IgG4-related disease
A fibroinflammatory disease of older men that forms tumour-like swellings in the pancreas, bile ducts, salivary and lacrimal glands, retroperitoneum and aorta. Why serum IgG4 neither proves nor excludes it, the biopsy features, the 2019 ACR/EULAR criteria, steroid response, and B-cell depletion (rituximab, inebilizumab in MITIGATE) for relapse.
Tier 2Condition
Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- IgG4-related disease (IgG4-RD) is an immune-mediated fibroinflammatory condition that forms tumour-like masses in one or many organs. It is driven by B cells, plasmablasts and CD4+ cytotoxic T cells; IgG4 itself is probably a bystander.
- Typical patient: man over 50, often with atopy. Onset is subacute; fever and high CRP are unusual.
- The big risk is mistaking it for cancer (pancreas, bile duct, lymphoma) or missing cancer by calling it IgG4-RD.
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Sources
- Wallace ZS et al. The 2019 American College of Rheumatology/European League Against Rheumatism classification criteria for IgG4-related disease. Ann Rheum Dis 2020;79:77-87ACR and EULAR, 2019 (current as of November 2026)
- Khosroshahi A et al. International consensus guidance statement on the management and treatment of IgG4-related disease. Arthritis Rheumatol 2015;67:1688-99International IgG4-RD Symposium, 2015 (superseded by the IgG4ward! Foundation guidelines, November 2026)
- Perugino CA et al. The IgG4ward! Foundation guidelines on the treatment of IgG4-related disease. Lancet Rheumatol 2026 (epub 9 November 2026)IgG4ward! Foundation, 2026 (28 statements, consensus on 22; full text not reviewed for this note)
- Stone JH et al. Inebilizumab for treatment of IgG4-related disease (MITIGATE). N Engl J Med 2025;392:1168-77New England Journal of Medicine, 2025
- Wallace ZS et al. Clinical phenotypes of IgG4-related disease: an analysis of two international cross-sectional cohorts. Ann Rheum Dis 2019;78:406-12Annals of the Rheumatic Diseases, 2019
- Therapeutic Guidelines: RheumatologyAU/NZTherapeutic Guidelines Limited (eTG complete), current online version, accessed November 2026
- Last updated
- 14 November 2026
What changed
- 14 November 2026 Personal emails, About story and Australian-style copy