Type 1 Autoimmune Pancreatitis in Europe: Clinical Profile and Response to Treatment.

BACKGROUND & AIMS: Autoimmune pancreatitis (AIP) is an immune-mediated disease of the pancreas with distinct pathophysiology and manifestations. Our aims were to characterize type 1 AIP in a large pan-European cohort and study the effectiveness of current treatment regimens. METHODS: We retrospectively analyzed adults diagnosed since 2005 with type 1 or not-otherwise-specified AIP in 42 European university hospitals. Type 1 AIP was uniformly diagnosed using specific diagnostic criteria. Patients with type 2 AIP and those who had undergone pancreatic surgery were excluded. The primary end point was complete remission, defined as the absence of clinical symptoms and resolution of the index radiologic pancreatic abnormalities attributed to AIP. RESULTS: We included 735 individuals with AIP (69% male; median age, 57 years; 85% White). Steroid treatment was started in 634 patients, of whom 9 (1%) were lost to follow-up. The remaining 625 had a 79% (496/625) complete, 18% (111/625) partial, and 97% (607/625) cumulative remission rate, whereas 3% (18/625) did not achieve remission. No treatment was given in 95 patients, who had a 61% complete (58/95), 19% partial (18/95), and 80% cumulative (76/95) spontaneous remission rate. Higher (≥0.4 mg/kg/day) corticosteroid doses were no more effective than lower (<0.4 mg/kg/day) doses (odds ratio, 0.428; 95% confidence interval, 0.054-3.387) and neither was a starting dose duration >2 weeks (odds ratio, 0.908; 95% confidence interval, 0.818-1.009). Elevated IgG4 levels were independently associated with a decreased chance of complete remission (odds ratio, 0.639; 95% confidence interval, 0.427-0.955). Relapse occurred in 30% of patients. Relapses within 6 months of remission induction were independent of the steroid-tapering duration, induction treatment duration, and total cumulative dose. CONCLUSIONS: Patients with type 1 AIP and elevated IgG4 level may need closer monitoring. For remission induction, a starting dose of 0.4 mg/kg/day for 2 weeks followed by a short taper period seems effective. This study provides no evidence to support more aggressive regimens.

Blue-collar work is a risk factor for developing IgG4-related disease of the biliary tract and pancreas.

BACKGROUND & AIMS: Immunoglobulin G4-related disease (IgG4-RD) of the biliary tract and pancreas is a fibroinflammatory disease of unknown origin with striking male predominance. We aimed to investigate whether blue-collar work and occupational contaminant exposure are risk factors for IgG4-RD of the biliary tract and pancreas. METHOD: We performed an age-/sex-matched case-control study in the largest academic medical centers of the Netherlands. Occupational history was surveyed by questionnaires. The International Standard Classification of Occupations (ISCO88) was used to classify jobs. Job exposure matrices ALOHA and DOM were utilized to assess the years individuals were exposed to compounds. The disease control cohort consisted of patients from 6 equally sized groups. Conditional logistic regression was used to assess effects of blue-collar work and exposure to occupational contaminants on developing IgG4-RD of the biliary tract and pancreas. RESULTS: Overall, 101 patients with IgG4-RD of the biliary tract and pancreas were matched 1:3 to 303 controls. Patients with IgG4-RD had a lower level of education (p = 0.001). Individuals who at least once performed blue-collar work (>1 year), had higher odds of developing IgG4-RD than individuals that only performed white-collar work (odds ratio [OR] 3.66; CI 2.18-6.13; p <0.0001). Being ever exposed (>1 year) to industrial ALOHA (e.g. mineral dust; vapors-dust-gases-fumes) and DOM compounds (e.g. asbestos) resulted in higher odds of IgG4-RD (OR 2.14; 95% CI 1.26-3.16; p <0.001 and OR 2.95; 95% CI 1.78-4.90; p <0.001, respectively). CONCLUSION: Blue-collar work is a risk factor for developing IgG4-RD of the biliary tract and pancreas putatively driven by exposure to selected industrial compounds; this may explain the striking male predominance among patients. LAY SUMMARY: Immunoglobulin G4-related disease (IgG4-RD) causes tumor-like lesions and typically affects middle-aged to elderly men. The background and cause of this disease remain relatively unknown. In this study, we identified blue-collar work as a risk factor for developing IgG4-RD of the biliary tract and pancreas, which may explain the striking male predominance among patients. Furthermore, these results suggest that toxic exposure to occupational contaminants may drive autoimmunity in IgG4-RD of the biliary tract and pancreas.

Testing for Anti-PBP Antibody Is Not Useful in Diagnosing Autoimmune Pancreatitis.

OBJECTIVES: Autoimmune pancreatitis (AIP) is a rare form of chronic pancreatitis, clinically mimicking pancreatic cancer. In 2009, a serological diagnostic test detecting antibodies against plasminogen-binding protein (PBP) of Helicobacter pylori was reported with outstanding test performances (NEJM 361:135). We aimed to validate these findings. METHODS: Between March 2007 and May 2011, sera were collected from consecutive patients presenting with type 1 AIP, pancreatic ductal adenocarcinoma (PDAC), chronic pancreatitis (CP), primary sclerosing cholangitis (PSC), and healthy controls (HC) with or without antibodies against H. pylori. Serum antibody binding to synthetic PBP peptide was quantified by enzyme-linked immunosorbent assay (ELISA), using standard curves of custom-made PBP rabbit polyclonal antibodies. A synthetic Flag peptide (DYKDDDK), to which no antibodies are found in human serum, was included as negative control. RESULTS: High sensitivity of PBP peptide recognition was demonstrated by selective binding of PBP peptide over Flag peptide by PBP-immunized rabbit serum. Competition assays with PBP peptide validated the selectivity for antibodies recognizing this antigen. A total of 114 patients were subsequently tested: 34 AIP, 29 PDAC, 17 CP, 16 PSC, and 18 HCs (9 positive and 9 negative for H. pylori). No significant differences in detection of antibodies against the PBP peptide were found between different the patient groups and healthy controls. CONCLUSIONS: Using a sensitive and selective ELISA-based assay, we did not find increased serum antibodies against PBP peptide in AIP patients. PBP serum antibodies are therefore not a useful diagnostic tool to diagnose AIP.

The Long-Term Impact of Autoimmune Pancreatitis on Pancreatic Function, Quality of Life, and Life Expectancy.

OBJECTIVE: To evaluate the long-term outcome of autoimmune pancreatitis. METHODS: Patients with at least 2 years of follow-up were included. Information was collected regarding disease characteristics, treatment outcome, diagnosed malignancies, and mortality. In addition, pancreatic function and quality of life were assessed prospectively. RESULTS: 107 patients were included (87% men, 90% with type 1), with a median follow-up of 74 (interquartile range, 49-108) months. One third was operated for suspected pancreatic cancer (32%). Most patients were (successfully) treated with steroids (83%), but relapses were common (52%), for which no risk factors could be identified. Pancreatic carcinoma was not observed.Prospective data were obtained from 64%, as 17% had died, 7% were lost to follow-up, and 13% refused to participate. After a median of 75 (interquartile range, 50-106) months, 46% still used active treatment. Exocrine and endocrine insufficiencies were highly prevalent (82% and 57%, respectively). Quality of life and survival were not impaired, as compared with a reference population. CONCLUSIONS: Despite an excellent initial treatment response, relapses are common, even in type 2, and almost half of the patients require maintenance therapy. Pancreatic insufficiency is highly prevalent, which calls for active screening. Pancreatic cancer was not observed, and quality of life and survival are not impaired.

Immunoglobulin G4-related prostatitis: a case-control study focusing on clinical and pathologic characteristics.

OBJECTIVE: To evaluate the occurrence and histopathologic characteristics of immunoglobulin G4 (IgG4)-related prostatic involvement in patients diagnosed with autoimmune pancreatitis. METHODS: Nine cases of IgG4-related prostatitis were identified among 117 men in the autoimmune pancreatitis and IgG4-associated cholangitis patient databases in 2 tertiary hospitals. Clinical information was retrieved, and available prostatic tissue samples and 18 prostatitis control samples were evaluated for characteristic IgG4-related disease (IgG4-RD) features: maximum number of IgG4-positive cells per high-power field; dense lymphoplasmacytic infiltrate; fibrosis, arranged at least focally in a storiform pattern; phlebitis with or without obliteration of the lumen; and increased number of eosinophils. RESULTS: The aspecific sign of urine retention was commonly present in IgG4-RD patients with prostatic involvement. In these patients with IgG4-related prostatitis, the median number of IgG4-positive cells in prostatic tissue was 150 (interquartile range, 20-150) per high-power field compared with a median of 3 (interquartile range, 1-11) in control patients (P = .008). Dense lymphoplasmacytic infiltrate was observed in most (86% in cases and 72% in control patients) tissue samples independent of the underlying cause of prostatitis. Fibrosis in at least a focally storiform pattern was seen rarely in both groups, and (obliterative) phlebitis was absent in all patients. Furthermore, eosinophil numbers were more often elevated in patients with IgG4-RD compared with controls (P <.001). In 2 cases, amelioration of the prostatitis symptoms on corticosteroid treatment was documented. CONCLUSION: Prostatic involvement might not be rare in patients with pancreatic or biliary IgG4-RD. Clinicians should consider this disease entity in patients with IgG4-RD and prostatic symptoms.

A comparative study of diagnostic scoring systems for autoimmune pancreatitis.

OBJECTIVE: Several diagnostic scoring systems for autoimmune pancreatitis (AIP) have been proposed including the Asian, HISORt (Histology, Imaging, Serology, Other organ involvement and Response to therapy), and International Consensus Diagnostic Criteria (ICDC), which have been compared by a few studies. We evaluated the diagnostic performance of these criteria in patients diagnosed with AIP between May 1992 and August 2011. METHODS: Scoring systems were applied retrospectively using data obtained in the initial evaluation period, before pancreatic resection was performed. RESULTS: One hundred fourteen cases with AIP were included. Eighty-two percent met the diagnostic criteria for AIP according to either the Asian, HISORt, or ICDC criteria. Only 33% met the Asian criteria, probably mainly related to a low rate of diagnostic pancreatography. In 18%, all scoring systems failed to confirm the diagnosis, even though these patients were considered to have a firm diagnosis of AIP. CONCLUSIONS: In this cohort of AIP patients, the 3 major diagnostic scoring systems for AIP proved to be complementary rather than overlapping. Our data indicate that one-fifth of our AIP patients do not meet any of these scoring systems. The ICDC, Asian, and HISORt criteria should be considered as useful clinical tools but not as criterion standard for the diagnosis.

Comparable efficacy of low- versus high-dose induction corticosteroid treatment in autoimmune pancreatitis.

OBJECTIVE: The objective of this study was to compare efficacy of high versus low doses of prednisone for induction of remission in autoimmune pancreatitis (AIP). METHODS: This is a retrospective, multicenter study including patients diagnosed with AIP between May 1992 and August 2011. Clinical, laboratory and imaging findings were assessed before treatment and at 1, 3, and 6 months after starting treatment. RESULTS: A total of 65 patients (57 males; median age, 63 years) were treated with an initial low dose (10-20 mg/d, n = 14), a medium dose (30 mg/d, n = 15), or a high dose (40-60 mg/d, n = 36) of prednisone. There were no significant differences in baseline characteristics between the treatment groups including age, presenting symptoms and laboratory results. During a follow-up period of 6 months, in nearly all patients, symptoms (jaundice, weight loss) resolved completely. After 6 months, treatment response with respect to symptomatic, radiological, and laboratory improvement was comparable for the different dosage groups. CONCLUSIONS: Response to therapy was comparable for AIP patients treated with doses of prednisone in the range of 10 to 60 mg/d. A prospective trial should be conducted to confirm efficacy of lower-dose prednisone treatment.