No abstract

Recently, the autoimmune hepatitis (AIH)/primary sclerosing cholangitis (PSC) overlap syndrome has been reported increasingly. In this syndrome, patients present with features of both AIH and PSC. It has been suggested that the 2 diseases may be sequential in their occurrence, whereby patients have features of AIH and then after a number of years develop features of PSC, but clear confirmation of evolution has not been documented in adults. We describe 6 adult cases in which PSC was diagnosed many years after well-established AIH. Six patients are described in whom AIH definitely was diagnosed at presentation. No evidence of biliary disease was noted on the initial liver biopsy or endoscopic retrograde cholangiography (ERCP). All patients responded well to immunosuppressive therapy. After an average duration of follow-up of 4.6 years they became resistant to immunosuppression, and developed clear features of PSC, which was confirmed by ERCP in all patients. The average age of the patients at first presentation was 31.3 years, 2 were women and 4 were men, and 3 had ulcerative colitis. We found no specific features at presentation that could predict this evolutionary outcome. In conclusion, patients with well-established AIH can, after variable duration of follow-up, develop PSC. In patients with AIH who become resistant to immunosuppression or develop significant cholestasis, PSC should be ruled out by ERCP.

No abstract

Nonalcoholic fatty liver disease (NAFLD) is a common diagnosis among patients referred to gastroenterology and hepatology clinics for the evaluation of elevated liver enzymes. The diagnosis of NAFLD is supported by blood work to exclude other liver diseases, and by ultrasound evidence of fat in the liver in patients without a significant history of alcohol intake. The gold standard, however, is a liver biopsy to show the typical histological features of NAFLD, which are almost identical to those of alcohol-induced liver damage and can range from mild steatosis to cirrhosis. A variety of retrospective series have linked NAFLD to obesity, diabetes, hyperlipidemia, total parenteral nutrition, jejunoileal bypass surgery and certain medications. A subset of patients with NAFLD that had an initial presentation of elevated liver enzymes was studied. Two hundred and two patients were reviewed, of whom 49 met the inclusion criteria including a liver biopsy. Patients were excluded if insufficient data were available, if the patients had a significant history of ethanol intake or if they had other coexisting liver disease. These patients were seen between 1996 and 2000 in gastroenterology and hepatology clinics in two community hospitals and one regional liver transplant centre in Edmonton, Alberta. NAFLD was associated with a spectrum of changes in the liver ranging from mild steatosis to more significant steatosis with inflammation and fibrosis. Cases of NAFLD with steatosis and mixed inflammatory infiltration but lacking ballooning degeneration or fibrosis were prevalent in young (20 to 40 years of age) patients with no other significant medical history except for obesity. NAFLD with biopsies showing significant fibrosis and ballooning cell degeneration was associated with obesity, diabetes and older age. It was concluded that, in this predominantly outpatient setting, age over 40 years and diabetes at any age are risk factors for both nonalcoholic steatohepatitis and nonalcoholic steatohepatitis with cirrhosis. It is therefore recommended that patients with raised liver enzymes and suspected NAFLD be targeted for liver biopsy in their evaluation.

During acute graft-versus-host disease (GVHD) the activation of macrophages (Mφ) is mediated by 2 signals, interferon (IFN)-γ and bacteria-derived lipopolysaccharide (LPS). A cascade of inflammatory responses that includes the release of mediators of tissue injury follows Mφ activation. Among the tissues characteristically targeted during acute GVHD are epithelial tissues of the skin and gastrointestinal tract that normally undergo continuous proliferation and are therefore sensitive to cytostatic processes. We have investigated whether Mφ can mediate cytostatic mechanisms capable of interrupting cell proliferation during acute GVHD. GVHD was induced in nonirradiated C57BL/6XAF1 (B6AF1) mice by the injection of 60 × 106 (acute GVHD) or 30 × 106 (nonlethal GVHD) C57BL/6 (B6) lymphoid cells. Mφ from animals undergoing acute GVHD could be triggered by normally insignificant quantities of LPS to mediate a cytostatic effect on target cells, resulting in the complete shutdown of cellular proliferation. The same amounts of LPS had no effect on Mφ from normal or syngeneically transplanted animals. Mφ mediated the release of significant quantities of intracellular iron from target cells undergoing cytostasis. Reversal of cytostasis occurred following inhibition of nitric oxide (NO) production by NG-monomethyl-L-arginine (NMMA). Production of NO by LPS-triggered Mφ reflected the severity of GVHD. NO release increased significantly during acute GVHD but was only transiently increased during nonlethal GVHD. The results provide evidence that, as a result of activation during acute GVHD, Mφ produce NO and induce the release of iron from target cells, resulting in a potent cytostatic effect that inhibits cellular proliferation.

During acute graft-versus-host disease (GVHD) the activation of macrophages (Mφ) is mediated by 2 signals, interferon (IFN)-γ and bacteria-derived lipopolysaccharide (LPS). A cascade of inflammatory responses that includes the release of mediators of tissue injury follows Mφ activation. Among the tissues characteristically targeted during acute GVHD are epithelial tissues of the skin and gastrointestinal tract that normally undergo continuous proliferation and are therefore sensitive to cytostatic processes. We have investigated whether Mφ can mediate cytostatic mechanisms capable of interrupting cell proliferation during acute GVHD. GVHD was induced in nonirradiated C57BL/6XAF1 (B6AF1) mice by the injection of 60 × 106 (acute GVHD) or 30 × 106 (nonlethal GVHD) C57BL/6 (B6) lymphoid cells. Mφ from animals undergoing acute GVHD could be triggered by normally insignificant quantities of LPS to mediate a cytostatic effect on target cells, resulting in the complete shutdown of cellular proliferation. The same amounts of LPS had no effect on Mφ from normal or syngeneically transplanted animals. Mφ mediated the release of significant quantities of intracellular iron from target cells undergoing cytostasis. Reversal of cytostasis occurred following inhibition of nitric oxide (NO) production by NG-monomethyl-L-arginine (NMMA). Production of NO by LPS-triggered Mφ reflected the severity of GVHD. NO release increased significantly during acute GVHD but was only transiently increased during nonlethal GVHD. The results provide evidence that, as a result of activation during acute GVHD, Mφ produce NO and induce the release of iron from target cells, resulting in a potent cytostatic effect that inhibits cellular proliferation.

The onset of acute graft-vs-host disease (aGVHD) is accompanied by macrophage (M phi) priming and the presence of bacteria-derived LPS in the sera of transplanted animals. Priming of M phi occurs during aGVHD despite the suppression of T cell function. We have investigated whether IL-12 mediates the continued production of IFN-gamma during the state of T cell immunosuppression that accompanies aGVHD. Acute GVHD was induced in nonirradiated AxC57BL/6F1 mice by the injection of C57BL/6 lymphoid cells. Despite T cell immunosuppression, M phi became primed, as shown by their expression of inducible nitric oxide synthase mRNA and their production of nitric oxide in response to LPS. Continual exposure to IFN-gamma was required to maintain a primed state in M phi during aGVHD. IL-12 p40 peptide mRNA was increased in M phi purified from animals undergoing aGVHD 14 days after transplantation. Target organs of aGVHD, including thymus, salivary gland, and lung, showed increased IFN-gamma mRNA between days 7 and 14 after transplantation. The increase was accompanied by an induction of mRNA for the p40 peptide of IL-12 and inducible nitric oxide synthase within the target organs. These results provide evidence for localized production of IFN-gamma within aGVHD target organs and suggest that it is mediated by LPS-induced production of IL-12 by M phi. Our data elucidate the mechanism of activation of M phi during aGVHD that results in TNF-alpha and nitric oxide production and delineates the effector role of M phi in the pathology of aGVHD.