow starts releasing large numbers of immature white blood cells known as blast cells.

As the number of blast cells increases there is a drop in the number of red blood cells and platelet cells. This drop causes the symptoms of anaemia, such as tiredness, and increases the risk of excessive bleeding.

Also, blast cells are less effective than mature white blood cells at fighting bacteria and viruses, making you more vulnerable to infection.

Despite being uncommon overall, acute lymphoblastic leukaemia is the most common type of cancer to affect children.

The cause or causes of acute leukaemia are uncertain, but known risk factors include:

• exposure to high levels of radiation
• exposure to benzene, a chemical used in manufacturing that is also found in cigarettes

Read more information about the causes of acute lymphoblastic leukaemia