What is acute lymphoblastic leukaemia?

Leukaemia (sometimes spelt as leukemia) is a cancer of the white blood cells. People with leukaemia usually have more white blood cells than normal but sometimes may have fewer. These leukaemia cells behave differently from healthy white blood cells.

The four main types of leukaemia are:

Each type of leukaemia has its own characteristics and treatment.

Acute lymphoblastic leukaemia (ALL)

Acute lymphoblastic leukaemia is a rare type of cancer. It affects about 800 adults a year in the UK. ALL is most common in children and young people up to the age of 25, and in older adults over 75. It affects slightly more males than females.

ALL is a cancer of the white blood cells. Normally, white blood cells divide and grow in an orderly and controlled way. In leukaemia this process has gone out of control. Signals that stop the body making too many white blood cells are ignored. So the cells go on dividing, but do not mature into normal lymphocytes.

People with ALL make too many immature blood cells, called lymphoblasts (sometimes referred to as blasts). As the lymphoblasts do not mature, they can’t fight infection as normal white blood cells do. These immature cells fill up the bone marrow, which means there is not enough space to make all the healthy white cells, red cells and platelets your body needs.

ALL and lymphoblastic lymphoma

ALL is very similar to lymphoblastic lymphoma, which is a cancer of the lymphatic system. In ALL, the abnormal lymphoblasts are generally in the blood and bone marrow, although occasionally they can build up in the lymph nodes. But in lymphoblastic lymphoma they are mainly in the lymph nodes or thymus gland. The two conditions are often treated in very similar ways.

Types of ALL

Knowing what type of ALL you have helps your doctors to plan your treatment. ALL is grouped into different types by the World Health Organisation (WHO). The types are based on the blood cell that has become cancerous.

There are two types of ALL:

  • B-lymphoblastic leukaemia – this is the most common type
  • T-lymphoblastic leukaemia.

Some people with B-lymphoblastic leukaemia have the Philadelphia chromosome in the leukaemia cells.

I didn’t really know much about leukaemia, even that it specifically was cancer.


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