Heavy Chain Diseases

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. 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 (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 connective tissue disorder and is characterized by excessive dryness of the eyes, mouth, and other mucous membranes. White blood cells can infiltrate... 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 some 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 (IgM heavy chain disease), the rarest of the three main 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 and amyloidosis Amyloidosis Amyloidosis is a rare disease in which abnormally folded proteins form into collections called amyloid fibrils that accumulate in various tissues and organs, sometimes leading to organ dysfunction... read more 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.