The second international, multicenter survey of AIP was conducted in 15 institutes from eight countries (Japan, Korea, Taiwan, India, the United States, Germany, Italy, and the United Kingdom) in 2010 and was published in 2011 [16]. A total of 731 AIP cases was enrolled, with 204 cases confirmed histologically as LPSP and 64 cases confirmed as IDCP. The AIP cases were diagnosed according to Asian diagnostic criteria [13] in Japan, Korea, and Taiwan; according to the HISORt criteria [12] in the United States, the United Kingdom, and India; according to the Mannheim criteria [17] and Asian criteria [13] in Germany; and according to the Italian criteria [18] in Italy.

LPSP patients were approximately 16 years older than IDCP patients (average age of all patients in the cohorts, 61.6 years vs. 44.8 years, respectively). No sex difference was observed between the 2 groups. Obstructive jaundice was a more frequent presentation in LPSP than in IDCP (75 % vs. 47 %, p < 0.001), whereas abdominal pain (41 % vs. 68 %, p < 0.001) and acute pancreatitis (5 % vs. 34 %, p < 0.001) were more frequent presentations in IDCP patients. Compared to IDCP patients, LPSP patients were more likely to have diffuse pancreatic swellings (40 % vs. 25 %, p = 0.037), increased serum IgG4 levels (63 % vs. 23 %, p < 0.001), retroperitoneal fibrosis (7 % vs. 0 %, p = 0.035), salivary gland swelling (12 % vs. 0 %, p = 0.002), and extensive lymphadenopathy (8 % vs. 0 %, p = 0.020), but they were less likely to have ulcerative colitis (1 % vs. 16 %, p < 0.001). IDCP patients more frequently underwent surgery (60 % vs. 78 %, p = 0.010). Good therapeutic responses to steroid treatment were seen in both groups, but IDCP patients had a significantly lower relapse rate (36 % vs. 5 %, p = 0.007). The clinical profiles of LPSP and IDCP patients were distinctly different. IDCP patients tended to have focal features, and they more frequently underwent surgical resection due to diagnostic difficulty (Table 27.2).

In non-histologically confirmed AIP patients, the average age at diagnosis ranged from 43.4 to 66.4 years, and the percentage of male patients ranged from 45 to 90 %. The most frequent initial symptom in six countries was obstructive jaundice, but it was less frequent in Italy (44 %) and Germany (13 %). Abdominal pain was the most frequent initial symptom in India (86 %) and Germany (63 %). Acute pancreatitis was seen frequently in Germany (66 %) and Italy (32 %). Diffuse pancreatic swelling was frequent in Korea (85 %), Japan (58 %), and the United States (57 %). However, segmental swelling of the pancreas was more frequent in the other five countries. Increased serum IgG4 levels were detected in 85–100 % of AIP patients in Japan, Taiwan, India, and the United States, but only in 50–61 % in other countries. Other organ involvement was present in 15–82 % of AIP patients. Other organ involvement was most frequently sclerosing cholangitis of the proximal bile duct in the United Kingdom (79 %), the United States (46 %), Germany (26 %), Taiwan (25 %), and India (19 %), salivary or lacrimal gland swelling in Japan (21 %), and retroperitoneal fibrosis in Korea (16 %). Italian AIP patients rarely showed other organ involvement, but they frequently had ulcerative colitis (30 %). Steroids were given in 69–100 % of AIP patients. The initial prednisolone dose was 1 mg/kg/day in three countries, 0.6 mg/kg/day in two countries, and 30–40 mg/day in the remaining three countries. This dose was tapered by 5 mg every 1–2 weeks. The time from initiation to cessation of steroid therapy ranged from 3 months to 2 years. All patients showed good responses to steroid treatment. The relapse rate in steroid-treated patients ranged from 15 to 64 % (Table 27.3).