IgG4-related disease (IgG4 - RD) and autoimmune pancreatitis

Immunoglobulin G4 (IgG4)-related systemic disease (IgG4-RSD) is a systemic entity associated with autoimmune pancreatitis (AIP)

• AIP is a distinct type of chronic pancreatitis and is characterized by abundant infiltration of Immunoglobulin G4 (IgG4)-positive plasma cells and associated fibrosis that lead to organ dysfunction
  • there are three recognized patterns of AIP
    • diffuse, focal, and multifocal
  • patients with AIP typically present with jaundice or abdominal discomfort, severe abdominal pain, or acute pancreatitis
    
    
• other organ involvements take the form of sclerosing cholangitis, sclerosing cholecystitis, sclerosing sialadenitis, retroperitoneal fibrosis, and interstitial nephritis
  
  
• lung diseases related to IgG4 have been described to occur with or without other organ involvement
  • these diseases include interstitial lung disease (ILD), pulmonary inflammatory pseudotumour, and lymphomatoid granulomatosis

Notes (3):

• autoimmune pancreatitis can present as acute or chronic pancreatitis
  • most common clinical presentation is painless jaundice
  • more commonly occurs in patients over age 60 with a three to one male predominance
  • serologic marker for autoimmune pancreatitis is an increased concentration of circulating IgG4
  • most often responsive to steroid treatment or alternatively to other immune modulators in steroid resistant cases

References:

1. Stone JH, Zen Y, Deshpande V. IgG4-related disease. N Engl J Med. 2012;366:539-51.
2. Khosroshahi A, Stone JH. A clinical overview of IgG4-related systemic disease. Curr Opin Rheumatol. 2011;23:57-66.
3. Hines O J, Pandol S J. Management of chronic pancreatitis BMJ 2024; 384 :e070920 doi:10.1136/bmj-2023-070920