Gastric emptying in patients with autoimmune pancreatitis

Autoimmune pancreatitis (AIP) and its extrapancreatic lesions seem to be clinical manifestations of organs involved in IgG4-related systemic disease. To clarify whether the stomach is a target organ, gastric function was evaluated in patients with AIP.

In 6 patients with AIP, gastric emptying was assessed by Carbon 13 (¹³C) acetate breath test before and after steroid therapy. Based on 4-hour breath samples, the half ¹³CO₂ excretion time (T(1/2)) and the time of maximal excretion (T(max)) were calculated as gastric emptying parameters. Data of 20 healthy volunteers were used as controls. The number of IgG4-positive plasma cells in gastrofiberscopic biopsy specimens was counted before and after steroid therapy.

Both T(1/2) and T(max) in patients with AIP decreased significantly after steroid therapy (T(1/2): 1.89 ± 0.21 hours vs 1.69 ± 0.15 hours, P = 0.046; and T(max): 1.1 ± 0.2 hours vs 0.96 ± 0.2 hours, P = 0.027), and became similar to those of the controls (T(1/2): 1.69 ± 0.32 hours and T(max): 0.98 ± 0.2 hour). The number of IgG4-positive plasma cells infiltrating the gastric mucosa decreased after steroid therapy.

Gastric emptying was impaired in patients with AIP and improved to the reference range after steroid therapy. The stomach may be a target organ of IgG4-related systemic disease.