Clinical implications of elevated serum interleukin-6 in IgG4-related disease

IgG4-related autoimmune pancreatitis and sclerosing cholangitis: A case report and literature review

RATIONALE

Immunoglobulin G4-related disease (IgG4-RD) can involve various organs throughout the body, primarily manifesting as endocrine dysfunction, visual impairment, jaundice, and limited sexual function. IgG4-related autoimmune pancreatitis is triggered by autoimmune reactions and characterized by structural changes in the pancreas and pancreatic ducts. The disease mainly affects middle-aged and elderly males, typically presenting as progressive painless jaundice and misdiagnosed as cholangiocarcinoma or pancreatic cancer.

PATIENT CONCERNS

This study reports a 54-year-old male who consulted with different institutions multiple times due to diabetes, pancreatitis, elevated liver enzymes, and jaundice.

DIAGNOSES

Magnetic resonance imaging revealed swollen head of the pancreas and atrophic tail. Liver and pancreatic tissue pathology showed IgG4 plasma cell infiltration, while liver biopsy indicated interface hepatitis, liver fibrosis, and pseudolobule formation, with no evidence of bile duct damage.

INTERVENTIONS

Following hormone therapy, the patient's serum IgG4 levels and liver enzyme levels returned to normal.

OUTCOMES

The disease relapsed 2 years after maintaining hormone therapy, and the patient underwent additional hormone-induced remission therapy combined with azathioprine.

LESSONS

The purpose of this research report is to enhance the awareness and understanding of IgG4-RD, emphasizing the necessity for personalized treatment strategies that take into account its recurrence, associations, and imaging features. This report provides valuable insights and guidance for clinicians in managing and diagnosing patients with IgG4-RD.

Unmet needs in biomarkers for autoimmune pancreatitis diagnosis

Autoimmune pancreatitis (AIP) is a rare chronic autoimmune disorder. The diagnosis of AIP mainly depends on histopathology, imaging and response to treatment. Serum immunoglobulin 4 (IgG4) is used only as collateral evidence in diagnostic criteria for AIP because of its moderate sensitivity. Serum IgG4 levels are normal in 15%-37% of type 1 AIP and most of type 2 AIP patients. In these patients, the indeterminate imaging and histopathology may lead to the difficulty in definitive diagnosis of AIP. Therefore, discovery of new biomarkers is important for AIP diagnosis. Here, we provide some views on the progression and challenges in identifying novel serological biomarkers in AIP diagnosis.

Long-term Outcomes after Steroid Pulse Therapy in Patients with Type 1 Autoimmune Pancreatitis

Objective Steroid pulse therapy is a regimen involving the intravenous administration of supra-pharmacological doses of corticosteroids in the short term. It is used to treat various inflammatory and autoimmune conditions. However, the strengths and limitations of steroid pulse therapy for induction of remission in type 1 autoimmune pancreatitis (AIP) are unknown. Methods Depending on the steroid therapy regimen administered, the 104 patients with type 1 AIP included in this retrospective study were divided into three groups: conventional oral prednisolone (PSL) regimen (PSL group), intravenous methylprednisolone (IVMP) pulse followed by oral PSL regimen (Pulse+PSL group), and IVMP pulse-alone regimen (Pulse-alone group). We then examined the relapse rate and adverse events among the three groups. Results The Kaplan-Meier estimates of the relapse rate at 36 months after steroid therapy were 13.6% in the PSL group, 13.3% in the Pulse+PSL group, and 46.2% in the Pulse-alone group. The log-rank test revealed that the relapse-free survival in the Pulse-alone group was significantly shorter than that in the PSL (p=0.024) and Pulse+PSL groups (p=0.014). The exacerbation of glucose tolerance after steroid therapy was less frequently observed in the Pulse-alone group (0%) than in the PSL group (17%, p=0.050) and Pulse+PSL groups (26%, p=0.011). Conclusion Although treatment with IVMP pulse alone resulted in unsatisfactory relapse prevention outcomes compared with conventional steroid therapy, the IVMP pulse-alone regimen might be an alternative treatment strategy for type 1 AIP from the perspective of avoiding adverse events from steroids.

Primary sclerosing encapsulating peritonitis: a case report

BACKGROUND

Sclerosing encapsulating peritonitis is a rare condition with a typical macroscopic appearance, with fibrocollagenous membrane enclosing loops of the small intestine, causing intestinal obstruction. Unexplained recurrent abdominal pain, obstruction, and a large array of other possible clinical signs and symptoms make sclerosing encapsulating peritonitis a diagnostic challenge.

CASE PRESENTATION

A 48-year-old man of Persian ethnicity was admitted multiple times to the emergency surgery department due to recurrent sudden abdominal pain and chronic obstruction without significant findings in medical history or clinical evaluation. Computed tomography was positive for proximal jejunal dilatation and duodenojejunal flexure stenosis due to internal mesenteric hernia. Exploratory laparoscopy, followed by laparotomy, confirmed thick membrane-like fibrous tissue with complete small intestinal loop envelopment. Extensive membrane excision and adhesiolysis was performed, but no mesenteric herniation was found. Early postoperative paralytic ileus with introduction of low-dose steroid therapy, based on histopathological and immunological results, confirming type III sclerosing encapsulating peritonitis, was completely resolved.

CONCLUSION

Sclerosing encapsulating peritonitis is a rare and difficult-to-diagnose condition, further divided into primary and secondary sclerosing encapsulating peritonitis, on the basis of underlying etiology, dictating treatment modality and prognosis. Intraoperative diagnosis and surgical treatment are mandatory, besides a wide variety of abdominal computed tomography scans, inconclusive results, and clinical presentations. There are so far no known specific markers for the diagnosis of sclerosing encapsulating peritonitis.

Correlation between serologic parameters and disease activity of IgG4-related disease: Differences between patients with normal and elevated serum IgG4 concentrations

Objective

We aimed to identify serologic parameters that correlate with the disease activity of IgG4-related disease (IgG4-RD) in patients with normal and elevated serum IgG4 concentrations, respectively.

Methods

This retrospective cohort study included 148 patients with IgG4-RD. Patients were categorized into normal (≤201 mg/dL) and elevated (>201 mg/dL) serum IgG4 concentration groups. Disease activity was assessed using the IgG4-RD responder index (RI). The correlations between IgG4-RD RI and serologic parameters (erythrocyte sedimentation rate [ESR], C-reactive protein, C3, C4, IgG4 concentration, IgG concentration, and IgG4/IgG ratio) were evaluated in each group, using Spearman’s correlation coefficient.

Results

Of the 148 patients with IgG4-RD, 38 (25.7%) and 110 (74.3%) patients were categorized into the normal and elevated serum IgG4 concentration groups, respectively. In the normal serum IgG4 concentration group, IgG concentration was the only serologic parameter that showed a significant correlation with IgG4-RD RI (rho=0.411, p=0.013). However, in the elevated serum IgG4 concentration group, ESR (rho=0.196, p=0.041), C3 (rho=-0.432, p<0.001), C4 (rho=-0.363, p=0.001), IgG4 concentration (rho=0.423, p<0.001), IgG concentration (rho=0.224, p=0.020), and IgG4/IgG ratio (rho=0.328, p=0.001) correlated with IgG4-RD RI. The combination of C3 and IgG4 concentration (rho=0.509, p<0.001) had the strongest correlation with IgG4-RD RI in this group.

Conclusion

Among the serologic parameters tested, IgG concentration was the only parameter that correlated with IgG4-RD RI in patients with normal serum IgG4 concentrations, whereas multiple parameters correlated with IgG4-RD RI in those with elevated serum IgG4 concentrations. The combination of C3 and IgG4 concentration had the strongest correlation coefficient in the latter group.

Management of retroperitoneal fibrosis with endovascular aneurysm repair in patients refractory to medical management

Background

Early diagnosis and treatment of under-recognized retroperitoneal fibrosis (RPF) are essential before reaching the poorly responsive fibrotic stage. Although most patients respond to medical therapy, relapses and unresponsiveness are common. However, open surgery in medically resistant patients is associated with major adverse clinical events.

Methods

This is a single-centre longitudinal study of optimal medical therapy (OMT) vs. endovascular aneurysm repair (EVAR) in patients presenting with RPF to our tertiary referral vascular centre. Out of 22,349 aortic referrals, we performed 1,555 aortic interventions over twenty years. Amongst them, 1,006 were EVAR, TEVAR and BEVAR. Seventeen patients (1.09%) had documented peri-aortic RPF.

Results

Out of the 17 RPF patients, 11 received OMT only, while 6 underwent EVAR after the failure of OMT. 82% (n = 14) were male, and the median follow-up was 62.7 months (IQR: 28.2–106). Nine (52%) had immunoglobulin G4-related disease (4 OMT vs. 5 EVAR). EVAR patients had 100% technical success without perioperative mortality. Furthermore, all the EVAR patients were symptom-free following the intervention. Pre-operative aortic RPF index (maximum peri-aortic soft tissue diameter/maximum aortic diameter) was higher in the EVAR than in OMT. However, there was a significant decrement in the aortic RPF index following EVAR (P = 0.04).

Conclusion

We believe that when optimal medical therapy fails in RPF, EVAR provides a promising outcome. Further studies are recommended to establish the role of endovascular repair.

An Autopsy Case of Multicentric Castleman Disease Presenting with Severe Jaundice

A 70-year-old man with multicentric Castleman disease (MCD) was admitted to our hospital with jaundice and ascites. Elevations in his bilirubin and interleukin-6 levels were noted, and computed tomography revealed hepatic atrophy and portal vein and bile duct disorders. Steroid therapy was started for MCD, but he died of hepatic failure. An autopsy revealed that the MCD activity was mild, but advanced fibrosis and cholestasis were observed in the liver. Mild infiltration of interleukin-6-positive plasma cells was noted in the highly fibrotic area of the liver. Although rare, liver and biliary tract damage may be also considered organ disorders of MCD.

IL-6 expression helps distinguish Castleman's disease from IgG4-related disease in the lung

Background

It is difficult to distinguish between multicentric Castleman’s disease (MCD) and IgG4-related lung disease (IgG4-LD), an IgG4-related disease (IgG4-RD) in the lung.

Methods

We focused on IL-6, which is elevated in MCD, to distinguish between MCD and IgG4-LD by RNAscope, a highly sensitive RNA in situ method. Six cases of MCD and four cases of IgG4-LD were selected.

Results

In all cases of MCD and IgG4-LD, 10 or more IgG4-positive cells were found in one high-power field. All MCD cases were inconsistent with the pathological IgG4-related comprehensive diagnostic criteria, but 2 of 6 cases had an IgG4/IgG ratio greater than 40%. In all IgG4-LD cases, histological features were consistent with the pathological IgG4-RD comprehensive diagnostic criteria. IL-6 expression was observed in all MCD and IgG4-LD cases except for one IgG4-LD biopsy. IL-6-expressing cells were mainly identified in the stroma. Sites of IL-6 expression were not characteristic and were sparse. IL-6 expression tended to be higher in MCD compared with IgG4-LD. A positive correlation was found between the IL-6 H-score and serum IL-6 level.

Conclusion

Differences in IL-6 expression may help distinguish between MCD and IgG4-LD. In addition, the presence of high IL-6 levels may help elucidate the pathological mechanisms of IgG4-LD.

Biomarkers in autoimmune pancreatitis and immunoglobulin G4-related disease

Solitary organ autoimmune disorders, formerly known as autoimmune pancreatitis (AIP), autoimmune sialadenitis, and autoimmune sclerosing cholangitis, are now considered organ-specific manifestations of systemic immunoglobulin G4-related disease (IgG4-RD). AIP and IgG4-RD are characterized by elevated serum concentration of IgG4 antibody (Ab), accumulation of IgG4-expressing plasmacytes in the affected organs, and involvement of multiple organs. It is well established that enhanced IgG4 Ab responses are a hallmark of AIP and IgG4-RD for diagnosis and monitoring disease activity. However, a significant fraction of patients with AIP and IgG4-RD who develop chronic fibroinflammatory responses have normal serum concentrations of this IgG subtype. In addition, disease flare-up is sometimes seen even in the presence of normalized serum concentrations of IgG4 Ab after successful induction of remission by prednisolone. Therefore, it is necessary to identify new biomarkers based on the understanding of the pathophysiology of AIP and IgG4-RD. Recently, we found that activation of plasmacytoid dendritic cells producing both interferon-α (IFN-α) and interleukin-33 (IL-33) mediate murine AIP and human IgG4-RD. More importantly, we provided evidence that serum concentrations of IFN-α and IL-33 could be useful biomarkers for the diagnosis and monitoring of AIP and IgG4-RD activity after induction of remission in these autoimmune disorders. In this Frontier article, we have summarized and discussed biomarkers of AIP and IgG4-RD, including Igs, autoAbs, and cytokines to provide useful information not only for clinicians but also for researchers.

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.