Standard steroid treatment for autoimmune pancreatitis

Review of Diagnostic Biomarkers in Autoimmune Pancreatitis: Where Are We Now?

Autoimmune pancreatitis (AIP) is a pancreatic manifestation of an IgG4-related disease (IgG4-RD). AIP lacks disease-specific biomarkers, and therefore, it is difficult to distinguish AIP from malignancies, especially pancreatic cancer. In this review, we have summarized the latest findings on potential diagnostic biomarkers for AIP. Many investigations have been conducted, but no specific biomarkers for AIP are identified. Therefore, further studies are required to identify accurate diagnostic biomarkers for AIP.

IgG4-Related Disease: A Retrospective Chinese Study of Features and Treatment Response of 98 Patients Including 4 Rare Cases

The features and treatment of 98 Chinese patients with immunoglobulin G4 (IgG4)-related disease (IgG4-RD) referred to a single tertiary referring centre were reviewed. Patients diagnosed with IgG4-RD according to the comprehensive diagnostic criteria (CDC) were included in the retrospective study from May 2012 to March 2019. We collected data on clinical, laboratory, imaging, histological features and treatment. Totally, 98 patients with IgG4-RD were enrolled. The common clinical manifestations included abdominal pain, salivary gland swelling and lymphadenopathy. 51% of the patients had multiple organs involvement. Lymph nodes, pancreas and salivary glands were most commonly involved. Four rare sites including ulna, cerebellum, scalp, and mammary gland were found. The serum IgG4 level was increased by 85.7%. The serum IgG4 level was positively correlated with the number of involved organs, IgG and IgG4/IgG. Low C3 and C4 levels were observed in 37.5% and 12.2% patients respectively, and all patients with kidney involvement had hypocomplementemia. A total of 54 patients underwent tissue biopsies, and 55.6%, 31.5% and 11.1% cases were diagnosed as definite, probable and possible IgG4-RD, respectively. Eighty-eight patients received glucocorticoids (GCs) therapy. Five patients underwent radical surgery to remove the lesion. 73% of them presented a complete or partial remission. IgG4-RD is a systemic fibroinflammatory disease with involvement of multiple organs throughout the body including some rare sites. Most IgG4-RD patients had increased serum IgG4 levels and patients with kidney involvement showed hypocomplementemia. GCs therapy is effective. More research is needed to provide a more reliable basis for the diagnosis and treatment of patients.

Multiple pleural nodules diagnosed as IgG4-related disease: a case report

BACKGROUND

Immunoglobulin G4 (IgG4)-related diseases are characterized by abnormal IgG4 levels, swelling, and marked infiltration and fibrosis of the lymphocytes and IgG4-positive plasma cells, causing hypertrophic lesions or nodules. The cause is currently not well understood. IgG4-related diseases involving lesions limited to the pleura are extremely rare. Herein, we report an IgG4-related disease presenting with multiple pleural nodules confirmed by thoracoscopic surgical biopsy.

CASE PRESENTATION

A 74 year-old man was referred to our department for definitive diagnosis of multiple pleural nodules after 1 year of follow-up. Computed tomography of the chest revealed multiple pleural nodules, while 2-deoxy-2-( 18F)-fluorodeoxyglucose positron emission tomography imaging exhibited tracer accumulation in the nodules. A thoracoscopic surgical biopsy was performed. Histopathological examination revealed hyalinized fibrous tissue with a high degree of plasma cell-based inflammatory cell infiltration. Immunohistochemically, IgG4-positive cells were conspicuous, accounting for 70.5% of the plasma cells. The postoperative serum IgG4 concentration was 289 mg/dL. We diagnosed the patient with an IgG4-related disease with multiple pleural nodules. The postoperative course was good, and the patient is currently being followed up.

CONCLUSION

IgG4-related disease should be considered in cases presenting with multiple pleural nodules.

Comparison of five-phase computed tomography images of type 1 autoimmune pancreatitis and pancreatic cancer: Emphasis on cases with atypical images

BACKGROUND/OBJECTIVES

International consensus diagnostic criteria (ICDC) include characteristic images of autoimmune pancreatitis (AIP); however, reports on atypical cases are increasing. The aims of this study were to compare CT findings between AIP and pancreatic cancer (PC), and to analyze type 1 AIPs showing atypical images.

METHODS

Five-phase CT images were compared between 80 type 1-AIP lesions and 80 size- and location-matched PCs in the case-control study. Atypical AIPs were diagnosed based on the four ICDC items.

RESULTS

ICDC items were recognized in most AIP lesions; pancreatic enlargement (87.7%), narrowing of the main pancreatic duct (98.8%), delayed enhancement (100%), and no marked upstream-duct dilation (97.5%). CT values of AIPs increased rapidly until the pancreatic phase and decreased afterward, while those of PCs gradually increased until the delayed phase (P < 0.0001). Atypical images were recognized in 14.8% of AIPs, commonly without pancreatic enlargement (18.5 mm) and sometimes mimicking intraductal neoplasms. The CT values and their ratios were different between atypical AIPs and size-matched PCs most significantly in the pancreatic phase, but similar in the delayed phase.

CONCLUSIONS

Ordinary type 1 AIPs can be diagnosed with the ICDC, but atypical AIPs represented a small fraction. "Delayed enhancement" is characteristic to ordinary AIPs, however, "pancreatic-phase enhancement" is more diagnostic for atypical AIPs.

Emerging therapy options for IgG4-related disease

INTRODUCTION

Awareness of IgG4-related disease (IgG4-RD) is increasing worldwide and specialists are now familiar with most of its clinical manifestations and mimickers. IgG4-RD promptly responds to glucocorticoids and repeated courses are typically used to induce and maintain remission because the disease relapses in most patients. If left untreated, it can lead to organ dysfunction, organ failure and death. Advancement in our understanding of IgG4-RD pathogenesis is leading to the identification of novel therapeutic targets and emerging treatments are now setting the stage for personalized therapies for the future.

AREAS COVERED

This review focuses on emerging treatment options for IgG4-RD based on our advancing understanding of disease pathophysiology. Research was performed in the English literature on Pubmed and clinicaltrials.gov databases.

EXPERT OPINION

Glucocorticoids remain the first-line induction treatment for the multi-organ manifestations of IgG4-RD. Alternative immunosuppressive agents for maintaining remission are warranted in order to avoid long-term steroid toxicity, and to offer a more mechanistic and personalized therapeutic strategy. Targeting B and T-lymphocyte activation represents the most promising approach, but randomized controlled trials are eagerly awaited to confirm positive preliminary experiences reported in case series and small cohort studies.

Differences in Clinical Features and Diagnostic Strategies Between IgG4-Related Autoimmune Cholangitis and Cholangiocarcinoma

IgG4-related autoimmune cholangitis (IgG4-AIC) is often difficult to distinguish from cholangiocarcinoma (CCA). This study aimed to determine a practical clinical strategy for distinguishing between IgG4-AIC and CCA to avoid unnecessary surgical resection. We retrospectively collected and compared the clinicopathological data between IgG4-AIC and CCA patients, including the clinical, serological, and radiological characteristics, to follow up on these patients to investigate the prognosis. Among the 377 patients who received surgical resection for suspecting CCA at the Sun Yat-Sen Memorial Hospital between June 2004 and June 2014, 14 patients were diagnosed as IgG4-AIC through histochemistry after surgery. Immunohistochemistry revealed that IgG4 was up-regulated in the plasma cells of IgG4-AIC tissues in 13 out of 14 patients. The serum CA19-9 level was significantly lower than in the CCA group. Patients with IgG4-AIC can only see slight or no enhancement under the contrast enhancement CT scan, while there are no signs of ring-like or delayed enhancement that is unique to CCA. Thirteen patients were followed up, and the time was 12 to 92 months. Three of them were regularly treated with prednisone after surgery, and original symptoms disappeared. Our study demonstrated that the combination of imaging with serum CA19-9 could improve the preoperative diagnostic value and reduce the rate of unnecessary resection.

Effectiveness and safety of Mizoribine for the treatment of IgG4-related Disease: A Retrospective Cohort Study

OBJECTIVE

Patients with IgG4-Related Disease (IgG4RD) usually require steroid-sparing agents due to relapse with tapering glucocorticoids (GC). The aim of this study was to determine the efficacy and safety of Mizoribine (MZR) among IgG4RD, which inhibits inosine monophosphate dehydrogenase, a rate-limiting enzyme in the de novo pathway of purine synthesis.

METHODS

We retrospectively reviewed records of IgG4RD patients at the Immuno-Rheumatology Center in St. Luke's International Hospital, Tokyo, Japan. Patients were classified into the MZR combination group, and those treated with GCs alone or with other immunosuppressants were included in the control group. Disease exacerbation, GC dose, IgG-IgG4 titre, and adverse events were evaluated using univariate analyses, including the Kaplan-Meier method. The Cox proportional hazard model was used to evaluate risk factors for exacerbation.

RESULTS

A total of 14 and 29 cases were included in the MZR combination and control groups, respectively. Multiple organ involvement (≥3 organs) was significantly more frequent in the MZR combination treatment group (10 [71.4%] vs 9 [31.0%], p= 0.021). Kaplan-Meier analysis revealed a significant reduction in exacerbation in patients with multiple organ involvement (p< 0.001), but not in total (p= 0.42). The adjusted hazard ratios of MZR use and multiple organ involvement for exacerbation were 0.34[0.12-1.01] (p= 0.052), and 3.51[1.29-9.51] (p= 0.014). The cumulative GC dose tended to be lower in the MZR combination group (1448[1003, 1642] vs 2179[1264, 3425]; p= 0.09).

CONCLUSION

MZR showed a significant steroid-sparing effect and decrease in exacerbation among IgG4RD patients with multi-organ involvement. MZR could be a treatment option for IgG4RD.

An enigmatic case of IgG4-related nephropathy and an updated review of the literature

IgG4-related disease (IgG4-RD) is still an underestimated disorder which affects multiple organs, and its recognition as a distinct clinical disease has been only proved in the recent decades. The renal involvement has been documented in approximately 15% of patients with IgG4-RD, and the typical manifestation is a tubulo-interstitial nephritis. The main histological findings in IgG4-RD are typically a dense tissue infiltration of IgG4-positive plasma cells, storiform fibrosis, obliterative phlebitis, and frequently elevated IgG4 serum levels. Herein we report our atypical and peculiar clinical presentation of an IgG4-related nephropathy (IgG4-RN) and the remarkable response to rituximab (RTX) treatment at the renal imaging with computerized tomography assessment. The current nephrological evidences support the renal function recovery after steroids or steroids plus RTX therapy, even if the renal imaging data are not always shown. In a complex and enigmatic clinical scenario such as the IgG4-RN, both the renal biopsy and the renal imaging before and after the immunosuppressive therapy become mandatory tools to thoroughly define the diagnosis, the management and the response to the immunological therapy.

Type 1 Autoimmune Pancreatitis Extending along the Main Pancreatic Duct: IgG4-related Pancreatic Periductitis

We herein report a unique form of autoimmune pancreatitis (AIP) spreading along the main pancreatic duct (MPD). A 70-year-old man was referred for a small lesion at the pancreatic neck, accompanying an adjacent cyst and dilated upstream MPD. Four years earlier, health checkup images had shown a pancreatic cyst but no mass lesion. Endoscopic ultrasonography showed a contrast-enhanced, tumorous lesion, mainly occupying the MPD. With a preoperative diagnosis of ductal neoplasms mainly spreading in the MPD, Whipple's resection was performed. The resected specimens showed MPD periductitis with IgG4-related pathology, indicating type 1 AIP. Clinicians should practice caution concerning the various AIP forms.

Regulation of p38 MAPK and glucocorticoid receptor activation by hydrocortisone in mono-and co-cultured pancreatic acinar and stellate cells

BACKGROUND/OBJECTIVES

Acute pancreatitis develops as an inflammatory response to pancreatic tissue injury. Postoperative pancreatitis has recently been associated with increased occurrence of complications. Activation of the mitogen-activated protein kinase p38 (p38 MAPK) pathway occurs early in acute pancreatitis and its inhibition has been suggested to alleviate pancreatic inflammation. Glucocorticoids are potent anti-inflammatory steroids whose use in the management of acute pancreatitis remains controversial. Our aim was to examine the effect of crosstalk between pancreatic acinar cells (PACs) and stellate cells (PSCs) on p38 MAPK and glucocorticoid receptor (GR) activation and to assess the impact of hydrocortisone on these events.

METHODS

The long-term co-culture setting for mouse PACs and PSCs developed in our laboratory was used. Parallel 4d mono- and co-cultures with or without 10 nM hydrocortisone were performed followed by immunocytochemical analysis of nuclear GR and phospho-p38 MAPK (pp38 MAPK).

RESULTS

Hydrocortisone inhibited pp38 MAPK up-regulation evoked by co-culture in PACs and PSCs and increased nuclear translocation of GR in PAC monocultures and in co-cultured PACs and PSCs. In PSC monocultures and co-cultured PACs, ligand-independent expression of nuclear GR was observed. In the former no change in nuclear GR but a significant decrease in total GR as analyzed by Western blot was caused by hydrocortisone.

CONCLUSIONS

Cellular microenvironment plays a significant role on p38 MAPK and GR activation in PACs and PSCs. Hydrocortisone is an effective means to inhibit p38 MAPK activation in PACs and PSCs. Both ligand-dependent and -independent regulatory roles for GR are suggested in the exocrine pancreas.

Clinical characteristics of IgG4-related retroperitoneal fibrosis versus idiopathic retroperitoneal fibrosis

Retroperitoneal fibrosis (RPF) is an uncommon condition characterized by inflammation and fibrosis in the retroperitoneal space. More than two-thirds of RPF are idiopathic, with the remaining stemed from a variety of secondary causes. It was suggested that IgG4-related RPF is a secondary form of RPF. We undertook this study to compare detailed demographic, clinical and laboratory characteristics of IgG4-related RPF and IRPF in a large Chinese cohort. We retrospectively reviewed the medical records of 132 RPF patients diagnosed at Peking University People’s Hospital between March 2010 and March 2018. Among the 132 patients, the mean age at disease onset was 54.8 years. IgG4-related RPF group showed greater male predominance compared to IRPF group. IgG4-related RPF patients showed a longer interval between symptom onset and diagnosis, and allergic diseases were more common in this group. Sixty-four patients (48.4%) had lower back pain, which was more common in IRPF group than that in IgG4-related RPF patients. In terms of organ involvement, although 42 of 47 patients (89.3%) with IgG4-related RPF had other organ involvement, there were no patients in the IRPF group with other organ involvement. In addition, the serum IgG4 level, elevated eosinophils counts and IgE level were significantly higher in IgG4-related RPF patients. We described the demographic, clinical and laboratory differences between IgG4-related RPF and IRPF patients, indicating their potential differences in pathogenesis, which was of great importance to diagnose and manage the two phenotypes.

Clinical characteristics and long-term prognosis of autoimmune pancreatitis with renal lesions

Autoimmune pancreatitis (AIP) is recognized as the pancreatic manifestation of a systemic IgG4-related disease that can involve various organs, including the kidney. However, renal lesions tend to be overlooked when AIP is diagnosed, and the clinical characteristics and long-term prognosis of AIP with renal lesions are unclear. We retrospectively reviewed 153 patients with AIP diagnosed at our hospital with a median follow-up period of 41 months (interquartile range, 10-86) and classified them into two groups: the KD group (n = 17), with characteristic renal imaging features, and the non-KD group (n = 136). Serum IgG4 levels were significantly higher in the KD group (663 vs. 304.5 mg/dl, P = 0.014). No differences were observed between the two groups in terms of steroid treatment [14/17 (82.4%) vs. 112/136 (82.4%), P = 1] or in the number of patients who exhibited exacerbation of renal function during treatment [1/17 (5.9%) vs. 8/136 (5.9%), P = 1]. However, the cumulative relapse rate was significantly higher in the KD group [61% vs. 21.9% (3 years), P < 0.001]. Patients in the KD group had different clinical features with high relapse rates compared with those in the non-KD group, and thus, it is important to confirm the presence of renal lesions in AIP patients.

IgG4-related nephritis and interstitial pulmonary disease complicated by invasive pulmonary fungal infection: a case report

Background

IgG4-related kidney disease (IgG4-RKD) can affect multiple organs, which was first reported as a complication or extra-organ manifestation of autoimmune pancreatitis in 2004. It is characterized by abundant IgG4-positive plasma cells infiltration in tissues involved.

Case presentation

A 69-year-old man presented with cough and renal dysfunction with medical history of hypertension and diabetes. Pathological findings revealed interstitial nephritis and he was initially diagnosed with IgG4-RKD. Prednisone helped the patient to get a remission of cough and an obvious decrease of IgG4 level. However, he developed invasive pulmonary fungal infection while steroid theatment. Anti-fungal therapy was initiated after lung puncture (around cavitary lung lesion). Hemodialysis had been conducted because of renal failure and he got rid of it 2 months later. Methylprednisolone was decreased to 8 mg/day for maintenance therapy. Anti-fungal infection continued for 4 months after discharge home. On the 4th month of follow-up, Chest CT revealed no progression of lung lesions.

Conclusions

The corticosteroids are the first-line therapy of IgG4-RD and a rapid response helps to confirm the diagnosis. This case should inspire clinicians to identify IgG4-related lung disease and secondary pulmonary infection, pay attention to the complications during immunosuppressive therapy for primary disease control.

IgG4 related disease as a cause of isolated retroperitoneal fibrosis with no other organ involvement; Case report

Introduction and importance

Retroperitoneal fibrosis (RPF) is a rare disease characterized by the replacement of normal tissue with fibrosis and inflammation. We present the case of a 40-years-old gentleman with RPF whose presenting complaints were bilateral flank pain and weight loss and was found to have IgG4 related disease. To the best of our knowledge, IgG4-related disease with isolated retroperitoneal involvement is a very rare occurrence.

Case presentation

The diagnosis of IgG4-Related retroperitoneal fibrosis was made based on clinical, radiological and histopathological criteria. Imaging revealed isolated retroperitoneal involvement and the patient was started on oral steroids with a good clinical response after ten days. Repeated imaging months later showed significant regression in the fibrosis.

Clinical discussion

RPF can occur due to many etiologies and is categorized to idiopathic and secondary. Factors associated with secondary RPF include medications, autoimmune disease, malignancy and IgG4 related disease. Almost all the reported cases of IgG4 related disease had evidence of multifocal involvement such as the pancreas, aorta and kidneys. Our patient was diagnosed with isolated RPF due to IgG4 disease. He met all the suggested diagnostic criteria, was started on oral steroids and had an excellent clinical outcome.

Conclusion

IgG4 related disease can present with isolated retroperitoneal fibrosis without involvement of other organ systems. The diagnosis should be based on specific criteria. Treatment with corticosteroids can lead to remission both clinically and radiographically.

Risks and characteristics of pancreatic cancer and pancreatic relapse in autoimmune pancreatitis patients

BACKGROUND AND AIM

We examined the differences in the risks and characteristics of pancreatic relapse (PR) and pancreatic cancer (PC) in patients with autoimmune pancreatitis (AIP).

METHODS

We retrospectively reviewed 123 type 1 AIP patients with a median follow-up of 55 months (interquartile range, 27-98). The following items were evaluated: (i) cumulative relapse rates and risk factors, (ii) the incidence of PC, (iii) PR versus PC, and (iv) outcomes after the appearance of morphological changes in the pancreas (focal enlargement, apparent mass lesions, or main pancreatic duct dilation).

RESULTS

(i) The cumulative PR rates were 1.7% within 1 year, 11.5% within 3 years, and 22.6% within 5 years. Lack of maintenance therapy, IgG4-related sclerosing cholangitis, and IgG4-related kidney disease were identified as independent predictors of relapse. (ii) Two patients (1.6%) were diagnosed with PC at 17 and 22 months after initial AIP diagnosis. (iii) Thirteen (59.1%) and four (18.2%) patients with PR had focal enlargement and main pancreatic duct dilation, respectively. The median CA19-9 level at initial diagnosis was significantly higher in PC patients (21 vs 220.5 U/mL, P = 0.014). (iv) Eight PR patients underwent endoscopic ultrasound-guided fine-needle aspiration, none of whom had malignant findings. PC was diagnosed by ultrasound-guided fine-needle aspiration in both cancer patients.

CONCLUSIONS

Although the incidence of PC is low, it may mimic PR in AIP patients. Surveillance is important, and when morphological changes occur, biopsy and evaluation of serum IgG4 and CA19-9 levels (particularly if the levels were high before) should be considered.

Atypical Manifestations of IgG4-Related Disease as Multiple Liver Abscesses with Subcapsular Tracts and Migratory Pulmonary Nodules Mimicking Parasitic Infection

Immunoglobulin G4-related disease (IgG4-RD) is a fibroinflammatory condition that becomes more recognized as multi-systemic disorders, characterized by three histological hallmarks of IgG4-positive lymphoplasmacytic tissue infiltrate, storiform fibrosis, and obliterative phlebitis. This disease has been reported in virtually every organ system, but the hepatic manifestations remain poorly defined. Moreover, IgG4-RD can mimic many malignancies, inflammatory disorders and infectious diseases. This report revealed IgG4-related liver disease with atypical presentation presenting with multiple liver abscesses and linear tracts mimicking parasitic infection.

Long-term clinical course and outcomes of immunoglobulin G4-related lung disease

Background

Immunoglobulin G4-related lung disease (IgG4-RLD) is the pulmonary manifestation of a systemic fibroinflammatory disease characterized by lymphoplasmacytic infiltration with an abundance of IgG4-positive plasma cells. Long-term clinical course and outcomes of IgG4-RLD remain unclear. We aimed to identify clinical characteristics, treatment outcomes, and longitudinal pulmonary function changes in patients with IgG4-RLD according to the radiologic classification.

Methods

Chest computed tomography findings of 37 subjects were classified into five subtypes: solid nodular, bronchovascular, alveolar interstitial, round ground glass opacity, and alveolar consolidative. Radiologic treatment outcomes and longitudinal pulmonary function changes were compared among the different radiologic subtypes.

Results

The mean age of the subjects was 55.6 years, and 78.4% were male. Among the five radiologic subtypes, alveolar consolidative and solid nodular type were most common, accounting for approximately 29.7% each of the total cases. Prednisone with or without azathioprine was administered to 31 patients (median treatment duration 14 months). In the treated patients, serial images showed complete response or partial response in 77.4%. However, relapse was documented in 25.0% of those who showed complete or partial response. In patients whose longitudinal lung function data were available (n = 20), the lung function was found to be stable during follow-up. Alveolar consolidative type showed the highest complete response rate, whereas alveolar interstitial type showed the lowest response rate, either complete or partial.

Conclusions

Most patients showed a favorable outcome with regards to radiologic improvement and maintenance of pulmonary function; however, the response differed according to the radiologic subtype.

Identification of serum IFN-α and IL-33 as novel biomarkers for type 1 autoimmune pancreatitis and IgG4-related disease

IgG4-related disease (IgG4-RD) is a multi-organ autoimmune disease characterized by elevated serum IgG4 concentration. Although serum IgG4 concentration is widely used as a biomarker for IgG4-RD and type 1 autoimmune pancreatitis (AIP), a pancreatic manifestation of IgG4-RD, a significant number of patients have normal serum IgG4 levels, even in the active phase of the disease. Recently, we reported that the development of experimental AIP and human type 1 AIP is associated with increased expression of IFN-α and IL-33 in the pancreas. In this study, we assessed the utility of serum IFN-α and IL-33 levels as biomarkers for type 1 AIP and IgG4-RD. Serum IFN-α and IL-33 concentrations in patients who met the diagnostic criteria for definite type 1 AIP and/or IgG4-RD were significantly higher than in those with chronic pancreatitis or in healthy controls. Strong correlations between serum IFN-α, IL-33, and IgG4 concentrations were observed. Diagnostic performance of serum IFN-α and IL-33 concentrations as markers of type 1 AIP and/or IgG4-RD was comparable to that of serum IgG4 concentration, as calculated by the receiver operating characteristic curve analysis. Induction of remission by prednisolone treatment markedly decreased the serum concentration of these cytokines. We conclude that serum IFN-α and IL-33 concentrations can be useful as biomarkers for type 1 AIP and IgG4-RD.

IgG4-related disease: an update on pathophysiology and implications for clinical care

IgG4-related disease (IgG4-RD) has only existed as a unique disease entity since 2003, yet remarkable progress has already been achieved in describing the essential features of the disease. A framework for systematic clinical studies has been created by the development of a quantitative disease activity tool (the IgG4-RD Responder Index) and the validation of classification criteria, both of which were the products of international, multi-centre investigations. In addition, substantial strides have been made in understanding the pathophysiology of IgG4-RD. In particular, the central role of B cells in the disease has been demonstrated by both the robust clinical responsiveness of IgG4-RD to B cell depletion and by the identification of multiple self-antigens that promote B cell expansion. CD4⁺ T cells have also been investigated in detail; CD4⁺ cytotoxic T lymphocytes (suspected of promoting disease) and a specific T follicular helper cell subset that contributes to IgG4 isotype switching have both been defined by multiple groups. The mechanisms by which these immune cells converge on target tissues, interact with fibroblasts and promote tissue remodelling are beginning to be understood and will be an important research focus in the coming years.

Immunoglobulin G4-related Disease of the Genitourinary System: Spectrum of Imaging Findings and Clinical-Pathologic Features

Immunoglobulin G4-related disease (IgG4-RD) is a systemic fibroinflammatory disease characterized by focal or diffuse organ infiltration of IgG4-bearing plasma cells. The diagnosis of IgG4-RD is based on a combination of clinical, serologic, radiologic, and histopathologic findings. IgG4-RD has been reported to affect almost all organ systems. The kidney is the most frequently involved of the genitourinary organs. The most common renal manifestation of IgG4-RD is IgG4-RD tubulointerstitial nephritis, followed by membranous glomerulonephropathy and, less frequently, obstructive nephropathy involving the renal pelvis, ureter, or retroperitoneum. Renal parenchymal lesions may appear as multiple nodular lesions, diffuse patchy infiltrative lesions, or a single nodular lesion. Multiple small nodular cortical lesions are the most common imaging findings of IgG4-RD involving the kidney. Renal pelvic, sinus, or perinephric lesions can also occur. IgG4-RD involvement of other genitourinary organs including the ureter, bladder, urethra, and male and female reproductive organs is rare compared with kidney involvement but may show variable imaging findings such as a localized mass within or surrounding the involved organ or diffuse enlargement of the involved organ. Imaging findings of IgG4-RD involving the genitourinary system are nonspecific but should be differentiated from inflammatory and neoplastic lesions that mimic IgG4-RD. The online slide presentation from the RSNA Annual Meeting is available for this article. ^©RSNA, 2020.

Autoimmune pancreatitis type 2

PURPOSE OF REVIEW

Type 2 autoimmune pancreatitis (AIP) is a rare inflammatory disease of the pancreas. Very few data have been published on this particular subtype, which differs from the 'classical' IgG4-related type 1 AIP in terms of pathological features, epidemiology and risk of relapse. The aim of the current review is to summarize the available literature, suggesting a diagnostic and therapeutic approach to this disease.

RECENT FINDINGS

Based on the International Consensus Diagnostic Criteria, to achieve a 'definitive' diagnosis of type 2 AIP, histology is required. If a definitive histological diagnosis is lacking (not-performed or inconclusive), concomitant presence of inflammatory bowel disease (IBD) and effective response to steroids are needed for a 'probable' diagnosis of type 2 AIP.

SUMMARY

Type 2 AIP is a selective pancreatic disease, without association to other organ involvement. The lack of validated serological markers makes the diagnosis challenging in clinical practice, particularly in focal forms. A careful evaluation of the clinical profile (especially of a concomitant IBD), associated with an accurate imaging, might help in clinical practice to suspect type 2 AIP. Response to steroids is crucial to achieve diagnosis in patients without a diagnostic histology.

Autoimmune pancreatitis - An ongoing challenge

Autoimmune pancreatitis is a rare form of chronic pancreatitis. The first descriptions of the disease date back to the 1990s. Etiology is multifactorial, with the use of genetic, environmental and complex immunological mechanisms. It is classified into two subtypes. Type 1 is part of a group of diseases called IgG4-related disease. Clinically is autoimmune pancreatitis manifested by icterus and abdominal discomfort. It can rarely present as acute pancreatitis. There is also a completely asymptomatic form of the disease. The diagnosis is based on abnormalities in histology, imaging methods, serology, the involvement of other organs in relation to IgG4-related disease, and a significant positive response to corticosteroid therapy. Differential diagnosis between the focal form of autoimmune pancreatitis and pancreatic cancer can be complicated, with endosonography playing an important role. In the treatment, we use corticosteroids and other immunosuppressants including biological therapy. Patients with the asymptomatic disease should also be treated to prevent late complications and exocrine and endocrine insufficiency. In addition to drug treatment, endoscopic and/or surgical treatment may be necessary. Even after recovery, the disease can relapse. The relationship between autoimmune pancreatitis and malignancies has not been clearly confirmed. The goal of this review is to provide a comprehensive look at autoimmune pancreatitis and translate latest scientific knowledge into clinical practice.

Steroid-responsive pancreatitides

Autoimmune pancreatitis has received considerable attention, especially due to the marked effect of corticosteroid therapy on its clinical course. Knowledge, especially regarding type 1 autoimmune pancreatitis, has significantly increased over the last decades, and despite significant differences in pathophysiology and outcomes, both type 1 and 2 autoimmune pancreatitis are still considered different types of the same disease. Some have proposed a different nomenclature reflecting these differences. Although the term steroid-responsive pancreatitides may be interpreted as synonymous to type 1 and 2 autoimmune pancreatitis, these are not the only pancreatic conditions that show a response to steroid therapy. Acute pancreatitis caused by vasculitis and connective tissue diseases and acute pancreatitis secondary to checkpoint inhibitors or programmed cell death receptor antibody-mediated blockage cancer therapy may also benefit from steroid treatment. This review presents current concepts on these disorders, aiming to increase awareness, analyze similarities and differences, and propose a new nomenclature that reflects their specific particularities, clustering them under the term "steroid-responsive pancreatitides".

PrescrAIP: A Pan-European Study on Current Treatment Regimens of Auto-Immune Pancreatitis

Introduction: Treatment of autoimmune pancreatitis (AIP) is based solely on consensus and has yet to become standardized. Consequently, therapeutic regimens vary greatly between countries and centers, and largely depend on the experience of the physician. At this moment, the optimal regimen for inducing disease remission and preventing relapse is unknown. Objectives: The primary objective of this study is to describe current treatment regimens used in Europe, and to compare their effectiveness in inducing remission and preventing and treating relapse. The secondary objectives are: to identify risk factors for relapse; to assess the diagnostic accuracy of the Unified-AIP criteria; to assess the performance of the M-ANNHEIM score for predicting relapse; and to assess long-term outcomes including pancreatic exocrine insufficiency and pancreatic cancer. Methods: This is an international, retrospective, observational cohort study, performed in over 40 centers from 16 European countries. Eligible are all patients diagnosed with AIP from 2005 onwards, regardless of the used diagnostic criteria. Data on study subjects will be retrieved from the hospital's electronic medical records and registered with a standardized, web-based, electronic case report form (eCRF). To compare the effectiveness of treatment regimens in inducing remission, preventing relapse, and treating relapse, subjects will be stratified in groups based on: type of therapy; initial therapy dose; cumulative therapy dose; therapy tapering speed and duration; and having received maintenance therapy or not. Ethics and Dissemination: Ethical and/or institutional review board approvals are obtained by all participating centers according to local regulations. The study complies with the General Data Protection Regulation (GDPR). All manuscripts resulting from the study will be submitted to peer-reviewed journals. Conclusion: This is the first pan-European retrospective registry for AIP. It will produce the first large-scale data on treatment of European patients with AIP, providing answers on the use and effectiveness of treatment regimens. In the future, this collaboration may provide a network for continuation into a prospective European registry.

IgG4-related disease in the abdomen and pelvis: atypical findings, pitfalls, and mimics

IgG4-related disease (IgG4-RD) is a systemic, autoimmune, fibroinflammatory disease that can cause multi-organ damage. Although there have been many trials and studies since its recognition in 2003, there is still much that is unknown. Furthermore, IgG4-RD can affect any organ in the body and often has many mimics and alternative diagnoses, which can make for a challenging workup. Imaging plays a substantial role in the diagnosis of IgG4-RD and is often the first occasion where IgG4-RD comes into consideration. Thus, knowledge about the imaging findings of various manifestations of IgG4-RD can aid in the diagnosis and have a significant impact on patient management. In this article, we review the wide array of imaging findings, both typical and atypical, as well as possible mimics of IgG4-RD in the abdomen and pelvis.

A case of IgG4-related anterior mediastinal sclerosing disease coexisting with autoimmune pancreatitis

Background

IgG4-related disease (IgG4-RD) is a systemic fibro-inflammatory condition that predominantly involves exocrine organs. Concerning its thoracic presentation, it often manifests as interstitial lung disease or fibrosing mediastinitis. It is very rare for IgG4-RD to form a well-defined mass in the anterior mediastinum, mimicking an encapsulated thymoma.

Case presentation

An 82-year-old man with autoimmune pancreatitis under treatment with oral corticosteroids was found to have peripancreatic lymphadenopathy on computed tomography. Subsequent positron emission tomography revealed abnormal uptake (maximal value 3.6) by a thymic mass as well as the peripancreatic lymph nodes. Exacerbation of IgG4-RD was suspected, and we increased the oral steroid dosage. As a result, the peripancreatic lymph nodes, and the anterior mediastinal mass, decreased in size. The thymic mass was suspected to be an encapsulated thymoma because of its lobulated shape, degree of fluorodeoxyglucose accumulation, and response to steroids, and the patient was referred to our department. The serum anti-acetylcholine receptor antibody test was negative. A thoracoscopic tumor resection was performed as diagnostic therapy. Histopathological analysis revealed dense lymphoplasmacytic infiltration with sclerotic stroma within the tumor. Immunohistochemical analysis revealed abundant IgG4-positive plasma cell infiltrates and over 50% IgG4/IgG-positive plasma cells. We did not see either keratin-positive thymocytes or terminal deoxynucleotidyl transferase-positive lymphocytes. Furthermore, deviation in the kappa chain and lambda chain-positive plasma cells was not noted. Accordingly, IgG4-related sclerosing disease was diagnosed.

Conclusions

IgG4-related sclerosing masses in the anterior mediastinum are very rare, and the effect of tumor resection on prognosis remains unclear. IgG4-RD had potentially been categorized as Castleman’s disease.

European Guideline on IgG4-related digestive disease - UEG and SGF evidence-based recommendations

The overall objective of these guidelines is to provide evidence-based recommendations for the diagnosis and management of immunoglobulin G4 (IgG4)-related digestive disease in adults and children. IgG4-related digestive disease can be diagnosed only with a comprehensive work-up that includes histology, organ morphology at imaging, serology, search for other organ involvement, and response to glucocorticoid treatment. Indications for treatment are symptomatic patients with obstructive jaundice, abdominal pain, posterior pancreatic pain, and involvement of extra-pancreatic digestive organs, including IgG4-related cholangitis. Treatment with glucocorticoids should be weight-based and initiated at a dose of 0.6-0.8 mg/kg body weight/day orally (typical starting dose 30-40 mg/day prednisone equivalent) for 1 month to induce remission and then be tapered within two additional months. Response to initial treatment should be assessed at week 2-4 with clinical, biochemical and morphological markers. Maintenance treatment with glucocorticoids should be considered in multi-organ disease or history of relapse. If there is no change in disease activity and burden within 3 months, the diagnosis should be reconsidered. If the disease relapsed during the 3 months of treatment, immunosuppressive drugs should be added.

IgG4 related disease in a seven year old girl with multiple organ involvement: A rare presentation

Autoimmune pancreatitis has been described as a pancreatic manifestation of immunoglobulin G4-related disease, which is characterized by typical histopathologic, radiologic, and clinical features. Immunoglobulin G4-related disease is usually accompanied by elevated serum immunoglobulin G4 level, and can involve multiple organ/systems. Immunoglobulin G4-related disease has rarely been reported in pediatric population. There are few reports of inflammatory bowel disease in association with immunoglobulin G4-related disease. We describe a 7-year-old girl who presented with pancreatitis and concurrent sclerosing cholangitis, and developed bloody diarrhea during follow-up. An endoscopic examination revealed inflammatory bowel disease, and later lacrimal gland involvement was also recognized. She was diagnosed as having immunoglobulin G4-related disease, and her clinical signs and symptoms improved dramatically after steroid treatment. Hence, awareness of the clinical picture is important and early diagnosis can prevent fibrosis and organ damage.

Advances in the diagnosis and management of IgG4 related disease

IgG4 related disease was recognized as a unified disease entity only 15 years ago. Awareness of IgG4 related disease has increased worldwide since then, and specialists are now familiar with most of its clinical manifestations. Involvement of the pancreato-biliary tract, retroperitoneum/aorta, head and neck, and salivary glands are the most frequently observed disease phenotypes, differing in epidemiological features, serological findings, and prognostic outcomes. In view of this multifaceted presentation, IgG4 related disease represents a great mimicker of many neoplastic, inflammatory, and infectious conditions. Histopathology remains key to diagnosis because reliable biomarkers are lacking. Recently released classification criteria will be invaluable in improving early recognition of the disease. IgG4 related disease is highly treatable and responds promptly to glucocorticoids, but it can lead to end stage organ failure and even death if unrecognized. Prolonged courses of corticosteroids are often needed to maintain remission because the disease relapses in most patients. Rapid advancement in our understanding of the pathophysiology of IgG4 related disease is leading to the identification of novel therapeutic targets and possible personalized approaches to treatment.

Management of biliary stricture in patients with IgG4-related sclerosing cholangitis

Background

We aimed to determine the optimal approach with endoscopic biliary drainage (EBD) and corticosteroid (CS) for the treatment of IgG4-related sclerosing cholangitis (ISC).

Methods

To evaluate the safety of EBD for treatment of biliary stricture caused by ISC, we assessed the risk of stent dislodgement and sought to determine the most appropriate time for stent removal. We also assessed the safety of treatment with CS alone for patients with obstructive jaundice, and the rate of and risk factors for biliary tract complications.

Results

Sixty-nine patients with ISC treated with CS were enrolled. Twenty-eight patients (40.6%) were treated with EBD for biliary stricture before CS initiation. Intentional stent removal was performed in thirteen (46.4%) after confirming CS-induced improvement. Eleven of thirteen patients (84.6%) underwent stent removal within 1 month after CS initiation and all their stent removals were safely carried out without early (within two weeks) recurrence of obstructive jaundice. Ten of twenty-eight patients (35.7%) experienced spontaneous stent dislodgement after CS initiation, and seven (70%) of them developed stent dislodgement two weeks to two months after CS initiation. Among forty-one patients treated with CS alone without EBD, 10 patients had obstructive jaundice at the time of CS initiation and all of them achieved clinical improvement without biliary tract infection. During the follow-up, three patients (4.3%), all of whom had undergone EBD, developed bile-duct stones, while none of those treated with CS alone developed bile-duct stones (p = 0.032). Long-term biliary stenting was a risk factor for bile-duct stones.

Conclusions

Biliary stent removal should be carried out within 2 weeks after CS initiation if biliary stricture improves to prevent stent dislodgement. Obstructive jaundice can be treated safely with CS alone in patients without infection. Clinicians should be aware of the possibility of bile-duct stones in patients treated with EBD.

Type 1 Autoimmune Pancreatitis in a Young Male

Autoimmune pancreatitis (AIP) is a rare entity leading to inflammation of the pancreas. It can be broadly categorized into two types. Type 1 AIP is more common and primarily presents with jaundice. Less commonly it can also progress to multiorgan involvement. Here we report a case of a 19-year-old male who presented to us with complaints of abdominal pain and vomiting. His laboratory investigations showed raised serum amylase and lipase. A contrast-enhanced CT revealed a diffuse enlargement of the pancreas with internal low-density foci. Due to the repeated episodes of pancreatitis, the patient's blood was tested for serum IgG4 (immunoglobulin type G4) which was markedly elevated pointing toward the diagnosis of AIP. Endoscopic ultrasound (EUS) showed a sausage-shaped pancreas with hyper- and hypoechoic strands. EUS-guided fine needle aspiration cytology of the lymph nodes performed in the celiac region showed a mixed population of lymphoid cells. Based on all the workup, our patient was diagnosed as type 1 AIP. He was managed with steroids and his condition progressively improved. This case is clinically significant because of the close resemblance of AIP with other pancreatic disorders like neoplasm. A timely diagnosis can prevent the unnecessary performance of invasive procedures in these patients. 

Clinical utility of serum IgG4 measurement

This article will review the structure and function of IgG4, methods of measuring serum IgG4 concentrations, clinical conditions associated with increased and decreased serum IgG4, and the test characteristics of serum IgG4 in the diagnosis and management of Immunoglobulin G4-Related Disease (IgG4-RD). The four subclasses of IgG were discovered in 1964 through experiments on monoclonal IgG in patients with myeloma. Since 2001, interest in measuring serum IgG subclasses has increased dramatically due to the emergence of IgG4-RD, a multisystem fibroinflammatory condition wherein polyclonal serum IgG4 concentration is increased in approximately 70% of cases. Increased serum IgG4 typically manifests as a restriction in the anodal gamma region on serum protein electrophoresis, often with beta-gamma bridging, and can be mistaken as a monoclonal protein or polyclonal increase in IgA. Limitations of current clinical methods used in quantitation of serum IgG4 concentrations will be discussed, including the common immunonephelometric assays and LC-MS/MS based assays. Polyclonal IgG4 elevation is not specific for IgG4-RD, and may also occur in conditions such as eosinophilic granulomatosis with polyangiitis (EGPA), lymphoma, and multicentric Castleman disease (MCD). Race and gender differences also affect interpretation of serum IgG4 concentrations, for instance Asians have a higher serum IgG4 concentration than Whites and males have a higher concentration than females.

Case report: IgG4-related renal disease co-existing with retroperitoneal fibrosis

A 51-year-old woman visited our clinic for orthopnea, chest discomfort, and facial and leg edema. Acute kidney injury and pleural effusion were diagnosed and she received hemodialysis. This is a rare case of IgG4-related disease diagnosed by renal biopsy in the patient with retroperitoneal fibrosis and severe acute kidney injury, which progressed rapidly and required hemodialysis without markedly elevated serum IgG4 level and urinary tract obstruction. Immunostaining of a kidney biopsy revealed IgG4-related renal disease and magnetic resonance imaging showed retroperitoneal fibrosis in the paraspinal and presacral areas. After 3 days of glucocorticoid treatment, renal function and bilateral pleural effusion were restored. Another 2 months of glucocorticoid treatment decreased the extent of retroperitoneal fibrosis on follow-up abdominal computed tomography. IgG4-related disease is a recently recognized fibro-inflammatory condition with a dense lymphoplasmacytic infiltration of IgG4-positive plasma cells. The kidney and retroperitoneum are the frequently associated organs in IgG4-related disease. This case shows that IgG4-related disease can involve the kidney and/or other organs and be diagnosed by kidney biopsy.

Does IgG4 level evaluation in pancreatic mass play role in avoiding major surgery in uncertain presentation: A case report

A 66-year-old male presented with chief complaints of anorexia associated with mild dull, intermittent epigastric pain for 6 months. The patient was a known diabetic on oral hypoglycemic and on routine checkup was found to have deranged liver function profile. On radiology, an ill-defined hypoechoic enhancing lesion involving head, neck, and uncinate process of pancreas was noted. Whipple's pancreaticodudenectomy was done and reported as IgG4-related autoimmune pancreatitis. Later, IgG (slightly) and IgG4 were found to be markedly raised. We report this case to highlight the importance of IgG4 evaluation prior to major surgery in uncertain pancreatic mass.

Corticosteroid Withdrawal after Complete Resection of Recurrent IgG4-Related Ophthalmic Disease

Corticosteroids are the first-line treatment for immunoglobulin G4-related ophthalmic disease (IgG4-ROD). However, the therapeutic effect of corticosteroids is unpredictable, and recurrences occur frequently. We present a case of a 60-year-old woman with IgG4-ROD of the lacrimal fossa. She was first treated with oral prednisolone, which was tapered within three months. However, proptosis recurred two months after prednisolone withdrawal. En bloc excision of the lesion was performed via the eyelid crease approach. The patient is lesion-free without corticosteroids at 18 months after surgery. Complete resection can be a powerful strategy for IgG4-ROD if a well-defined lesion is located in accessible areas.

Prediction of pancreatic atrophy after steroid therapy using equilibrium-phase contrast computed tomography imaging in autoimmune pancreatitis

Background and Aims

Imaging tools for predicting pancreatic atrophy after steroid therapy in autoimmune pancreatitis (AIP) have not been established. As delayed equilibrium‐phase contrast enhancement in computed tomography (CE‐CT) may reflect interstitial fibrosis, we evaluated the ability of equilibrium‐phase CT imaging for predicting pancreatic atrophy.

Methods

Forty‐six steroid‐treated AIP patients who underwent contrast‐enhanced CT at our university hospital were included in this retrospective study. CT attenuation (Hounsfield units [HU]) values in noncontrast images (NC) and equilibrium‐phase images (EP) and the differences in HU values between NC and EP images (SUB) were measured. Pancreatic volume was measured in CE‐CT before (Vol_pre) and after (Vol_post) steroid therapy. The volume reduction rate was calculated. The relationships of CT values with pancreatic atrophy, Vol_post, volume reduction rate, and diabetes exacerbation were investigated.

Results

CT values in the EP and SUB images before steroid therapy were associated with pancreatic atrophy after steroid therapy (atrophy vs nonatrophy 114.5 ± 12.8 vs 99.5 ± 11.1, P = 0.0002; 70.9 ± 14.72 vs 57.2 ± 13.1, P = 0.003, respectively), but CT values in NC images were not (P = 0.42). CT values in EP and SUB images before steroid therapy were correlated with Vol_post (EP images r = −0.70, P = 0.002; SUB images r = −0.68, P = 0.03) and volume reduction rate after steroid therapy (EP images: r = −0.55, P < 0.0001; SUB images r = −0.45, P = 0.002). Diabetes exacerbation was associated with higher EP and SUB values (P = 0.009 and P = 0.04, respectively).

Conclusion

Equilibrium‐phase contrast CT imaging may facilitate prediction of pancreatic atrophy after steroid therapy in AIP.

IgG4-related disease: a case report

IgG4-related disease (IgG4-RD) is a condition that was first described recently, and is capable of affecting any organ of the body. Diagnosis is based on the correlation of clinical findings with histopathological findings and elevated serum IgG4. Treatment involves corticosteroids and rituximab for the most severe cases. We report the case of a symptomatic patient diagnosed of IgG4-RD whose diagnosed was guided by elevated serum IgG4 levels.

Review of a novel disease entity, immunoglobulin G4-related disease

Immunoglobulin G4 (IgG4)-related dacryoadenitis and sialoadenitis (IgG4-DS) are part of a multiorgan fibroinflammatory condition of unknown etiology termed IgG4-related disease (IgG4-RD), which has been recognized as a single diagnostic entity for less than 15 years. Histopathologic examination is critical for diagnosis of IgG4-RD. CD4+ T and B cells, including IgG4-expressing plasma cells, constitute the major inflammatory cell populations in IgG4-RD and are thought to cause organ damage and tissue fibrosis. Patients with IgG4-RD who have active, untreated disease exhibit significant increase of IgG4-secreting plasmablasts in the blood. Considerable insight into the immunologic mechanisms of IgG4-RD has been achieved in the last decade using novel molecular biology approaches, including next-generation and single-cell RNA sequencing. Exploring the interactions between CD4+ T cells and B lineage cells is critical for understanding the pathophysiology of IgG4-RD. Establishment of pathogenic T cell clones and identification of antigens specific to these clones constitutes the first steps in determining the pathogenesis of the disease. Herein, the clinical features and mechanistic insights regarding pathogenesis of IgG4-RD were reviewed.

Steroid Therapy and Steroid Response in Autoimmune Pancreatitis

Autoimmune pancreatitis (AIP), a unique subtype of pancreatitis, is often accompanied by systemic inflammatory disorders. AIP is classified into two distinct subtypes on the basis of the histological subtype: immunoglobulin G4 (IgG4)-related lymphoplasmacytic sclerosing pancreatitis (type 1) and idiopathic duct-centric pancreatitis (type 2). Type 1 AIP is often accompanied by systemic lesions, biliary strictures, hepatic inflammatory pseudotumors, interstitial pneumonia and nephritis, dacryoadenitis, and sialadenitis. Type 2 AIP is associated with inflammatory bowel diseases in approximately 30% of cases. Standard therapy for AIP is oral corticosteroid administration. Steroid treatment is generally indicated for symptomatic cases and is exceptionally applied for cases with diagnostic difficulty (diagnostic steroid trial) after a negative workup for malignancy. More than 90% of patients respond to steroid treatment within 1 month, and most within 2 weeks. The steroid response can be confirmed on clinical images (computed tomography, ultrasonography, endoscopic ultrasonography, magnetic resonance imaging, and 18F-fluorodeoxyglucose-positron emission tomography). Hence, the steroid response is included as an optional diagnostic item of AIP. Steroid treatment results in normalization of serological markers, including IgG4. Short- and long-term corticosteroid treatment may induce adverse events, including chronic glycometabolism, obesity, an immunocompromised status against infection, cataracts, glaucoma, osteoporosis, and myopathy. AIP is common in old age and is often associated with diabetes mellitus (33-78%). Thus, there is an argument for corticosteroid therapy in diabetes patients with no symptoms. With low-dose steroid treatment or treatment withdrawal, there is a high incidence of AIP recurrence (24-52%). Therefore, there is a need for long-term steroid maintenance therapy and/or steroid-sparing agents (immunomodulators and rituximab). Corticosteroids play a critical role in the diagnosis and treatment of AIP.

Clinical features and outcomes in a cohort of patients with immunoglobulin G4-related disease at a university hospital in Spain

Background

Immunoglobulin G4-related disease (IgG4-RD) is a fibro-inflammatory, immune-mediated disorder, which characteristically affects the glandular tissue but has the potential to affect any organ.

Methods

We retrospectively reviewed clinical, laboratory, histological characteristics and treatment response during 12 months of follow-up of a cohort of patients with IgG4-RD diagnosed at a tertiary public hospital. Disease activity was assessed by means of the IgG4-RD responder index (IgG4-RD RI).

Results

In all, 15 patients have been diagnosed at our Institution and herein studied (80% men), with a median age of 60.7 years and a mean affectation of 2.8 organs per patient. We identified six patients with definitive diagnosis and nine with possible IgG4-RD, according to the Japanese diagnostic algorithm. IgG4-RD RI decreased from a median of 11.3 at baseline to 4.0 after 6 months and 6.2 after 12 months. Relapse occurred in five patients and was associated with lower cumulative steroid doses. Five patients (33.3%) required additional immunosuppressive (IS) drugs. Five adverse events were seen during follow-up: three infections, one deep vein thrombosis and one gastrointestinal bleeding. One patient died of pneumonia.

Conclusions

IgG4-RD is an inflammatory disease that can affect any organ. Glucocorticoids were an effective first line of treatment; however, this treatment is associated with important adverse events and relapses occurred in patients with low cumulative doses. As an alternative, IS treatment with rituximab could be an interesting option in those patients.

Tumefactive Inflammatory Diseases of the Pancreas

Advances in the past two decades have resulted in the recognition of several tumefactive pancreatic lesions that, on histologic evaluation, show a varying combination of inflammation and fibrosis. Autoimmune pancreatitis, the prototypic tumefactive pancreatic fibroinflammatory lesion, is composed of two distinct diseases, type 1 autoimmune pancreatitis and the less common type 2 autoimmune pancreatitis. Although designated as autoimmune pancreatitis, the two diseases show little morphologic or pathogenic overlap. In type 1 disease, subsets of T lymphocytes (type 2 helper T cells, regulatory T cells, and T follicular helper 2 cells) are hypothesized to drive the inflammatory reaction. The B-cell response is characterized by an oligoclonal expansion of plasmablasts, with dominant clones that vary among patients and distinct clones that emerge at the time of relapse. Although the precise role of IgG4 in this condition remains uncertain, recent studies suggest that other IgG subclasses (eg, IgG1) may mediate the immune reactions, whereas IgG4 represents a response to dampen excessive inflammation. A recent study of type 2 autoimmune pancreatitis highlights the role of CXCL8 (alias IL-8), with duct epithelium and infiltrating T lymphocytes expressing this chemokine; the latter may contribute to the distinct form of neutrophilic inflammation in this disease. The review also highlights other forms of mass-forming chronic pancreatitis: follicular pancreatitis, groove pancreatitis, and those associated with rheumatologic diseases.

A feasible CT feature to differentiate focal-type autoimmune pancreatitis from pancreatic ductal adenocarcinoma

BACKGROUND

To investigate whether the relative computed tomography (CT) value (rCT) of adjacent pancreatic parenchyma can distinguish focal-type autoimmune pancreatitis (fAIP) from pancreatic ductal adenocarcinoma (PDAC).

METHODS

A total of 13 patients with fAIP and 20 patients with PDAC were included in this study. The rCT was calculated as the ratio of the CT value of adjacent pancreatic parenchyma to that of muscle. The diagnostic performance of rCT for discriminating fAIP from PDAC was evaluated using receiver operating characteristic (ROC) analysis.

RESULTS

Both fAIP and PDAC presented hyper-fibrosis histologically and delayed enhancement on CT examination. Moreover, the pancreatic parenchyma of fAIP presented serious inflammation. The mean rCT of the parenchyma was significantly lower in fAIP than in PDAC in all phases. The best diagnostic performance of the rCT value was found in the pancreatic phase, with an area under the ROC curve of 0.912, while the areas under the ROC curve of the portal and delayed phases were 0.812 and 0.754, respectively. The optimal cut-off value for distinguishing fAIP from PDAC was 1.62 in the pancreatic phase.

CONCLUSIONS

The rCT of the pancreatic parenchyma during the pancreatic phase may be a feasible CT feature for differentiating fAIP from PDAC.

IgG4-Related Disease with Esophageal Involvement

We report the case of a 56-year-old man who presented with dysphagia and weight loss. An esophagoduodenoscopy revealed a severe esophageal stricture in the distal esophagus. After surgical resection, the final pathologic analysis revealed that the tumor was comprised of benign-appearing fibroinflammatory cells with an increase and predominance of IgG4-positive plasma cells. He did not, however, have any other symptoms indicative of systemic autoimmune disease or connective tissue disorders. Histologically, abundant infiltration of IgG4-positive plasma cells and lymphocytes was observed. The patient was diagnosed with IgG4-related disease, definitive, with esophageal involvement.

Autoimmune Pancreatitis and IgG4-Related Disease: The Storiform Discovery to Treatment

Autoimmune pancreatitis (AIP) is an entity that has been recognized since 1961. Prior to the discovery of elevated serum IgG4 as a useful biomarker for its diagnosis, Dr. Yoshida in 1995 first described the entity of AIP, which in retrospect closely resembles the current concept of type 1 AIP. Since the discovery of IgG4 as a biomarker (the IgG4-era), a novel concept of IgG4-related disease (IgG4-RD) has been accepted as being comprised of two subtypes of AIP: type 1 defined as the pancreatic manifestation of IgG4-RD, and type 2 characterized by granulocytic epithelial lesions. The characteristic features of type 1 AIP are increased serum IgG4 levels, lymphoplasmacytic sclerosing pancreatitis (abundant infiltration of IgG4+ plasmocytes and lymphocytes, storiform fibrosis, and obliterative phlebitis), extrapancreatic manifestations of IgG4-RD (e.g., sclerosing cholangitis, sclerosing sialadenitis, retroperitoneal fibrosis), and steroid responsiveness. These entities can be differentiated from mimickers by a combination of serum IgG4 level, imaging features, and histopathological findings. The current first-line therapy is corticosteroids, or rituximab in high-risk patients with steroid intolerance. Although relapse rates are high, treatment of relapsed disease remains experimental.

Management of IgG4-related disease

IgG4-related disease was unrecognised as a unified disease entity until this century, yet in a short period of time the disease has been appreciated to have a worldwide distribution, and its clinical, pathological, and radiological features have been described in considerable detail. The disease has strong organ predilections, and many of the clinical presentations of disease are increasingly familiar to both generalists and specialists. Early recognition of IgG4-related disease is crucial because although the disease is highly treatable, it can lead to serious organ damage and even death if undiagnosed until advanced stages. Its indolent nature often makes diagnosis challenging, and IgG4-related disease is one of the great mimickers of other diseases in the current era. Glucocorticoids are an effective treatment for IgG4-related disease, but their long-term use is problematic in a disease that frequently affects middle-aged to elderly individuals and often leads to pancreatic dysfunction. Our understanding of the pathophysiology of the disease is surprisingly advanced given the relatively recent recognition of this condition. Insights into disease pathophysiology offer the possibility of a variety of targeted treatment approaches. Looking ahead, biological therapies could profoundly alter the way in which IgG4-related disease is managed, permitting the use of specific therapies that are tailored to patients' clinical phenotypes.

Pancreatic tumor in type 1 autoimmune pancreatitis: a diagnostic challenge

Background

The co-occurrence of type 1 autoimmune pancreatitis (AIP) and pancreatic tumor (PaT) has been previously reported. Pure AIP cases have favorable prognosis and are primarily treated with steroids, while AIP cases with PaT are associated with poor prognosis where the primary management is pancreatic resection. However, it’s a challenge to timely identify the concurrent PaT in AIP because of their similar clinical and radiological manifestations.

Methods

We retrospectively reviewed the data in two medical centers from January 2010 to April 2019. The inclusion criteria were as follows: 1) completion of abdominal CT imaging before invasive procedures to the pancreas, 2) a final diagnosis of type 1 AIP using the 2011 international consensus diagnostic criteria, 3) follow-up duration of at least one month unless AIP and PaT were identified simultaneously. The presence of PaT in AIP was made based on histopathological confirmation, and the absence of PaT in AIP was defined as no pathological or radiological evidence of concurrent PaT. Clinical and radiological characteristics including gender, age, surveillance period, serum IgG4 and Ca-199 levels, biopsy, extrapancreatic involvement, CT and MR (if performed) imaging characteristics were compared between AIP with and without PaT. The Fisher’s exact test was used for qualitative variables, and nonparametric Mann-Whitney test for quantitative variables. A p value ≤0.05 was considered statistically significant.

Results

A total of 74 patients with type 1 AIP were included, of which 5 (6.7%) had the concurrent PaT. The subtypes were pancreatic ductal adenocarcinoma (3/5), solitary extramedullary plasmacytoma in the pancreas (1/5) and cholangiocarcinoma in the pancreatic segment (1/5), respectively. Gender (p = 0.044), the pattern of pancreatic enlargement (p = 0.003), heterogeneity (p = 0.015), low-density (p = 0.004) on CT and rim enhancement on MRI (p = 0.050) differed significantly between AIP with and without PaT. None of the low-density characteristics on CT or other assessed MRI characteristics could significantly differentiate the two groups (p>0.05).

Conclusions

Female, focal pancreatic enlargement, pancreatic heterogeneity, low-density on CT and rim enhancement on MRI are suggestive of the concurrent PaT in type 1 AIP. The characteristics of low-density on CT or other MRI characteristics did not provide further diagnostic values.