(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 .)
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. People with a large quantity of the M protein often have reduced levels of other antibodies. In some cases, the antibody produced is incomplete, consisting of only light chains or heavy chains (functional antibodies normally consist of two pairs of two different chains called a light chain and heavy chain).
There are 5 classes of antibodies— IgM, IgG, IgA, IgE, and IgD. Each class has its own type of heavy chain.
Heavy chain diseases are categorized according to the type of heavy chain produced:
Alpha (from IgA)
Gamma (from IgG)
Mu (from IgM)
Alpha Heavy Chain Disease
Alpha heavy chain disease (IgA heavy chain disease) affects mainly younger adults of Middle Eastern or Mediterranean ancestry. Infiltration of the intestinal tract wall by cancerous plasma cells often prevents proper absorption of nutrients from food (malabsorption Overview of Malabsorption Malabsorption syndrome refers to a number of disorders in which nutrients from food are not absorbed properly in the small intestine. Certain disorders, infections, and surgical procedures can... read more ), resulting in severe diarrhea and weight loss. A rare form affects the respiratory tract.
Doctors do blood tests when they suspect alpha heavy chain disease. Such tests include serum protein electrophoresis (SPEP), measurement of immunoglobulins, and immunoelectrophoresis. SPEP is a test that measures specific proteins in the plasma Plasma The main components of blood include Plasma Red blood cells White blood cells Platelets read more to help identify some diseases. Immunoelectrophoresis is a more specialized version of this test, in which proteins are separated out and identified based on the detectable immunologic reactions they produce. Urine tests may also be needed, and sometimes tissue from the intestine is removed and examined (biopsy).
Alpha heavy chain disease progresses rapidly, and some affected people die within 1 to 2 years. In other people, treatment with cyclophosphamide, prednisone (a corticosteroid), and antibiotics may slow the progression of the disease or lead to a remission.
Gamma Heavy Chain Disease
Gamma heavy chain disease (IgG heavy chain disease) affects mainly older men. Some people with gamma heavy chain disease have no symptoms. Some people also have other immune system disorders such as rheumatoid arthritis Rheumatoid Arthritis (RA) Rheumatoid arthritis is an inflammatory arthritis in which joints, usually including those of the hands and feet, are inflamed, resulting in swelling, pain, and often destruction of joints.... read more , Sjögren syndrome Sjögren Syndrome Sjögren syndrome is a common autoimmune rheumatic disorder and is characterized by excessive dryness of the eyes, mouth, and other mucous membranes. White blood cells can infiltrate and damage... read more , or systemic lupus erythematosus Systemic Lupus Erythematosus (SLE) Systemic lupus erythematosus is a chronic autoimmune inflammatory connective tissue disorder that can involve joints, kidneys, skin, mucous membranes, and blood vessel walls. Problems in the... read more (lupus). Infiltration of the bone marrow by cancerous plasma cells causes other people to have symptoms of recurring infections, such as repeated episodes of fever and chills associated with a decreased number of white blood cells, and fatigue and weakness associated with severe anemia Overview of Anemia Anemia is a condition in which the number of red blood cells is low. Red blood cells contain hemoglobin, a protein that enables them to carry oxygen from the lungs and deliver it to all parts... read more . Cancerous plasma cells may also enlarge the liver and spleen.
Blood and urine tests are needed to make the diagnosis.
People with symptoms may respond to chemotherapy drugs, corticosteroids, and radiation therapy. But gamma heavy chain disease usually progresses rapidly, and about half of affected people die within about a year.
Mu Heavy Chain Disease
Mu heavy chain disease (IgM heavy chain disease), the rarest of the three heavy chain diseases, most often affects people over 50. It may cause enlargement of the liver and spleen as well as enlargement of the lymph nodes in the abdomen. Fractures may also occur.
Blood and urine tests are typically done. Bone marrow examination is usually needed for diagnosis.
Treatment usually includes chemotherapy drugs and corticosteroids. Length of survival and response to treatment vary widely.
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