IgG4-Related Systemic Disease Program

About the program

Addressing IgG4-RSD as a systemic disease

IgG4-related systemic disease (IgG4-RSD) links a number of inflammatory disorders that previously were considered unrelated. Various clinical manifestations of the condition can cause fibrosis (the formation of excessive connective tissue) in a growing list of organs and tissues.

Mass General Brigham is one of the only U.S. health systems to recognize and treat IgG4-RSD as a systemic (i.e. whole-body) disease that affects multiple organs and tissues. Our research on this emerging disease has led to several important milestones, including:

• Pioneering a new treatment (rituximab)
• Establishing IgG4-RSD's link with thoracic aortitis and with Riedel's thyroiditis
• Organizing the first international symposium on IgG4-RSD

Part of Rheumatology, Inflammation, and Immunity

What to expect

Many patients are referred to us by a pathologist who suspects IgG4-RSD.

Your doctor will review your medical history, perform a physical examination and, because information about IgG4-RSD is so hard to find, educate you about the disease. If necessary, we may recommend blood tests or review your biopsy specimen with a Mass General Brigham pathologist to confirm a diagnosis.

For many patients, receiving the diagnosis of IgG4-RSD comes as a relief. The condition often causes organ swelling, which previously may have been mistaken for a malignant tumor. Some patients have even undergone unnecessary surgery for this reason.

If IgG4-RSD is diagnosed early, we can usually control the inflammation within organs and prevent further damage. In addition, our multispecialty expertise is essential in managing problems within organs that can result from damage associated with IgG4-RSD.

Exploring a promising new treatment option

Treatment for IgG4-RSD traditionally has involved prednisone, a steroid medication. Prednisone has proven very effective in treating this condition but also leads to side effects such as weight gain, osteoporosis, high blood pressure and diabetes.

Mass General is hosting a clinical trial of rituximab, which to date has shown to be as effective as prednisone in IgG4-RSD but without the side effects. As a patient in our program, you will begin treatment for IgG4-RSD with two months of prednisone therapy. However, if symptoms subsequently return, you may be eligible to participate in the study of rituximab.

We typically see patients in our program monthly for the first three months of treatment and then every three months thereafter.

About IgG4-related systemic disease

IgG4-related systemic disease (IgG4-RSD) typically affects multiple organs and tissues—most commonly the:

• Aorta tissue
• Kidneys
• Lacrimal glands (which produce tears)
• Lungs
• Pancreas
• Retroperitoneal tissue (in the abdominal area)
• Salivary glands

The condition causes fibrosis, in which the formation of excessive connective tissue prevents normal organ/tissue function. It may also lead to swelling that can be mistaken for tumors.

Particularly if diagnosed early, IgG4-RSD is highly treatable. Our program offers both traditional steroid therapy (prednisone) and, should that prove ineffective, a medication called rituximab that has shown great promise in treating the condition.