Waldenström macroglobulinaemia (“WM”) is the term for lymphoplasmacytic lymphoma (“LPL”) accompanied by production of IgM (Immunoglobulin M) paraprotein. Occasionally the protein may be IgG or IgA, but this does not affect the treatment or prognosis. LPL is a rare type of low grade non-Hodgkin lymphoma.
Jan Waldenström was the Swedish doctor who first described the disease now known as Waldenström macroglobulinaemia (“WM”) in 1944. “Macroglobulinaemia” was the word he used to describe the high levels of IgM “paraprotein” (meaning an abnormal type of the usually normal IgM protein) seen in the blood stream of 95% of patients with LPL.
The bone marrow is the source of all our blood cells, including red cells (which carry oxygen), white cells (which fight infections) and platelets (which help the blood to clot when needed). The blood cells made in the bone marrow are continuously released from the bone marrow into the bloodstream. The lymphatic system is part of the body’s immune system and helps us fight infection, and consists of organs such as the bone marrow, thymus, spleen, and the lymph nodes (or lymph glands). Lymph nodes are connected by a network of tiny lymphatic vessels that contain lymph fluid and are found in groups, particularly in the armpits, the neck and the groin.
“B lymphocytes” are a type of white blood cell that provide defence against infection. Some B lymphocytes develop into “plasma cells”, and these cells make antibodies to help fight infections. Antibodies are made from a special type of protein called “immunoglobulin” and there are 5 types of immunoglobulins (Ig) in the body: IgG, IgA, IgM, IgD and IgE. Each of these antibodies has a different function and size. Usually, antibodies are made in response to infections in order to help the body fight against them and so develop immunity. IgM is the largest of these, as it circulates in groups of five. WM affects B lymphocytes when they are in the process of developing into plasma cells. These developing cells are called “lymphoplasmacytic cells”, because they have features of both lymphocytes and plasma cells, which is where the name “lymphoplasmacytic lymphoma” comes from.
In WM, the bone marrow produces abnormal lymphoplasmacytic cells. Although they are of no use to the body, these cells keep being made. As their numbers increase, they build up within the bone marrow, lymph nodes, spleen and other organs. In the bone marrow the result of this build-up is that the normal blood cells are ‘crowded out’ and this leads to a gradual reduction of normal blood counts. If the build-up occurs in the lymph nodes, spleen or even elsewhere, these tissues swell up and lumps sometimes form that can be visible or felt, although this is not as common a finding as in other lymphomas.
WM often develops over a long period of time and many people have no symptoms at all. This means that sometimes the condition is found by chance while having investigations for another condition or on a routine blood test.
Most people with WM will have abnormal B lymphocytes and plasma cells in their bone marrow. When these cells fill up the bone marrow, it is not able to make as many normal blood cells as usual.
Symptoms of WM can be:
- a tendency to develop infections
- a tendency to bruise or bleed easily
- night sweats
- weight loss.
If there is a large amount of IgM protein in the bloodstream in WM, this can make the blood thicker and more slow-flowing than normal. This is called hyperviscosity.
This can cause symptoms such as:
- blurring or loss of vision
- dizziness or headaches
- drowsiness, poor concentration or confusion
- shortness of breath due to heart or lung failure.
The IgM protein can also affect the small nerves in the hands and feet and this can cause neuropathy ( numbness or tingling) affecting the fingers and toes
The cause of WM is not known. WM is not infectious and cannot be passed on to other people, but may cluster in some families.
WM is a rare cancer. It can affect adults of any age, but most people who develop WM are over 60. It is slightly more common in men than in women.
WM rarely can occur in clusters within families. It has been noticed that about a quarter of people with WM will have a relative with either WM or a similar condition such as chronic lymphocytic leukaemia (CLL) or another non-Hodgkin lymphoma. This familial tendency is the subject of ongoing research. There are no recommendations to check family members at present, but if you are concerned about this, please speak to your specialist and they will give you more information.
Although WM is not currently curable, it is very treatable and most people live with this disease for many years. Some people who are diagnosed with WM do not need any treatment at first. WM often develops slowly over several years, and the term often used to describe this gradual behaviour is ‘indolent’. This means that some people may not need treatment for months or, very often, years. If this is the approach your doctor recommends, you will have regular check-ups in the outpatient clinic. This active monitoring is often called 'watch and wait' or 'watchful waiting'.