IgA Nephropathy (or IgAN) is a disorder that damages the tiny filters (the glomeruli) of the kidney. IgA is a protein that is normally produced by the body to help fight infection. For reasons that are unclear, this naturally occurring antibody deposits in the kidney filters and causes injury (inflammation) and scarring in the kidney. This is referred to as glomerulonephritis. This leads to leaking of blood (hematuria) and protein (albumin/proteinuria) across the filters in the urine.

IgAN is a very common cause of glomerular disease (glomerulonephritis) around the world. It is more common in whites and in Asians. It is rare in the black population both in the United States and in Africa . It is unclear why it affects one race more than the others. The disease can affect people of all ages but it is most commonly diagnosed in the second and third decade of life.

The cause(s) of IgA nephropathy are not completely understood. The IgA antibodies produced in affected individuals appears to be abnormal and this causes them to stick to other antibodies in the blood as well as to the filters of the kidney leading to damage. IgA nephropathy is usually an isolated kidney disease. However, the same pattern of kidney injury can be associated with other diseases that affect the entire body such as various infections, gastrointestinal disorders (such as liver disease) and certain autoimmune diseases. In some, the disease is inherited and extensive research is ongoing at the Glomerular Center at Columbia Universityto understand how and why this occurs.

Symptoms :

Almost all of affected individuals will have blood in their urine (hematuria). In some, the blood will be visible to the naked eye and may give a brown or red appearance to the urine. This is more common in children and is often associated with a recent upper respiratory tract infection (such as a “cold) or after strenuous exercise. In many others, the blood is first picked up on urine tests (urinalysis) performed by the doctor as part of the routine physical examination or as part of the evaluation of another problem such as high blood pressure (hypertension), swelling of the body (edema) or abnormal kidney function tests seen in the blood. In addition to the blood in the urine, many will also have protein leaking into the urine. This may cause the urine to look foamy or bubbly.

Diagnosis :

A kidney biopsy is done to establish the diagnosis of IgA nephropathy and to distinguish it from other diseases that may also cause blood and protein losses in the urine and abnormal kidney function.

Treatment :

Some treatment is used to control the symptoms associated with the disease as well as slow down the progression of the disease. A specific group of drugs is usually used to help control blood pressure. These medications called angiotensin converting enzyme inhibitors (ACE inhibitors) and angiotensin receptor blockers (ARB) have also been shown to be helpful in decreasing the amount of protein that is lost by the kidney. Other drugs are often used to help reduce high blood cholesterol. Diuretics are used to control swelling that may be present. In most cases, a moderate low protein diet is usually recommended.

Many people will show improvement in kidney function and have a decrease in urine protein losses with these therapies and will not require additional medications. In those who do not respond to this conservative treatment and continue to show deterioration of kidney function, more specific treatments may be used to help suppress the immune system from making abnormal IgA antibodies and to try to cure the disease. There are several treatments available. Steroids (such as prednisone) are often tried for several months, particularly in people who have large amounts of protein leakage from the kidney. Other immunosuppression drugs may be used in addition to or instead of the steroids. These include chemotherapy drugs (cyclophosphamide and imuran/azathioprine). The physicians at the Glomerular Center are very interested in determining which treatments are best for people with IgAN and have the least side effects (toxicity). We are currently enrolling patients in a national study that will help determine if the immunosuppressant medication called mycophenolate mofetil /MMF (used in many transplant patients) is beneficial in the treatment of this disease.

Fish oils may also be recommended in high doses (such as 12 grams/day). The use of fish oils in the treatment is controversial as it is unclear whether they have a definite benefit in the treatment of this disease. However, since they have not been shown to cause any harm to the kidney and may have potential benefit, fish oils are often used in addition to other treatments. Some people do not tolerate the fishy aftertaste of the pills.

Other controversial therapies include tonsillectomy. The reason this was believed to be a good treatment for the disease is because of the association of upper respiratory tract infections and blood in the urine. However, currently there is a lack of convincing data to suggest that this therapy is useful.

Prognosis :

The natural history of IgAN varies a great deal. For many, the disease remains stable or progresses very slowly. Conservative treatment may cure the disease (remission) in some or at least slow down the progression of the disease. Others will continue to slowly lose kidney function over many years despite treatment and may need to be on dialysis or require a kidney transplant.