As a Graves eye disease specialist in Denver, I take pride on being at the cutting edge new technologies and research about the disease. As we continue this journey to a cure and simple treatment for Graves eye disease, it is important to offer my patients the most current treatment options for Graves. One of the most recent discoveries about Graves disease is that it may be related to a second inflammatory disease called IgG4 disease..
A recent study has found a subtype of patients with Graves eye disease who have elevated levels of IgG4 immunoglobulin. This represents 6% of patients with Graves disease. Immunoglobulin G4-related disease is a recently recognized immune-mediated disease comprised of a collection of disorders that share particular pathologic, serologic, and clinical features.
The shared features of IgG four disease include:
Swelling of involved organs
Increase in IgG4 cells
Fibrosis or scarring
Diagnostic criteria is finding a level of serum IgG4 over 135 mg/dl and more than 40% of plasma cells being IgG4 cells.
One characteristic of IgG4 disease in patients with Graves disease is that is that they tend to be older (mean age 54.7) than Graves patients without the disease. Why is this important? This subtype of Graves patients may respond differently to steroids, radiation and surgery than the rest of Graves patients. Because the discovery of this subtype is new, we are learning how these patients are different than their peers with normal IgG4 and Graves.
I routinely test my Denver Graves patients with IgG4 level to determine if they are part of this minority group. In Graves disease, patients can have enlarged extaocular muscles and fat in their eye socket. Patients who have increase in the size of their lacrimal gland or tear gland is not part of the physical findings of Graves disease and warrant IgG4 testing. Enlarged salivary glands and lacrimal glands are part of the IgG4 disease but not part of Graves disease.
IgG4 disease is similar to Graves disease in that steroids and rituxan are treatments for both diseases. Because both have been so steroid responsive, they may have easily been confused for each other. Though we don’t know everything about the IgG4 subtype of Graves disease, it is important for patients to be tested to see if they are part of this group. Only by identifying a large group of these patients can we define how their disease and treatment characteristics are different.