Immune Complex Membranoproliferative Glomerulonephritis (IC-MPGN)

Many diseases can affect your kidney function by attacking and damaging the glomeruli, the tiny filtering units inside your kidney where blood is cleaned. The conditions that affect your glomeruli are called glomerular diseases. Glomerular diseases include many conditions with many different causes. One of these conditions is Immune Complex Membranoproliferative Glomerulonephritis (IC-MPGN). IC- MPGN happens when your body’s defense system does not work normally. Your body’s defense system is called your immune system. Healthcare providers refer to the three different types of IC-MPGN, based on how your immune system hurts the kidneys and which part of your glomeruli gets damaged.

In IC-MPGN, your immune system starts to attack the healthy cells in your kidneys which damage the glomeruli. Your immune system makes proteins called antibodies to attack substances in your body that they see as harmful. The harmful substances are called antigens. Antigens combine with antibodies to make immune complexes. These immune complexes get stuck in your kidneys and cause damage.

You may notice the following signs symptoms of IC-MPGN:

• Blood in the urine (hematuria): Glomerular disease can cause your glomeruli to leak blood into your urine. Your urine may look pink or light brown from blood.
• Protein in the urine (proteinuria): Glomerular disease can cause your glomeruli to leak protein into your urine. Your urine may be foamy because of the protein.
• Edema: Glomerular disease can cause fluid to build in your body. The extra fluid can cause swelling in body parts like your hands, ankles, or around your eyes.
• Nephrotic Syndrome: A set of symptoms that happen together and affect your kidneys. These include:
  • Swelling in body parts like your legs, ankles, or around your eyes (edema)
  • Large amounts of protein in your urine (proteinuria)
  • Loss of protein in your blood
  • High levels of fat lipids in your blood (high cholesterol)
  • High blood pressure

• Urine test: A urine test will help find protein and blood in your urine.
• Blood test: A blood test will help find levels of protein, cholesterol, and wastes in your blood.
• Glomerular filtration rate (GFR): A blood test will be done to know how well your kidneys are filtering the wastes from your body.

• Kidney biopsy: In this test, a tiny piece of your kidney is removed with a special needle, and looked at under a microscope. Because IC-MPGN is so rare, and because knowing the class of your disease can help your healthcare provider decide on the best treatment, it is very important that the person looking at your biopsy is an expert in glomerular diseases. You or your doctor may need to contact a large research center to find such an expert.

  Genetic Testing: A test may be done to see if the cause of your IC-MPGN comes from genes you inherited from your family.

Before a treatment plan is made, the doctor will try to find the cause of your IC-MPGN. If IC-MPGN is not caused by another disease, such as hepatitis C, your treatment plan will be different. Treatment with many medications can slow the progress of the disease and help you manage your symptoms like high blood pressure, proteinuria, and edema. The following may be given to you to help slow the process of kidney damage:

• Corticosteroids (often called “steroids”)
• Immunosuppressive drugs
• ACE inhibitors and ARBs
• Complement inhibitors 
• Diet change

Corticosteroids and immunosuppressive drugs

These medications are used to calm your immune system (your body’s defense system) and stop it from attacking your glomeruli.

ACE inhibitors and ARBs

These are blood pressure medications used to reduce protein loss and control blood pressure.

Complement Inhibitor

Complement inhibitors (or complement-targeting therapies) are medicines that can target the complement system. The complement system is part of the immune system. In certain diseases, the complement system can become overactive and damage glomeruli, tiny filtering units within the kidneys. 

In July 2025, The FDA approved pegcetacoplan for the treatment of IC-MPGN. Pegcetacoplan is a complement C3 inhibitor. This drug works by binding to and inhibiting C3. C3, or complement 3, is a blood protein with a role in immunity and the disease. This approval also included pegcetacoplan for the treatment of complement 3 glomerulopathy (C3G). C3G is a similar to C3G, but it is a distinct disease. The drug previously received an approval to treat paroxysmal nocturnal hemoglobinuria (PNH).

Diet change

Some diet changes may be needed, such as reducing salt (sodium) and protein in your food choices to lighten the load of wastes on the kidneys.

For both adults and children, the general treatment plan will be the same. The goal of your treatment is to stop your immune system from causing harm to your kidneys by giving you certain types of medications. There’s no cure for the disease. Treatment focuses on controlling your symptoms and slowing the progression of the disease.