Presentation and management of post-treatment relapse in autoimmune pancreatitis/immunoglobulin G4-associated cholangitis.

BACKGROUND & AIMS: Autoimmune pancreatitis (AIP) is a multisystem disorder that often has extrapancreatic manifestations such as immunoglobulin G4-associated cholangitis (IAC). Patients respond rapidly to steroids but can relapse after therapy. We assessed the clinical management of relapse in a group of patients with AIP/IAC. METHODS: We performed a prospective study of patients diagnosed with AIP from 2004-2007 who received steroids. Treatment outcome was defined clinically, radiologically, and biochemically as response to steroids, remission after steroids, failure to wean steroids, and relapse. Steroids +/- azathioprine (AZA) were used to treat patients who failed, relapsed, or could not be weaned from steroids. RESULTS: Twenty-eight patients with AIP were studied; 23 (82%) had IAC. All patients responded within 6 weeks to prednisolone therapy. Twenty-three patients achieved remission after a median of 5 months of treatment (range, 1.5-17 months), whereas 5 patients (18%) could not be weaned because of a disease flare. Of the patients who achieved remission, 8 of 23 (35%) subsequently relapsed. Overall, 13 of 23 patients (57%) with AIP/IAC relapsed, compared with 0 of the 5 with isolated AIP (P = .04, Fisher exact test). Steroids were increased/restarted in all patients who relapsed; 10 also received AZA. Remission was achieved and maintained in 7 patients; they remain on AZA monotherapy at a median of 14 months (range, 1-27 months). CONCLUSIONS: Relapse or failure to wean steroids occurred in 46% of patients with AIP. Patients with IAC are at particularly high risk of relapse. AZA appears to be effective in patients with post-treatment relapse or who cannot be weaned from steroids. To view this article's video abstract, go to the AGA's YouTube Channel.

IgG4-related systemic sclerosing disease - an emerging and under-diagnosed condition.

Autoimmune pancreatitis was first described in 1961, although it was not more widely recognized as an autoimmune condition until 1995. It has now become apparent that this form of pancreatitis is part of a clinical syndrome that is commonly multisystem in nature. One of the most common histopathological features is the presence of IgG4+ plasma cells within involved tissues. Many terms have been proposed to describe the condition, but 'IgG4-related systemic sclerosing disease' appears most appropriate. Commonly affected extrapancreatic tissues include the biliary tract, liver, kidneys and lung, but a wide range of other sites may be involved. Histological examination reveals features that are not entirely disease-specific, but that are often sufficiently characteristic to provide useful support to a clinicopathological diagnosis. The disease often responds well to systemic steroid therapy, unlike some of the conditions that it may simulate clinically. The emergence of this disease as a specific and treatable entity has favourably altered the clinical outlook for patients in whom steroid therapy might not previously have been considered appropriate.

The use of immunoglobulin g4 immunostaining in diagnosing pancreatic and extrapancreatic involvement in autoimmune pancreatitis.

BACKGROUND & AIMS: Autoimmune pancreatitis (AIP) is recognized increasingly as a multisystem disorder. We evaluated the use of immunoglobulin (Ig)G4 immunostaining of pancreatic and extrapancreatic biopsy specimens to make a definitive diagnosis of AIP. METHODS: Seventeen biopsy specimens and 3 gallbladder resections were assessed from 11 patients with clinical and radiologic features of AIP. Biopsy specimens from pancreas, liver, colon, stomach, duodenum, bone marrow, salivary gland, and kidney were analyzed morphologically, immunostained for IgG4-positive plasma cells, and compared with controls. RESULTS: Positive IgG4 immunostaining enabled a definitive diagnosis in 10 of 11 (91%) AIP patients. In both pancreatic and extrapancreatic tissues, high levels of IgG4 immunostaining (>10 IgG4-positive plasma cells/high-power field) were found in 17 of 20 (85%) specimens from AIP patients compared with 1 of 175 (0.6%) specimens from controls (P < .05). Positive extrapancreatic IgG4 immunostaining was found in 8 of 11 (73%) patients, including all those with diagnostic features in the pancreas. Increased tissue IgG4 was found irrespective of serum IgG4 level. CONCLUSIONS: The finding of IgG4 immunostaining within a range of clinically involved tissues supports the hypothesis that AIP is a multisystem disease. Positive IgG4 immunostaining in extrapancreatic tissues may allow a definitive diagnosis of AIP to be made in those with evidence of pancreatic disease, without the necessity of pancreatic biopsy or surgical exploration. Immunostaining of involved tissue for IgG4 may be particularly useful when AIP is suspected clinically but the serum IgG4 level is normal.

Autoimmune pancreatitis: clinical and radiological features and objective response to steroid therapy in a UK series.

OBJECTIVE: Most cases of autoimmune pancreatitis (AIP) have been reported from Japan. We present data on a UK series, including clinical and radiological features at presentation, and longitudinal response to immunosuppression. METHODS: Over an 18-month period, all patients diagnosed in our center with AIP were studied. Endoscopic biliary stenting was performed as required, and patients were treated with prednisolone, with response assessed longitudinally. In cases of disease relapse following steroid reduction, azathioprine was instituted. RESULTS: Eleven patients met diagnostic criteria for AIP. Diffuse pancreatic enlargement was seen in eight patients (73%), and pancreatic duct strictures in all. Seven patients required biliary stents. Extrapancreatic involvement occurred in all, including intrahepatic stricturing and renal disease. Eight weeks after starting steroids, the median serum bilirubin level had fallen from 38 mumol/L to 11 mumol/L (P= 0.001), and ALT from 97 IU/L to 39 IU/L (P= 0.002). Stents were removed in all cases, with no recurrence of jaundice. Improvements in mass lesions and pancreaticobiliary stricturing occurred in all patients. During a median 18-month follow-up, six patients relapsed, four of whom responded to azathioprine. Two patients discontinued steroids and remained well. CONCLUSIONS: Extrapancreatic disease was an important feature of AIP in this UK series. Initial response to immunosuppressive therapy was excellent, but disease relapse was common. Optimal long-term management remains to be established.