From the Guidelines
The primary treatment for IgG4-related pancreatitis is corticosteroid therapy, typically starting with prednisone at a dose of 0.6-1 mg/kg/day (usually 30-40 mg daily) 1. This initial dose is maintained for 2-4 weeks, followed by a gradual taper over 3-6 months. Most patients show rapid improvement within 2-4 weeks of starting treatment. For maintenance therapy or steroid-sparing approaches, immunomodulators like azathioprine (2-2.5 mg/kg/day), mycophenolate mofetil (1000-1500 mg twice daily), or rituximab (typically 1000 mg IV on days 1 and 15) may be used, especially in relapsing cases 1. Treatment response should be monitored through clinical symptoms, serum IgG4 levels, and imaging studies. Corticosteroids are effective because they suppress the abnormal immune response characterized by IgG4-positive plasma cell infiltration and fibrosis in the pancreas. Even after successful treatment, regular follow-up is essential as relapse occurs in approximately 30-50% of patients, particularly after steroid discontinuation 1. Patients should also be monitored for potential complications like diabetes, as the disease can affect pancreatic function.
Some key points to consider in the treatment of IgG4-related pancreatitis include:
- The use of corticosteroids as first-line treatment, with a strong recommendation for their use in active IgG4-SC 1
- The consideration of immunosuppressive therapy for long-term care, including agents like azathioprine, mycophenolate mofetil, and rituximab 1
- The importance of monitoring treatment response and adjusting therapy as needed to minimize the risk of relapse and complications 1
- The potential benefits of maintenance steroid treatment, as well as the use of biological therapies like rituximab in patients who fail to respond to first- or second-line treatment 1
From the Research
Definition and Characteristics of IgG4 Pancreatitis
- IgG4 pancreatitis, also known as autoimmune pancreatitis (AIP), is a rare form of chronic pancreatitis characterized by lymphoplasmacytic infiltrate, storiform fibrosis, obliterative phlebitis, and increased IgG4(+) plasma cells 2.
- It is often associated with elevated serum IgG4 levels and can involve other organs, such as the bile ducts, salivary glands, and kidneys 3, 2.
- IgG4-related disease (IgG4-RD) is a systemic disease that can manifest in various organs, including the pancreas, and is characterized by elevated IgG4 levels and similar histologic changes 2, 4.
Treatment of IgG4 Pancreatitis
- The current first-line therapy for IgG4 pancreatitis is corticosteroids, which can induce remission in most patients 3, 5.
- In cases of steroid intolerance or aggressive disease, other immunosuppressive drugs, such as rituximab or azathioprine, may be used 3, 4.
- Maintenance treatment is often employed to prevent relapse, especially in type 1 AIP, which has a higher relapse rate compared to type 2 AIP 5.
- Hormone therapy and personalized treatment strategies may also be effective in managing IgG4-RD, taking into account its recurrence, associations, and imaging features 4.
Diagnosis and Biomarkers
- Diagnosis of IgG4 pancreatitis is based on a combination of serum IgG4 level, imaging features, and histopathological findings 3, 5.
- Elevated serum IgG4 levels are a hallmark of AIP and IgG4-RD, but normal serum concentrations do not rule out the disease 6.
- New biomarkers, such as interferon-α (IFN-α) and interleukin-33 (IL-33), may be useful for diagnosis and monitoring of AIP and IgG4-RD activity 6.