What is acute lymphoblastic leukaemia (ALL?)

Acute lymphoblastic leukaemia (ALL) is an acute leukaemia. Acute means that it develops very quickly. In ALL, white blood cells known as lymphocytes multiply in an uncontrolled manner in the bone marrow. Lymphocytes help the body fight infections as part of the immune system. Of the three types of lymphocytes that exist, only the B-cell and T-cell lymphocytes are involved in ALL. Natural killer cell (NK-cell) lymphocytes lead to a different type of leukaemia, not covered here.

In the United Kingdom (UK), the incidence of ALL (both B-cell and T-cell ALL) is 1.1 per 100,000 people per year. This means that around 800 people in the UK are given a diagnosis of ALL every year.

In adults with ALL:

• 75% of cases involve early immature B-cell lymphocytes (B-cells)
• 25% of cases involve early immature T-cell lymphocytes (T-cells)

We have more information about B-cell ALL and T-cell ALL, why they develop, and how they are diagnosed and treated.