Differences in clinical profile and relapse rate of type 1 versus type 2 autoimmune pancreatitis.
OBJECTIVE
Autoimmune pancreatitis (AIP) has been divided into subtypes 1 (lymphoplasmacytic sclerosing pancreatitis) and 2 (idiopathic duct centric pancreatitis). We compared clinical profiles and long-term outcomes of types 1 and 2 AIP.


METHODS
We compared clinical presentation, relapse, and vital status of 78 patients with type 1 AIP who met the original HISORt criteria and 19 patients with histologically confirmed type 2 AIP.


RESULTS
At presentation, patients with type 1 AIP were older than those with type 2 AIP (62 +/- 14 vs 48 +/- 19 years; P < .0001) and had a greater prevalence of increased serum levels of immunoglobulin G4 (47/59 [80%] vs 1/6 [17%]; P = .004). Patients with type 1 were more likely than those with type 2 to have proximal biliary, retroperitoneal, renal, or salivary disease (60% vs 0; P < .0001). Inflammatory bowel disease was associated with types 1 and 2 (6% vs 16%; P = .37). During median clinical follow-up periods of 42 and 29 months, respectively, 47% of patients with type 1 and none of those with type 2 experienced a relapse. In type 1 AIP, proximal biliary involvement (hazard ratio [HR], 2.12; P = .038) and diffuse pancreatic swelling (HR, 2.00; P = .049) were predictive of relapse, whereas pancreaticoduodenectomy reduced the relapse rate (vs the corticosteroid-treated group; HR, 0.15; P = .0001). After median follow-up periods of 58 and 89 months (types 1 and 2, respectively), the 5-year survival rates for both groups were similar to those of the age- and sex-matched US population.


CONCLUSIONS
Types 1 and 2 AIP have distinct clinical profiles. Patients with type 1 AIP have a high relapse rate, but patients with type 2 AIP do not experience relapse. AIP does not affect long-term survival.
Sah
Raghuwansh P
RP
Fiterman Center for Digestive Diseases, Mayo Clinic, Rochester, Minnesota 55905, USA.
Chari
Suresh T
ST
Pannala
Rahul
R
Sugumar
Aravind
A
Clain
Jonathan E
JE
Levy
Michael J
MJ
Pearson
Randall K
RK
Smyrk
Thomas C
TC
Petersen
Bret T
BT
Topazian
Mark D
MD
Takahashi
Naoki
N
Farnell
Michael B
MB
Vege
Santhi S
SS
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001327:Autoimmune Diseases / Q000145:classification* / Q000401:mortality / Q000473:pathology / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D016577:Pancreaticoduodenectomy; D050500:Pancreatitis, Chronic / Q000145:classification* / Q000401:mortality / Q000473:pathology / Q000601:surgery; D016016:Proportional Hazards Models; D012008:Recurrence