Aetiopathogenesis of primary sclerosing cholangitis

Survival without biliary complications after liver transplant for primary sclerosing cholangitis

OBJECTIVES

Patients who have a liver transplant for primary sclerosing cholangitis may develop recurrent disease and biliary complications, organ loss necessitating revision liver transplant, or death. We evaluated long-term outcomes in patients who had liver transplant for primary sclerosing cholangitis.

MATERIALS AND METHODS

In 71 patients who had a liver transplant for end-stage liver disease because of primary sclerosing cholangitis, a retrospective review was done to evaluate biliary complication-free survival, transplanted organ survival, and death. Human leukocyte antigen typing and matching were reviewed.

RESULTS

There were 39 patients (55%) who had biliary complications, loss of the liver transplant, or death at a mean 12.1 years after transplant. The 5- and 10-year event-free survival reached 74.6% and 45% (53 patients after 5 years, and 32 patients after 10 years). Male sex of transplant recipients was a significant risk factor for biliary complications, revision liver transplant, or death. Most patients had inflammatory bowel disease, primarily ulcerative colitis. The human leukocyte antigen profile or number of mismatches had no effect on complication-free survival.

CONCLUSIONS

Biliary complications, revision liver transplant, and death are a useful combined primary endpoint for recurrent primary sclerosing cholangitis after liver transplant.

CD8 T cells primed in the gut-associated lymphoid tissue induce immune-mediated cholangitis in mice

The pathogenesis of primary sclerosing cholangitis (PSC) remains poorly understood. Since PSC predominantly occurs in patients with inflammatory bowel disease, autoimmunity triggered by activated T cells migrating from the gut to the liver is a possible mechanism. We hypothesized that T cells primed in the gut-associated lymphoid tissue (GALT) by a specific antigen migrate to the liver and cause cholangitis when they recognize the same antigen on cholangiocytes. We induced ovalbumin-dependent colitis in mice that express ovalbumin in biliary epithelia (ASBT-OVA mice) and crossed ASBT-OVA mice with mice that express ovalbumin in enterocytes (iFABP-OVA mice). We analyzed T-cell activation in the GALT and crossreactivity to the same antigen in the liver as well as the effects of colitis per se on antigen-presentation and T-cell activation in the liver. Intrarectal application of ovalbumin followed by transfer of CD8 OT-I T cells led to antigen-dependent colitis. CD8 T cells primed in the GALT acquired effector function and the capability to migrate to the liver, where they caused cholangitis in a strictly antigen-dependent manner. Likewise, cholangitis developed in mice expressing ovalbumin simultaneously in biliary epithelia and enterocytes after transfer of OT-I T cells. Dextran sodium sulfate colitis led to increased levels of inflammatory cytokines in the portal venous blood, induced activation of resident liver dendritic cells, and promoted the induction of T-cell-dependent cholangitis.

CONCLUSION

Our data strengthen the notion that immune-mediated cholangitis is caused by T cells primed in the GALT and provide the first link between colitis and cholangitis in an antigen-dependent mouse model.

Current update on primary and secondary sclerosing cholangitis

Sclerosing cholangitis can be idiopathic (primary) or secondary to an identifiable cause. Irrespective of cause, sclerosing cholangitis usually progresses to end-stage liver disease and warrants orthotopic liver transplantation. Recent studies provide new insights into the etiopathogenesis, natural history, diagnosis, and management of these different entities.

Genetic polymorphisms associated with inflammatory bowel disease do not confer risk for primary sclerosing cholangitis

OBJECTIVES

Approximately 80% of patients with primary sclerosing cholangitis (PSC) of Northern European origin have concurrent inflammatory bowel disease (IBD). The majority have ulcerative colitis, but there is also an association with Crohn's colitis. The pathogenetic link between PSC and IBD is unknown. We aimed to assess whether genetic risk factors in PSC can be identified on the basis of known IBD susceptibility genes and the shared PSC-IBD phenotype.

METHODS

IBD-associated polymorphisms in the CARD15, TLR-4, CARD4, SLC22A4, SLC22A5, DLG5, and MDR1 genes were genotyped in a large cohort of 365 Scandinavian PSC patients and 368 healthy controls using TaqMan technology.

RESULTS

No significant association between any of the investigated genetic IBD risk variants and overall susceptibility to PSC was observed. Apart from a tendency toward an increased carrier frequency of the mutant CARD15 alleles in PSC patients with concurrent Crohn's disease as compared with healthy controls (15.6%vs 9.0%, P = 0.22), no association with any of the polymorphisms investigated was evident even when considering only PSC patients with concurrent IBD.

CONCLUSION

It seems unlikely that IBD-associated polymorphisms in the CARD15, TLR-4, CARD4, SLC22A4, SLC22A5, DLG5, and MDR1 genes confer susceptibility to PSC. The current knowledge of genetic risk factors in IBD may not contribute to our understanding of molecular mechanisms involved in the pathogenesis of PSC or the IBD phenotype in PSC.

Immunopathogenesis of primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease of unknown etiology;however, lymphocytic portal tract infiltration is suggestive of an immune-mediated basis for PSC. Associations with inflammatory bowel disease--especially ulcerative colitis--and with other auto-immune diseases, together with genetic associations, further suggest that PSC may be an immune-mediated disease. The immunogenetics of PSC have been the subject of active research, and several human leukocyte antigen (HLA)- and non-HLA-associated genes have been implicated in the development of the disease. Lymphocytes derived from the inflamed gut may enter the liver via the enterohepatic circulation to cause hepatic disease.PSC may be triggered in genetically susceptible individuals by infections or toxins entering the portal circulation through a permeable colon and, therefore, evoking an abnormal immune response.

Primary sclerosing cholangitis in two brothers: report of a family with special emphasis on molecular HLA and MICA genotyping

Immune mechanisms play a role in the pathogenesis of primary sclerosing cholangitis (PSC), as suggested by its association with certain HLA haplotypes. Genetic predisposition is supported by its occurrence in families, but data are scarce. Our aim is to report on two brothers with PSC, and to investigate HLA and MICA alleles in this family. The clinical, biochemical, radiological, and pathological findings in two brothers with PSC as well as in their sister and parents were reviewed. Molecular genotyping of HLA class II and MICA alleles was performed in all five family members. In two brothers, p-ANCA positive PSC was found. The youngest also had ulcerative colitis, and had evolved into cirrhosis at the age of 17 years. Their mother had positive p-ANCA and mild cholestatic changes. Their father and sister were unaffected. Both brothers were homozygous for the MICA*00801 allele, and were positive for the susceptibility HLA haplotypes DR3-DQ2 and DR6-DQ6. Their unaffected father and sister both carried the protective DR4 allele. The presence of PSC in two brothers, and the distribution of HLA haplotypes and MICA alleles, adds supportive evidence for an immunogenetic origin of PSC.

Hepatic metabisulfite sensitivity in a patient with sclerosing cholangitis

BACKGROUND

Primary sclerosing cholangitis is an uncommon chronic cholestatic liver disease with a poor prognosis in symptomatic cases. Genetic and immunologic alterations have been identified, and many possible etiologies have been entertained. Most treatments have limited benefit, and primary sclerosing cholangitis is a common cause for liver transplantation.

OBJECTIVE

To describe a patient with documented primary sclerosing cholangitis associated with chronic ulcerative colitis, who developed hepatic toxicity following ingestion of metabisulfite.

RESULTS

A placebo-controlled oral challenge suggested metabisulfite hypersensitivity with liver toxicity. He was treated with cobalamin (to prevent sulfite toxicity), low-sulfite diet, steroids, and antibiotics and has had an unusually benign course for 19 years.

CONCLUSIONS

The hypersensitivity to oral metabisulfite in our patient appeared to be a significant trigger to flare-ups of his disease. Controlling the response to metabisulfite (along with recurrent antibiotic and steroid therapy) may have contributed significantly to the remarkably good outcome in this patient.

Aberrant local renin-angiotensin II responses in the pathogenesis of primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is an idiopathic inflammatory disorder of the biliary tract characterized by diffuse biliary tract stricture formation, progressive chronic cholestasis and the development of secondary biliary cirrhosis. Biliary tract ischemia can produce morphological changes identical to PSC. We propose the existence of a localized renin-angiotensin system within the liver and extend the hypothesis that aberrant production of angiotensin II within the portal tract is the critical event contributing to the pathogenesis of PSC. A chronic reparative and proliferative state caused by chronic ischemia may promote carcinogenesis. Proof of this hypothesis will have implications for future therapeutic approaches given that current treatments for PSC aimed at reducing inflammation or the effects of cholestasis have proven ineffective.

Sclerosing pancreatitis presenting as a periampullary tumour

BACKGROUND

Sclerosing lesions of the pancreatic duct are rare and may be secondary to primary sclerosing cholangitis (PSC) or the result of a primary sclerosing process (the recently described lymphoplasmacystic sclerosing pancreatitis, LSP). Occasionally this process may present as a mass lesion.

CASE OUTLINE

A 21 -year-old man presented with abdominal pain and jaundice, giving a high index of suspicion for a periampullary malignancy. There were minimal symptoms suggestive of PSC. The resected head of the pancreas demonstrated changes of chronic pancreatitis with a fibro-inflammatory process of the pancreatic duct suggesting an underlying ductal sclerosing process.

DISCUSSION

Clinical presentation and imaging characteristics of PSC involving the pancreas are often misleading and may suggest a neoplasm as the underlying disorder. Conclusive diagnosis is usually not determined until after surgical intervention. Although racial differences in pancreatic duct involvement have been suggested, the underlying histopathology is the same as in PSC involving the biliary ducts.

Risk factors for recurrence of primary sclerosing cholangitis of liver allograft

Primary sclerosing cholangitis (PSC) is a disease of unknown cause that effects the biliary tree and is closely associated with inflammatory bowel disease. We did a retrospective analysis of the risk factors associated with recurrence of PSC in an allograft after liver transplantation. Recurrence of disease, assessed by liver histology or imaging the biliary tree, occurred in 56 of 152 patients (37%) at a median of 36 months (range 1.4-120 months). Multivariate analysis showed that being male (relative risk 1.2, 95% CI 0.73-2.15) and an intact colon before transplantation (8.7, 1.19-64.48) were associated with recurrence. These observations could help elucidate the pathogenesis of the disease.