Hepatitis viruses (other than hepatitis B and C viruses) as causes of hepatocellular carcinoma: an update.

Chronic hepatitis B and C virus infections are universally accepted as causes of hepatocellular carcinoma in humans. Hepatitis A and E viruses cause only acute self-limiting infections of the liver. Of the remaining hepatitis viruses - Delta hepatitis, hepatitis G (GB-C), TT and SEN - all have at some time been incriminated as causes of hepatocellular carcinoma. Delta hepatitis virus requires helper functions from hepatitis B virus to become invasive. Chronic Delta/hepatitis B viral co-infection runs a more severe course than that resulting from chronic hepatitis B virus infection alone, with progression to cirrhosis being more likely and more rapid. A substantial majority of the early studies did not find an increased incidence of hepatocellular carcinoma in co-infected individuals. But more recently, an increased incidence of the tumour has been recorded more often than no increase. Further studies are needed to draw a firm conclusion with regard to the hepatocarcinogenic effect of dual Delta/hepatitis B virus co-infection. With one exception, no published study (of 13) has incriminated chronic infection with hepatitis G virus as a cause of hepatocellular carcinoma. The dissenting study, published in 1999, was the only one performed in the United States. Fewer studies of the hepatocarcinogenic effect of TT virus have been performed. Apart from one study, published in 1999, no convincing evidence is available that supports a causal role for TT virus in hepatocarcinogenesis. The exception was in Japanese patients with high hepatitis C viral loads but independent of chronic hepatitis C virus infection. No evidence has been produced to indicate that SEN virus causes hepatocellular carcinoma.

Nurses at risk for occupationally acquired blood-borne virus infection at a South African academic hospital.

AIM: We aimed to ascertain if there had been any improvement in the number of nurses being immunised against hepatitis B virus (HBV) infection in a large academic hospital in which, 10 years previously, only 30.6% of the nurses were immune to infection with the virus, and to ascertain the incidence of infection with hepatitis C virus (HCV) and human immunodeficiency virus (HIV) in these nurses. METHODS: We studied 170 predominantly black nurses. Their blood was tested for the presence of active or past HBV infection using appropriate immunoassays, HCV infection by chromatographic immunoassays confirmed by polymerase chain reaction assays, and HIV using a rapid test confirmed by enzyme-linked immunosorbent assays. RESULTS: Serum of 89 (52.4%) nurses was positive for hepatitis B surface antibody (anti-HBs). Of these nurses 18 said that they had not received the vaccine; the serum of 9 of these was positive for anti-hepatitis B core antibody (anti-HBc) as well as anti-HBs, indicating natural infection with the virus. Of the nurses positive for anti-HBs, 89 were tested for anti-HBc; 28.2% tested positive for anti-HBc. Three nurses gave dates of immunisation that fell outside of their nursing careers; 3 (1.8%) were actively infected with the virus; 2 (1.8%) were infected with HCV; 10 nurses (5.9%) were positive for HIV. CONCLUSION: Nurses at this academic hospital remain at high risk of work-related HBV infection.

Liver resection for non-cirrhotic hepatocellular carcinoma in South African patients.

BACKGROUND: We describe the clinicopathologic features and outcome of South African patients who have undergone hepatic resection for hepatocellular carcinoma (HCC) arising in a non-cirrhotic liver. METHODS: We utilised the prospective liver resection database in the Surgical Gastroenterology Unit at Groote Schuur Hospital, Cape Town, to identify all patients who underwent surgery for HCC with non-cirrhotic liver parenchyma between 1990 and 2008. RESULTS: Twenty-two patients (10 men, 12 women, 3 black, 19 white, median age 47 years, range 21-79 years) underwent surgery for non-cirrhotic HCC. Sixteen patients had non-fibrolamellar HCC (Group 1); 6 patients had fibrolamellar HCC (Group 2). Group 1 had a median age of 55 years, and 6 (38%) were men; group 2 had a median age of 21 years, and 5 (83%) were men. Most patients had a solitary tumour at diagnosis; median largest tumour diameters in Groups 1 and 2 were 10 cm (range 4-21) and 12 cm (range 4-17), respectively. Patients in Group 1 underwent extended right hepatectomy (N=3), right hepatectomy (N=3), left hepatectomy (N=3), partial hepatectomy (N=7), cholecystectomy (N=6), and appendicectomy (N=1). Patients in Group 2 underwent extended right hepatectomy (N=1), right hepatectomy (N=1), left hepatectomy (N=2), segmentectomy (N=2), and portal lymphadenectomy (N=3). Recurrence rates in Groups 1, 2, and overall were 81%, 100% and 86%, respectively. Median overall survival was 46 months, with 1-, 3-, and 5-year survival rates of 95%, 59% and 45%, respectively. In Group 1, median survival was 39 months, with 1-, 3-, and 5-year survival rates of 100%, 56% and 38% respectively. In Group 2, median survival was 61 months, with 1-, 3-, and 5-year survival rates of 83%, 67% and 67%, respectively. CONCLUSION: Despite aggressive surgical resection, HCC arising in normal liver parenchyma has a high recurrence rate and an ultimately poor outcome. This finding is similar to both the recent international experience of non-cirrhotic HCC and local experience of fibrolamellar HCC.

Epidemiology of chronic hepatitis B virus infection, hepatocellular carcinoma, and hepatitis B virus-induced hepatocellular carcinoma.

Approximately 360 million people worldwide are chronically infected with hepatitis B virus (HBV) and are at high risk of developing hepatocellular carcinoma (HCC). Chronic HBV infection is the most prevalent cause of this tumour, accounting for 55% of global cases, and 89% of those in endemic regions for HBV infection. Relative risks for developing HCC in the presence of chronic HBV infection may be as high as 49 in case-control studies, and 98 in cohort studies. HCC is the sixth most common cancer in the world today, with approximately 630,000 new cases occurring each year. It ranks third in annual cancer mortality rates. Approximately 80% of HCCs occur in developing countries where HBV infection is endemic, with the highest incidences being in the Asia-Pacific region, and sub-Saharan Africa. In the chronic carriers of the virus who are at greatest risk of developing HCC, the infection is acquired at birth or in the early months or years of life, either perinatally or horizontally, and frequently becomes chronic. The risks are greater in males, and older individuals, and are increased by co-exposure to aflatoxin B(1), the presence of cirrhosis, obesity, or diabetes mellitus, and possibly co-infection with hepatitis C virus. Viral factors that influence the risk of HCC are high viral load, the presence of certain mutations, and genotypes. Although the incidence of chronic HBV infection is beginning to decrease as a result of the universal infant immunization programme, HBV-induced HCC incidence is projected to increase for at least another two decades.

Altered lipid profile, oxidative status and hepatitis B virus interactions in human hepatocellular carcinoma.

Altered membrane integrity in hepatocellular carcinoma (HCC) tissue was indicated by an elevation in cholesterol and significant decrease in phosphatidylcholine (PC). The resultant decreased phosphatidylcholine/phosphatidylethanolamine (PC/PE) and increased cholesterol/phospholipid ratios are associated with decreased fluidity in the carcinoma tissue. The lower PC was associated with a decrease in the quantitative levels of the saturated (C16:0, C18:0), omega6 (C18:2, C20:4) and omega3 (C22:5, C22:6) fatty acids (FAs), resulting in reduced long-chain polyunsaturated fatty acids (LCPUFAs), total PUFA and an increase in omega6/omega3 FA ratio. In PE, the saturated and omega3 (C22:5, C22:6) FAs were reduced while the total omega6 FA level was not affected, leading to an increased omega6/omega3 FA ratio. Increased levels of C18:1omega9, C20:2omega6 and reduction of 22:6omega3 in PC and PE suggest a dysfunctional delta-6 desaturase. The reduced PC/PE ratio resulted in a decreased C20:4omega6 (PC/PE) ratio, implying a shift towards synthesis of the 2-series eicosanoids. Lipid peroxidation was reduced in both hepatitis B negative (HBV(-)) and positive (HBV(+)) HCC tissues. Glutathione (GSH) was decreased in HCC while HBV had no effect, suggesting an impairment of the GSH redox cycle. In contrast HBV infection enhanced GSH in the surrounding tissue possibly to counter oxidative stress as indicated by the increased level of conjugated dienes. Apart from the reduced LCPUFA, the low level of lipid peroxidation in the carcinoma tissue was associated with increased superoxide dismutase and glutathione peroxidase activity. The disruption of the redox balance, resulting in increased cellular antioxidant capacity, could create an environment for resistance to oxidative stress in the carcinoma tissue. Alterations in membrane cholesterol, phospholipids, FA parameters, C20:4omega6 membrane distribution and low lipid peroxidation are likely to be important determinants underlying the selective growth advantage of HCC cells.

Hepatitis B Virus Infection: the Burden of Disease in South Africa

Hepatitis B virus infection; both acute and chronic; occurs commonly in the black population of South Africa; and chronic infection and its sequelae of cirrhosis and hepatocellular carcinoma are major public health threats. Chronic hepatitis B virus infection is rare in the other population groups; with the exception of the very small Chinese community. Prevalences of chronic carriage of hepatitis B virus in South African blacks are 5-16in rural males; 8-9in urban males; 4-12in rural females; and 2.7-4in urban females. The overall male to female ratio is 2.6:1.0. There are now three to four million South African blacks who are chronically infected with this virus. In rural black populations chronic hepatitis B virus infection is acquired very early in life; predominantly as a result of horizontal transmission of the virus; and by the age of 5 years carrier rates approach those seen in adulthood. A further slight increase occurs at school-going age and a greater increase at the time of becoming sexually active. Urban black carrier rates are significantly lower and the infection is acquired later in life. The decreased urban viral carriage rates occur mainly in the first generation born in an urban environment. Hepatitis B virus accounts for about 60of clinically evident acute viral hepatitis among blacks and about 10of chronic hepatitis and cirrhosis. It is the cause of the majority of the many cases of hepatocellular carcinoma that occur in black South Africans. The tumour is more common in males and in rural-born than in urban-born blacks. The close association between chronic hepatitis B virus infection and hepatocellular carcinoma holds true in rural and urban patients and males and females. The association is age-related; being closer in younger patients. Genotypes A and D of hepatitis B virus predominate in South African isolates; with genotype A and its subtype Aa having aparticularly high hepatocarcinogenic potential

Interaction between hepatitis B and C viruses in hepatocellular carcinogenesis.

Although hepatitis B (HBV) and C viruses (HCV) are, individually, major causes of hepatocellular carcinoma, the interaction, if any, between the carcinogenic effects of the two viruses is uncertain. Equal numbers of published studies have reported no risk interaction or a synergistic risk interaction. These conflicting results are explained by the rarity of concurrent infection with HBV and HCV in individuals without clinically evident liver disease, which severely limits the ability to accurately estimate the hepatocarcinogenic risk of dual infection compared with that of either infection alone. In an attempt to circumvent this difficulty, two meta-analyses have been performed, one based on studies published from a number of countries and the other on studies confined to Chinese patients. Both analyses concluded that a synergistic carcinogenic interaction existed between the two viruses and that the increased risk was super-additive but not multiplicative. If confirmed, this risk interaction will occur against a background of negative confounding effects on viral replication between HBV and HCV, which may be reciprocal. The mechanisms responsible for the carcinogenic interaction between the viruses are unknown. One possibility is that the increased incidence of cirrhosis with concurrent HBV and HCV infections acts as an even more potent tumour promoter than occurs with either virus alone. Synergism between the direct hepatocarcinogenic effects of the two viruses is another possible mechanism, but proof will have to await a fuller understanding of the pathogenetic mechanisms involved with the individual viruses.

Membranous obstruction of the inferior vena cava and its causal relation to hepatocellular carcinoma.

Although rare in most countries, membranous obstruction of the inferior vena cava (MOIVC) occurs more frequently in Nepal, South Africa, Japan, India, China, and Korea. The occlusive lesion always occurs at approximately the level of the diaphragm. It commonly takes the form of a membrane, but may be a fibrotic occlusion of variable length. Controversy exists as to whether MOIVC is a developmental abnormality or a result of organization of a thrombus in the hepatic portion of the inferior vena cava. The outstanding physical sign associated with MOIVC are large truncal collateral vessels with a cephalad flow. A dilated vena azygous is seen on chest radiography. Definitive diagnosis is made by contrast inferior vena cavography. The long-standing obstruction to hepatic venous flow causes severe centrolobular fibrosis and predisposes to the development of hepatocellular carcinoma (HCC). Percutaneous balloon angioplasty, transatrial membranotomy, or more complex vena caval and portal decompression surgery should be performed to prevent these complications. HCC occurs in more than 40% of South African Black and Japanese patients with MOIVC, but less often in other populations. It is thought to result from the tumour-promoting effect of continuous hepatocyte necrosis, although the associated environmental risk factors have not been identified.

Relationship of genotypes of hepatitis B virus to mutations, disease progression and response to antiviral therapy.

SUMMARY: Phylogenetic analysis has led to the classification of hepatitis B virus into eight genotypes, designated A to H. The genotypes have differences in biological properties and show heterogeneity in their global distribution. These attributes of the genotypes may account not only for differences in the prevalence of hepatitis B virus mutants in various geographic regions, but also be responsible for differences in the clinical outcome and response to antiviral treatment in different population groups.

Hepatitis B virus and human immunodeficiency virus co-infection in sub-Saharan Africa: a call for further investigation.

A growing body of evidence indicates that human immunodeficiency virus (HIV)-positive individuals are more likely to be infected with hepatitis B virus (HBV) than HIV-negative individuals, possibly as a result of shared risk factors. There is also evidence that HIV-positive individuals who are subsequently infected with HBV are more likely to become HBV chronic carriers, have a high HBV replication rate, and remain hepatitis Be antigen positive for a much longer period. In addition, it is evident that immunosuppression brought about by HIV infection may cause reactivation or reinfection in those previously exposed to HBV. Furthermore, HIV infection exacerbates liver disease in HBV co-infected individuals, and there is an even greater risk of liver disease when HIV and HBV co-infected patients are treated with highly active anti-retroviral therapy (HAART). Complicating matters further, there have been several reports linking HIV infection to 'sero-silent' HBV infections, which presents serious problems for diagnosis, prevention, and control. In sub-Saharan Africa, where both HIV and HBV are endemic, little is known about the burden of co-infection and the interaction between these two viruses. This paper reviews studies that have investigated HIV and HBV co-infection in sub-Saharan Africa, against a backdrop of what is currently known about the interactions between these two viruses.

Lack of susceptibility of Chacma baboons (Papio ursinus orientalis) to hepatitis C virus infection.

The main reason to ascertain whether baboons are susceptible to infection with hepatitis C virus (HCV) is the need to replace chimpanzees, which are endangered, as an animal model for undertaking research into the biology and host-virus interactions of HCV, and for developing a vaccine against this virus. A second reason is that baboons are a possible source of xenografts for human liver transplantation. We inoculated serum containing HCV into four Chacma baboons and monitored them for 52 weeks for evidence of infection. Serum was tested for antibody to HCV, HCV RNA, and aminotransferase concentrations at 2-week intervals for 26 weeks and thereafter at 4-week intervals. Liver tissue was examined at 28 and 52 weeks for histopathological changes and viral RNA, and at 52 weeks for viral particles using electron microscopy. Reverse transcription-polymerase chain reaction assay was used to detect HCV RNA, and the results were confirmed by Southern hybridization. Serum aminotransferase concentrations remained within the normal range and liver histology was normal during the follow-up period. Passive transmission of anti-HCV to the baboons was observed during the first 4 weeks. HCV RNA was not detectable in any serum or liver sample and electron microscopy failed to reveal viral particles in liver tissue. In conclusion, we did not find Chacma baboons to be susceptible to infection with HCV, although we cannot deny that in an immunosuppressed liver transplant recipient, infection of a baboon xenograft might occur. Another animal model for HCV infection must be sought.

Molecular analysis of hepatitis B virus genomes isolated from black African patients with fulminant hepatitis B.

To investigate further the possible role of mutant hepatitis B viruses in the pathogenesis of fulminant hepatitis B, the genomic sequence of hepatitis B virus isolates from 9 South African blacks with this disease, including 5 entire genomes, was analysed. Seven of the isolates were genotype A. The mutation most often reported in patients with fulminant hepatitis B, the G1896A precore stop-codon substitution, was, as expected, not present in the genotype A isolates with the exception of one in which it was accompanied by a compensatory C1858T substitution. G1896A was, however, present in the one genotype D isolate. No other precore-defective mutants were detected. The other mutation commonly found in patients with fulminant hepatitis B, the paired A1762T, G1764A substitution in the basic core promoter, was present in only one patient and G1764A in one other. The pre-surface initiation-codon mutation documented in a number of patients with fulminant hepatitis B was not found in our isolates. An 18-amino acid deletion present in the pre-surface region of one isolate has not previously been described in fulminant hepatitis B. Variations within the surface region were mainly genotype specific and not previously described. A relatively large number of mutations were present in the middle region of the core gene in those isolates without G1896A or A1762T, G1764A mutations, although the pattern was not consistent with those in published studies. Thus, as in other published series in which the entire genome of hepatitis B virus responsible for fulminant hepatitis was sequenced, we detected many mutations in different genes, but none was common to all the reported isolates.

Sister Joseph's nodule in hepatocellular carcinoma.

We describe three black South African patients in whom hepatocellular carcinoma metastasized to the umbilicus. Sister Joseph's nodule has previously been reported in only two patients with this tumour. A number of routes for this spread are possible: malignant hepatocytes in the portal venous system may reach the umbilicus via a patent umbilical vein; the tumour may propagate directly along the ligamentum teres hepatis to the umbilicus; contiguous spread of the tumour to the umbilicus from anterior peritoneal tissue, either directly infiltrated by hepatocellular carcinoma or the site of metastatic nodules, may occur; embolization of malignant hepatocytes to the umbilicus might take place by way of its arterial blood supply; or hepatocellular carcinoma might reach the umbilicus as a result of retrograde lymphatic spread from para-aortic lymph nodes or from the anterior abdominal wall, to which the tumour has metastasized.

Hepatitis B virus DNA in serum of healthy black African adults positive for hepatitis B surface antibody alone: possible association with recombination between genotypes A and D.

In some patients with chronic liver disease induced by hepatitis B virus, viral DNA is known to persist in low concentration in serum after seroconversion to hepatitis B surface antibody-positivity. This phenomenon has, however, not been documented in asymptomatic black African carriers of hepatitis B virus. Using nested amplification by the polymerase chain reaction, we detected low concentrations of hepatitis B virus DNA in the serum of 6 of 23 (26%) healthy black African adults with normal liver function and with hepatitis B virus surface antibody as the only serological marker of the virus. This finding offers one explanation for the earlier observation of integrated hepatitis B virus DNA in hepatocellular carcinomas in black Africans whose serum was positive for surface antibody alone. A number of genetic changes were found in the six isolates that might be responsible for evasion of the immune response and persistence of the virus. Isolated mutations were detected in the "a" determinant of the surface gene and in the encapsidation signal. In all five isolates sequenced in the core promoter, mutations were present in the upstream regulatory region. Recombination between genotypes A and D was present in three of the isolates, including both of those in which the entire genome was sequenced. This change in genotype also overlapped the amino end of the polymerase domain and may result in sufficiently low levels of replication to allow viral persistence. Topoisomerase 1 specific trinucleotides were concentrated in the vicinity of the recombination breakpoints.

Expression of c-myc promoter binding protein (MBP-1), a novel eukaryotic repressor gene, in cirrhosis and human hepatocellular carcinoma.

We have examined the expression of c-myc and c-myc promoter binding protein (MBP-1), a novel eukaryotic repressor, in human hepatocellular carcinoma and cirrhosis by semiquantitative reverse transcription PCR amplification. Levels were normalized for glyceraldehyde-3-phosphate dehydrogenase messenger RNA and then compared between these two groups and to normal liver. We found that MBP-1 expression was significantly decreased in cirrhosis and c-myc and MBP-1 were even further diminished in hepatocellular carcinoma. There was no clear correlation between MBP-1 and c-myc messenger RNA levels. Our results therefore suggest that expression of MBP-1 and c-myc are decreased in a stepwise fashion in the presence of chronic liver disease and hepatocellular carcinoma in humans and that further study of the interactions of these two genes and their products is warranted to determine their role in human hepatocarcinogenesis.

Characterization of proteinuria in asymptomatic family members and household contacts of children with hepatitis B virus-associated membranous nephropathy.

The biosocial background in which the hepatitis B virus (HBV) carrier state with membranous nephropathy (MN) develops was studied by evaluating HBV carriage and proteinuria among 195 family members and household contacts of 31 index HBV carrier children with MN. Unrelated individuals from the communities of these index cases who were negative for HBV served as controls (n = 123). HBV was determined by using third-generation enzyme-linked immunosorbent assay, slot-blot hybridization, and nested polymerase chain reaction. Patterns of proteinuria were determined by using sodium dodecyl sulfate-polyacrylamide gel electrophoresis; immunoglobulin G and haptoglobulin were suggestive of MN. Seventy-two members (36.9%) of the study group (n = 195) were HBV carriers; 21 of these carriers (29.2%) had proteinuria. Twenty-eight members (41.2%) of the study group who were HBV negative (n = 68) and 26.8% of the controls showed proteinuria. This lack of association between HBV carriage and proteinuria remained when controlled for sex and family relationship. HBV was not protective against the development of proteinuria. Proteinuria suggestive of MN was strongly associated with an abnormal protein-creatinine ratio (P: = 0.001), but was not significantly different between subjects and controls (8.7% versus 6.5%; P: = 0.5). Genetic influences or environmental exposures in these subjects may be responsible for the proteinuria, suggesting underlying glomerular basement membrane damage. Discordance between the HBV carrier state and patterns of proteinuria in the study group suggest that HBV and MN may not be causally related or may reflect exceptional interaction between specifically vulnerable individuals and HBV.

Transfusion-transmissible virus and hepatocellular carcinoma: a case-control study.

Although transfusion-transmissible virus (TTV) is often present in the serum of patients with acute and chronic non-A-C liver diseases, its hepatotropism, pathogenicity to the liver and hepatocarcinogenicity have not been proven. We used a case-control format to compare the prevalence of TTV infection among 148 southern African Blacks with hepatocellular carcinoma and 148 matched hospital-based controls, and to test for possible interactive effects between this virus and hepatitis B virus (HBV) and hepatitis C virus (HCV) in the development of the tumour. We also determined the prevalence of TTV in 988 blood donors in Gauteng province of South Africa. The presence of TTV DNA in serum samples was detected by using the polymerase chain reaction, Southern hybridization and nucleotide sequencing. Individuals infected with TTV did not have an increased risk of developing hepatocellular carcinoma (relative risk 1.1; 95% confidence limits 0.5-2.4). Moreover, co-infection with TTV did not further increase the risk of tumour development in patients chronically infected with HBV and/or HCV. TTV was present in the serum of 2.2% of blood donors: 4.0% in Black and 1.5% in White donors. We conclude that TTV is unrelated to the development of hepatocellular carcinoma in Black Africans.

Susceptibility of chacma baboons (Papio ursinus orientalis) to infection by hepatitis B virus.

BACKGROUND: Because baboons are being considered as a source of xenografts for human liver transplantation in patients with hepatitis B virus- (HBV) induced cirrhosis to forestall infection of the graft by the virus, we undertook a study to ascertain if baboons are resistant to HBV infection. METHODS: Six chacma baboons were inoculated with serum containing HBV and were followed for 52 weeks to detect transmission of infection. RESULTS: Anti-HBc was detected in the serum of four baboons 16 weeks after inoculation. Virions, small spherical particles, and tubular forms were seen at this time in the serum of the one baboon studied by transmission electron microscopy. HBV DNA was detected by polymerase chain reaction in the serum of the same four baboons throughout the period of follow-up, as well as in liver tissue obtained after 52 weeks. The specificity of the DNA was confirmed by Southern hybridization. Nucleotide sequences showed complete sequence identity between the HBV DNA in each of the baboon sera and one of the two HBV genotypes inoculated. Serum transaminase levels tested at 4-weekly intervals were always normal and histological examination of liver tissue after 52 weeks showed no evidence of chronic hepatitis. Examination of squash preparations of liver tissue by electron microscopy in one baboon revealed core-like particles. CONCLUSIONS: Chacma baboons are susceptible to HBV infection and appear to develop a chronic carrier state. The use of xenografts from baboons should preferably be avoided, but if they are used again for HBV-infected patients it would be prudent to treat the patients as if they had received an organ from a human donor.