Although many people have no symptoms, some people have abnormal bleeding, recurring bacterial infections, and bone fractures due to severe osteoporosis.
Blood tests and bone marrow examination are needed to make the diagnosis.
Macroglobulinemia is not curable, but progression can be slowed with chemotherapy drugs.
Plasma cells develop from B cells (B lymphocytes B cells One of the body's lines of defense ( immune system) involves white blood cells (leukocytes) that travel through the bloodstream and into tissues, searching for and attacking microorganisms and... read more ), a type of white blood cell that normally produces antibodies Antibodies One of the body's lines of defense ( immune system) involves white blood cells (leukocytes) that travel through the bloodstream and into tissues, searching for and attacking microorganisms and... read more (immunoglobulins). Antibodies are proteins that help the body fight infection. If a single plasma cell B cells One of the body's lines of defense ( immune system) involves white blood cells (leukocytes) that travel through the bloodstream and into tissues, searching for and attacking microorganisms and... read more multiplies excessively, the resulting group of genetically identical cells (called a clone) produces a large quantity of a single type of antibody Antibodies One of the body's lines of defense ( immune system) involves white blood cells (leukocytes) that travel through the bloodstream and into tissues, searching for and attacking microorganisms and... read more . Because this antibody is made by a single clone, it is called a monoclonal antibody and also is known as the M-protein. (See also Overview of Plasma Cell Disorders Overview of Plasma Cell Disorders Plasma cell disorders are uncommon. They begin when a single plasma cell multiplies excessively. The resulting group of genetically identical cells (called a clone) produces a large quantity... read more .)
Men are affected by macroglobulinemia more often than women, and the average age at which the disorder appears is 65 years. Its cause is unknown.
Symptoms of Macroglobulinemia
Many people who have macroglobulinemia have no symptoms, and the disorder is discovered by chance when an elevated level of blood proteins is found during routine blood tests.
Other people have symptoms resulting from interference with blood flow to the skin, fingers, toes, nose, and brain that occurs when the large quantity of macroglobulins thickens the blood (hyperviscosity syndrome). These symptoms include bleeding from the skin and mucous membranes (such as the lining of the mouth, nose, and digestive tract), fatigue, weakness, headache, confusion, dizziness, and even coma. The thickened blood also may worsen heart conditions and cause increased pressure in the brain. Tiny blood vessels in the back of the eyes can become filled with blood and may bleed, resulting in damage to the retina and impaired eyesight.
People who have macroglobulinemia may also have swollen lymph nodes and an enlarged liver and spleen due to infiltration by cancerous plasma cells. Recurring bacterial infections resulting from inadequate production of normal antibodies may cause fever and chills. Anemia, which may result in weakness and fatigue, occurs when cancerous plasma cells prevent production of normal blood-forming cells in the bone marrow. Infiltration of bones by cancerous plasma cells may cause loss of bone density (osteoporosis Osteoporosis Osteoporosis is a condition in which a decrease in the density of bones weakens the bones, making breaks (fractures) likely. Aging, estrogen deficiency, low vitamin D or calcium intake, and... read more ), which can weaken bones and increase the risk of fractures.
Some people develop a condition called cryoglobulinemia Cryoglobulinemia Conditions that cause an abnormal protein or an abnormal amount of certain normal proteins in the blood can cause blood vessels to become fragile. When these fragile blood vessels break, people... read more . Cryoglobulinemia involves the development of antibodies that clog up the blood vessels in cold temperatures.
Diagnosis of Macroglobulinemia
Additional laboratory tests
Blood tests are done when macroglobulinemia is suspected. The three most useful tests are serum protein electrophoresis, measurement of immunoglobulins, and immunoelectrophoresis (a process by which proteins are separated out from plasma Plasma The main components of blood include Plasma Red blood cells White blood cells Platelets read more and identified based on the detectable immunologic reactions they produce). The occurrence of specific mutations in a specific gene, MYD88 (myeloid differentiation primary response gene), commonly occur among patients with macroglobulinemia.
Doctors may do other laboratory tests as well. For example, doctors may check a blood sample to determine if the numbers of red and white blood cells and platelets are normal. In addition, serum viscosity, which is a test to check the thickness of the blood, is often done. Blood clotting test results may be abnormal, and other tests may detect cryoglobulins. An examination of a urine sample may show Bence Jones proteins (pieces of abnormal antibodies). A bone marrow biopsy Bone Marrow Examination Red blood cells, most white blood cells, and platelets are produced in the bone marrow, the soft fatty tissue inside bone cavities. Sometimes a sample of bone marrow must be examined to determine... read more may reveal an increased number of lymphocytes and plasma cells, which helps confirm the diagnosis of macroglobulinemia, and the appearance of these cells helps differentiate this disorder from multiple myeloma Multiple Myeloma Multiple myeloma is a cancer of plasma cells in which abnormal plasma cells multiply uncontrollably in the bone marrow and occasionally in other parts of the body. People often have bone pain... read more .
X-rays may show a loss of bone density (osteoporosis Osteoporosis Osteoporosis is a condition in which a decrease in the density of bones weakens the bones, making breaks (fractures) likely. Aging, estrogen deficiency, low vitamin D or calcium intake, and... read more ). Computed tomography (CT) may reveal an enlarged spleen, liver, or lymph nodes.
Treatment of Macroglobulinemia
Other drugs that target the immune system
Often, people need no treatment for many years. However, when treatment is needed, corticosteroids are often helpful because they change the protein composition of cells, damaging or killing the cancerous cells.
Chemotherapy, usually with chlorambucil or fludarabine, can slow the growth of abnormal plasma cells. Other chemotherapy drugs, such as bendamustine, melphalan, or cyclophosphamide, and corticosteroids are sometimes used, alone or in combination.
Drugs that work differently from the chemotherapy drugs may be helpful. The monoclonal antibody rituximab is effective at slowing the growth of the abnormal plasma cells. Other drugs that affect the immune system in different ways include thalidomide, lenalidomide, pomalidomide, bortezomib, carfilzomib, ibrutinib, acalabrutinib, zanubrutinib, idelalisib, and everolimus are being used with some success, especially when they are used with corticosteroids and/or chemotherapy.
A person whose blood is thickened must be treated promptly with plasma exchange Plasma exchange In apheresis, blood is removed from a person and then returned after substances are removed from it. Apheresis can be used to Obtain healthy blood components from a donor to transfuse to a person... read more , a procedure in which blood is withdrawn, the abnormal antibodies are removed from it, and the red blood cells are returned to the person. Only a small number of people with macroglobulinemia require this procedure; however, in those people the procedure often needs to be repeated.
The disease remains incurable, but people typically survive 7 to 10 years after diagnois.