Sclerosing cholangitis: a focus on secondary causes

Systematic review: management options for primary sclerosing cholangitis and its variant forms - IgG4-associated cholangitis and overlap with autoimmune hepatitis

BACKGROUND

Primary sclerosing cholangitis (PSC) remains a challenging disease to manage. The main goals are prevention of disease progression and reduction of the increased cancer risk.

AIMS

To review the management strategies for PSC and its variant forms based on published studies.

METHODS

Publications were identified using Pubmed, Medline and Ovid search engines.

RESULTS

Distinguishing PSC from variants, such as IgG4-associated cholangitis, and overlap with autoimmune hepatitis is essential to guide treatment decisions. There is no proven efficacious medical treatment for PSC. Ursodeoxycholic acid has been disappointing in low and moderate doses, and potentially dangerous in higher doses, although its role and optimal dose in chemoprevention requires investigation. The novel bile acid, 24-norursodeoxycholic acid, has shown promise in mouse models; human trials are in progress. Dominant strictures are optimally managed by dilatation and stenting to relieve obstructive complications, although exclusion of biliary malignancy is essential. Liver transplantation is the only proven therapy for those with advanced disease. Cholangiocarcinoma remains the most unpredictable and feared complication. In highly selected groups, neo-adjuvant chemoradiation with liver transplantation seems promising, but requires further validation. Screening for inflammatory bowel disease and surveillance for colorectal carcinoma should not be overlooked.

CONCLUSIONS

The effective management of PSC and its variants is hindered by uncertainties regarding pathogenesis of disease and factors responsible for its progression. Genome studies may help to identify further targets for drug therapy and factors leading to malignant transformation.

AIDS Cholangiopathy in an Asymptomatic, Previously Undiagnosed Late-Stage HIV-Positive Patient from Kenya

AIDS-associated cholangiopathy is a form of biliary tract inflammation with stricture formation seen in AIDS patients who are severely immunosuppressed. It is no longer common in countries in which HAART therapy is widely employed but is still seen in underdeveloped countries. The majority of patients are symptomatic at the time of presentation. Herein, we describe a seventy-four-year-old woman who presented with unilateral leg swelling after a prolonged airplane flight. She was otherwise entirely asymptomatic. Routine laboratory testing was notable for a hypochromic microcytic anemia, slight leukopenia, and mild hypoalbuminemia. Liver enzymes were all elevated. Deep venous thrombosis was confirmed, and a CT scan of the chest disclosed no pulmonary emboli. However, the visualized portion of the abdomen showed dilatation of the common bile and pancreatic ducts. This was confirmed on ultrasonography and MRCP, and no obstructive lesions were noted. An ERCP revealed a dilated common bile duct without filling defects or strictures. A balloon occlusion cholangiogram showed strictures and beading of the intrahepatic ducts. Shortly thereafter, serology for HIV returned positive along with a depressed CD4 cell count, and the patient was diagnosed with AIDS-associated cholangiography.

Pathogenesis of cholestatic liver disease and therapeutic approaches

Cholestatic liver disorders are caused by genetic defects, mechanical aberrations, toxins, or dysregulations in the immune system that damage the bile ducts and cause accumulation of bile and liver tissue damage. They have common clinical manifestations and pathogenic features that include the responses of cholangiocytes and hepatocytes to injury. We review the features of bile acid transport, tissue repair and regulation, apoptosis, vascular supply, immune regulation, and cholangiocytes that are associated with cholestatic liver disorders. We now have a greater understanding of the physiology of cholangiocytes at the cellular and molecular levels, as well as genetic factors, repair pathways, and autoimmunity mechanisms involved in the pathogenesis of disease. These discoveries will hopefully lead to new therapeutic approaches for patients with cholestatic liver disease.

Primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is a chronic bile duct disease leading to fibrotic biliary strictures and liver cirrhosis. The patient population is heterogeneous with regard to disease progression and the presence of co-morbidities, complicating the practical handling of patients as well as studies of pathogenetic mechanisms. The aetiology of PSC is unknown, but the recent findings of several robust susceptibility genes emphasise the importance of genetic risk factors. There is no effective medical treatment available to delay the disease progression, but endoscopic therapy of biliary stenoses may be indicated. Follow-up of patients includes management of the inflammatory bowel disease that is found in the majority of cases along with investigations aimed at the early detection of cholangiocarcinoma and colorectal cancer, which also occur at increased frequencies. In the present review, we aim to summarise the present knowledge of PSC with a particular emphasis on the possible basis of disease variability.

Treatment options for primary sclerosing cholangitis

Primary sclerosing cholangitis is a cholestatic liver disease characterized by inflammation and fibrosis of intra-/extrahepatic bile ducts, leading to multifocal strictures. Primary sclerosing cholangitis exhibits a progressive course resulting in cirrhosis and the need for liver transplantation over a median period of 12 years. The disease is frequently associated with inflammatory bowel disease and carries an increased risk of colorectal cancer and cholangiocarcinoma. Despite extensive research, there is currently no effective medical treatment. Multiple drugs are shown to be ineffective in halting disease progression, including ursodeoxycholic acid, the most widely evaluated drug. High-dose ursodeoxycholic acid (28-30 mg/kg/day) was recently shown to increase the adverse events rate. Endoscopic or radiological dilatation of a 'dominant' stricture may lead to symptomatic and biochemical improvement. However, liver transplantation is the only life-prolonging treatment for patients with end-stage disease. Studies with promising drugs, such as antibiotics, antifibrotic agents and bile acid derivatives, are eagerly awaited.

Update on primary sclerosing cholangitis

Early studies in primary sclerosing cholangitis (PSC) were concerned with disease characterization, and were followed by epidemiological studies of PSC and clinical subsets of PSC as well as a large number of treatment trials. Recently, the molecular pathogenesis and the practical handling of the patients have received increasing attention. In the present review we aim to give an update on the pathogenesis of PSC and cholangiocarcinoma in PSC, as well as to discuss the current opinion on diagnosis and treatment of PSC in light of the recent European Association for the Study of the Liver and the American Association for the Study of Liver Diseases practice guidelines.

Purine nucleoside phosphorylase deficiency with fatal course in two sisters

Purine nucleoside phosphorylase (PNP) deficiency is a rare combined immunodeficiency disorder presenting with clinically recurrent infections, failure to thrive, various neurological disorders, malignancies, and autoimmune diseases. Here, we report two sisters with a fatal course of PNP deficiency due to delay in diagnosis. The first patient developed a liver abscess by Aspergillus fumigatus and the second patient developed Mycobacterium tuberculosis complex lymphadenitis and probable pulmonary tuberculosis due to disseminated BCG infection. The patients also suffered from sclerosing cholangitis. Mutation analysis of the PNP gene from both sisters revealed a homozygous mutation for a G>A at nucleotide 349 (349 G>A transition), which changes alanine 117 to theronine in exon 4 (A117T). An increased awareness of early signs, symptoms, and abnormal laboratory findings of PNP deficiency will establish the early prognosis and treatment.

IgG4-associated cholangitis: a comparative histological and immunophenotypic study with primary sclerosing cholangitis on liver biopsy material

IgG4-associated cholangitis is a steroid-responsive hepatobiliary inflammatory condition associated with autoimmune pancreatitis that clinically and radiologically mimics primary sclerosing cholangitis. In this study, we conducted a morphological and immunohistochemical analysis of liver material obtained from individuals with IgG4-associated cholangitis, and compared these with well-characterized cases of primary sclerosing cholangitis. The study group consisted of 10 patients (9 biopsy and 1 hepatectomy case) with IgG4-associated cholangitis and 17 patients with primary sclerosing cholangitis (16 needle biopsy and 1 hepatectomy case). All patients with IgG4-associated cholangitis had pancreatic involvement as well, and six pancreatectomy samples revealed characteristic histopathological features of autoimmune pancreatitis. Primary sclerosing cholangitis cases were defined by the presence of a characteristic ERCP appearance. Clinical, pathological, radiological, and follow-up data were recorded for all cases. Portal and periportal inflammation was graded according to Ishak's guidelines. Immunohistochemical stains for IgG and IgG4 were performed. The cohort of patients with IgG4-associated cholangitis (mean age: 63 years) was older than individuals with primary sclerosing cholangitis (mean age: 44 years). Seven of these cases showed intrahepatic biliary strictures. IgG4-associated cholangitis liver samples showed higher portal (P=0.06) and lobular (P=0.009) inflammatory scores. Microscopic portal-based fibro-inflammatory nodules that were composed of fibroblasts, plasma cells, lymphocytes, and eosinophils were exclusively observed in five of the IgG4-associated cholangitis cases (50%). More than 10 IgG4-positive plasma cells per HPF (high power field) were observed in 6 of the IgG4-associated cholangitis cases (mean: 60, range: 0-140 per HPF), whereas all primary sclerosing cholangitis cases showed significantly lesser numbers (mean: 0.08, range: 0-1 per HPF). On a liver biopsy, the histological features of IgG4-associated cholangitis may be distinctive, and in conjunction with IgG4 immunohistochemical stain, may help distinguish this disease from primary sclerosing cholangitis.

Secondary sclerosing cholangitis

Secondary sclerosing cholangitis (SSC) is a chronic cholestatic biliary disease, characterized by inflammation, obliterative fibrosis of the bile ducts, stricture formation and progressive destruction of the biliary tree that leads to biliary cirrhosis. SSC is thought to develop as a consequence of known injuries or secondary to pathological processes of the biliary tree. The most frequently described causes of SSC are longstanding biliary obstruction, surgical trauma to the bile duct and ischemic injury to the biliary tree in liver allografts. SSC may also follow intra-arterial chemotherapy. Sclerosing cholangitis in critically ill patients is a largely unrecognized new form of SSC, and is associated with rapid progression to liver cirrhosis. The mechanisms leading to cholangiopathy in critically ill patients are widely unknown; however, the available clinical data indicate that ischemic injury to the intrahepatic biliary tree may be one of the earliest events in the development of this severe form of sclerosing cholangitis. Therapeutic options for most forms of SSC are limited, and patients with SSC who do not undergo transplantation have significantly reduced survival compared with patients with primary sclerosing cholangitis. Sclerosing cholangitis in critically ill patients, in particular, is associated with rapid disease progression and poor outcome.

Resected case of eosinophilic cholangiopathy presenting with secondary sclerosing cholangitis

Eosinophilic cholangiopathy is a rare condition characterized by eosinophilic infiltration of the biliary tract and causes sclerosing cholangitis. We report a patient with secondary sclerosing cholangitis with eosinophilic cholecystitis. A 46-year-old Japanese man was admitted to our hospital with jaundice. Computed tomography revealed dilatation of both the intrahepatic and extrahepatic bile ducts, diffuse thickening of the wall of the extrahepatic bile duct, and thickening of the gallbladder wall. Under the diagnosis of lower bile duct carcinoma, he underwent pylorus-preserving pancreatoduodenectomy and liver biopsy. On histopathological examination, conspicuous fibrosis was seen in the lower bile duct wall. In the gallbladder wall, marked eosinophilic infiltration was seen. Liver biopsy revealed mild portal fibrosis. He was diagnosed as definite eosinophilic cholecystitis with sclerosing cholangitis with unknown etiology. The possible etiology of sclerosing cholangitis was consequent fibrosis from previous eosinophilic infiltration in the bile duct. The clinicopathological findings of our case and a literature review indicated that eosinophilic cholangiopathy could cause a condition mimicking primary sclerosing cholangitis (PSC). Bile duct wall thickening in patients with eosinophilic cholangitis might be due to fibrosis of the bile duct wall. Eosinophilic cholangiopathy might be confused as PSC with eosinophilia.

Current status of therapy in autoimmune liver disease

Therapeutic strategies for autoimmune liver diseases are increasingly established. Although proportionately uncommon, specialist centers have with time refined the best approaches for each disease, based on an improved understanding of the spectrum of presentation. The major treatment aims are to prevent end-stage liver disease and its associated complications. As a result of drugs such as ursodeoxycholic acid, predniso(lo)ne and azathioprine, both primary biliary cirrhosis and autoimmune hepatitis are now less commonly indications for liver transplantation. Unfortunately, the same inroads in treatment efficacy have as yet not been made for primary sclerosing cholangitis, although the recognition that a subset of patients may have a treatable secondary sclerosing cholangitis (IgG4 related) is helping a proportion. With better biological understanding, more specific interventions are expected that will benefit all those with autoimmune liver diseases.

Sclerosing cholangitis in the era of target chemotherapy: a possible anti-VEGF effect

Preoperative systemic chemotherapy is generally applied in patients who undergo hepatic resection for colorectal metastases. Although the tumour response rate has been improved recently with the development of new molecular targeted therapies the related hepatic injury is ill defined. Bevacizumab is a monoclonal antibody to vascular endothelial growth factor. It can achieve high response rates and is accepted as a first line treatment in the metastatic colorectal disease. However, the data about its hepatotoxicity profile is still limited. We describe a case of secondary sclerosing cholangitis in a patient with liver metastases treated by Bevacizumab in the neoadjuvant setting and liver resection. It is possible that Bevacizumab may have induced a hypercoagulative condition that was further precipitated by surgery.

Marked eosinophilia as the first manifestation of sclerosing cholangitis

We encountered a 45-year-old man who presented with marked eosinophilia as the first manifestation of sclerosing cholangitis. He was found to have a liver dysfunction during a regular physical check up and thereafter consulted our hospital. The laboratory data on admission indicated an elevation of AST (96 IU/L), ALT (136 IU/L) and ALP (1,025 IU/L). Furthermore, the leukocyte count was 18,190/mm(3) and he also showed marked eosinophilia (54.5%, 9,914/mm(3)). There were no atypical findings in the eosinophils. Other diseases causing eosinophilia, including parasite infection, allergic disorders, hypereosinophilic syndromes, drug-induced eosinophilia, malignancies, etc. were all investigated and ruled out. A liver biopsy revealed marked eosinophilic infiltration in the portal area and interlobular bile duct injury. Magnetic resonance cholangiopancreatography (MRCP) demonstrated a slight dilatation of the left intrahepatic bile ducts, but no clear diagnosis could be made at that time. A follow-up liver biopsy and endoscopic retrograde cholangiopancreatography (ERCP) finally revealed a diagnosis of secondary sclerosing cholangitis due to eosinophilic cholangiopathy. According to previous Japanese reports, eosinophilia of more than 5% was reported in 39 of 142 (27.0%) primary sclerosing cholangitis (PSC) patients. Eosinophilic cholangiopathy could cause a condition mimicking PSC and it might be confused as PSC with eosinophilia. The literature contains only about 40 case reports on eosinophilic cholangiopathy, and therefore, to date little attention has been paid to this condition. We should therefore pay attention to this condition when making a differential diagnosis of either PSC or IgG4-related sclerosing cholangitis.

Portal hypertensive biliopathy: a rare cause of childhood cholestasis

Portal hypertensive biliopathy (PHB) is defined as abnormal biliary changes that take place most likely secondary to extrahepatic portal vein obstruction (EHPVO) with portal hypertension. This condition may be asymptomatic or could lead to a cholestatic state, which is not well-described in children. We report a child who developed a cholestatic nature with portal hypertension some time after having neonatal surgery for duodenal atresia. We discuss the differential diagnosis and management of this rare condition. Symptomatic PHB has been only rarely reported in children. It should be suspected in patients with portal hypertension and having features of biliary obstruction. Hepaticojejunostomy may have a therapeutic role in selected patients in whom endoscopic or percutaneous manipulation of the biliary tree is unsuccessful and who have not responded to a surgical portal-systemic shunt procedure.

Mimics of cholangiocarcinoma: spectrum of disease

Cholangiocarcinoma is the second most common primary malignant hepatobiliary neoplasm, accounting for approximately 15% of liver cancers. Diagnosis of cholangiocarcinoma is challenging and the prognosis is uniformly poor, with recurrence rates of 60%-90% after surgical resection. A wide spectrum of neoplastic and nonneoplastic conditions of the biliary tract may masquerade as cholangiocarcinoma, adding to the complexity of management in patients suspected to have cholangiocarcinoma. Mimics of cholangiocarcinoma constitute a heterogeneous group of entities that includes primary sclerosing cholangitis, recurrent pyogenic cholangitis, acquired immunodeficiency syndrome cholangiopathy, autoimmune pancreatitis, inflammatory pseudotumor, Mirizzi syndrome, xanthogranulomatous cholangitis, sarcoidosis, chemotherapy-induced sclerosis, hepatocellular carcinoma, metastases, melanoma, lymphoma, leukemia, and carcinoid tumors. These entities demonstrate characteristic histomorphology and variable clinicobiologic behaviors. The imaging findings of these disparate entities are protean and may be indistinguishable from those of cholangiocarcinoma. In most cases, a definitive diagnosis can be established only with histopathologic examination of a biopsy specimen.

Secondary sclerosing cholangitis after intensive care unit treatment: clues to the histopathological differential diagnosis

Secondary sclerosing cholangitis (SSC) is a chronic cholestatic disorder caused by mechanical, infectious, toxic, or ischemic factors. A new variant of SSC occurring after long-term treatment in intensive care units (ICU) has been recently described and characterized from the clinical point of view. The aim of this study was the histomorphological characterization of ICU-treatment-related SSC (ICU-SSC) and the definition of histological changes occurring over time based on the morphological findings. Liver biopsies of ten patients affected by ICU-SSC obtained at different time points (1.5 to 57 months) after the initial injury were analyzed. The main morphological alterations included degenerative changes of portal bile ducts, portal edema, inflammation, and fibrosis as well as biliary interface activity and bilirubinostasis. Perivenular necroses and bile infarcts were found in eight and six patients, respectively. Bile duct loss was not observed. No correlation between morphological features of biopsies and liver chemistry tests or outcome could be established. Based on the morphological observation, a possible disease-progression model starting with an initial damage of portal bile ducts (primary insult) with associated portal/periportal changes (inflammation, ductular reaction) and resulting in secondary parenchymal changes is proposed.

New insights into autoimmune liver diseases

Autoinflammatory liver disease represents an important aspect of global hepatological practice. The three principal disease divisions recognized are autoimmune hepatitis, primary sclerosing cholangitis and primary biliary cirrhosis. Largely, but not exclusively, these diseases are considered to be autoimmune in origin. Increased recognition of outlier and overlap syndromes, changes in presentation and natural history, as well as the increased awareness of IgG4-associated sclerosing cholangitis, all highlight the limitations of the classic terminology. New insights continue to improve the care given to patients, and have arisen from carefully conducted clinical studies, therapeutic trials, as well as genetic and laboratory investigations. The challenges remain to treat patients before liver injury becomes permanent and to prevent the development of organ failure.

Gallbladder disease in patients with primary sclerosing cholangitis

BACKGROUND/AIMS

Gallbladder abnormalities may be part of the spectrum in primary sclerosing cholangitis (PSC). The aim of the present study was to evaluate the occurrence and prognostic importance of gallbladder abnormalities in patients with PSC.

METHODS

Presence of gallbladder abnormalities was assessed in 286 patients with PSC treated at the Liver Unit, Karolinska University Hospital, Huddinge, between 1970 and 2005.

RESULTS

One or more gallbladder abnormalities were found in 41% of the patients. Gallstones were found in 25% and cholecystitis in 25%. Cholecystitis among patients with extrahepatic involvement of PSC (30% (65/214)) was significantly higher than among those with intrahepatic involvement (9% (6/70)) (P<0.0001). A gallbladder mass lesion with a mean size of 21 (+/-9) mm (S.D.) was found in 18 (6%) patients, in 56% (10/18) of whom it constituted gallbladder carcinoma. In 9 patients without a gallbladder mass lesion, histological re-evaluation disclosed epithelial dysplasia of the gallbladder.

CONCLUSIONS

Gallbladder disease is common in patients with PSC. Dysplasia and carcinoma are commonly found in gallbladder epithelium, suggesting that regular examination of the gallbladder in PSC patients could be of value for early detection of a gallbladder mass lesion. Cholecystectomy is recommended when such a lesion is detected, regardless of its size.

Primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is a chronic and slowly progressive cholestatic liver disease of autoimmune etiology characterized by injury of the intrahepatic bile ducts that may eventually lead to liver failure. Affected individuals are usually in their fifth to seventh decades of life at time of diagnosis, and 90% are women. Annual incidence is estimated between 0.7 and 49 cases per million-population and prevalence between 6.7 and 940 cases per million-population (depending on age and sex). The majority of patients are asymptomatic at diagnosis, however, some patients present with symptoms of fatigue and/or pruritus. Patients may even present with ascites, hepatic encephalopathy and/or esophageal variceal hemorrhage. PBC is associated with other autoimmune diseases such as Sjogren's syndrome, scleroderma, Raynaud's phenomenon and CREST syndrome and is regarded as an organ specific autoimmune disease. Genetic susceptibility as a predisposing factor for PBC has been suggested. Environmental factors may have potential causative role (infection, chemicals, smoking). Diagnosis is based on a combination of clinical features, abnormal liver biochemical pattern in a cholestatic picture persisting for more than six months and presence of detectable antimitochondrial antibodies (AMA) in serum. All AMA negative patients with cholestatic liver disease should be carefully evaluated with cholangiography and liver biopsy. Ursodeoxycholic acid (UDCA) is the only currently known medication that can slow the disease progression. Patients, particularly those who start UDCA treatment at early-stage disease and who respond in terms of improvement of the liver biochemistry, have a good prognosis. Liver transplantation is usually an option for patients with liver failure and the outcome is 70% survival at 7 years. Recently, animal models have been discovered that may provide a new insight into the pathogenesis of this disease and facilitate appreciation for novel treatment in PBC.

Is preoperative histological diagnosis necessary before referral to major surgery for cholangiocarcinoma?

Major surgical resection is often the only curative treatment for cholangiocarcinoma. When imaging techniques fail to establish the accurate diagnosis, biopsy of the lesion is unavoidable. However, biopsy is not necessarily required for topography of the cholangiocarcinoma (intrahepatic or extrahepatic). 1) In extrahepatic cholangiocarcinoma (ECC), clinical features and radiological imaging relate to biliary obstruction. Provided that between 8% and 43% of bile duct strictures are not ECC, the lesions mimicking ECC that should be ruled out are gallbladder cancer, Mirizzi syndrome, primary sclerosing cholangitis (PSC), autoimmune pancreatitis and portal biliopathy. Systematic biopsy is usually difficult and has poor sensitivity, but a good knowledge of these mimicking ECC diseases, along with precise analysis of clinical and imaging semiology, may lead to a correct diagnosis without the need for biopsy. 2) Intrahepatic cholangiocarcinoma (ICC) developing in normal liver appears as a hypovascular tumour with fibrotic component and capsular retraction that can be confused with fibrous metastases such as breast and colorectal cancers. The lack of the primary site, a relatively large tumour size and ancillary findings such as bile duct dilatation may provide a clue to the diagnosis. If not, we advocate local resection with lymph node dissection, since ICC is the most likely diagnosis and surgery is the only curative treatment. In the event of adenocarcinoma from unknown primary, surgery is an effective treatment even if prognosis is poor.

Genetic epidemiology of primary sclerosing cholangitis

The aetiology of primary sclerosing cholangitis (PSC) is not known. A more than 80-fold increased risk of PSC among first-degree relatives emphasizes the importance of genetic factors. Genetic associations within the human leukocyte antigen (HLA) complex on chromosome 6p21 were detected in PSC 25 years ago. Subsequent studies have substantiated beyond doubt that one or more genetic variants located within this genetic region are important. The true identities of these variants, however, remain to be identified. Several candidate genes at other chromosomal loci have also been investigated. However, according to strict criteria for what may be denominated a susceptibility gene in complex diseases, no such gene exists for PSC today. This review summarises present knowledge on the genetic susceptibility to PSC, as well as genetic associations with disease progression and clinical subsets of particular interest (inflammatory bowel disease and cholangiocarcinoma).

The patient with unexplained elevated serum liver enzymes

The pattern of elevated serum liver enzymes in symptomatic or asymptomatic patients allows for an initial classification of liver diseases into cholestatic or hepatocellular diseases. A female patient with extrahepatic cholestasis due to segmental bile duct strictures and a localized mass lesion within the pancreas is presented. Although many diagnostic procedures were performed in this case the diagnosis was not obtained before surgical laparotomy was initiated with bioptic sampling from bile ducts, lymph nodes and pancreatic tissue. Microscopic examination of the specimen revealed extensive biliary and pancreatic scarring together with periductal infiltrates composed of lymphocytes and plasma cells consistent with sclerosing cholangitis in systemic autoimmune pancreatitis. The patient completely recovered upon treatment with prednisone and azathioprine. The difficult approach to the final diagnosis is discussed in light of established and modern diagnostic tools.

Th2 and regulatory immune reactions are increased in immunoglobin G4-related sclerosing pancreatitis and cholangitis

Immunoglobin G (IgG) 4-related sclerosing pancreatitis and cholangitis (autoimmune pancreato-cholangitis [AIPC]) are recently recognized disease entities characterized by high serum IgG4 concentrations and sclerosing inflammation with numerous IgG4-positive plasma cells, although the underlining immune mechanism remains only speculative. In this study, the immunopathogenesis of AIPC was examined with respect to the production of cytokines in situ and the possible involvement of regulatory T cells (Tregs) using fresh (5 cases) and formalin-fixed (28 cases) specimens of AIPC and related extra-pancreatobiliary lesions. Quantitative real-time polymerase chain reaction revealed that AIPC and extra-pancreatobiliary lesions had significantly higher ratios of interleukin (IL)-4/interferon-gamma (IFN-gamma) (45.8-fold), IL-5/IFN-gamma (18.7-fold), IL-13/interferon (IFN)-gamma (20.7-fold), IL-10/CD4 (45.3-fold), and tumor growth factor (TGF)-beta/CD4 (39.4-fold) than did primary sclerosing cholangitis (PSC) and primary biliary cirrhosis (PBC). Lymphocytes with signals for IL-4 and IL-10 were frequently found in AIPC by in situ hybridization. The expression of Foxp3 messenger RNA, a transcription factor specific for naturally arising CD4(+)CD25(+) Tregs, was significantly increased in AIPC and extra-pancreatobiliary lesions in comparison to PSC and PBC (36.4-fold). Immunohistochemically, CD4(+)CD25(+)Foxp3(+) cells were frequently found in AIPC, while few were found in PSC and other disease controls. Taken together, AIPC could be characterized by the over-production of T helper (Th) 2 and regulatory cytokines. Tregs might be involved in the in situ production of IL-10 and TGF-beta, which could be followed by IgG4 class switching and fibroplasia.

CONCLUSION

AIPC is a unique inflammatory disorder characterized by an immune reaction predominantly mediated by Th2 cells and Tregs.

Sclerosing cholangitis

PURPOSE OF REVIEW

Primary sclerosing cholangitis is a chronic cholestatic liver disease characterized by strictures of the biliary tree complicated by cirrhosis and cholangiocarcinoma. It is immune mediated, although the precise aetiology remains unknown.

RECENT FINDINGS

Research into etiopathogenesis and epidemiology, diagnosis of cholangiocarcinoma, associations with inflammatory bowel disease and autoimmune pancreatitis, and medical therapy are discussed.

SUMMARY

Multiple gene polymorphisms associated with primary sclerosing cholangitis have been investigated. Common inflammatory bowel disease-associated polymorphisms do not confer any susceptibility to primary sclerosing cholangitis; the role of intercellular adhesion molecule-1 gene polymorphisms and CCR5 mutations remain unclear. Elevated IgG4 has been demonstrated in a subgroup of primary sclerosing cholangitis patients, which may indicate an overlap with autoimmune pancreatitis and possible responsiveness to steroids. Biliary brush cytology may assist in diagnosis of cholangiocarcinoma, although further clinical indicators are required. Animal studies suggest the superiority of 24-norursodeoxycholic acid over ursodeoxycholic acid in reducing histological disease progress; translational studies in humans are now required.