Leukaemia literally means ‘many white cells in the blood'. The white cells are part of the body’s immune system, and there are several sub-groups of white cells that have different sorts of roles in recognising and dealing with ‘invaders’ such as bacteria and viruses as well as other types of foreign protein. All of the blood cells originate in the bone marrow and leukaemia (blood cancer) is a disease where the bone marrow produces large numbers of abnormal white cells. This means that the normal marrow is pushed into smaller and smaller areas. This results in fewer normal cells being produced and gives rise to some of the symptoms.

There are many types of leukaemia, each of which is classified according to the exact cell type affected by the disease.

Chronic leukaemia is a slowly progressive form of leukaemia and tends to involve more mature cell types. It may not need treatment immediately, but if treatment is required it is usually chemotherapy, given in the form of tablets.

It is possible to have chronic leukaemia for months or even years without knowing it.

The symptoms are varied, but many people notice:

• tiredness (due to anaemia)
• bruising easily (often without having had any blow or fall)
• repeated infections
• enlarged lymph glands
• weight loss
• night sweats
• fever.