IgG4-related diseases of the digestive tract

Autoimmune pancreatitis and IgG4-related cholangitis are frequent manifestations of IgG4-related disease (IgG4-RD). Here, Lohr and colleagues present current understanding of the pathophysiology of IgG4-RD and describe all IgG4-RD manifestations in the digestive tract. Diagnosis, prognosis and treatment of IgG4-RD are also discussed. IgG4-related conditions affecting the digestive tract are part of a multi-organ fibro-inflammatory disorder termed IgG4-related disease (IgG4-RD), with autoimmune pancreatitis and IgG4-related cholangitis being the most prominent manifestations. Gastrointestinal symptoms include jaundice, weight loss, abdominal pain, biliary strictures, and pancreatic and hepatic masses that mimic malignant diseases. IgG4-RD manifestations occur less frequently elsewhere in the digestive tract, namely in the oesophagus, retroperitoneum or intestine. Evidence-based European guidelines frame the current state-of-the-art in the diagnosis and management of IgG4-related digestive tract disease. Diagnosis is based on histology (if available), imaging, serology, other organ involvement and response to therapy (HISORt criteria). Few biomarkers beyond serum IgG4 concentrations are reliable. The first-line therapy (glucocorticoids) is swiftly effective but disease flares are common at low doses or after tapering. Second-line therapy might consist of other immunosuppressive drugs such as thiopurines or rituximab. Further trials, for example, of anti-CD19 drugs, are ongoing. Although an association between IgG4-RD and the development of malignancies has been postulated, the true nature of this relationship remains uncertain at this time.

Automated summary

IgG4-RD is a fibro-inflammatory disorder involving multiple organs, with common manifestations including autoimmune pancreatitis and IgG4-related cholangitis, presenting symptoms such as jaundice, weight loss, and abdominal pain. Diagnosis is based on histology, imaging, serology, other organ involvement, and response to therapy. Treatment mainly involves glucocorticoids, with disease flares common at low doses or after tapering.