Prevalence of autoantibody against human AMY-2A in patients with various pancreatic diseases. A: Prevalence of autoantibody against human AMY-2A in patients with AIP (n = 15), chronic alcoholic pancreatitis (CP, n = 25), pancreatic tumor (PT, n = 25), control subjects from healthy volunteers (C, n = 100), and Hashimoto's thyroiditis (H, n = 47) was examined by ELISA, as described in research design and methods. The data are the mean of triplicate values. The dotted line shows a cutoff value. Fisher's exact test was carried out between AIP and control groups. *P < 0.001. B: Time course of anti-AMY antibody and IgG4 of AIP patients. AIP patient (A.O.), whose IgG was used to screen λTriplEx2 human pancreas cDNA library, was treated with prednisolone (arrow). Before and after the treatment, anti-AMY antibody (•-•) and IgG4 (○-○) were measured. In the other AIP patient (T.M.), titer of the anti-AMY antibody (▴-▴) was also measured before and after prednisolone treatment (arrow).