IgG4-related disease
What is it?
IgG4-associated disease is a fibroinflammatory disease first described around the 2000s in the context of autoimmune pancreatitis. Today, it is known that many organs other than the pancreas can be affected. IgG4-correlate disease is characterized by the appearance of tumors affecting one or more organs at the same time, a tendency to chronic relapse, and increased levels of IgG4 (immunoglobulin G subclass 4) in blood tests.
Causes and risk factors
IgG4-related diseases are more common in men than in women and are more common after 40-50 years of age. Pediatric cases are rarely described. Although epidemiological data are still incomplete, IgG4-associated disease appears to be more common in Japan.
Which are the symptoms?
The clinical manifestations of IgG4-associated disease are associated with the compressive effect exerted by the fibrous mass on the affected organ and can be very different from each other.
How is it diagnosed?
Therefore, a final diagnosis requires a biopsy of the affected tissue and a histological examination.
However, there are clinical, radiological, and laboratory elements that can aid in the diagnosis:
- allergy in history;
- visible swelling of the large salivary glands, lacrimal glands, or orbit;
- inflamed pancreas with a "sausage" appearance on CT and MRI;
- increase in the level of immunoglobulins IgG4 and IgE in blood tests.
Suggested exams
How is it treated?
Early recognition of IgG4-RD is extremely important in order to avoid organ failure, chronic morbidities, and overtreatment with unnecessary surgical procedures or chemotherapies. IgG4-RD, in fact, promptly responds to immunosuppressive treatments. Glucocorticoids represent the first line treatment to induce disease remission. Methotrexate or azathioprine are used as steroid sparing agents to maintain remission. Rituximab (a B cell depleting monoclonal antibody for intravenous infusion) has been recently shown to induce remission of IgG4-RD in the majority of case and is now used as the preferred second-line agent in tertiary care referral centers for treating IgG4-RD relapse.
Where do we treat it?
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