IgG4-Related Disease (IgG4-RD)

IgG4-related disease (IgG4-RD) is a rare, chronic inflammatory condition that can cause tumor-like masses and/or enlarged organs. The masses aren’t cancerous. But the condition can lead to organ damage.

IgG4-RD can affect any organ. And it usually affects more than one at a time. The most commonly impacted tissues include:

• Major salivary (spit) glands
• The bony cavity that protects your eye (orbit) and lacrimal (tear) glands
• Pancreas and biliary tree
• Lungs
• Kidneys
• Aorta
• The space behind the lining of your abdominal cavity (retroperitoneum)
• Meninges
• Thyroid gland

This condition is relatively new to the medical community. Researchers first classified it in the early 2000s. So, it may take time to get a proper diagnosis. The good news is that IgG4-RD is often treatable.

Symptoms of IgG4-related disease

IgG4-related disease symptoms can vary greatly depending on which organ(s) it affects. Symptoms can also range in severity. They typically develop gradually.

Head and neck symptoms of IgG4-RD may include:

• Painless lacrimal and/or salivary gland swelling
• Dry eyes and mouth
• Poor tear drainage
• Double vision
• Bulging eyes
• Chronic rhinitis symptoms, like sneezing and a runny nose
• Nasal polyps
• An enlarged and firm thyroid gland, which may cause trouble swallowing or breathing

Symptoms from affected organs elsewhere in your body may include:

• Unexplained weight loss
• A yellow tint to your skin (jaundice)
• Swollen lymph nodes
• Abdominal pain
• Flank or back pain
• Cough, difficulty breathing or sharp chest pain

It’s possible to have no symptoms. You may find out you have this condition after getting imaging tests for other reasons.

IgG4-related disease causes

Researchers don’t know what causes IgG4-related disease. But they’re actively studying it.

IgG4-RD is a type of immune-mediated disease. This means that it happens because of an issue with your immune system. Your immune system doesn’t act as it should. It causes tissue damage from excessive inflammation.

IgG (immunoglobulin G) is a type of antibody that your body makes to help you fight off infections. IgG4 is one of four subtypes of IgG. Normally, your immune system makes immunoglobulins to defend itself from viruses or bacteria that have infected you in the past. With IgG4-RD, the immunoglobulins harm your body instead of protecting it.

Complications of this condition

IgG4-RD complications include organ damage and failure. This may happen if you have a delayed diagnosis. Or if the condition gradually gets worse without any obvious symptoms.

How doctors diagnose this condition

IgG4-RD can be tricky to diagnose. It can “look” many ways. And it’s a newer condition. A large part of the process is ruling out other conditions. You’ll likely get several tests before you get an official diagnosis. There’s no specific specialist for IgG4-RD. You’ll likely see healthcare providers based on your symptoms or test results.

Tests may include:

• Various blood tests
• Urinalysis
• Imaging tests, like CT or MRI scans
• Biopsies

This process may be daunting. Don’t hesitate to ask your healthcare provider questions. You may also want to consider getting a second opinion.

How is it treated?

Treatment for IgG4-RD involves corticosteroids and/or anti B-cell therapy:

• Corticosteroids: In most cases, you’ll first take corticosteroid pills. Nearly everyone improves within four weeks. Once there’s an improvement, your provider will gradually decrease the dose, aiming to stop entirely.
• Anti B-cell therapy: If you’re unable to tolerate or discontinue corticosteroids, your provider may prescribe rituximab or inebilizumab. These are monoclonal antibodies that deplete B cells, which make the IgG4. You may also get this medicine if IgG4-RD comes back within 12 months of stopping corticosteroids.

Some people may require surgery or other procedures.

You’ll see your healthcare provider throughout your treatment. They’ll want to make sure your symptoms are getting better.

What can I expect if I have this condition?

The outlook for IgG4-related disease can vary. Typically, tumor-like masses or organ enlargement go back to normal after treatment. If this doesn’t happen, it may be a sign of permanent organ fibrosis (scarring). This is why early diagnosis and treatment are key. After stopping treatment, it’s possible for the condition to come back (relapse).

Your healthcare team will give you a better idea of what to expect based on your unique situation. Lean on them for guidance.