Usefulness of biopsying the major duodenal papilla to diagnose autoimmune pancreatitis: a prospective study using IgG4-immunostaining.

AIM

To examine the histological and immunohistochemical findings of biopsy specimens taken from the major duodenal papilla of autoimmune pancreatitis (AIP) patients.

METHODS

The major duodenal papilla in the resected pancreas of 3 patients with AIP and of 5 control patients [pancreatic carcinoma (n = 3) and chronic alcoholic pancreatitis (n = 2)] was immunostained using anti-CD4-T cell, CD8-T cell and IgG4 antibodies. Forceps biopsy specimens taken from the major duodenal papilla of 2 patients with AIP and 5 control patients with suspected papillitis were prospectively taken during duodenoscopy and immunohistochemically examined.

RESULTS

Moderate or severe lymphoplasmacytic infiltration including many CD4-positive or CD8-positive T lymphocytes and IgG4-positive plasma cells (>or=10/HPF), was observed in the major duodenal papilla of all 3 patients with AIP. The same findings were also detected in the biopsy specimens taken from the major duodenal papilla of 2 patients with AIP, but in controls, there were only a few (<or=3/HPF) IgG4-positive plasma cells infiltrating the major duodenal papilla.

CONCLUSIONS

An abundant infiltration of IgG4-positive plasma cells is specifically detected in the major duodenal papilla of patients with AIP. Although this is a preliminary study, IgG4-immunostaining of biopsy specimens taken from the major duodenal papilla may support the diagnosis of AIP.