What are Immunoglobulin G4 (IgG4)-related diseases?

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Last updated: May 1, 2025View editorial policy

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From the Guidelines

IgG4-related disease should be treated with corticosteroids as the first-line treatment, specifically prednisone at 0.5 to 0.6 mg/kg/d, as recommended by the most recent guidelines 1.

Treatment Overview

The treatment of IgG4-related disease typically involves the use of corticosteroids, with the goal of reducing inflammation and preventing organ damage.

  • The initial dose of prednisone is usually 0.5 to 0.6 mg/kg/d, which is then tapered over time based on the patient's response to treatment.
  • For patients who do not respond adequately to steroids or who relapse, immunosuppressive medications such as azathioprine, mycophenolate mofetil, or rituximab may be added to the treatment regimen.

Key Considerations

  • Regular monitoring of IgG4 levels, organ function, and imaging studies is essential to assess treatment response and adjust the treatment plan as needed.
  • The disease is thought to result from an abnormal immune response involving T helper cells and B cells, leading to excessive IgG4 production and tissue infiltration by IgG4-positive plasma cells.
  • Early diagnosis and treatment are crucial to prevent irreversible organ damage and fibrosis.

Treatment Recommendations

  • Corticosteroids should be used as the first-line treatment for IgG4-related disease, with a starting dose of 0.5 to 0.6 mg/kg/d 1.
  • Immunomodulators such as azathioprine or mycophenolate mofetil may be considered for maintenance therapy to reduce the risk of relapse.
  • Rituximab may be considered for patients who do not respond to first-line treatment or who experience relapse.

Important Notes

  • The treatment of IgG4-related disease should be individualized based on the patient's specific needs and response to treatment.
  • Regular follow-up and monitoring are essential to adjust the treatment plan and prevent complications.
  • Referral to a specialist or center with experience in managing IgG4-related disease is recommended for optimal care.

From the Research

Overview of IgG4-Related Disease

  • IgG4-related disease (IgG4-RD) is a systemic inflammatory disease that can affect various organs, leading to fibrosis and potentially causing irreversible damage 2, 3, 4.
  • The disease is characterized by lymphoplasmocytic infiltration, fibrosis, and elevated IgG4 serum levels, with a predominance of IgG4+ plasma cells 3, 4.

Diagnosis and Treatment

  • Diagnosis of IgG4-RD is based on a combination of radiological findings, elevated serum IgG4 levels, histopathological findings, and response to steroids 4.
  • Systemic glucocorticoids are the first-line treatment for IgG4-RD, with an initial recommended dose of 0.6 mg/kg/day of oral prednisolone, gradually tapered to a maintenance dose of 2.5-5 mg/day over 2-3 months 4.
  • Rituximab, a B cell depletion therapy, has shown promising results in treating IgG4-RD, particularly in patients refractory to conventional therapy 3, 5, 6.
  • Disease-modifying anti-rheumatic drugs (DMARDs) may have a role in IgG4-RD, but their efficacy is limited, and more prospective studies are needed 2, 5.

Treatment Outcomes and Response

  • Glucocorticoids and rituximab have been shown to induce substantial responses in IgG4-RD patients, with high response rates and low recurrence rates 2, 3, 6.
  • Surgical intervention and radiotherapy may also be effective in inducing clinical remission, particularly in cases of local disease 2.
  • The IgG4 responder index (IgG4-RI) is a promising outcome measure in IgG4-RD, but it is still in development, and treatment algorithms are not well defined 5.

Patient Characteristics and Disease Activity

  • IgG4-RD typically affects male patients aged 50-70 years, with multiple organs involved, and an average of 3.5 compromised organs 3.
  • The disease can present with various clinical manifestations, including orbital, glandular, and lymph-node compromise 3.
  • Serum IgG4 concentrations may be a reliable measure of disease activity, and repeated courses of rituximab may lead to progressive declines in serum IgG4 concentrations and better disease control 6.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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