Chronic Lymphocytic Leukaemia (CLL) is the most common form of adult leukaemia and occurs predominantly in patients over 55 years. It's estimated that approximately 14990 (2010 data) people will be diagnosed with CLL this year.
The vast majority of CLL cases are a slowly progressive form of cancer involving mature white blood cell B-lymphocytes that tend to proliferate and live much longer than normal. These B-lymphocytes which are not fully developed and which do not work properly, accumulate in the blood, bone marrow, lymph nodes and spleen. This results in overcrowding of these areas and suppression of the formation and function of blood cells. Additionally, the cancerous lymphocytes themselves do not function normally, leading to a further reduction in the body's ability to fight infection.
Blood cells are normally produced in a controlled way, but in CLL the process gets out of control. The lymphocytes multiply too quickly and live too long, so there are too many of them circulating in the blood. These Leukaemia lymphocytes look normal, but are in fact not fully developed and do not work properly. Over a period of time the abnormal cells replace the normal white and red cells in the bone marrow.
Many cases of CLL are detected by routine blood tests in persons with no symptoms and these are said to be asymptomatic. This "smouldering" condition can continue for many years whilst others may experience more rapid onset of symptoms and a more aggressive form of the disease. Symptoms may include enlarged lymph nodes, enlarged spleen and liver, fatigue, bone pain, abnormal bruising, excessive sweating, loss of appetite, weight loss, re-occurring infections and lack of energy. Complications can arise in CLL for a number of reasons with the malfunctioning immune system being the most common. An immune system which is operating below specification can result in persistent bacteria, fungi and viral infections. On the other hand an overactive immune system can result in the body destroying key cell lines such as red cells and platelets (AIHA).
Another problem that can occur is that the bone marrow can become so over crowded with CLL cells that its function becomes impaired. This results in the reduced production of red cells, platelets and normal white blood cells.