Utility and cost evaluation of multiparametric magnetic resonance imaging for the assessment of non-alcoholic fatty liver disease.

BACKGROUND: Validated diagnostic tools that are accurate, cost effective and acceptable to patients are required for disease stratification and monitoring in NAFLD. AIMS: To investigate the performance and cost of multiparametric MRI alongside existing biomarkers in the assessment of NAFLD. METHODS: Adult patients undergoing standard of care liver biopsy for NAFLD were prospectively recruited at two UK liver centres and underwent multiparametric MRI, blood sampling and transient elastography withing 2 weeks of liver biopsy. Non-invasive markers were compared to histology as the gold standard. RESULTS: Data were obtained in 50 patients and 6 healthy volunteers. Corrected T1 (cT1) correlated with NAFLD activity score (ρ = 0.514, P < .001). cT1, enhanced liver fibrosis (ELF) test and liver stiffness differentiated patients with simple steatosis and NASH with AUROC (95% CI) of 0.69 (0.50-0.88), 0.87 (0.77-0.79) and 0.82 (0.70-0.94) respectively and healthy volunteers from patients with AUROC (95% CI) of 0.93 (0.86-1.00), 0.81 (0.69-0.92) and 0.89 (0.77-1.00) respectively. For the risk stratification of NAFLD, multiparametric MRI could save £150,218 per 1000 patients compared to biopsy. Multiparametric MRI did not discriminate between individual histological fibrosis stages in this population (P = .068). CONCLUSIONS: Multiparametric MRI accurately identified patients with steatosis, stratifies those with NASH or simple steatosis and reliably excludes clinically significant liver disease with superior negative predictive value (83.3%) to liver stiffness (42.9%) and ELF (57.1%). For the risk stratification of NAFLD, multiparametric MRI was cost effective and, combined with transient elastography, had the lowest cost per correct diagnosis.

Operator training requirements and diagnostic accuracy of Fibroscan in routine clinical practice.

BACKGROUND: Fibroscan is a quick, non-invasive technique used to measure liver stiffness (kPa), which correlates with fibrosis. To achieve a valid liver stiffness evaluation (LSE) the operator must obtain all the following three criteria: (1) ≥10 successful liver stiffness measurements; (2) IQR/median ratio <0.30 and (3) ≥60% measurement success rate. OBJECTIVES: To assess the operator training requirements and the importance of adhering to the LSE validity criteria in routine clinical practice. METHODS: We retrospectively analysed the LSE validity rates of 2311 Fibroscans performed (1 August 2008 to 31 July 2011) in our tertiary liver outpatients department at the University Hospital Birmingham, UK. The diagnostic accuracy of Fibroscan was assessed in 153 patients, by comparing LSE (valid and invalid) with the modified Ishak fibrosis stage on liver biopsy. RESULTS: Learning curve analysis highlighted that the greatest improvement in validity of LSE rates occurs in the operator's first 10 Fibroscans, reaching 64.7% validity by the 50th Fibroscan. The correlation between LSE and the fibrosis stage on liver biopsy was superior in patients with a valid LSE (n=97) compared with those with an invalid LSE (n=56) (rs 0.577 vs 0.259; p=0.022). Area under receiving operating characteristics for significant fibrosis was greater when LSE was valid (0.83 vs 0.66; p=0.048). Using an LSE cut-off of 8 kPa, the negative predictive value of valid LSE was superior to invalid LSE for the detection of significant (84% vs 71%) and advanced fibrosis (100% vs 93%). CONCLUSIONS: Fibroscan requires minimal operator training (≥10 observed on patients), and when a valid LSE is obtained, it is an accurate tool for excluding advanced liver fibrosis. To ensure the diagnostic accuracy of Fibroscan it is essential that the recommended LSE validity criteria are adhered to in routine clinical practice.

Pinworm infection masquerading as colorectal liver metastasis.

Enterobius vermicularis is responsible for a variety of diseases but rarely affects the liver. Accurate characterisation of suspected liver metastases is essential to avoid unnecessary surgery. In the presented case, following a diagnosis of rectal cancer, a solitary liver nodule was diagnosed as a liver metastasis due to typical radiological features and subsequently resected. At pathological assessment, however, a necrotic nodule containing E. vermicularis was identified. Solitary necrotic nodules of the liver are usually benign but misdiagnosed frequently as malignant due to radiological features. It is standard practice to diagnose colorectal liver metastases solely on radiological evidence. Without obtaining tissue prior to liver resection, misdiagnosis of solitary necrotic nodules of the liver will continue to occur.

Is histological diagnosis of primary liver carcinomas with fibrous stroma reproducible among experts?

AIMS: In the era of targeted therapeutics, histological typing of hepatobiliary carcinomas has major clinical implications. Little is known about the reproducibility of the pathological diagnosis of primary liver carcinomas. Therefore, this study aimed to evaluate the worldwide variation in the pathological expert diagnoses of primary liver carcinomas with fibrous stroma in patients who did not have cirrhosis. METHODS: A single set of slides was selected from 25 tumours, and this set was reviewed independently by 12 pathologists who have worldwide expertise in liver tumours. Reproducibility of the diagnoses was evaluated by Light's kappa, and diagnoses were clustered by multidimensional scaling. Immunohistochemistry was performed after histological review. RESULTS: The interobserver reproducibility for diagnosis of hepatocellular carcinoma subtypes and cholangiocarcinomas was poor (kappa 0.23-0.52), even when the experts considered that the diagnosis required no additional stains or clinical information. Interestingly, multidimensional scaling revealed three main clusters of tumours: hepatocellular carcinoma with no other specifications (n = 13), fibrolamellar hepatocellular carcinoma (n = 3) and cholangiocarcinoma (n = 9). Using immunohistochemistry, these histological clusters correlated with expression of anti-hepatocyte and anti-cytokeratin 19 (p<0.001). CONCLUSIONS: The results demonstrate the poor reproducibility among experts of the pathological diagnosis of primary liver carcinomas with fibrous stroma in patients who did not have cirrhosis, and highlight that the systematic use of immunohistochemistry may improve the diagnostic accuracy.

Cholangiocarcinoma complicating primary sclerosing cholangitis: a 24-year experience.

AIM: To report the prevalence and outcome of cholangiocarcinoma arising in primary sclerosing cholangitis for a British tertiary referral centre. METHODS: All patients diagnosed with primary sclerosing cholangitis and concurrent cholangiocarcinoma were identified from a prospectively maintained departmental database, and the mode of presentation, management and outcome were determined. RESULTS: Of 370 patients with primary sclerosing cholangitis, 48 patients (13%) were diagnosed with a cholangiocarcinoma within a median time of 0.51 months (range: 0-73.12) from presentation to the unit. Mode of presentation included: inoperable tumours (n = 14); incidental findings in transplant hepatectomy specimens (n = 13); primary sclerosing cholangitis follow-up (n = 9); transplant work-up (n = 5); transplant waiting list (n = 5); suspected tumour confirmed at transplant (n = 1), and incidental finding at cholecystectomy (n = 1). The diagnosis was confirmed by: radiology-guided biopsy (n = 27); MRI (n = 3); CT (n = 2); laparoscopy or laparotomy (n = 2), and frozen section at transplant (n = 1). Management consisted of: transplantation (n = 14, including 1 abandoned); hepatic resection (n = 8), and palliation through stenting (n = 26). The overall median survival of the cohort was 4.9 months (range: 0.09-104.5). Median survival ranged from 2.6 months (range: 0.09-35.3) for palliation to 7.6 months (range: 0.6-99.6) for transplantation and 52.8 months (range: 3.7-104.5) for resection. There was no difference in survival between the transplant and resection groups (p = 0.14). CONCLUSIONS: Cholangiocarcinoma is a common finding in primary sclerosing cholangitis and regular screening of this cohort of patients at referring centres is advocated to detect early tumours, as surgical treatment at an early stage offers significantly better outcomes for this cohort of patients.

Effect of preoperative chemotherapy on liver resection for colorectal liver metastases.

AIM: To compare the effects of preoperative chemotherapy on liver parenchyma morphology, as well as morbidity and mortality after liver resection for colorectal liver metastases. METHODS: Prospectively collected data on 173 patients undergoing liver resection for CLM between 1/2003 and 9/2005 was analysed in three groups: A: preoperative oxaliplatin (Ox, n=70); B: other chemotherapeutic agents (OC, n=60); and C: surgery alone without chemotherapy (SA, n=43). Blood transfusion, hospital stay, operative procedure, peak postoperative bilirubin levels, complications and histopathology of the resected liver were compared. RESULTS: Intra-operative blood transfusion requirement (34%) and biliary complications (16%) was higher in patients receiving oxaliplatin-based chemotherapy (p=0.01 and p=0.06, respectively). Oxaliplatin-based chemotherapy was also associated with sinusoidal dilatation of mild grade in 52.8% vs. 26.6% and 23.3% patients (p=0.007 and p=0.004) in other groups, respectively. Steatosis was similarly distributed across the study group. Postoperative mortality was 2, 1 and 4 patients, respectively (p=ns). CONCLUSION: Oxaliplatin-based preoperative chemotherapy is associated with vascular alterations in the liver parenchyma without significantly increasing the risk of steatosis, or postoperative morbidity and mortality.

Primary hepatocellular cancer in the explanted liver: outcome of transplantation and risk factors for HCC recurrence.

AIM: To evaluate the risk of recurrence of hepatocellular cancer (HCC) after liver transplantation (LT). METHODS: The clinical records of 104 patients with HCC in the explanted liver were examined. RESULTS: HCC recurrence occurred in 12 patients. Recurrence was observed in all patients with a single nodule greater than 5 cm. Among the 5 patients with more than 3 tumours with a maximum diameter of 4.5 cm, no recurrence occurred. The survival rates were 81% and 64% at 1 and 5 years, respectively; the recurrence-free survival at 1 and 5 years was, respectively, 93% and 82%. Pre-LT alpha-fetoprotein (AFP) increased at a greater magnitude in patients who experienced recurrence, compared to those who did not. Tumour diameter, differentiation, satellitosis, AFP and the magnitude of AFP increase were predictive of recurrence. The 1- and 5-year recurrence-free survival for the 68 patients who had a single nodule up to 5 cm, or up to 3 nodules all less than 4.5 cm and with a maximum cumulative diameter of 8 cm, or more than 3 nodules all less than 2.5 cm, were 95% and 92%, respectively. For the 13 patients not meeting these criteria, the 1- and 5-year recurrence-free survival was, respectively, 75% and 54% (log Rank test p=0.019). CONCLUSIONS: Patients with more than 3 small HCC nodules before LT could still have a good outcome without recurrence. A rapid increase in AFP could be useful in identifying patients with a greater risk of post-LT HCC recurrence.

Histological assessment of non-alcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) is an important complication of the metabolic syndrome, which is becoming an increasingly common cause of chronic liver disease. Histological changes typically mainly affect perivenular regions of the liver parenchyma and include an overlapping spectrum of steatosis, steatohepatitis and persinusoidal or pericellular fibrosis, in some cases leading to cirrhosis. Once cirrhosis has developed, typical hepatocellular changes are often no longer conspicuous, leading to such cases being mistakenly diagnosed as 'cryptogenic'. Portal inflammation, ductular reaction and periportal fibrosis can also be seen as part of the morphological spectrum of NAFLD, particularly in the paediatric population. Hepatocellular carcinoma has also been described as a complication of NAFLD-associated cirrhosis. NAFLD is also an important cofactor in other chronic liver diseases, especially hepatitis C. Histological assessments have an important role to play in the diagnosis and management of NAFLD. These include making the potentially important distinction between simple steatosis and steatohepatitis and providing pointers to the aetiology, including cases where a dual pathology exists. A number of systems have been devised for grading and staging the severity of fatty liver disease. These require further evaluation, but have a potentially important role to play in determining prognosis and monitoring therapeutic responses.

The polycomb group proteins, BMI-1 and EZH2, are tumour-associated antigens.

We used SEREX technology to identify novel tumour-associated antigens in patients with primary hepatocellular carcinoma and found serological responses to the polycomb group (PcG) protein BMI-1, which is overexpressed in a range of different tumour types. Further studies identified T-cell responses to both BMI-1 and another PcG protein, EZH2, in cancer patients and at relatively lower levels in some normal donors. We next identified several CD8+ T-cell epitopes derived from BMI-1 and EZH2 and demonstrated that EZH2-derived peptides elicited more significant interferon-gamma (IFN-gamma) release than BMI-1-derived peptides. That CD8(+) T cells were responsible for the observed responses was confirmed for EZH2 by both IFN-gamma capture assays and tetramer staining using an HLA-A0201-restricted, EZH2-derived YMSCSFLFNL (aa 666-674) epitope. The ability of YMSCSFLFNL (aa 666-674) to stimulate the in vitro expansion of specific T cells from peripheral blood lymphocytes was greatly enhanced when the CD25(+) T-cell population was depleted. EZH2-specific cytotoxic T lymphocyte clones specific for two HLA-A0201 epitopes were generated and found to recognise endogenously processed EZH2 in both HLA-matched fibroblasts and tumour cell lines. Given the widespread overexpression of PcG proteins in cancer and their critical role in oncogenesis, these data suggest that they may be useful targets for cancer immunotherapy.

Revealing the cause of cryptogenic cirrhosis by posttransplant liver biopsy.

INTRODUCTION: Because of the tendency for preexisting diseases to recur following liver transplantation, studying the course of patients who were transplanted for their cryptogenic cirrhosis may reveal features of the original cause. We examined the clinicopathological posttransplant progression of patients transplanted due to cryptogenic cirrhosis with emphasis on the detection of posttransplant steatosis and steatohepatitis. METHODS: The data on all patients transplanted for cryptogenic cirrhosis and their routine 1-year posttransplant liver biopsies were compared to a control group of a randomized sample of patients transplanted for other indications matched for length of follow-up. The posttransplant histological diagnosis was based on the latest available biopsy. RESULTS: Among 1710 patients, 39 present with cryptogenic etiology survived at least 1 year after transplantation. The control group consisted of 78 patients. The mean ages of the two groups were 50.7 and 49.3 years and the mean follow-up periods 6.2 and 5.7 years, both of which were similar. There was a significantly greater prevalence of posttransplant steatosis and steatohepatitis among the cryptogenic group (37.5 vs 16.7%, P = .048). The difference in patients with at least moderate steatosis was more pronounced (18.8 vs 3.3%, P = .035). Half of these cases progressed to fibrosis and cirrhosis after 48 months. CONCLUSIONS: This study found a greater incidence of allograft steatosis and steatohepatitis among patients transplanted for cryptogenic cirrhosis compared with a control group. A significant proportion of these patients developed a picture resembling nonalcoholic steatohepatitis, which progressed to fibrosis and cirrhosis.

Acute myeloid leukaemia presenting as cholestatic hepatitis.

A 40 year old man presented with abdominal pain, jaundice, weight loss, and hepatosplenomegaly. Liver function tests revealed cholestatic jaundice and a computed tomography scan showed an enlarged liver, with a normal biliary tree. Liver biopsy showed diffuse infiltration by neutrophils, monocytoid cells, and blasts. Peripheral blood film and bone marrow were consistent with acute myeloid leukaemia. After treatment with chemotherapy using an acute myeloid leukaemia protocol (UK Medical Research Council AML-12), there was complete resolution of jaundice and the patient went into complete molecular remission.

Antidepressant induced cholestasis: hepatocellular redistribution of multidrug resistant protein (MRP2).

BACKGROUND: We report two cases of antidepressant induced cholestasis. CASE REPORTS: We describe the first reported case of acute cholestasis due to citalopram (selective serotonin reuptake inhibitor) occurring in a patient who also experienced obstetric cholestasis in association with each of three pregnancies; in a second patient cholestasis developed due to dothiepin (tricyclic antidepressant), and six years later due to paroxetine. In both cases liver biopsies showed features of a "pure" cholestasis with total resolution within 1-6 months after withdrawal of the causative drug. Immunostaining for the canalicular transporter, multidrug resistant protein 2 (MRP2), responsible for biliary secretion of several organic anions including bilirubin glucuronides, showed sustained expression in both biopsies as well as relocalisation with appearance of strong staining of the basolateral membrane of the hepatocyte. This finding has also not been reported previously. CONCLUSIONS: We postulate that intracellular redistribution of MRP2 may reflect an adaptive compensatory mechanism which helps in the elimination of the drug or its cholestatic metabolites from the hepatocyte back to the sinusoidal space and subsequent excretion in urine. Changes seen in these two patients differ from findings previously reported in rats where downregulation of mrp2 occurs in response to experimentally induced cholestasis. We speculate that the rat is more advanced than humans in its ability to downregulate canalicular transporter expression as protection against progressive intrahepatic cholestasis.

CD40 activation-induced, Fas-dependent apoptosis and NF-kappaB/AP-1 signaling in human intrahepatic biliary epithelial cells.

Fas-mediated mechanisms of apoptosis are thought to be involved in the bile duct loss that characterizes diseases such as primary biliary cirrhosis (PBC). We have previously shown that activation of CD40 on hepatocytes can amplify Fas-mediated apoptosis; in the present study, we investigated interactions between CD40 and Fas in biliary epithelial cells (BEC). We report that the bile ducts in PBC liver tissue frequently express increased levels of Fas, Fas ligand (FasL), and CD40 associated with apoptotic BEC. The portal mononuclear infiltrate contains CD40L+ve T cells and macrophages, thereby demonstrating a potential mechanism for CD40 engagement in vivo. Primary cultures of human BEC also expressed Fas, FasL, and CD40 but not CD40L protein or mRNA. Activation of CD40 on BEC using recombinant CD40L increased transcriptional expression of FasL and induced apoptosis, which was inhibited by neutralizing antibodies to either Fas or FasL. Thus, CD40-induced apoptosis of BEC is mediated through Fas/FasL. We then investigated the intracellular signals and transcription factors activated in BEC and found that NF-kappaB and AP-1 were both activated after CD40 ligation. Increased functional NF-kappaB was seen early after CD40 ligation, but returned to baseline levels after 4 h. In contrast, the rapid up-regulation of AP-1 was sustained over 24 h. This study provides further functional evidence of the ability of CD40 to induce Fas/FasL-dependent apoptosis of liver epithelial cells supporting the importance of cross-talk between tumor necrosis factor (TNF) receptor family members as an amplification step in apoptosis induction. Sustained activation of AP-1 in the absence of NF-kappaB signaling may be a critical factor in determining the outcome of CD40 engagement.

CD44 is the physiological trigger of Fas up-regulation on rheumatoid synovial cells.

CD44 is a ubiquitous molecule known as a hyaluronan receptor. However, the relevance of CD44 to inflammatory processes, for example, rheumatoid synovitis, remains unclear. In this study, we propose a novel function for CD44 using synovial cells from rheumatoid arthritis (RA) patients and demonstrated that CD44 cross-linking augmented Fas expression and subsequent Fas-mediated apoptosis of the cells: 1) cross-linking of CD44 on RA synovial cells markedly augmented Fas expression and its mRNA transcription; 2) engagement of CD44 up-regulated Fas on the cells within 3 h, much more than IL-1beta and TNF-alpha did; 3) the Fas-mediated early apoptotic change of the cells was amplified by CD44 cross-linking; and 4) hyaluronan, especially when fragmented, also augmented Fas-mediated early apoptosis of the cells. Based on these findings, we postulate a new concept: that interaction of CD44 on RA synovial cells with hyaluronan fragments present in the surrounding extracellular matrix augments Fas expression as well as Fas-mediated apoptosis of synovial cells. This may lead to spontaneous growth arrest through Fas-Fas ligand pathway observed in synovial cells of RA synovitis in vivo.

Are parenchymal changes in early post-transplant biopsies related to preservation-reperfusion injury or rejection?

BACKGROUND: The progression of parenchymal changes in liver allograft biopsies due to preservation-reperfusion injury (PRI) and their differentiation from rejection related changes is poorly understood. The aim of this study was to determine which changes in a 1-week posttransplant biopsy could be attributed to PRI and which to acute rejection. METHODS: One week protocol liver transplant biopsies from patients with mild PRI (day 1 AST<400 IU/L) were compared with those from patients with severe PRI (day 1 AST>2000 IU/L). Parenchymal changes (cholestasis, ballooning, steatosis, necrosis) and rejection-related inflammatory features (portal tract inflammation, bile duct inflammation, portal vein endothelial inflammation, hepatic vein endothelial inflammation, and centrilobular inflammation) were blindly assessed semiquantitatively. RESULTS: Fat, cholestasis, and hepatocyte ballooning were significantly worse in the severe PRI group, and these features showed no correlation with histological features related to acute rejection. Centrilobular hepatocyte necrosis correlated with hepatic venular endothelial inflammation and centrilobular inflammation but not with rejection related features in portal tracts or with PRI. These findings suggest that centrilobular necrosis is a manifestation of a rejection-related parenchymal injury and may involve different pathogenetic mechanisms to rejection-related features in portal tracts. CONCLUSIONS: This study indicates that in early posttransplant biopsies, fat, cholestasis, and ballooning can largely be attributed to PRI. By contrast, centrilobular hepatocyte loss should be suspected as a rejection related phenomenon, even if typical portal tract changes are not prominent, and augmentation of immunosuppression should be considered.

Visualization of the transport of primary and secondary bile acids across liver tissue in rats: in vivo study with fluorescent bile acids.

BACKGROUND/AIMS: Lysyl fluorescein conjugated bile acid analogues (LFCBAA) closely parallel their natural counterparts. To assess LFCBAA as a tool for the visualization of bile acid transport within liver tissue. METHODS: Wistar rats were administered physiological concentrations of the primary bile acid analogue cholyllysyl fluoroscein (CLF) and of the secondary bile acid analogue lithocholyllysyl fluorescein (LLF) and serial liver biopsies were taken at fixed intervals. Both compounds were also injected retrogradely into the biliary tree. Frozen sections were examined by fluorescence microscopy. RESULTS: Both CLF and LLF were rapidly taken up from sinusoidal blood but differed significantly in their hepatic handling. CLF was rapidly transported into bile, whereas LLF transport was slower and produced significantly more bile duct fluorescence. LLF clearance showed a lobular gradient with last remaining bile acid being confined largely to zone 3. Both compounds were avidly taken up by cholangiocytes after injection intravenously or retrogradely into the biliary tree. CONCLUSIONS: Visualization of LFCBAA by fluorescence microscopy may yield further information regarding hepatobiliary bile acid localization during studies of physiological and pathological mechanisms involved in transport of bile acids. The presence of both compounds within cholangiocytes strongly suggests that they may undergo a degree of chole-hepatic recirculation.

Recurrent and de novo non-alcoholic steatohepatitis following orthotopic liver transplantation.

BACKGROUND: Non-alcoholic steatohepatitis was coined in 1980 to describe pathological and clinical features of non-alcoholic disease associated with pathological features, commonly seen in alcoholic-liver disease itself. It is now a well-recognised cause of end-stage liver disease and a rare cause of orthotopic liver transplantation. A small number of cases with recurrent non-alcoholic steatohepatitis following liver transplantation have been reported, however de novo non-alcoholic steatohepatitis in the liver allograft is not well recognised. AIMS/RESULTS: We report four cases of non-alcoholic steatohepatitis following orthotopic liver transplantation describing the factors related with the pathology. The recurrence of fatty infiltration occurred within 21 months and transition from mild steatosis to non-alcoholic steatohepatitis and early fibrosis was observed within 60 months post transplant in all four patients. All four cases had association with one or multiples risk factors (obesity, type 2 diabetes and/or hyperlipidemia). CONCLUSIONS: Management of this risk factors may play a therapeutic role in the prevention of recurrent and de novo non-alcoholic steatohepatitis following orthotopic liver transplantation.

Differential expression of chemokines and chemokine receptors shapes the inflammatory response in rejecting human liver transplants.

BACKGROUND: Graft rejection after liver transplantation is associated with a lymphocytic infiltrate, the nature of which will be determined by, among various factors, the local activity of chemokines that attract particular subsets of effector cells to the graft. METHODS: The expression of chemokines and receptors in human liver allografts was studied by immunohistochemistry of tissue and flow cytometry of blood and liver-derived lymphocytes. Receptor function was assessed with in vitro chemotaxis. RESULTS: We report increased expression of chemokine receptors CXCR3, CXCR4, and CCR5 on circulating and graft-infiltrating lymphocytes after liver transplantation. Liver-derived T cells responded to the ligands for these receptors in vitro, which suggests that the receptors are functionally active. The chemokine ligands for these receptors were detected in rejecting allografts. CXCR3 ligands interferon-inducible protein 10 and monokine-induced by gamma interferon were detected on sinusoidal endothelium and interferon-inducible T-cell alpha chemoattractant was detected on portal and hepatic vascular endothelium, whereas the CXCR4 ligand, stromal-derived factor (SDF), was restricted to biliary epithelium. CCR5 ligands have previously been shown on portal endothelium. An in vitro model of T-cell alloactivation demonstrated a similar pattern of expression of functional CXCR3, CXCR4, and CCR5 on T cells. Increased expression of chemokine receptors, especially CCR3 and CCR5, was associated with redistribution of activated Kupffer cells in rejecting grafts. CONCLUSIONS: The patterns of chemokine expression in liver allografts during rejection suggest that the recruitment and positioning of lymphocytes is mediated by specific chemokines. Although ligands for the receptors CXCR3 and CCR5 are important for recruitment, the restriction of SDF to bile ducts suggests that CXCR4 may be involved in the retention of alloactivated lymphocytes at sites of graft damage.

Intercellular adhesion molecule 1 underlies the functional heterogeneity of synovial cells in patients with rheumatoid arthritis: involvement of cell cycle machinery.

OBJECTIVE: To investigate whether synovial cells from rheumatoid arthritis (RA) synovium can be divided into 2 functionally different subpopulations: active or proliferative cells and apoptotic cells. METHODS: Expression of cell surface and cytoplasmic molecules on synovial cells was assessed by immunohistochemistry, flow cytometry, or Western blotting. Cells were categorized as intercellular adhesion molecule 1 (ICAM-1) positive or negative based on positive and negative selection of antibody-coated beads. Cell cycle and apoptosis were assessed using propidium iodide staining, TUNEL method, and DNA fragmentation. RESULTS: Expression of ICAM-1 and Fas was noted mainly in the synovial lining to sublining layer in vivo, and synovial cells could be clearly distinguished as ICAM-1 positive or negative. The expression of Fas was higher on ICAM-1-positive cells than on ICAM-1-negative cells in vitro. The functional and phenotypic heterogeneity between ICAM-1-positive and -negative cells was further emphasized by cell cycle machinery. The majority of ICAM-1-positive cells were arrested at the G0/G1 phase, whereas many of the ICAM-1-negative cells were at the S to G2/M proliferating phase. In ICAM-1-positive cells, p53 and p21 expression was up-regulated and cyclin-dependent protein kinase 6 activity was inhibited. Most ICAM-1-positive cells were apoptotic (as evidenced by TUNEL positivity and DNA fragmentation). ICAM-1-positive cells were induced not only by interleukin-1beta, but also by Fas crosslinking. CONCLUSION: ICAM-1-positive synovial cells represent growth arrest and subsequent apoptosis, whereas ICAM-1-negative cells are proliferative. Such differences in regulation of the cell cycle based on ICAM-1 status are important determinants of the lifespan, proliferation, and growth arrest of RA synoviocytes.