Autoimmune pancreatitis: A review

Acute Pancreatitis: A Possible Side Effect of COVID-19 Vaccine

For the first time, the mRNA technology was utilized to produce a vaccine against COVID-19 after the unprecedented pandemic equally affected every part of the world. Pfizer-BioNTech (BNT162b2) mRNA vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was granted emergency use authorization (EUA) by Food and Drug Administration (FDA) in December 2020. EUA has been widely discussed in the medical literature and the general public. The safety of the BNT162b2 vaccine has been investigated in short-term trials with data available for three months. We present a case of a 96-year-old female with a past surgical history of cholecystectomy who presented with acute onset severe abdominal pain a few days after getting the first dose of Pfizer-BioNTech COVID-19 vaccine. She was diagnosed with acute pancreatitis with a lipase level of 4036 U/L. Extensive history and investigations were unable to find any etiology. The patient was conservatively managed and discharged home without any complications. There has been some data available in medical literature showing an association between acute pancreatitis and COVID-19 infection. Trial data of Pfizer COVID-19 also shows one case of acute pancreatitis in the treatment group. There have also been individual cases of unexplained acute pancreatitis shared by medical professionals on online forums. Our main goal to write this case is to make medical literature aware of possible emerging side effects of the COVID-19 vaccine, one of such side effects being self-resolving uncomplicated acute pancreatitis.

Serum Immunoglobulin G4 in Discriminating Autoimmune Pancreatitis From Pancreatic Cancer: A Diagnostic Meta-analysis

OBJECTIVE

Differentiation between autoimmune pancreatitis (AIP) and pancreatic cancer (PC) is a clinical challenge. Emerging published data on the accuracy of serum immunoglobulin G4 (IgG4) for the differential diagnosis between AIP and PC are inconsistent. The objective of our study was to perform a meta-analysis evaluating the clinical utility of serum IgG4 in the differential diagnosis between AIP and PC.

METHODS

We performed a systematic literature search of multiple electronic databases. The methodological quality of each study was assessed according to the Quality Assessment of Diagnostic Accuracy Studies checklist. Random-effects model was used to summarize the diagnostic odds ratio and other measures of accuracy.

RESULTS

Eleven studies comprising 523 AIP patients and 771 PC patients were included in the meta-analysis. The summary estimates for serum IgG4 in distinguishing AIP from PC were as follows: diagnostic odds ratio, 57.30 (95% confidence interval [CI], 23.17-141.67); sensitivity, 0.72 (95% CI, 0.68-0.76); specificity, 0.93 (95% CI, 0.91-0.94). The area under the curve of serum IgG4 in distinguishing AIP from PC was 0.9200.

CONCLUSIONS

Our meta-analysis found that serum IgG4 has high specificity and relatively low sensitivity in the differential diagnosis between AIP and PC. Therefore, serum IgG4 is useful in distinguishing AIP from PC.

Acute Pancreatitis in Pediatric Patients: Demographics, Etiology, and Diagnostic Imaging

OBJECTIVE

The objective of this article is to provide updates on acute pancreatitis in children regarding the imaging findings, causes, and complications based on a review of the current studies in the pediatrics literature. We discuss the epidemiology of acute pancreatitis, the role of imaging and imaging findings in the diagnosis of acute pancreatitis, and the causes and complications of acute pancreatitis.

CONCLUSION

The incidence of acute pancreatitis is increasing in children. Imaging plays an important role in the diagnosis of acute pancreatitis because imaging findings can be used to establish the cause of acute pancreatitis, evaluate for complications of acute pancreatitis, and possibly predict the course of the disease.

Autoimmune Pancreatitis Presenting with Mass and Biliary Obstruction

We report a case of autoimmune pancreatitis in a 31-year-old man with signs and symptoms of biliary tract obstruction. Evaluation with sonography, computed tomography, and ultimately endoscopic retrograde cholangiopancreatography, demonstrated a 5 by 2 cm hypoechoic, hypodense mass near the head of the pancreas that extended into the porta hepatis. Common bile duct obstruction with proximal dilatation was present. Following fine needle aspiration of the mass, cytology showed findings consistent with autoimmune pancreatitis. Treatment with common bile duct stent was followed by resolution of the patient's symptoms.

RNA recognition by human TLR8 can lead to autoimmune inflammation

High expression level of human TLR8 in mice results in spontaneous, multiorgan inflammation attributable in part to increased DC activation.

Studies on the role of the RNA receptor TLR8 in inflammation have been limited by its different function in human versus rodents. We have generated multiple lines of transgenic mice expressing different levels of human TLR8. The high copy number chimeras were unable to pass germline; developed severe inflammation targeting the pancreas, salivary glands, and joints; and the severity of the specific phenotypes closely correlated with the huTLR8 expression levels. Mice with relatively low expression levels survived and bred successfully but had increased susceptibility to collagen-induced arthritis, and the levels of huTLR8 correlated with proinflammatory cytokines in the joints of the animals. At the cellular level, huTLR8 signaling exerted a DC-intrinsic effect leading to up-regulation of co-stimulatory molecules and subsequent T cell activation. A pathogenic role for TLR8 in human diseases was suggested by its increased expression in patients with systemic arthritis and the correlation of TLR8 expression with the elevation of IL-1β levels and disease status. We found that the consequence of self-recognition via TLR8 results in a constellation of diseases, strikingly distinct from those related to TLR7 signaling, and points to specific inflammatory diseases that may benefit from inhibition of TLR8 in humans.

Primary sclerosing cholangitis associated with elevated immunoglobulin-g4: a preliminary study

Background. Immunoglobulin IgG4-associated cholangitis (IAC) disease is a systemic disease histologically characterized by extensive T lymphocytes and IgG4 positive plasma cell infiltration in various organs. Prevalence of IAC in PSC patients was reported to be between 7% and 11.6% in a few previous studies. This study was carried out to evaluate frequency of serum IgG4 level in PSC patient referred to the gastroenterology ward of Taleghani educational hospital in Tehran, Iran. Material and Methods. This study was a prospective analytical cross-sectional study. Clinical presentation, laboratory values, imaging changes, inflammatory bowel disease (IBD), esophageal varices, ascites, and child score in newly PSC patients with elevated IgG4 were determined and compared with PSC patients with normal levels of IgG4. Data was analyzed by using SPSS software. The frequency and standard deviations were calculated. Differences among groups were evaluated by using the chi-square, fisher exact, and Mann-Whitney U tests. Results. 34 patients with PSC were examined in the study period, of which 9 cases (26.5%) had high IgG4 levels. Most of the patients were male, 23 cases (67.6%) and nonsmoker, 26 cases (76.5%). Patient average age was 47 years old (range 21-67 years). There was not any significant relationship among patients with IAC and PSC patients in terms of variables such as age, smoking, presence of IBD, ascites, esophageal varices, child score, and imaging findings (P > 0.05). Conclusion. IAC should be suspected in cases of unexplained biliary strictures with increased serum IgG4. Testing PSC patients for IgG4 and treating those who have high levels with corticosteroids in clinical trials should be considered in future studies.

Autoimmune pancreatitis characterized by predominant CD8+ T lymphocyte infiltration

Autoimmune pancreatitis (AIP) is a rare form of pancreatitis characterized by prominent lymphocyte infiltration and pancreatic fibrosis resulting in organ dysfunction. The pathogenesis and pathology of AIP remain unknown. A 64-year-old Chinese man presented with symptoms and signs of bile duct obstruction diffuse enlargement of the head of pancreas, elevated IgG levels, and negative autoimmune antibody responses. A pylorus-preserving pancreatoduodenectomy was performed and a pancreatic tumor was suspected. However, periductal lymphoplasmacytic infiltration and fibrosis were found in the head of pancreas and nearby organs instead of tumor cells. Four months after surgery, the patient was readmitted because of reoccurrence of severe jaundice and sustained abdominal distension. Prednisone 30 mg/d was administered orally as an AIP was suspected. One and a half months later, the symptoms of the patient disappeared, and globulin, aminotransferase and bilirubin levels decreased significantly. Over a 9-mo follow-up period, the dose of prednisone was gradually decreased to 10 mg/d and the patient remained in good condition. We further demonstrated dominant CD3+/CD8+ populations, CD20+ cells and a few CD4+ cells in the pancreatic parenchyma, duodenum and gallbladder wall by immunohistochemical assay. This AIP case presented with significant CD8+ T lymphocyte infiltration in the pancreas and extra-pancreatic lesions, indicating that this cell population may be more important in mediating AIP pathogenesis than previously known and that AIP might be a poorly defined autoimmune disease with heterogeneous pathogenesis.

Incidence of benign disease in patients that underwent resection for presumed pancreatic cancer diagnosed by endoscopic ultrasonography (EUS) and fine-needle aspiration (FNA)

INTRODUCTION

The lack of accurate markers makes preoperative differentiation between pancreatic cancer and non-malignant head lesions clinically challenging. In this study, we investigated the incidence of benign disease in patients that underwent resection for presumed pancreatic cancer diagnosed by EUS and EUS-guided FNA.

METHODS

Medical records of consecutive patients who underwent pancreaticoduodenectomy at Duke University were reviewed. Demographics, clinicopathologic characteristics, preoperative imaging, EUS, EUS-guided FNA, and postoperative outcomes were analyzed.

RESULTS

Seven percent of the total 494 patients studied were found to have benign disease on postoperative pathology. Fifty-nine percent of these patients with benign disease underwent preoperative EUS. EUS was positive for a head mass in 70%, demonstrated enlarged lymph nodes in 27%, and showed signs concerning for vascular invasion in 13%. FNA was suspicious or indeterminate for cancer in 63% of patients. Postoperative complications occurred in 47% and one patient died after surgery. The overall pancreatic leak rate was 15%.

CONCLUSIONS

Even with aggressive use of preoperative evaluation, there is still a small subset of patients where malignancy cannot be excluded without pancreaticoduodenectomy.

Toll-like receptor 3 signaling induces chronic pancreatitis through the Fas/Fas ligand-mediated cytotoxicity

Innate immunity plays important roles in host defense against pathogens, but may also contribute to the development of autoimmune diseases under certain conditions. Toll-like receptors (TLRs) recognize various pathogens and induce innate immunity. We herein present a mouse model for chronic pancreatitis, which was induced by TLR3 signaling that generated the Fas/Fas ligand (FasL)-mediated cytotoxicity. An analogue of viral double-stranded RNA, polyinosinic:polycytidylic acid (poly I:C), which is recognized by TLR3, was injected into autoimmune-prone strains: MRL/Mp mice (MRL/+), MRL/Mp mice with a deficit of Fas (MRL/lpr) and MRL/Mp mice with a deficit of functional FasL (MRL/gld). The pancreatitis in MRL/+ mice was initiated by the destruction of pancreatic ductules, and its severity was significantly higher than that in MRL/lpr mice or MRL/gld mice. Using a pancreatic duct epithelial cell line MRL/S-1 newly established from the MRL/gld mouse that lacks FasL, we showed that treatment with poly I:C significantly induced the expression of Fas on the cultured cells. MRL/S-1 cells were destructed when co-cultured with splenocytes bearing intact FasL prepared from MRL/+ or MRL/lpr mice, but the magnitude of cytotoxicity was smaller with splenocytes of MRL/gld mice. Likewise, synthetic FasL protein showed cytotoxicity on MRL/S-1 cells. Furthermore, MRL/S-1 cells expressed higher levels of chemokines after the treatment with poly I:C, suggesting that the poly I:C-mediated induction of chemokines may be responsible for recruitment of lymphoid cells to the pancreatic periductular regions. These findings indicate that TLR3 signaling generates the Fas/FasL-mediated cytotoxicity, thereby leading to the development of chronic pancreatitis.

Autoimmune pancreatitis in an 11-year-old boy

We report a case of histopathologically proven autoimmune pancreatitis in an 11-year-old boy. Abdominal US and MRI showed a focal swelling of the pancreatic head, the latter also showing delayed contrast enhancement. There was diffuse irregular pancreatic duct narrowing, compression of the intrapancreatic common bile duct, and mild proximal biliary dilatation on MR cholangiopancreatography. Laboratory results revealed normal serum IgG and subclass 4 with negative autoimmune antibodies, and slightly elevated carbohydrate antigen 19-9. This highlights the differentiation of autoimmune pancreatitis from pancreatic head cancer and, to a lesser extent, other forms of pancreatitis in children.