What is MPGN?
Membranoproliferative Glomerulonephritis (MPGN) is a specific type of glomerular disease that occurs when the body’s immune system functions abnormally. The immune system, which is responsible for fighting disease, begins to attack healthy cells in the kidney, destroying the function of the filtering units of the kidney. MPGN is characterized by immune complex deposits in the kidneys glomerular mesangium AND a thickening of the basement membrane.
How is MPGN Diagnosed?
MPGN can only be diagnosed, with certainty via a kidney biopsy. There are 3 different sub-types of MPGN (type 1,type 2, and type 3), each of which has a different appearance under the microscope.
Type I is characterized by immune complex deposits found in the mesangium and subendothelial space. Immune complexes are combinations of antigens and antibodies which bind to each other and then become lodged in the capillary of the kidney. These immune complexes activate the immune system causing inflammation and eventual damage to the kidney.
Type II is also called Dense Deposit Disease. Under microscopy, flowing dense ribbon-like deposits are found along the basement membrane, tubules, and Bowman’s capsule. Type II has no known association with immune complexes, unlike types I and III.
Type III is also an immune complex disease, similar to type I. However, the immune complexes are found deposited in the subepithelial space. There are also large open areas in the glomerular basement membrane.
What are the Symptoms of MPGN?
Patients with MPGN generally have hematuria (blood in the urine), which may or may not be visible with the naked eye. Urine may be cloudy or dark (cola or tea colored) Many of the red blood cells are dysmorphic (malformed or misshapen). In addition, mild or severe protein in the urine can be found causing edema (swelling), foamy urine and in severe cases decrease in urine output.
Who gets MPGN?
MPGN is usually a secondary disease and found in patients who have other diseases such as autoimmune diseases, cancer, or infections. In rare cases there is no known cause of MPGN, meaning it is idopathic or a primary disease.
The idiopathic type of MPGN is seen most commonly in persons aged 8-30. Most cases of primary MPGN are type I. MPGN II is rare and it accounts for <20% of cases of MPGN in children and only a fractional percentage of cases in adults. (3) MPGN accounts for approximately 4% of primary nephrotic syndrome in children and 7% in adults. (1)
How is MPGN Treated?
There’s no cure for primary MPGN and no definitive way of knowing what course the disease will take.
Treatment with a number of medications can slow the progress of the disease and help manage symptoms such as high blood pressure, protein in the urine, and swelling.
It is important to see a kidney specialist on a regular basis to monitor kidney function, degree of proteinuria, cholesterol and blood pressure. Many different types of immunosuppressants, or drugs that suppress the immune system can also be considered. Steroids a often not successful in treatment of MPGN.
If remission is not obtained, it is important to be on a medication that reduces the amount of protein in the urine. These medications are called ACE-inhibitors (angiotensin converting enzyme inhibitors) and ARBs (angiotensin II receptor blockers).
Your nephrologist may also recommend:
- Diuretics to help eliminate excess fluids in the body
- Low Sodium diet help to control edema
- Anticoagulants to prevent blood clots
- Blood Pressure medications to lower high blood pressure
- Statins to lower the cholesterol level
- Maintaining a healthy diet: Correct amounts of protein and fluid intake according to your nephrologist’s recommendations. A healthy diet consists of low salt with emphasis on fruits and vegetables, low in saturated fat and cholesterol.
- Not smoking
Click here for specific information about each treatment option.
Patients with MPGN may progress to end-stage renal disease (ESRD) and require dialysis and/or kidney transplantation. Patients who undergo transplantation for primary MPGN commonly recur, or the disease process returns in the transplanted kidney.
(1)Orth SR, Ritz E: The nephrotic syndrome. N Engl J Med 338 : 1202 –1211, 1998
(3) Habib R, Gubler MC, Loriat C, et al.: Dense deposit disease. A variant of membranoproliferative glomerulonephritis. Kidney Int 7 : 204 –215, 1975