leukaemia

n.

any of a group of malignant diseases in which the bone marrow and other blood-forming organs produce increased numbers of certain types of white blood cells (leucocyte). Overproduction of these white cells, which are immature or abnormal forms, suppresses the production of normal white cells, red cells, and platelets. This leads to increased susceptibility to infection (due to neutropenia), anaemia, and bleeding (due to thrombocytopenia). Other symptoms include enlargement of the spleen, liver, and lymph nodes.

Leukaemias are classified into acute or chronic varieties depending on the rate of progression of the disease. They are also classified according to the type of white cell that is proliferating abnormally; for example acute lymphoblastic leukaemia (see lymphoblast), chronic lymphocytic leukaemia (see lymphocyte), acute myeloblastic leukaemia (see myeloblast), hairy-cell leukaemia (see hairy cell), and monocytic leukaemia (see monocyte). (See also myeloid leukaemia.) Leukaemias can be treated with cytotoxic drug or monoclonal antibody, which suppress the production of the abnormal cells, or occasionally with radiotherapy.