Cancer - Monoclonal B-cell Lymphocytosis

You are receiving this leaflet because your blood test has shown a condition called Monoclonal B-cell Lymphocytosis (MBL).

This leaflet explains what Monoclonal B-cell Lymphocytosis is, how it is diagnosed and managed.

What is Monoclonal B-Cell Lymphocytosis?

Monoclonal B-cell Lymphocytosis is a blood condition and is not a cancer of the blood.

Monoclonal B-cell Lymphocytosis is often detected following a routine blood test, usually for an unrelated concern or condition or as part of ongoing health checks by your GP.

Monoclonal B-cell Lymphocytosis is when your blood test shows a higher-than-normal level of abnormal white blood cells. The abnormal blood cells do not work properly. People with MBL do not have any symptoms related to the condition.

The abnormal white cells are the same as the cells of a blood cancer called Chronic Lymphocytic Leukaemia (CLL). CLL is a common form of blood cancer in adults and often does not need any treatment.

Monoclonal B-cell Lymphocytosis (MBL) is not the same as having Chronic Lymphocytic Leukaemia (CLL).

What is the difference between MBL and CLL?

The abnormal white cells found in MBL and CLL are the same. However, people with MBL do not have CLL.

You have MBL when the abnormal white cells are at a very low level. When the cells go above a certain level this is CLL.

A small number of people with MBL will develop CLL which needs treatment. Studies have shown this to be 1-2% likelihood that this would happen. This means that out of 1000 people between 10 and 20 people will develop CLL in one year.
However, progressing to CLL does not mean you will need treatment. You will continue to be monitored.

How is MBL managed?

You will have a blood test (full blood count), once every 6-12 months. This will measure the number of abnormal white cells in your blood along with red blood cells and platelets.

You may also need a physical examination by your GP or a member of the Haematology Team. This will assess for swollen glands and an enlarged liver or spleen.

Are there any risks for people with MBL?

There is an increased risk of developing infections. This is because lymphocytes are part of your body’s immune system, they help to protect your body from infection. MBL affects your lymphocytes, and you may be more at risk than someone who doesn’t have MBL of getting an infection.

It is recommended that you have the annual flu vaccine. You should avoid live vaccines. If you are unsure consult your GP.

How will I know if MBL has progressed to CLL?

You will have regular blood tests to check the number of lymphocytes in your blood. This will tell us whether the MBL has changed.

The symptoms of CLL include:

• Swollen lymph glands
• Drenching night sweats (need to change nightwear and bedding)
• Fast and significant weight loss
• High temperatures with no signs of infection
• Repeated Infections

What do I do if I am worried about any symptoms?

In the first instance please contact your GP who can arrange for a blood test and can also physically examine you.

Many of the symptoms of CLL are the same as those found when you have an infection. It is important to rule out infection and whether you need antibiotics.