Type 1 Autoimmune Pancreatitis Can Transform into Chronic Pancreatitis: A Long-Term Follow-Up Study of 73 Japanese Patients

Abstract

Some patients with autoimmune pancreatitis (AIP) form pancreatic stones suggestive of transformation into chronic pancreatitis (CP). The present study examined the underlying risk factors and mechanism of AIP progression to confirmed CP. We compared the clinical and laboratory parameters of subjects who progressed to confirmed CP with those of the subjucts who did not in a cohort of 73 type 1 AIP patients. A total of 16 (22%) AIP patients progressed to CP. Univariate analysis revealed that relapse was significantly more frequent in the progression group, and multivariate analysis indicated that pancreatic head swelling (OR 12.7, P = 0.023) and nonnarrowing of the main pancreatic duct in the pancreatic body (OR 12.6, P = 0.001) were significant independent risk factors for progression to CP. Kaplan-Meier testing showed that the progression rate to CP was approximately 10% at 3 years and 30% at 10 years in total AIP patients and 30% at 3 years and 60% at 10 years in subjects with both risk factors. AIP with pancreatic head swelling and a history of relapse may cause pancreatic juice stagnation and nonnarrowing of the main pancreatic duct in the pancreatic body, which can progress to advanced stage chronic pancreatitis.

Autoimmune pancreatitis associated with pancreatic cyst: how can we manage it?

“…The active inflammatory process would persist even in AIP patients in remission, because the serum IgG4 concentration remained slightly elevated in 60% of the patients with clinical remission after CST [28]. Pancreatolothiasis has been reported to develop in 11-18% of patients with AIP [27,29]. However, our data indicated elevation of the pancreatic enzymes, which suggested there was no chronic phase, even in cases with cyst formation.…”

“…Autoimmune pancreatitis is regarded as reversible with CST; however, in some patients, AIP changes to chronic pancreatitis, irreversible to CST, because of portal vein thrombosis, varix formation, cyst formation and pancreatolithiasis . Could AIP develop into chronic pancreatitis?…”

Amendment of the Japanese Consensus Guidelines for Autoimmune Pancreatitis, 2013 II. Extrapancreatic lesions, differential diagnosis

“…In this instance AIP becomes indistinguishable from ordinary chronic pancreatitis (Fig. 13) [28,[97][98][99].…”

Relationship between autoimmune pancreatitis and pancreatic cancer: A single-center experience

“…However, persistently high IgG4 serum concentrations and relapses of pancreatic swelling and narrowing of the MPD occur in 60% and 58% of AIP patients, respectively, after steroid therapy, indicating that chronic inflammation of the pancreas in AIP patients may continue histologically even after remission of the disease is induced by steroid therapy 36,37 . Indeed, a recent paper reported that type 1 AIP patients with 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 15 pancreatic head swelling or MPD nonnarrowing in the pancreatic body may progress to an advanced stage of CP due to pancreatic juice stagnation 38 . As biologic evidence that supports an association between AIP and PaC, the prevalence of PanIN in AIP patients was reported to be higher than that in non-autoimmune forms of pancreatitis, although this comparison did not reach the level of statistical significance.…”