What is leukaemia?

Leukaemia is a cancer of the white blood cells, which are produced by the bone marrow. The four main types of leukaemia are acute myeloid (AML), acute lymphoblastic (ALL), chronic myeloid (CML) and chronic lymphocytic (CLL). Each type has its own characteristics and treatment.

The bone marrow

Bone marrow is a spongy material that fills the middle of some bones and produces the blood stem cells. These are immature cells that develop into the three different types of mature blood cells:

• red blood cells which carry oxygen to all the cells in the body
• white blood cells which are essential for fighting infection
• platelets which help the blood to clot and so control bleeding.

All these cells normally stay inside the bone marrow until they are fully developed and can circulate in the blood and perform their functions properly.

White blood cells

The bone marrow produces two main types of white blood cells: granulocytes and lymphocytes. These work together to fight infection in the body. The fully developed white blood cells circulate around the body in the blood.

Lymphocytes can also pass into the lymphatic system, which is part of the body’s natural defence against infection. The lymphatic system is made up of the tonsils, liver, spleen and the lymph glands. There are lymph glands in the neck, armpits, in each groin, and in the chest and abdomen. The spleen is under the ribs on the left hand side of your abdomen.