IgG4-RD can impact people in many different ways. People may have IgG4-RD for months or even years before a diagnosis is confirmed. This can result in organ damage before the individual is even aware. IgG4-RD is diagnosed by different specialties as the condition affects multiple different organs. Therefore, a combination of tests and findings is required for a diagnosis of IgG4-RD.

• Elevated serum IgG4 levels are seen in some patients with IgG4-RD, however, IgG4 levels alone do not lead to a diagnosis.

• A diagnosis should be supported by histopathological findings, including an abundance of IgG4-positive plasma cells and lymphocytes, storiform fibrosis (swirling pattern of fibrosis that can be patchy), and obliterative phlebitis (destruction of veins from cell inflammation).

• The presence of mass forming lesions are a common characteristic of IgG4-RD. These lesions can cause swelling of the lacrimal and salivary glands, as well as a sausage-shaped pancreas due to immune cell infiltration.‍

• Biopsies of the affected organs are conducted to confirm a diagnosis, measure condition progression, and rule out any other diseases

Treatments options for IgG4-RD include:

• Glucocorticoids (steroid hormones) can be effective in disease control in the early stages of the disease. As a result, glucocorticoids are typically the initial course of treatment, but many patients are unable to achieve remission with this alone.

• B-cell depletion therapy is given through an IV. A common B-cell depletor for IgG4-RD is Rituxan, which has been successful in terms of remission.
  

• Other treatments that are sometimes used include non-steroid immunosuppressant medications like cyclophosphamide, mycophenolate mofetil, azathioprine, mercaptopurine, and methotrexate.