Waldenstrom macroglobulinemia is a rare type of blood cancer that affects a specific type of white blood cell called B lymphocytes, which normally produce immunoglobulins like IgM.
The increased number of B lymphocytes results in the production of high levels of IgM. This can ultimately cause the blood to become very thick, almost jelly-like, which prevents the normal, smooth blood flow throughout the body.
Some of the signs and symptoms of Waldenstrom macroglobulinemia are caused by blood flow changes.
If there’s involvement of the retina, the inner lining of the eye, individuals may present with impaired or blurred vision.
Accumulation of B lymphocytes in the bone marrow can lead to anemia, which occurs when there aren’t enough red blood cells to deliver sufficient oxygen to body tissues.
As a result, individuals may experience fatigue and weakness. Patients may also experience tingling in the extremities, like fingers and toes.
Lastly, the immunoglobulins tend to accumulate in the lymph nodes, spleen, and liver, making these organs enlarge.
B lymphocytes develop in the bone marrow. As they become more mature, they leave the bone marrow and move into the blood and lymphatic tissues.
Mature B lymphocytes produce specific proteins called antibodies, also known as immunoglobulins or Ig for short, which circulate around the body and help identify and fight off infections.
There are a few types of antibodies, one of which is IgM. Since it is the largest of the antibodies, it’s considered a macroglobulin.
In Waldenstrom macroglobulinemia, B lymphocytes do not function properly. They abnormally divide and accumulate in the bone marrow and lymphatic tissues.
And as their cell numbers increase, so does the amount of IgM in the blood. Excessive amounts of IgM thicken the blood, making it more difficult to flow smoothly through the blood vessels around the body. This can cause blood vessels to tear.
The underlying cause of the B lymphocytes’ abnormal behavior is unknown. But it tends to occur more commonly in males than females; as well as in caucasian individuals; and in those who are over 50 years old.
Most people with Waldenstrom macroglobulinemia have a specific change, or mutation, in the MYD88 gene and 30-40% of affected people have a mutation in the CXCR4 gene. These mutations occur in the Waldenstrom cells only and are not inherited.