IgA nephropathy is a kidney disorder caused by deposits of the protein immunoglobulin A (IgA) inside the glomeruli (filters) within the kidney. These glomeruli (the singular form is glomerulus) normally filter wastes and excess water from the blood and send them to the bladder as urine. The IgA protein prevents this filtering process, leading to blood and protein in the urine and swelling in the hands and feet. This chronic kidney disease may progress over a period of 10 to 20 years. If this disorder leads to end-stage renal disease, the patient must go on dialysis or receive a kidney transplant.
The IgA protein, an antibody, is a normal part of the body's immune system, the system that protects against disease. We do not know what causes IgA deposits in the glomeruli. But, since IgA nephropathy may run in families, genetic factors probably contribute to the disease.
Kidney disease usually cannot be cured. Once the tiny filtering units are damaged, they cannot be repaired. Treatment focuses on slowing the progression of the disease and preventing complications. One complication is high blood pressure, which further damages glomeruli. A class of medicines called ACE inhibitors protects kidney function not only by lowering blood pressure but also by reducing the loss of protein into the urine.
Some patients may benefit from limiting protein in their diet to reduce the buildup of waste in the blood. Patients with IgA nephropathy often have high cholesterol. Reducing cholesterol—through diet, medication, or both—appears to help slow the progression of IgA nephropathy.
Corticosteroids may suppress the production of IgA but can have harmful side effects. In preliminary studies, fish oil supplements containing omega 3 fatty acids also appear to slow the progression of the kidney disease. A new immunosuppressive agent called mycophenolate mofetil (MMF) is also being tested.