Transfusion-associated hepatitis not due to viral hepatitis type A or B

Fifty landmark discoveries in gastroenterology during the past 50 years. A brief history of modern gastroenterology at the millennium: Part II. Gastrointestinal motility, nutrition, and diseases of the lower gastrointestinal tract, liver, and pancreas

During the last half century, many outstanding discoveries have revolutionized the clinical practice and science of gastroenterology. Although the scientific results are widely disseminated, the discoverers have received inadequate recognition and the history of their discoveries is largely unstudied and unknown. At the millennium, a committee selected 50 landmark discoveries in gastroenterology during the past 50 years. A brief history of each landmark discovery is presented. Part I was presented in the previous issue of Gastroenterology Clinics of North America. Part II presents landmark discoveries in gastrointerintal (GI) motility, clinical trials, nutrition, and diseases of the lower GI tract, liver, biliary tree, and pancreas.

Hepatitis C: an update on the silent epidemic

Hepatitis C virus (HCV) currently infects an estimated 2-3 million people in the United States and 175 million people globally. Over 80% of infected patients go on to develop chronic disease. Most patients remain asymptomatic despite silent, insidious progression of the disease. The sequelae of HCV-induced chronic liver disease accounts for 8,000-10,000 deaths annually in the United States and is currently the leading indication for liver transplantation. The cost of this epidemic to the United States was estimated in 1991 at $600 million in terms of medical expenses (excluding costs related to liver transplantation) and work lost. Over the last decade, since the viral genome of HCV was first sequenced in 1989, there has been a great increase in understanding of this infection. This review summarizes current knowledge about the hepatitis C epidemic with particular reference to epidemiology of infection, viral characteristics, risk factors for disease, diagnostic testing, clinical manifestations, and current, as well as potential, therapeutic options.

Viral hepatitis A, B, and C

Mankind probably has known viral hepatitis for many centuries; however, the major and most dramatic developments in our knowledge of these diseases have taken place during the second half of the 20th century. During this relatively short period of time, the infectious nature of hepatitis A, B, and C has been proven, leading to their identification and description. The advent of serologic markers has provided the means for establishing the diagnosis. Epidemiologic studies have provided important information that led to exciting achievements in detection and prevention of transmission. Molecular biology studies and cell culture techniques have established our knowledge of the viral genomes, and led to the development of specific vaccines for hepatitis A and B. Anti-viral therapy has been developed and aggressive combination therapy has emerged as a promising strategy for chronic hepatitis B and C. This article reviews some of the main fields of progress and achievement related to viral hepatitis A, B, and C in the 20th century.

Discovery of non-A, non-B hepatitis and identification of its etiology

The discovery of hepatitis C was the direct result of the landmark discoveries of hepatitis B virus (HBV) and hepatitis A virus (HAV) and their serologies. Screening tests for HAV and HBV made it possible in the mid-1970s to examine cases of transfusion-associated hepatitis (TAH) and to demonstrate that only approximately 25% resulted from HBV and that none were related to HAV. Consequently, approximately 75% of TAH became classified as non-A, non-B hepatitis (NANBH). Subsequently, chimpanzee studies demonstrated that NANBH was a result of a transmissible agent Although it has been difficult to convince clinicians that NANBH was a serious disease because the overt manifestations are generally mild, it gradually became apparent that the NANBH agent often resulted in chronic hepatitis and sometimes evolved into cirrhosis. The NANBH agent remained a virologic enigma for the next decade until researchers at the Chiron Corporation used an ambitious molecular approach on large volumes of high-titer infectious chimpanzee plasma from the Centers for Disease Control and Prevention (CDC). They extracted RNA, cloned it into an expression vector, and screened the expressed product with presumed immune sera. A single positive clone was found in the millions screened, and, within a year, the entire genome was sequenced and the agent was identified as a novel flavivirus--the hepatitis C virus (HCV). Retrospective analysis of pedigreed samples at the National Institute of Health (NIH) showed that 70% to 90% of NANBH cases were HCV related. The impact of HCV blood donor screening has been enormous. The single-antigen first-generation enzyme immunoassay (EIA-1) prevented 40,000 HCV infections within the first year, and the second-generation assay (EIA-2) has actually reduced new transfusion-related HCV infections to almost zero.

Cell-based and animal models for hepatitis B and C viruses

Reliable cell-based assays and animal models have been developed for evaluating agents against hepatitis B virus. Although much progress has been made, in vitro and in vivo assays for hepatitis C virus are still on the horizon. Advances towards establishing inexpensive and reliable experimental models have accelerated the development of therapeutic modalities for these life-threatening viral infections. The characterization of well-defined viral targets coupled with improved molecular diagnostic technologies have illuminated this field.

10-Year follow-up after interferon-alpha therapy for chronic hepatitis C

Sustained responses to interferon-alpha occur in 10% to 25% of patients with chronic hepatitis C, but the long-term outcome is not well defined. We evaluated the long-term clinical, histological, and virological outcomes of 10 patients with chronic hepatitis C who were treated between 1984 and 1987 with interferon-alpha-2b for 52 +/- 6 weeks (total doses of 492 +/- 116 MU). Before therapy, all 10 had hepatitis C virus (HCV) RNA, elevations of serum aminotransferases, and chronic hepatitis with fibrosis on liver biopsy. Clinical follow up was 6 to 13 years, and liver biopsies were done 5 to 11 years after initiation of therapy. HCV RNA was assayed by qualitative and quantitative reverse transcriptase-polymerase chain reaction assays. Among 5 patients who had a 6-month sustained response after therapy, all remained HCV RNA negative, and at last follow-up, 4 had normal and 1 minimally elevated serum aminotransferase levels. Liver biopsy specimens were nonreactive for HCV RNA, and all the patients showed improvements in both inflammation and fibrosis and were either normal or had mild, nonspecific inflammatory changes. Among 5 patients without a sustained response, all continued to have HCV RNA in serum and persistent or intermittent aminotransferase elevations. Liver biopsy specimens showed little or no change in necrosis and inflammation; all except 1 patient had progression of fibrosis scores or cirrhosis. All 5 patients had symptoms of chronic hepatitis, 1 underwent liver transplantation, and another had progressive hepatic decompensation. In conclusion, patients with a 6-month posttreatment virological response have a favorable long-term clinical and histological outcome.

Current risks of viral hepatitis from blood transfusions

The incidence of transfusion-associated hepatitis in the United States has fallen dramatically since the late 1960s. Where once the risks were so great that as many as one in three transfused patients contracted hepatitis, now they are infinitesimal. Many factors share responsibility for this accomplishment; however, two stand above the rest: (i) improved donor selection and screening criteria, especially elimination of paid blood donations; and (ii) major advances in testing for viral hepatitis carriers. Currently, four tests are used for the prevention of transfusion-associated hepatitis: (i) hepatitis B surface antigen; (ii) hepatitis C virus antibody; (iii) hepatitis B core antibody; and (iv) alanine aminotransferase. The first two tests are largely responsible for the current low risks of transfusion-associated hepatitis due to hepatitis B virus and hepatitis C virus of 1 in 63,000 and 1 in 125,000, per unit, respectively. To further reduce the risks of transfusion-associated hepatitis will require the enhanced sensitivity provided by nucleic acid amplification techniques (e.g. polymerase chain reaction). Currently, however, no such tests are licensed and practical, automated, or inexpensive enough for individual blood donor screening. We have made such great strides in the prevention of transfusion-transmitted hepatitis that background rates of viral hepatitis now greatly exceed the risk of transmission via transfusion. For this reason, while it may still be reasonable to consider a transfusion as a possible cause for hepatitis, it is imperative that many other possibilities (e.g., iatrogenic and other risk factors) be ruled out.

[From non-A non-B hepatitis to hepatitis C]

In 1974, the existence of hepatitis serologically distinct from hepatitis A and B was recognized. They were tentatively designated non-A non-B. They accounted for 90% of post-transfusional hepatitis. During 15 years numerous studies failed to identify agent(s) responsible for these hepatitis. In 1989 the virus responsible for parenteral non-A non-B hepatitis was identified and named hepatitis C virus. Shortly after, the virus responsible for enteral non-A, non-B was also discovered (hepatitis E virus). During these 15 years, a 60% reduction of post-transfusional hepatitis was obtained both by the measures instituted to prevent AIDS transmission and by the introduction of surrogate assays (ALT levels and anti-HBc antibody).

Patterns of progression: unpredictability and risk of decompensated cirrhosis

Hepatitis C virus (HCV) infection appears to have a slow but progressive evolution to chronic hepatitis and cirrhosis in a significant percentage of patients. Chronic hepatitis develops in 60-80% of patients. Worldwide prospective studies have shown that a further 20-30% of patients with chronic active hepatitis will develop cirrhosis regardless of the possible source of HCV infection. The percentage of cirrhotics is generally believed to increase progressively as the length of follow-up increases. In patients with chronic HCV, there also is high risk for the development of hepatocellular carcinoma. Factors influencing the rate of progression from chronic hepatitis to cirrhosis appear to include age at time of exposure, duration of infection, degree of liver damage at initial biopsy, immunological status, and possibly HCV genotype. The mean intervals between the time of initial infection and the diagnosis of chronic hepatitis, cirrhosis, and hepatocellular carcinoma have been estimated to be 10, 20, and 30 years, respectively. The progression of disease is variable and is not always orderly and sequential. Patients can progress from chronic persistent hepatitis or chronic active hepatitis directly to hepatocellular carcinoma without first developing cirrhosis, especially those with genotype 1b. In addition, cirrhosis does not appear to lead to clinically apparent hepatic failure in all patients. Because of the variability in the clinical presentation and clinical progression of chronic HCV, long-term follow-up studies may be necessary to fully assess the sequelae of chronic HCV infection. Most patients with chronic HCV have abnormal liver histology but can present as otherwise healthy individuals. In contrast, patients with chronic HCV who have normal hepatic chemistries can have substantial hepatocellular damage. Consequently, treatment at diagnosis offers the greatest likelihood of eliminating the virus and preventing progression to more severe liver disease.

GB virus C/hepatitis G virus and other putative hepatitis non A-E viruses

The identification of the major agents causing human hepatitis (Hepatitis A, B, C, D and E Viruses) was achieved during the last 30 years. These viruses are responsible for the vast majority of human viral hepatitis cases, but there are still some cases epidemiologically related to infectious agents without any evidence of infection with known virus, designated as hepatitis non A-E. Those cases are considered to be associated with at least three different viruses: 1--Hepatitis B Virus mutants expressing its surface antigen (HBsAg) with altered epitopes or in low quantities; 2--Another virus probably associated with enteral transmitted non A-E hepatitis, called Hepatitis F Virus. Still more studies are necessary to better characterize this agent; 3--Hepatitis G Virus or GB virus C, recently identified throughout the world (including Brazil) as a Flavivirus responsible for about 10% of parenteral transmitted hepatitis non A-E. Probably still other unknown viruses are responsible for human hepatitis cases without evidence of infection by any of these viruses, that could be called as non A-G hepatitis.

Evaluation and treatment of chronic hepatitis C infection

Hepatic C virus (HCV) has been recognized increasingly as a major public health crisis in the United States, causing infection in an estimated 3.5 million people and resulting in 8000 to 10,000 deaths annually from liver-related complications. This article focuses on the clinical aspects and diagnosis of hepatitis C, the importance of excluding other chronic liver diseases, and the current basis and strategy for treatment of HCV infection with interferon. Ideally, it will help primary care providers with the task of evaluating, diagnosing, teaching, and caring for patients with this chronic, potentially debilitating, and lethal disease.

Fibrosis and other histological features in chronic hepatitis C virus infection: a statistical model

AIMS

To study the inter-relation between hepatic fibrosis and other histological features of chronic hepatitis C virus (HCV) infection.

METHODS

Liver biopsy specimens from 200 consecutive patients with chronic HCV infection were graded and staged separately for necro-inflammatory activity and for fibrosis. The interaction between fibrosis and other histological features was evaluated by univariate and multivariate analysis, followed by hierarchical log linear modelling.

RESULTS

The most striking feature was the presence of portal tract inflammation in 177 (89%) of 200 samples. Lymphoid aggregates/follicles were observed either alone or as part of the general inflammatory infiltration of the portal tracts in 120 (60%) of 200 samples. Fatty change (macro- and microvesicular steatosis) was observed in 76 (38%) samples: mild to moderate in 60 (30%) and diffuse in 16 (8%). Bile duct damage was found in 30 (15%) of 200 specimens. Lobular activity was found in 154 (77%) of 200 samples and was significant in 44; piecemeal necrosis was present in 79 (40%). Thirty one (16%) patients had stage 0 liver fibrosis, 27 (14%) had stage 1, 69 (35%) had stage 2, 43 (22%) had stage 3, 16 (8%) had stage 4, and 12 (6%) had stage 5. On log linear analysis, piecemeal necrosis, lobular inflammation and steatosis were linked directly with fibrosis. Portal tract inflammation was linked directly and indirectly via piecemeal necrosis and lobular inflammation with fibrosis. The presence of lymphoid aggregates was associated with bile duct damage.

CONCLUSIONS

Portal tract inflammation with lymphoid aggregates or follicles, together with fatty change, bile duct damage and/or lobular activity, are characteristic of chronic HCV infection, confirming previous reports. Piecemeal necrosis, lobular inflammation, portal inflammation, and steatosis are linked directly with fibrosis in this statistical model, suggesting a close inter-relation in the development of fibrosis/cirrhosis.

Molecular approaches to the identification of unculturable infectious agents

New molecular biologic techniques, particularly representational difference analysis, consensus sequence-based polymerase chain reaction, and complementary DNA library screening, have led to the identification of several previously unculturable infectious agents. New agents have been found in tissues from patients with Kaposi's sarcoma, non-A, non-B hepatitis, hantavirus pulmonary syndrome, bacillary angiomatosis, and Whipple's disease by using these techniques without direct culture. The new methods rely on identifying subgenomic fragments from the suspected agent. After a unique nucleic acid fragment belonging to an agent is isolated from diseased tissues, the fragment can be sequenced and used as a probe to identify additional infected tissues or obtain extended portions of the agent's genome. For agents that cannot be cultured by standard techniques, these approaches have proved invaluable for identification and characterization studies. Applying these techniques to other human diseases of suspected infectious etiology may rapidly elucidate novel candidate pathogens.

Visualization of hepatitis C virions and putative defective interfering particles isolated from low-density lipoproteins

Hepatitis C virus (HCV) in highly infectious sera has been shown to be predominantly associated with low-density lipoproteins. To determine whether the association is specific to low-density lipoproteins (LDL) or very low-density lipoproteins (VLDL), we fractionated HCV-containing plasma by a column chromatographic procedure known to separate these classes. Hepatitis C virus RNA detected by polymerase chain reaction (PCR) was associated primarily with the very low-density (VLDL) fraction. However, it could not be ruled out that virus-associated LDL may have eluted with this fraction. Hepatitis C virus virions isolated from sera having sufficient titre for visualization by electron microscopy are generally coated with antiviral antibodies, therefore we utilized the lipid association to isolate antibody-free virions. Very low-density lipoproteins were isolated by ultracentrifugal flotation and then treated with deoxycholate to release the virions. These were then isolated in a highly purified form by centrifugation in a sucrose gradient. The 1.10-1.11 g ml-1 region of the gradients contained 60-70 nm particles. Particles with similar surface structure but having a diameter of only 30-40 nm constituted about 30% of the total. The latter may represent defective interfering particles. The identity of both small and large particles with HCV virions and associated particles was confirmed by their trapping on grids by an anti-HCV E2 monoclonal antibody, and by their aggregation by rabbit antiserum to an amino-terminal peptide of E1. Thus, both E1 and E2 epitopes are displayed on the surface of intact HCV virions.

Hepatitis C virus genotypes among blood donors and their recipients in Iceland determined by the polymerase chain reaction

Eight antibody-positive individuals were detected among 12,000 blood donations during the first year of screening blood donors for hepatitis C virus (HCV) antibodies in Iceland. All 8 were found to have a history of intravenous drug abuse. Six of these 8 individuals had previously donated blood to 27 patients who could be traced and examined for HCV infection. The great majority (23/27, 85%) of the recipients had demonstrable HCV antibodies. Furthermore, RNA analysis with the polymerase chain reaction showed that all patients with HCV antibodies had HCV RNA in their serum and in one hemodialysis patient without HCV antibodies viral RNA could be demonstrated. Genotyping of the HCV strains showed that the genotype of the donor was also identified in all but one of the infected recipients of his/her blood or blood products. This study, therefore, substantiates high infectivity of the HCV by blood or blood factor donation and shows that viremic HCV antibody-negative individuals exist.

Presence of anti-hepatitis C virus serum markers in a dental school patient population

Hepatitis C virus (HCV) has joined the list of infections liver diseases of which the practicing dentist must be aware. This recently described RNA virus causes between 20% to 40% of reported cases of viral hepatitis in the United States. Patients with HCV show symptoms only one quarter of the time, but chronicity is maintained longer than with the other liver infections. The major mode of transmission is percutaneous, so dentists are potentially at risk to contact the virus. To assess the presence of exposure to HCV, a total of 500 dental school patients were screened for serum antibody to this virus (second-generation anti-HCV). In addition, participants were required to fill out a special screening questionnaire designed to indicate high-risk groups. Their serum was also analyzed for serum chemistries known to be associated with acute and chronic liver disease. Analysis of the 15 response questionnaires revealed statistical significance relating to questions inquiring about previous exposure to blood (transfusions, surgical procedures, etc) but little significance relating to lifestyle. In either case responses were not of practical predictive value. More than 5% of our sample patients were found to be positive reactors to anti-HCV, indicating previous HCV exposure. A significant number of those positive for anti-HCV also showed elevation of serum chemistries associated with hepatitis.

Transfusion reactions: the changing priorities

Over the last dozen years the relative frequencies of specific transfusion reactions have markedly altered, in general for the better. Although AIDS remains the Public's primary concern, the risk of AIDS from a transfusion is extremely low at this point. Hepatitis remains the most common infectious complication of blood transfusion, but only 1 in 6,000 units now carry a risk, whereas in the early 1980's the risk is believed to have been close to 10% per patient. Transmission of HTLV-I/II has also been markedly reduced by tests of donor sera. In contrast, cytomegalovirus has become of increased importance in view of the large number of patients immunosuppressed for transplantation and cancer therapy; bacterial growth in blood components appears to be increasingly common; and Chagas disease is likely to become a serious transfusion problem in this country. More widespread use of filters which remove three logs or more of white blood cells from components should play a major role in reducing transfusion reactions further.

Serum alanine aminotransferase measurement as a guide to selective testing for hepatitis C during medical checkup

The efficiency of elevated serum alanine aminotransferase values for selecting subjects to be tested for hepatitis B or C infections in a large French population undergoing a medical checkup was investigated. For 5 consecutive weeks, serum alanine aminotransferase values were controlled in 9044 subjects; 308 subjects (202 males) were selected with alanine aminotransferase levels 1.2-fold above the normal value (58 iu/l for men, 34 iu/l for women). For each selected case, an age- and sex-cross-matched control was included. Of the 308 subjects with elevated alanine aminotransferase values, one was HBsAg positive and 15 (seven males) were anti-HCV positive. All anti-HCV sera tested by enzyme immunoassay were also positive by three immunoblots and 11/15 (73%) were HCV-RNA positive by reverse transcription-polymerase chain reaction. Of the 308 control subjects, two were HBsAg positive and four (two males) were weakly anti-HCV positive by enzyme immunoassay. Only one weakly anti-HCV positive serum was reactive by one immunoblot and all were HCV-RNA negative. This study shows the usefulness of alanine aminotransferase screening to detect hepatitis C virus infection in the general French population. Many of the anti-HCV positive subjects detected in this study were not aware of their hepatitis C virus seropositivity (12/15) or that they were viremic (11/15). Use of this low-cost assay will considerably reduce the number of subjects to be tested for hepatitis C virus serological status and therefore the cost. It may make possible the investigation of large populations by setting up public health programs to detect and treat hepatitis C virus. Hepatitis C virus infected subjects detected in these programs could benefit from medical follow up, including antiviral therapy.

Hepatitis C: progress and problems

The hepatitis C virus (HCV), a single-stranded RNA virus, is the major cause of posttransfusion hepatitis. HCV isolates differ in nucleotide and amino acid sequences. Nucleotide changes are concentrated in hypervariable regions and may be related to immune selection. In most immunocompetent persons, HCV infection is diagnosed serologically, using antigens from conserved regions. Amplification of RNA may be necessary to detect infection in immunosuppressed patients. Transmission by known parenteral routes is frequent; other means of spread are less common and may represent inapparent, percutaneous dissemination. Infection can lead to classical acute hepatitis, but most infected persons have no history of acute disease. Once infected, most individuals apparently remain carriers of the virus, with varying degrees of hepatocyte damage and fibrosis ensuing. Chronic hepatitis may lead to cirrhosis and hepatocellular carcinoma. However, disease progression varies widely, from less than 2 years to cirrhosis in some patients to more than 30 years with only chronic hepatitis in others. Determinants important in deciding outcome are unknown. Alpha interferon, which results in sustained remission in selected patients, is the only available therapy. Long-term benefits from such therapy have not been demonstrated. Prevention of HCV infection by vaccination is likely to be challenging if ongoing viral mutation results in escape from neutralization and clearance.

Molecular cloning of HCV and clinical application

Fifty-five clones encoding epitopes of HCV were isolated from Japanese patients. Their amino acid homology (AAH) to the sequence of prototype (HCV-1) ranged from 47% to 94%. These sequences cover 60% of the HCV genome lacking M/E and NS2 regions suggesting a very low or lacking immunogenicity for these regions. Two test kits for detection of anti-HCV antibody were developed using a combination of a synthetic peptide (AR142) containing the epitope of N14 (QRKTKRSTNRR) having a homology to the core of HCV of 8/11AA and a non-fusion recombinant protein Y19 starting from amino acid number (AAN) 1380 to 1507 in the NS3 region showing a AAH to the HCV-1 of 90%, and a combination of a mixture of three synthetic peptides of S29 AAN of 1-30, 38-65 and 47-74 of the core and a non-fused recombinant protein S4 AAN of 1287-1506 having a 93% AAH of the NS3 region. They showed almost the same order of sensitivity and specificity of the second-generation kits when tested with serum from blood donors and patients with non-A, non-B hepatitis. It should also be stressed that in all of the complete responders of a recombinant alpha-interferon therapy, the antibody levels against AR142 gradually decreased during and after the treatment. In 1992, studies performed for 125 patients with hepatocellular carcinoma in our clinic shows that of these 16 patients might developed from either chronic non-B, non-C liver diseases or chronic liver diseases caused by mutant(s) of HCV as their serum were negative for HBsAg and second-generation of anti-HCV.

Hepatitis C virus: historical perspective and current concepts

Over the past 30 years, hepatitis C has emerged from shadowy enigma to important public health problem. The existence of the etiological agent of this disease was first appreciated two decades ago but significant progress in its understanding had to await its molecular characterization within the past 5 years. The virus is a member of the family Flaviviridae and is the cause of approximately 20% of clinical viral hepatitis in the United States. While the control of the transmission of hepatitis C virus in blood and blood products has been nothing less than spectacular, the control of community-acquired hepatitis C will be a major challenge to the scientific and medical communities.

Pruritus as a symptom of hepatitis C

Recent isolation, cloning, and sequencing of the hepatitis C genome, which has led to the development of an enzyme-linked immunosorbent assay, has produced increasing recognition of a hepatic disease that frequently leads to potentially lethal, chronic active hepatitis. We describe four patients who had pruritus or in whom pruritus developed as a consequence of hepatitis C. The symptom of pruritus should be added to a growing list of cutaneous manifestations of this newly recognized inflammatory viral hepatitis.

Hepatitis viruses: changing patterns of human disease

Viral hepatitis is a disease of antiquity, but evidence for more than one etiologic agent has been recognized only since the 1940s, when two viruses (hepatitis A virus and hepatitis B virus) were thought to account for all disease. In the past 20 years, three additional hepatitis agents (hepatitis C virus, hepatitis D virus, and hepatitis E virus) have been discovered, and there is evidence for at least one additional virus. Each of the five recognized hepatitis viruses belongs to a different virus family, and each has a unique epidemiology. The medical impact of these viruses on society has been strongly influenced by changes in human ecology. This has resulted in some cases in diminished disease and in others in increases in the incidence of disease.

[Hepatitis C]

Hepatitis C virus (HCV), identified in 1989, is the main agent of Non-A, Non-B hepatitis. The number of HCV carriers in France is estimated between 500,000 and 2 millions. The main risk factors for HCV infection are blood products transfusion and i.v. drug abuse. Cirrhosis occurs in 30% of cases with a delay ranging from 10 to 30 years, and hepatocellular carcinoma in 2.5% of cases. Interferon is, for instance, the only effective therapy in patients with chronic hepatitis C; however, prolonged response (in terms of transaminase normalization) after stopping treatment occurs only in 20% of patients.

Chronic hepatitis in haemophilia

Chronic hepatitis affects almost all haemophiliacs treated with non-virally inactivated clotting factor concentrates. The virus responsible is hepatitis C (HCV) and most patients have non-neutralising antibodies with circulating virus. Although the majority also have evidence of past infection with hepatitis B, less than 5% are chronic carriers of HBsAg. Chronic hepatitis C can be associated with severe and progressive liver disease but the development of complications is slow. Treatment with recombinant interferon alpha given subcutaneously normalises the liver function in 50% of patients, but 50% of responders relapse on stopping treatment. Liver transplantation is successful in patients with advanced liver disease and it offers the added advantage of phenotypic cure of the haemophilic state.

Hepatitis C virus infection: its role in chronic liver diseases

In order to find out the infectious rate of hepatitis C virus (HCV) among chronic liver diseases, we investigated antibodies against hepatitis C virus and HCVRNA by method of ELISA, RIBA and RT-PCR in 410 patients with chronic liver disease. The prevalence of HCV infection was found to be 4%. Whereas the positive rate of HBsAg and HBV-DNA of these cases was 69% and 58%, respectively. There is no statistical significance between HCV infectious rate of patients with positive and negative HBsAg. The relative low infectious rate of HCV infection among chronic hepatic diseases indicates that HBV infection plays a more important role in causing chronic hepatitis than that of HCV. Thus, special emphasis should be paid to the preventive and therapeutic measures against hepatitis B in China.

Lower prevalence of anti-hepatitis C antibody in dialysis and renal transplant patients in Ireland

It is well recognised that haemodialysis and renal transplant patients are at increased risk of developing non-A, non-B hepatitis. Recently the genome of hepatitis C virus (HCV), the major causative agent for non-A, non-B hepatitis, has been isolated. Anti-HCV seroprevalence was assessed in all haemodialysis patients (266) in Ireland who in March 1990 had been dialysed for at least 6 months. For comparative purposes, 272 patients who had functioning renal transplants for greater than 6 months were also studied. Potential risk factors such as age, number of blood transfusions and time on dialysis were evaluated. The prevalence of HCV infection as evidenced by antibody detection was only 1.1% for transplant and 1.7% for haemodialysis patients. This compares to a reported incidence of between 10% and 50% found elsewhere. Two of the 5 anti-HCV positive haemodialysis patients and 2 of the 3 transplant patients had biochemical evidence of liver disease. From stored sera it was possible to ascertain when patients acquired HCV. Whether the very low prevalence of anti-HCV in Irish patients is due to the low prevalence of the virus in the general population, the policy of non reimbursement of blood donors, genetic or other factors, remains to be determined.

Frequency of hepatitis C in acute post-transfusion hepatitis after open-heart surgery: a prospective study in 1,476 patients

Post-transfusion hepatitis was studied prospectively in 1,476 patients undergoing open-heart surgery between 1985 and 1988. Thirty-three (2.2%) patients suffered from post-transfusion hepatitis. Acute post-transfusion hepatitis was attributed to hepatitis B in one case and to hepatitis C in ten patients (0.7%). Four additional patients had preexisting serologic markers of hepatitis C. In 22 (1.5%) patients, hepatitis B or C was excluded as a cause of liver disease. Seroconversion for hepatitis C virus occurred from 3 weeks to more than 6 months after infection. Chronic hepatitis C developed in four patients. In addition, seroconversion to anti-HCV was observed in four patients with moderately elevated aminotransferases. In the control patients anti-HCV antibodies were found in 0.5%. The characteristics of acute hepatitis C after blood transfusion are shown and compared to 22 patients with acute hepatitis non-A, non-B, non-C. The etiology of these 22 cases is discussed.

Hepatitis C virus antibodies in acute and chronic liver disease in India

The prevalence of serum antibodies to hepatitis C virus was assessed by an enzyme-linked immunosorbent assay in patients with epidemic non-A, non-B hepatitis (14), sporadic non-A, non-B hepatitis (42), chronic hepatitis (14) and cirrhosis (26). None of the patients with epidemic non-A, non-B hepatitis (14) and acute self-limiting sporadic non-A, non-B hepatitis without prior parenteral exposure (38) tested positive for hepatitis C virus antibody. Based on epidemiologic features, hepatitis E virus is presumably the etiologic agent for both these entities. Hepatitis C virus (HCV) antibody was positive in none of the patients with cryptogenic chronic hepatitis (11) and in 2(8%) patients with cryptogenic cirrhosis (25). It was concluded that cryptogenic chronic hepatitis and cirrhosis in India may be caused by alternative viral agents of the non-A, non-B type or by hepatotoxins to which the population may be exposed. Of 8 patients with prior parenteral exposure (transfusions 6, needle pricks 2) 5 (62.5%) patients tested positive for HCV antibody. HCV antibody was detected in 1 (25%) patient with acute self-limiting, parenterally transmitted non-A, non-B hepatitis and in 4 (100%) patients with chronic parenterally transmitted non-A, non-B hepatitis.

Molecular organization and replication of hepatitis E virus (HEV)

The recently characterized fecal-orally transmitted agent of hepatitis E (formerly known as enterically transmitted non-A, non-B hepatitis) has been determined to be a new type of positive strand RNA virus. The complete sequencing of four different geographic isolates of the hepatitis E virus (HEV) has confirmed a similar genetic organization not previously recognized in nonenveloped positive strand RNA viruses. The approximately 7.5 kb RNA genome (including polyA tail) has nonstructural genes located at the 5' end and structural genes at the 3' end. Expression of these viral genes occurs in at least 3 different forward open reading frames. The largest open reading frame begins 27 nucleotides (nt) downstream of the apparent noncoding 5' end and extends 5,079 nt. Multiple nonstructural gene motifs/domains have been recognized in this 5' ORF1 including a methyltransferase, a papain-like protease, a helicase and the RNA-dependent, RNA polymerase. The second major ORF2 begins 37nt downstream of ORF1 and extends 1980 nt before terminating 65 nt upstream of the polyadenylation site. A third ORF of only 369 nt was identified by immunoscreening experiments as encoding an immunogenic epitope of the virus. Expression of the downstream ORF2 may occur through internal subgenomic RNA initiation at a sequence element found to have homology to internal RNA initiation sequences in Sindbis virus. This element in the HEV genome maps near the apparent 5' end of one of two identified subgenomic messages. The genomic organization and expression of HEV will be discussed and a hypothesis presented regarding the viral replication strategy.

Infection of hemophiliacs with HIV

HIV was introduced into the blood supply at least 4 years before there was any clinical illness in hemophiliacs. While viral removal and inactivation techniques of plasma products have improved, contamination with a very stable virus is still a possibility.

Assessment of screening tests for transfusion-associated non-A non-B hepatitis

Non-A non-B hepatitis is the most common serious sequela of blood transfusion, and its screening has become an essential goal of blood transfusion centers. Before 1989, two surrogate screening tests (for alanine aminotransferase and for antibody to hepatitis B core antigen) were used; in 1989, a direct test for the antibody to hepatitis C virus (the main agent of this hepatitis) was developed. The French National Agency for the Development of Medical Evaluation undertook an investigation to determine the optimal prevention strategy for posttransfusion non-A and non-B hepatitis (PTH). A detailed literature review was performed, complemented by expert group opinion. The performance of each test was derived indirectly by calculating the number of cases of PTH averted by each test. Hepatitis C virus testing is probably the most promising strategy, but different policies can be developed given the uncertainties of scientific data. Cost considerations should be taken into account in identifying the best screening strategy.

Long-term mortality after transfusion-associated non-A, non-B hepatitis. The National Heart, Lung, and Blood Institute Study Group

BACKGROUND

Acute non-A, non-B hepatitis after blood transfusion often progresses to chronic hepatitis and sometimes culminates in cirrhosis or even hepatocellular carcinoma. However, the frequency of these sequelae and their effects on mortality are not known.

METHODS

We traced patients with transfusion-related non-A, non-B hepatitis who had been identified in five major prospective studies conducted in the United States between 1967 and 1980. We matched each patient with two control subjects (identified as the first and second controls) who received transfusions but who did not have hepatitis. The mortality rates in the three groups were determined with use of data from the National Death Index and Social Security Death Tapes. Cause-specific mortality was determined by reviewing death certificates.

RESULTS

Vital status was established for over 94 percent of the 568 patients who had had non-A, non-B hepatitis and the two control groups (526 first controls and 458 second controls). After an average follow-up of 18 years, the estimate by life-table analysis of mortality from all causes was 51 percent for those with transfusion-associated non-A, non-B hepatitis, as compared with 52 percent for the first controls and 50 percent for the second controls. The survival curves for the three groups were virtually the same. Mortality related to liver disease was 3.3, 1.1, and 2.0 percent, respectively, among the three groups (P = 0.033 for the comparison of the group with non-A, non-B hepatitis with the combined control group). Seventy-one percent of the deaths related to liver disease occurred among patients with chronic alcoholism.

CONCLUSIONS

In this long-term follow-up study, there was no increase in mortality from all causes after transfusion-associated non-A, non-B hepatitis, although there was a small but statistically significant increase in the number of deaths related to liver disease.

Lack of protective immunity against reinfection with hepatitis C virus

Some individuals infected with hepatitis C virus (HCV) experience multiple episodes of acute hepatitis. It is unclear whether these episodes are due to reinfection with HCV or to reactivation of the original virus infection. Markers of viral replication and host immunity were studied in five chimpanzees sequentially inoculated over a period of 3 years with different HCV strains of proven infectivity. Each rechallenge of a convalescent chimpanzee with the same or a different HCV strain resulted in the reappearance of viremia, which was due to infection with the subsequent challenge virus. The evidence indicates that HCV infection does not elicit protective immunity against reinfection with homologous or heterologous strains, which raises concerns for the development of effective vaccines against HCV.

Hepatitis C as the cause of chronic non-A, non-B hepatitis: high sensitivity of simultaneous measurement of core and non-structural antibodies

First generation serologic tests (ELISA-1) for hepatitis C virus infection measure antibodies directed against a short non-structural segment of the virus (anti-c100-3). A major disadvantage of this test is that it lacks sensitivity in the identification of hepatitis C virus among patients at risk of infection. Thus, only 70-90% of chronic non-A, non-B cases are ELISA-1 positive. The present study set out to determine whether antibodies directed against the core region would be a more sensitive indicator of hepatitis C virus infection in patients with chronic non-A, non-B hepatitis. Sera were studied from 97 patients with raised serum alanine aminotransferase levels for more than 6 months in whom other causes of abnormal alanine aminotransferase were excluded. Using ELISA-1, 85 sera (87%) were anti-c100-3 positive. Sera were then tested for presence of antibody directed against Po, a core peptide of a Japanese strain of hepatitis C virus, using an ELISA method. Eighty-eight sera (91%) were anti-Po positive. Among the 12 anti-c100-3 negative patients, six were anti-Po positive. A second generation ELISA for anti-HCV (ELISA-2) incorporates a different antibody to the core region (c22-3) in addition to an expanded non-structural region, c200, which consists of c100-3 plus c33c. With these tests, all sera but one were positive, including 11 of 12 ELISA-1 negative and eight of nine anti-Po negative sera.(ABSTRACT TRUNCATED AT 250 WORDS)

Cause and frequency of posttransfusion hepatitis after open-heart surgery

A total of 1476 patients who underwent open-heart surgery between 1986 and 1988 participated in a prospective study examining posttransfusion hepatitis. They received a total of 8327 units of whole blood, packed erythrocytes, or fresh frozen plasma. The aminotransferase activities were measured preoperatively and 1, 2, 3, 4, 6, 9, 12, and 24 weeks after the operation. Thirty-four patients in all (2.3% of the transfused patients) developed posttransfusion hepatitis, which could be identified as hepatitis B in 1 patient and hepatitis C in 14 patients. No cause for posttransfusion hepatitis could be found in 19 cases (hepatitis of unknown origin). Hepatitis C became chronic in 5 patients. In contrast to hepatitis C, the 19 patients with hepatitis of unknown origin all showed a milder clinical course with lower maximal aminotransferase activities and a shorter duration of the hepatitis. A chronic course was not observed among them. The cause of hepatitis of unknown origin is discussed.

HCV and HBV infection among multitransfused thalassemics from eastern Sicily

Serum specimens from 152 Sicilian multitransfused thalassemic subjects were tested for antibodies to hepatitis C virus (anti- HCV) and for HBV markers by enzyme linked immunoassay and with reference to anti-HCV, confirmed by recombinant immunoblot assay. A high rate (47%) of subjects was anti-HCV positive. HBsAg was found in 8% of patients and 55% had anti-HBs or anti-HBc antibodies or both. Contrary to HBV infection, anti-HCV seropositivity was related to the number of transfused units. The highest anti-HCV prevalence was observed between 16 and 20 years; 100% of persons older than 50 years had at least one marker of HBV infection. In conclusion, HCV and HBV are widespread among multitransfused thalassemic. Probably in our area, particularly during the pre-HBsAg screening era, several multitransfused patients were infected by HBV more readily than by HCV.

Antibody to hepatitis C virus in risk groups in Canada

The prevalence of antibodies against hepatitis C virus (HCV) was studied in hemophiliacs, hemodialysis patients, intravenous drug abusers, female prisoners, homosexuals, individuals with no markers of recent hepatitis A or B virus infections and normal individuals (federal public servants), by an enzyme immunoassay (Ortho Diagnostic Systems Inc). Repeat positive samples were further tested by recombinant immunoblot assay (riba) HCV (Chiron Corp, California). The number of samples positive for antibodies to HCV (anti-HCV) was higher with enzyme immunoassay than by riba HCV in most cases. A high prevalence of anti-HCV was detected in hemophiliacs by both enzyme immunoassay (68.8%) and riba HCV (53.7%). Among intravenous drug abusers and female prisoners the prevalence rates for anti-HCV were 42.8% and 29.8%, respectively, by riba HCV; the results with enzyme immunoassay were only slightly higher. The prevalence rate was also high by both tests (54.2%) in hemodialysis patients' sera taken during 1980-82, when many cases of non-A,non-B hepatitis were suspected in this group. In contrast, only 14.1% of sera taken during 1990 were positive by riba HCV. In individuals with no markers of recent hepatitis A or B infections, 13.4% were positive by enzyme immunoassay, whereas only 4.5% were reactive by riba HCV. The lowest prevalence was seen in homosexuals (2.3%) and normal individuals (1.2%) by riba HCV. These results indicate a high prevalence of anti-HCV in high risk groups tested in Canada.