What Are Haematological Malignancies?

This page contains general information about haematological (blood) diseases. Information about particular conditions (leukaemia and lymphoma, for example) can be found by following the links on the previous page.

'Haematology' and 'haematological' refer to blood, so in order to understand these diseases it is useful to know something about the normal composition and functions of blood.

There are three essential functions of blood: -

• Transport - blood carries oxygen, carbon-dioxide, nutrients, and blood cells around the body
• Temperature regulation - the flow of blood helps regulate and maintain an even body temperature
• Immunity - blood is an important part of the immune system

The major components of blood are plasma (the liquid part), blood cells and platelets:-

Blood cells are produced in the bone marrow, which in adults is mostly found in the bones of the pelvis, sternum and spine. This is why you may have had a bone marrow sample taken from your hip (pelvis) or the front of your chest (sternum).

All blood cells originate from stem cells that divide and mature in the bone marrow. This process is known as haematopoiesis. Blood cells are produced from two main stem cell lines: myeloid and lymphoid. Myeloid stem cells produce red cells, platelets and specific types of white cell. Lymphoid stem cells produce two types of white cell - T-cells and B-cells.

Haematopoeisis - click the links below the image to switch between simple (default) and detailed views.

Simple | Detailed

Blood cells usually stay in the bone marrow until they are mature enough to be released into the blood stream to carry out their functions.

In haematological disease the orderly procedure of cell development goes wrong. The type of disease that develops depends on where, and at what stage, the error occurs.