G. McCaughan

A systematic review of hepatitis C virus epidemiology in Asia, Australia and Egypt

Background: The hepatitis C pandemic has been systematically studied and characterized in North America and Europe, but this important public health problem has not received equivalent attention in other regions.

Asian-Pacific consensus statement on the management of chronic hepatitis B: a 2005 update

Background/Aims: A large amount of new data on the treatment of chronic hepatitis B has become available such that the 2003 consensus statement requires revision and update.

Ledipasvir and sofosbuvir plus ribavirin in patients with genotype 1 or 4 hepatitis C virus infection and advanced liver disease: a multicentre, open-label, randomised, phase 2 trial

BACKGROUND Treatment options are limited for patients infected by hepatitis C virus (HCV) with advanced liver disease. We assessed the safety and efficacy of ledipasvir, sofosbuvir, and ribavirin in patients with HCV genotype 1 or 4 and advanced liver disease. METHODS We did an open-label study at 34 sites in Europe, Canada, Australia, and New Zealand. Cohort A included patients with Child-Turcotte-Pugh class B (CTP-B) or CTP-C cirrhosis who had not undergone liver transplantation. Cohort B included post-transplantation patients who had either no cirrhosis; CTP-A, CTP-B, or CTP-C cirrhosis; or fibrosing cholestatic hepatitis. Patients in each group were randomly assigned (1:1) using a computer-generated randomisation sequence to receive 12 or 24 weeks of ledipasvir (90 mg) and sofosbuvir (400 mg) once daily (combination tablet), plus ribavirin (600-1200 mg daily). The primary endpoint was the proportion of patients achieving a sustained virological response 12 weeks after treatment (SVR12). All patients who received at least one dose of study drug were included in the safety analysis and all patients who received at least one dose of study drug and did not undergo liver transplantation during treatment were included in the efficacy analyses. Estimates of SVR12 and relapse rates and their two-sided 90% CI (Clopper-Pearson method) were provided. This exploratory phase 2 study was not powered for formal comparisons among treatment groups; no statistical hypothesis testing was planned or conducted. The trial is registered with EudraCT (number 2013-002802-30) and ClinicalTrials.gov (number NCT02010255). FINDINGS Between Jan 14, 2014, and Aug 19, 2014, 398 patients were screened. Of 333 patients who received treatment, 296 had genotype 1 HCV and 37 had genotype 4 HCV. In cohort A, among patients with genotype 1 HCV, SVR12 was achieved by 20 (87%, 90% CI 70-96) of 23 CTP-B patients with 12 weeks of treatment; 22 (96%, 81-100) of 23 CTP-B patients with 24 weeks of treatment; 17 (85%, 66-96) of 20 CTP-C patients (12 weeks treatment); and 18 (78%, 60-91) of 23 CTP-C patients (24 weeks treatment). In cohort B, among patients with genotype 1 HCV, SVR12 was achieved by 42 (93%, 84-98) of 45 patients without cirrhosis (12 weeks treatment); 44 (100%, 93-100) of 44 patients without cirrhosis (24 weeks treatment); 30 (100%, 91-100) of 30 CTP-A patients (12 weeks treatment); 27 (96%, 84-100) of 28 CTP-A patients (24 weeks treatment); 19 (95%, 78-100) of 20 CTP-B patients (12 weeks treatment); 20 (100%, 86-100) of 20 CTP-B patients (24 weeks treatment); one (50%, 3-98) of two CTP-C patients (12 weeks treatment); and four (80%, 34-99) of five CTP-C patients (24 weeks treatment). All five patients with fibrosing cholestatic hepatitis achieved SVR12 (100%, 90% CI 55-100). Among all patients with genotype 4 HCV, SVR12 was achieved by 14 (78%, 56-92) of 18 patients (12 weeks treatment) and 16 (94%, 75-100) of 17 patients (24 weeks treatment). Seven patients (2%) discontinued ledipasvir-sofosbuvir prematurely due to adverse events. 17 patients died, mainly from complications of hepatic decompensation. INTERPRETATION Ledipasvir-sofosbuvir and ribavirin provided high rates of SVR12 for patients with advanced liver disease, including those with decompensated cirrhosis before or after liver transplantation. FUNDING Gilead Sciences.

Hepatitis C virus drug resistance and immune-driven adaptations: Relevance to new antiviral therapy†

The efficacy of specifically targeted anti‐viral therapy for hepatitis C virus (HCV) (STAT‐C), including HCV protease and polymerase inhibitors, is limited by the presence of drug‐specific viral resistance mutations within the targeted proteins. Genetic diversity within these viral proteins also evolves under selective pressures provided by host human leukocyte antigen (HLA)‐restricted immune responses, which may therefore influence STAT‐C treatment response. Here, the prevalence of drug resistance mutations relevant to 27 developmental STAT‐C drugs, and the potential for drug and immune selective pressures to intersect at sites along the HCV genome, is explored. HCV nonstructural (NS) 3 protease or NS5B polymerase sequences and HLA assignment were obtained from study populations from Australia, Switzerland, and the United Kingdom. Four hundred five treatment‐naïve individuals with chronic HCV infection were considered (259 genotype 1, 146 genotype 3), of which 38.5% were coinfected with human immunodeficiency virus (HIV). We identified preexisting STAT‐C drug resistance mutations in sequences from this large cohort. The frequency of the variations varied according to individual STAT‐C drug and HCV genotype/subtype. Of individuals infected with subtype 1a, 21.5% exhibited genetic variation at a known drug resistance site. Furthermore, we identified areas in HCV protease and polymerase that are under both potential HLA‐driven pressure and therapy selection and identified six HLA‐associated polymorphisms (P ≤ 0.05) at known drug resistance sites. Conclusion: Drug and host immune responses are likely to provide powerful selection forces that shape HCV genetic diversity and replication dynamics. Consideration of HCV viral adaptation in terms of drug resistance as well as host “immune resistance” in the STAT‐C treatment era could provide important information toward an optimized and individualized therapy for chronic hepatitis C. (HEPATOLOGY 2009.)

The role of sphingosine kinase 1 in cancer: oncogene or non-oncogene addiction?

Sphingosine kinase 1 (SphK1) is a lipid kinase that catalyses the phosphorylation of sphingosine to sphingosine-1-phosphate. There is strong evidence from cellular or animal systems that SphK1 is involved in the major mechanisms underpinning oncogenesis, namely, the promotion of cellular survival, proliferation and transformation, the prevention of apoptosis and the stimulation of angiogenesis. Furthermore there is also good evidence from clinical samples that SphK1 is overexpressed in many, if not most tumor types examined and that many inhibitors of SphK1 render tumors sensitive to chemotherapeutic agents. A major question that remains concerns the exact mechanism of action of SphK1 in cancer. The tools available to probe SphK1 function perturb a set of cellular functions, and it is possible that several of these are involved in driving its oncogenic role. Furthermore, the importance of SphK1 functions in normal physiology and the lack of mutations of SphK1 in cancer, suggest that the mechanism in cancer might be an over reliance on this system of cellular signaling; an example of non-oncogene addiction.

Early up-regulation of macrophages and myofibroblasts : A new marker for development of chronic renal allograft rejection

BACKGROUND Increased numbers of macrophages and myofibroblasts are observed to occur in chronic renal allograft rejection (CR). The aim of this study was to examine the expression of cellular markers for the macrophage and myofibroblast in early renal transplant biopsy specimens and correlate these findings with allograft outcome. METHODS The first postengraftment biopsy specimens from 53 patients who underwent renal transplantation between January 1993 and December 1995 were studied using immunohistochemistry with antibodies to alpha-smooth muscle actin, which identifies myofibroblasts and CD68, a marker for monocytes and macrophages. Patients were followed until December 1998 (mean follow-up 4.7+/-1.2 years). RESULTS Nine patients had progressed to CR by the time of the study, whereas 44 patients continued to have stable renal function. A marked increase in both macrophages (P=0.02) and myofibroblasts (P=0.04) was noted in the first biopsy specimen obtained after engraftment in the patients who developed CR compared with those with stable allograft function. There was a positive correlation between alpha-smooth muscle actin and collagen expression (P=0.0001). CONCLUSION Significant increases in macrophages and myofibroblasts occur in the first renal biopsy specimen in those patients who later develop CR.

Evidence that portal tract microvascular destruction precedes bile duct loss in human liver allograft rejection.

In liver allograft rejection, interlobular bile ducts are thought to be the main target of rejection. In contrast, in other organ allografts the capillary bed of the graft appears to be the primary target. To determine whether portal tract microvasculature is destroyed in liver allografts during rejection, we have identified portal tract microvasculature in 11 normal livers and 38 liver allograft biopsy specimens using monoclonal antibodies to capillary endothelium in immunohistochemical staining. El.5, CD31 and EL-4 antibodies identified portal microvascular endothelium in normal liver that had the morphology of capillaries. In allograft biopsies the number of microvascular structures per portal tract was reduced markedly in acute cellular rejection to 1.1 ±0.6 (n=25) and to 0.65±0.9 (n=15) in chronic ductopenic rejection compared with nonrejecting allografts (2.8± 0.6)(n=4) or normal liver (3.8±0.7)(n=11). To determine whether loss of microvascular structures preceded bile duct destruction in rejection, sections were double-stained to identify both microvasculature and bile ducts. The number of microvascular structures per bile duct was significantly lower in acute cellular rejection (0.5± 0.4)(n=18) or chronic rejection (0.3±0.4)(n=8) compared with normal liver (2.3±0.6)(n=7) (P<0.0001), demonstrating that components of the portal vasculature are destroyed prior to bile ducts. There was a correlation between the severity of rejection and the loss of microvascular structures per bile duct (P<0.001). In conclusion, in common with other allografted organs, the microvasculature of liver allografts appears to be an early target of rejection.

Vascular endothelial growth factor expression in human chronic renal allograft rejection.

BACKGROUND Chronic renal allograft rejection is characterized by interstitial fibrosis and vasculopathy. Vascular endothelial growth factor (VEGF) is an endothelial mitogen with increased expression in inflammation and vasculopathy. METHODS Renal tissue from 17 patients with chronic rejection was examined for VEGF protein and the presence of CD 68-positive macrophages, and compared to biopsies from patients with temporary allograft dysfunction, acute rejection, and native kidneys with thin membrane disease. RESULTS In the chronic rejection group, there was markedly increased expression of VEGF protein in the interstitium (P<0.0001). In serial sections, VEGF colocalized with the expression of CD 68-positive macrophages. Significantly more macrophages were in the tubulointerstitium in tissue with chronic rejection than in those with temporary allograft dysfunction (P<0.005). Additionally, VEGF protein expression in the glomeruli and the vascular compartment of patients with chronic rejection was increased. CONCLUSION The up-regulation of VEGF in chronic renal allograft rejection may be important in inflammation and development of fibrosis.

Thrombocytopenia post liver transplantation: Correlations with pre-operative platelet count, blood transfusion requirements, allograft function and outcome

This study reports that thrombocytopenia is a universal phenomenon post hepatic transplantation. In 53 consecutive adult patients undergoing liver transplantation the platelet count fell by a mean of 63% (157 x 10(9)/l to 50 x 10(9)/l). The platelet count reached a nadir at Day 5 post-transplant but returned to pre-operative levels by Day 14. Non-parametric regression analysis found that pre-operative platelet count, blood transfusion requirements and maximum post-operative ALT values were independent predictors of the percentage fall in platelet count. No correlation was seen with length of graft cold ischaemic time or the use of University of Wisconsin (UW) solution. The nadir day correlated with maximum post-operative bilirubin and ALT, graft ischaemic time and use of UW solution. Maximum post-operative ALT was also an independent predictor of nadir platelet count. It was observed that patients who did not survive the hospital admission had lower post-operative platelet counts and these did not return to pre-operative levels by Day 14. The percentage fall in platelet count was an independent predictor of survival. Severe thrombocytopenia was associated with cerebral haemorrhage in 3 patients. This report provides evidence that allograft dysfunction (maximum post-operative bilirubin and/or AST/ALT) was the most consistent independent predictor of the nadir platelet count, nadir day and percentage fall in platelet count post liver transplantation although the exact mechanism(s) of the platelet changes remain uncertain.

Divergent adaptation of hepatitis C virus genotypes 1 and 3 to human leukocyte antigen–restricted immune pressure

Many hepatitis C virus (HCV) infections worldwide are with the genotype 1 and 3 strains of the virus. Cellular immune responses are known to be important in the containment of HCV genotype 1 infection, and many genotype 1 T cell targets (epitopes) that are presented by host human leukocyte antigens (HLAs) have been identified. In contrast, there is almost no information known about the equivalent responses to genotype 3. Immune escape mechanisms used by HCV include the evolution of viral polymorphisms (adaptations) that abrogate this host–viral interaction. Evidence of HCV adaptation to HLA‐restricted immune pressure on HCV can be observed at the population level as viral polymorphisms associated with specific HLA types. To evaluate the escape patterns of HCV genotypes 1 and 3, we assessed the associations between viral polymorphisms and specific HLA types from 187 individuals with genotype 1a and 136 individuals with genotype 3a infection. We identified 51 HLA‐associated viral polymorphisms (32 for genotype 1a and 19 for genotype 3a). Of these putative viral adaptation sites, six fell within previously published epitopes. Only two HLA‐associated viral polymorphisms were common to both genotypes. In the remaining sites with HLA‐associated polymorphisms, there was either complete conservation or no significant HLA association with viral polymorphism in the alternative genotype. This study also highlights the diverse mechanisms by which viral evasion of immune responses may be achieved and the role of genotype variation in these processes. Conclusion: There is little overlap in HLA‐associated polymorphisms in the nonstructural proteins of HCV for the two genotypes, implying differences in the cellular immune pressures acting on these viruses and different escape profiles. These findings have implications for future therapeutic strategies to combat HCV infection, including vaccine design. (HEPATOLOGY 2009.)