Association between serum IgE level and adverse clinical endpoints in primary sclerosing cholangitis

Autoimmune Biliary Diseases: A Review of Primary Biliary Cholangitis, Primary Sclerosing Cholangitis, Immunoglobulin G4-Related Sclerosing Cholangitis, and Autoimmune Hepatitis

Autoimmune and immune-mediated biliary diseases represent a small proportion of biliary disorders, but owing to their progressive nature, lead to end-stage liver disease, necessitating liver transplantation for definitive management.

The Role of Inflammation in Cholestatic Liver Injury

Cholestasis is a common clinical event in which bile formation and excretion are blocked, leading to retention of bile acids or bile salts; whether it occurs intra- or extrahepatically, primary or secondary, its pathogenesis is still unclear and is influenced by a combination of factors. In a variety of inflammatory and immune cells such as neutrophils, macrophages (intrahepatic macrophages are also known as Kupffer cells), mast cells, NK cells, and even T cells in humoral immunity and B cells in cellular immunity, inflammation can be a "second strike" against cholestatic liver injury. These cells, stimulated by a variety of factors such as bile acids, inflammatory chemokines, and complement, can be activated and accumulate in the cholestatic liver, and with the involvement of inflammatory mediators and modulation by cytokines, can lead to destruction of hepatocytes and bile duct epithelial cells and exacerbate (and occasionally retard) the progression of cholestatic liver disease. In this paper, we summarized the new research advances proposed so far regarding the relationship between inflammation and cholestasis, aiming to provide reference for researchers and clinicians in the field of cholestatic liver injury research.

Allergic manifestations in autoimmune gastrointestinal disorders

Allergic disorders target a young population, are increasing in both incidence and prevalence and are associated with significant disease burden. They result from the complex interplay between (epi)genetic and environmental factors, resulting in a Th2 inflammatory process targeting the epithelium of the respiratory tract (allergic rhinitis and asthma), skin (atopic dermatitis), and gastrointestinal tract (food allergy). Although the exact pathogenic mechanisms remain elusive, an altered immune system response in the gut is increasingly recognized as a relevant step. Allergic and gastrointestinal autoimmune disorders share several epidemiological, pathogenic and risk factors and several treatment modalities. Here we revise the current literature and show that allergic disorders are highly prevalent in gastrointestinal autoimmune diseases, including celiac disease, inflammatory bowel disease, autoimmune pancreatitis, and autoimmune cholangiopathies. No data are available for some autoimmune diseases, such as autoimmune gastritis and autoimmune enteropathy. To ensure the comprehensive care of patients with autoimmune gastrointestinal disorders, along with disease-specific factors, the presence of allergic disorders should be evaluated and treated when present, possibly targeting shared molecular pathways. Future studies are needed to define the exact pathogenic mechanisms underpinning the association between allergic and autoimmune diseases of the gastrointestinal tract.

Blockade of BAFF Reshapes the Hepatic B Cell Receptor Repertoire and Attenuates Autoantibody Production in Cholestatic Liver Disease

Defects in biliary transport proteins, MDR3 in humans and Mdr2 in mice, can lead to a spectrum of cholestatic liver disorders. Although B cell disorders and the aberrant Ab production are the leading extrahepatic manifestations of cholestatic liver diseases, the mechanism underlying this phenomenon is incompletely understood. Using mice with deficiency of Mdr2 that progressively develop cholestatic liver disease, we investigated the contributions of BAFF to aberrant IgG autoantibody production and hepatic fibrosis. In Mdr2^-/- mice, hepatic B lymphocytes constitutively produced IgG during fibrosis progression, which correlated with elevated serum levels of BAFF, antinuclear Abs (ANA) and immune complexes. The elevated BAFF and ANA titers were also detected in human patients with primary sclerosing cholangitis and hepatobiliary cholangiopathies. Consistent with the higher BAFF levels, liver-specific selection of the focused BCR IgH repertoire was found on hepatic B cells in Mdr2^-/- mice. Interestingly, the administration of anti-BAFF mAb in Mdr2^-/- mice altered the BCR repertoire on hepatic B lymphocytes and resulted in reduced ANA and immune complex titers. However, anti-BAFF treatment did not attenuate hepatic fibrosis as measured by collagen deposition, hepatic expressions of collagen-1a, α-smooth muscle actin, and mononuclear cell infiltration (CD11b⁺ Ly-6c^hi monocytes and CD11b⁺ Gr1⁺ neutrophils). Importantly, depletion of B cells by anti-CD20 mAb reduced both hepatic fibrosis and serum levels of ANA and immune complexes. Our findings implicate B cells as the potential therapeutic targets for hepatic fibrosis and targeting BAFF specifically for attenuating the autoantibody production associated with cholestatic liver disease.

Association between serum IgG level and clinical course in primary sclerosing cholangitis

Background

Primary sclerosing cholangitis is a chronic cholestatic liver disease. The pathomechanism is still not fully understood, but there is evidence that immune-mediated processes may contribute to disease progression.

Methods

We studied the prognostic relevance of serum immunoglobulin G (IgG) elevated above the upper limit of normal as a marker for immune activation at initial diagnosis and its influence on transplantation-free survival in a well-defined cohort of PSC patients.

Results

The final study cohort comprises of 148 PSC patients. Elevated IgG levels were found in 66 patients (44.6%). Apart from their younger age at first diagnosis, there was no significant difference between patients with or without elevated IgG levels. The presence of a concomitant inflammatory bowel disease, an autoimmune hepatitis or immunosuppressive medication was equally distributed between both groups. Patients with elevated IgG levels reached the combined endpoint (34 (59.6%) vs. 23 (40.4%); p = 0.004) significantly more often and had reduced transplantation-free survival (Log-rank: 24.0 (10.2–37.9) vs. 14.0 (8.5–19.5); p < 0.05). Cox regression analysis including age, gender, presence of IBD, presence of dominant stricture (DS), Mayo Risk Score (MRS), immunosuppression, biochemical response to UDCA and elevated IgG-levels confirmed MRS (p = 0.03), DS (p = 0.04), biochemical response (p = 0.04) and elevated IgG level (p = 0.04) as independent risk factors for reduced transplantation-free survival.

Conclusion

We identified elevated serum IgG levels at first diagnosis as an independent risk factor for reduced transplant free-survival in patients with PSC.

Primary sclerosing cholangitis: A review and update

Primary sclerosing cholangitis (PSC) is a rare, chronic, cholestatic liver disease of uncertain etiology characterized biochemically by cholestasis and histologically and cholangiographically by fibro-obliterative inflammation of the bile ducts. In a clinically significant proportion of patients, PSC progresses to cirrhosis, end-stage liver disease, and/or hepatobiliary cancer, though the disease course can be highly variable. Despite clinical trials of numerous pharmacotherapies over several decades, safe and effective medical therapy remains to be established. Liver transplantation is an option for select patients with severe complications of PSC, and its outcomes are generally favorable. Periodic surveillance testing for pre- as well as post-transplant patients is a cornerstone of preventive care and health maintenance. Here we provide an overview of PSC including its epidemiology, etiopathogenesis, clinical features, associated disorders, surveillance, and emerging potential therapies.

Duration of Inflammatory Bowel Disease Is Associated With Increased Risk of Cholangiocarcinoma in Patients With Primary Sclerosing Cholangitis and IBD

OBJECTIVES

Primary sclerosing cholangitis (PSC) often coexists with inflammatory bowel disease (IBD) and can be complicated by cholangiocarcinoma (CCA), a lethal malignancy for which reliable predictors remain unknown. We aimed to characterize the influence of colectomy and IBD duration on risk of CCA in patients with PSC-IBD.

METHODS

A retrospective review of patients with PSC-IBD seen at the Mayo Clinic, Rochester, between January 2005 and May 2013 was performed. The primary outcome was time to development of CCA and our goal was to determine whether the risk differed between patients with and without colectomy. Risk factors were assessed using univariable and multivariable Cox proportional hazard models where colectomy, IBD disease duration, and development of advanced liver disease were treated as time-dependent covariates.

RESULTS

A total of 399 patients with PSC-IBD were included in the study, of whom 137 had a colectomy and 123 patients developed CCA. Age-adjusted univariate Cox proportional hazard models demonstrated that colectomy (hazard ratio (HR) 1.53, 95% confidence interval (CI) 1.05-2.22, P=0.02) and duration of IBD (HR 1.37, 95% CI 1.15-1.63, P<0.01) were associated with an increased risk of CCA, and colonic neoplasia (HR 1.52, 95% CI 0.97-2.37, P=0.06) and colectomy for colonic neoplasia (HR 1.62, 95% CI 1.01-2.61, P=0.05) approached significance. Among patients with a history of colectomy, colonic neoplasia as the indication for surgery was associated with a particularly increased risk of CCA (HR 2.91, 95% CI 1.24-6.84, P=0.01) compared with medically refractory disease. On multivariate analysis, duration of IBD remained significantly associated with CCA (HR 1.33, 95% CI 1.11-1.60, P<0.01). The influence of IBD duration on CCA risk was not modified after colectomy (P=0.69).

CONCLUSIONS

Prolonged duration of IBD is associated with an increased risk of CCA in patients with PSC-IBD, and colectomy itself does not modify this risk. These findings identify a subset of patients who are at high risk of this lethal complication and in need of close surveillance.