Primary amyloidosis occurs when the body’s antibody-producing cells do not function properly and produce abnormal protein fibers made of antibody fragments. Some people with primary amyloidosis have a condition called multiple myeloma. The antibody fragments come together to form amyloid deposits in different organs, including the kidneys, where they cause serious damage. Injured kidneys can’t function effectively and may be unable to remove urea and other wastes from the blood. Elevated levels of these protein fibers can also damage the heart, lungs, brain, and digestive system.
One common sign of kidney amyloidosis is the presence of abnormally high levels of protein in the urine, a condition known as proteinuria. Healthy kidneys prevent protein from entering the urine, so the presence of protein may be a sign that the kidneys aren’t working properly. A physician who finds large amounts of protein in the urine may also perform a biopsy—take a small sample of tissue for examination with a microscope—to confirm amyloidosis.
Current treatments are aimed at slowing the progression of amyloid build-up. Combination drug therapy with melphalan, a cancer drug, and prednisone, an anti-inflammatory steroid drug, may improve organ function and survival rates by interrupting the growth of the abnormal cells that produce amyloid protein. These are the same drugs used in chemotherapy to treat certain cancers, such as multiple myeloma, and they may have serious side effects, such as nausea and vomiting, hair loss, and fatigue.
Some clinics have reported promising results treating amyloidosis by transplanting the patient’s own blood stem cells to replace diseased or damaged bone marrow. The therapy also requires high doses of melphalan, so side effects can be serious. Patients with heart problems may not be considered for this treatment.