Chronic non-A, non-B hepatitis carrier state: transmissible agent documented in one patient over a six-year period

Breakthroughs in hepatitis C research: from discovery to cure

In the 1970s, an unknown virus was suspected for documented cases of transfusion-associated hepatitis, a phenomenon called non-A, non-B hepatitis. In 1989, the infectious transmissible agent was identified and named hepatitis C virus (HCV) and, soon enough, the first diagnostic HCV antibody test was developed, which led to a dramatic decrease in new infections. Today, HCV infection remains a global health burden and a major cause of liver cirrhosis, hepatocellular carcinoma and liver transplantation. However, tremendous advances have been made over the decades, and HCV became the first curable, chronic viral infection. The introduction of direct antiviral agents revolutionized antiviral treatment, leading to viral eradication in more than 98% of all patients infected with HCV. This Perspective discusses the history of HCV research, which reads like a role model for successful translational research: starting from a clinical observation, specific therapeutic agents were developed, which finally were implemented in national and global elimination programmes.

Epidemiology of Hepatitis C Virus: A Battle on New Frontiers

The hepatitis C virus (HCV) is a leading cause of liver-related morbidity and mortality in the United States and other parts of the world. The epidemiology of the disease is highly variable between and within countries, and strategies to deal with HCV identification and treatment must be tailored to the geographic location and the political and economic environment of the region. Although great strides have been made in improving HCV transmission risk in blood supply products, new challenges related to changing patterns of disease incidence continue to require fresh evaluation and new approaches to disease prevention.

Drift in the hypervariable region of the hepatitis C virus during 27 years in two patients

Serial serum samples were obtained over a 27-year period from a hepatitis C virus (HCV)-infected patient and from a nurse who appeared to become infected by this patient. The hypervariable region 1 (HVR1) and 5'noncoding region (5'NCR) of the HCV genome were amplified from each serum sample by polymerase chain reaction (PCR) and cloned. In the first serum specimen from the patient and the first two serum specimens from the nurse, most of the 20 clones from each serum sample had one common sequence in the HVR1 gene. All later serum samples contained a heterogeneous mixture of HCV quasispecies. The uniformity of the HVR1 sequence in the early samples and the emergence of greater diversity in later serum samples is consistent with the apparent transmission of HCV between the patient and nurse and the eventual emergence of other quasispecies as the virus replicated in the new host. In addition, the immune globulin given to the nurse may have been responsible for some of the HCV quasispecies changes observed in her serum.

Comparative features of hepatitis C virus infection in humans and chimpanzees

Several features of human HCV infection are recapitulated in the chimpanzee model. Most importantly, the frequency of persistent infection is high in both species, and virus replication occurs despite evidence of cellular and humoral immune responses. A key difference is that necroinflammatory lesions in chronically infected chimpanzees are almost always mild, whereas in humans the disease spectrum is very wide, ranging from mild to severe hepatitis and end-stage cirrhosis requiring transplantation. Understanding the basis for both the similarities and differences in persistent hepatitis C in the two species will probably be important for the development of effective prevention and therapy of HCV infection.

Rheumatic manifestations of hepatitis C infection

With the advent of serological testing for the hepatitis C virus (HCV) clinicians can better recognize disorders associated with a subset of non-A, non-B hepatitis. As with hepatitis A and B virus infections, HCV disease may be associated with arthritis. Three patients with atypical arthritis who were subsequently discovered to have HCV infection are described. HCV infection should be considered in the differential diagnosis in patients with atypical arthritis.

Hepatitis C virus antibody detection by a line immunoassay and (near) full length genomic RNA detection by a new RNA-capture polymerase chain reaction

A rapid and simple RNA-capture polymerase chain reaction assay (RCPA) for detection of hepatitis C virus (HCV) is described. The assay detects specifically the presence of (near) full length genomic RNA of HCV by capturing HCV-RNA at the 3' terminal end on magnetic beads, followed by cDNA synthesis and PCR with 5' end specific primers. Sera were obtained from 30 chimpanzees inoculated with non-A, non-B hepatitis material from various sources, 28-122 months after infection. The sera were tested for the presence of HCV-RNA by RCPA and for HCV antibodies by a Line ImmunoAssay (Inno-LIA HCV Ab). Both tests were compared and show a high degree of agreement. Screening of 30 chimpanzee sera revealed either clearing of the virus below detection level (22/30) or development of a HCV carrier state (8/30). Only 1 of 11 LIA-indeterminate samples was positive by RCPA. As the RCPA is more sensitive, it can be used to test for the presence of HCV in sera which are classified indeterminate by the LIA. The outcome of the infection seems to be independent of the nature of the inocula, suggesting that the individual immune response could determine either clearing of the virus or the development of chronic infection.

A study of hepatitis C virus antibodies and serum alanine amino transferase in blood donors in Hong Kong Chinese

The reference range of serum alanine amino transferase (ALT) for the local population was established by testing 5,000 random voluntary Chinese blood donors of various age groups of both sexes. In addition, 1,769 serum samples with elevated ALT levels were also collected for anti-HCV assays using both the Abbott and Ortho anti-hepatitis C virus (HCV) assay kits. The relationship between serum ALT and anti-HCV tests was studied and the performances of both kits used were compared. It was found that while the prevalence of serum anti-HCV was 0.4% among hepatitis B surface antigen-negative donors with normal ALT, subjects with ALT between 2 and 3 standard deviations (SD) and greater than 3 SD above the mean level had respective prevalence of anti-HCV 3 and 9.5 times that of the normal ALT subjects. Both anti-HCV kits were found to identify in majority the same positive population among the different groups of subjects studied. In addition, it was observed that for subjects who were anti-HCV-positive, the higher the serum ALT level, the higher the mean anti-HCV ELISA ratio and this observation was similar for both anti-HCV kits used. We conclude that: (1) there is a direct relationship between serum ALT level and anti-HCV positivity by EIA; (2) there is a direct correlation between serum ALT level and anti-HCV ELISA ratio, and (3) both Abbott and Ortho anti-HCV kits perform similarly in the identification of positive serum samples.

Occupational risk for hepatitis C virus infection among New York City dentists

Health-care workers have an occupational risk of infection with hepatitis C virus (HCV). However, neither the magnitude of this risk nor the practices associated with it have been defined. Since dentists have numerous patients and are exposed to blood, they are likely to have the maximum risk. Therefore, we have assessed occupational risk for HCV infection among dentists in the New York City area. Individuals who admitted present or previous intravenous drug use or (men) who were homosexual or bisexual were excluded. Demographic, occupational, and behavioural data were recorded, and sera were tested for antibodies to HCV (anti-HCV). Anti-HCV was found in 8 (1.75%) of 456 dentists compared with 1 (0.14%) of 723 controls (odds ratio [OR] 12.9, 95% confidence interval [CI] 1.7 to 573). Anti-HCV was found in 4 (9.3%) of 43 oral surgeons compared with 4 (0.97%) of 413 other dentists (OR 10.5, 95% CI 1.9 to 58). Seropositive dentists claimed to have treated more intravenous drug users in the week (p = 0.04) or month (p = 0.03) before the study than did seronegative dentists. Our findings show that dentists are at increased risk for hepatitis C infection. All health-care workers should regard patients as potentially infected with a communicable bloodborne agent.

Detection of antibodies to hepatitis C virus in U.S. blood donors

An enzyme immunoassay (EIA) which utilizes a solid phase coated with a recombinant antigen (c100-3) derived from the hepatitis C virus (HCV) genome was evaluated for efficacy in the detection of antibodies to HCV (anti-HCV). The sensitivity of the antibody test was demonstrated by the detection of anti-HCV in a well-characterized panel of human specimens known to contain the infectious agent of non-A, non-B hepatitis. The specificity of the anti-HCV test was evaluated by testing 6,118 serum specimens from volunteer blood donors considered to be at low risk for exposure to HCV. The specificity of the anti-HCV EIA was demonstrated to be 99.56%, since 6,069 of 6,096 specimens from this low-risk group were nonreactive. A total of 49 (0.80%) of the 6,118 specimens were repeatedly reactive in the test, and 22 (46.81%) of the 47 specimens available for additional testing were confirmed as positive for antibodies to HCV c100-3. Among commercial plasma donors, 390 (10.49%) of 3,718 specimens were repeatedly reactive in the EIA. A total of 375 (97.40%) of the 385 specimens available for further testing were confirmed as positive. These limited data indicate that the prevalence of antibodies to HCV is 0.36% (22 confirmed positives among 6,118 specimens) among volunteer blood donors and 10.08% (375 confirmed positives among 3,718 specimens) among commercial plasma donors. The importance of confirmatory testing is discussed.

Hepatitis C

The major cause of chronic post-transfusion hepatitis, the hepatitis C virus (HCV), has been identified. HCV is a single-stranded linear RNA virus with characteristics similar to the flaviviruses. A different agent, the hepatitis E virus, is associated with epidemic (enterically-transmitted) non-A, non-B hepatitis. At present, infection with HCV is recognized by the finding of anti-HCV antibodies, positive in up to 90% of patients with chronic non-A, non-B post-transfusion hepatitis. Antibodies to HCV are detected in 1% of normal volunteer blood donors and in the majority of donors implicated in post-transfusion hepatitis. HCV antibodies are also found in patients with autoimmune liver disease and hepatocellular carcinoma. Moreover, HCV infection may contribute to the pathogenesis of liver disease in alcoholic patients. The role of HCV infection in fulminant non-A, non-B hepatitis and hepatitis-associated aplastic anemia has not been elucidated as yet. Therapy of chronic non-A, non-B hepatitis with recombinant human alpha-interferon has been shown to improve or normalize aminotransferase levels in approximately 50% of patients, most of whom have evidence of HCV infection. However, relapse after cessation of treatment is common. In the future, screening blood for evidence of HCV infection may prevent most cases of non-A, non-B post-transfusion hepatitis.

Clinicopathological studies and operative results of hepatocellular carcinoma with liver cirrhosis, comparing HB-associated cirrhosis to alcoholic and post-transfusion cirrhosis

The present study was undertaken to elucidate clinicopathological findings and operative results of HCC with HB-associated cirrhosis, compared with those in HCC patients with alcoholic and post-transfusion cirrhosis. The number of the HBV group was 26 cases, consisting of 17 in sAg(+), 4 in eAg(+) and 5 in eAb(+) subgroups. The number of the post-transfusion group was 7 and that of alcoholic group was 12. A high incidence of hypersplenism and esophageal varix in the eAg(+) subgroup was found. ICG R15 was the highest, KICG and ICG Rmax were the lowest in the eAg(+) subgroup. The mean diameter of tumors was the largest, 6.6 +/- 3.9 cm, in the sAg(+) subgroup and was the smallest, 2.2 +/- 1.7 cm, in the eAg(+) subgroup. The incidence of postoperative jaundice, hyperammoninemia and live dysfunction were the highest in the sAg(+) and eAg(+) subgroup. One and three-year survival rate were 76.9% and 48.1% in the sAg(+) subgroup, 60.0% and 30.0% in the eAb(+) subgroup, and the one-year survival rate in the eAg(+) subgroup was 50.0%. The three-year survival rate could not be calculated because 3 years had not passed since the operation. The prognosis was the poorest in the HBV group among all groups. This study suggests that in HBV-associated cirrhosis, hepatectomy might induce "acute on chronic" changes (acute hepatitis and fulminant hepatitis). Therefore we should select operative procedures by considering surgical risk and the etiology of liver cirrhosis in hepatectomy.

An epidemiological and clinical study of transaminase levels and hepatitis B antibodies in 1,100 blood donors

In order to provide epidemiological and clinical information on surrogate testing of blood donations, the respective prevalences of serum hepatitis B virus (HBV) markers and elevated transaminase levels were studied in 1,100 blood donors according to their geographic origin and socioeconomic level. The frequency of serum HBV markers varied as a function of HBV endemicity in the country of origin; however, it was inversely correlated (p less than 0.05) to the socioeconomic level of the donors, even in those originating from countries of low HBV endemicity. There was no association between serum HBV markers and the increased transaminase level which was observed in 48 (4.3%) donors. Twenty-five of these accepted further clinical evaluation. A diagnosis appeared probable in 12 of the 25: alcohol in 5; drugs in 6; non-A, non-B hepatitis in 1. Seven of the remaining 13 subjects were more than 25% above ideal body weight. Transaminase activities determined at the time of clinical assessment were normal in 14. In addition, serum HBV DNA was found in 5 of 247 donors, even in the absence of any usual HBV marker and/or hypertransaminasemia. This could account for the few cases of B and B-like posttransfusion hepatitis which are known to still occur despite careful HBsAg screening of blood donors.

Non-A, non-B hepatitis

Diagnosis of non-A, non-B hepatitis (NANB) is made after exclusion of other known causes of hepatitis. Parenterally spread non-a, non-B hepatitis (PNANB) and enterally transmitted non-A, non-B hepatitis (ENANB) almost certainly appear to be two different diseases. The definite causative agents have not hitherto been identified. Much of our knowledge of NANB is based on (i) experimental studies on chimpanzees; and (ii) epidemiological studies. Parenterally spread non-A non-B hepatitis caused by whole blood transfusion and blood-product infusion has different incubation periods and may be caused by different agents. It is a mild disease clinically, and the majority of the patients are asymptomatic. It can be prevented only by judicious use of blood transfusion. Whenever possible, blood/blood products should be derived from individual volunteer donors who are anti-HBc sero-negative and have serum alanine transaminase of under 45 IU/l. Enterally-transmitted non-A non-B hepatitis is endemic in the Indian subcontinent, South-East Asia, North and East Africa and Latin America. Epidemic NANB is usually transmitted by water supply contaminated with feces. ENANB has a predilection for young adults. The disease is usually mild, except in pregnant women, who have a high case-fatality rate from fulminant hepatic failure. Control measures include provision of clean water supplies, safe disposal of human excreta and sound personal and food hygiene practices.

Rationale for surrogate testing to detect non-A, non-B hepatitis

NANB hepatitis was initially recognized in 1975 and 13 years later, the exact etiology of this presumed viral disease remains uncertain. The acute illness is relatively mild with only about 25% of patients becoming icteric. Nevertheless, at least one half of the patients have evidence of chronic infection, and, as recently recognized, 10% to 20% develop severe liver disease. Because approximately 2% of patients who receive transfusions and whose underlying medical condition permits long term follow-up develop posttransfusion hepatitis, procedures for reducing this risk are considered prudent. Unfortunately specific tests for detecting NANB hepatitis are not available, and it is unlikely that such tests will be available in the near future. Hence, testing by surrogate or nonspecific tests (ALT and anti-HBc) were recommended because evidence from two studies conducted during the 1970s showed these tests identify some donors thought to transmit the infection. However, randomized, controlled prospective studies to determine whether these tests will, in fact, reduce NANB posttransfusion hepatitis were not performed. By the mid-1980s it was apparent these studies would not be performed nor were studies to determine the incidence of NANB posttransfusion hepatitis in the post-AIDS screening era likely to be initiated. Therefore, surrogate testing, as the best available method for reducing posttransfusion hepatitis, was implemented in the United States in 1986-87.

Chronic non-A, non-B hepatitis. A long-term follow-up study in 49 patients

Forty-nine patients with biopsy-verified chronic non-A, non-B hepatitis (NANBH) of both percutaneously transmitted and sporadic types were followed up for up to 20 years (mean, 62 months +/- 44 months). Drug addicts were not included. Twenty-four patients had chronic persistent hepatitis (CPH), and 25 had chronic active hepatitis (CAH) or cirrhosis on the basis of the first biopsy. Patients with CPH were significantly younger than patients with CAH (mean age, 31 and 51 years, respectively; p less than 0.001). Standard laboratory data (means) correlated with histology, but great variations made liver biopsy essential for the diagnosis. Twenty-one patients were rebiopsied, and 24% had more severe lesions. In total, 16 patients (33%) had signs of cirrhosis. The disease seemed to resolve in eight patients (16%), whereas two patients died of it. Some patients with CPH might progress to CAH, and the frequent finding of cirrhosis in CAH implies the possibility of hepatic failure and fatality in chronic NANBH.

Biophysical properties and morphology of purified antigen associated with non-A, non-B hepatitis

The antigen from a non-A, non-B antigen-antibody system previously described was purified and, when tested by immunodiffusion, was shown to produce patterns of identity with all antigen-positive sera of the system. The sedimentation coefficient S20,w of the antigen was estimated by rate zonal ultracentrifugation to be 48. Isopycnic ultracentrifugation in CsCl gradient of non-A, non-B antigen generated a single sedimentation peak at the density of 1.28. SDS-polyacrylamide-agarose gel electrophoresis showed that I125-labelled antigen migrated as a single band (molecular weight 3.0 X 10(6)); in addition, labelled material also migrated to the albumin region. With SDS-PAGE under reducing conditions, the antigen was shown to consist of seven polypeptides. Spherical particles of 23 nm in diameter, demonstrated by electron microscopy, could be aggregated by purified non-A, non-B antibody. They probably represent the antigen and not a complete viral particle. The characteristics of this antigen associated with non-A, non-B hepatitis appear therefore to be close to those of hepatitis B surface antigen.

Immune response to purified non-A, non-B hepatitis-related antigen demonstrated by leukocyte migration inhibition in patients recovering from the infection

Eight patients, convalescent from acute hepatitis, all negative for HBsAg, anti-HBc, anti-HA-IgM, anti-CMV and anti-EB, and all positive for non-A, non-B related antigen and/or antibody in at least one sample during the course of disease, were investigated. Their specific cell-mediated immunity was tested using the leukocyte migration inhibition test in presence of a previously described non-A, non-B related antigen. A control group consisted of ten individuals (two normal subjects, six patients recovering from acute hepatitis B and two with autoimmune chronic active hepatitis). Leukocyte migration was inhibited by the antigen in seven of the eight patients. The test was negative in all control subjects. It is thus demonstrated that after recovery, patients with non-A, non-B viral hepatitis develop a cellular immune response specific for purified non-A, non-B related antigen. The association between the described antigen and viral hepatitis non-A, non-B can now be established not only by immunoprecipitation, but also by a cellular test.

A glycoprotein associated with the non-A, non-B hepatitis agent(s): isolation and immunoreactivity

A glycoprotein was isolated and purified to homogeneity from the serum of a patient with chronic non-A, non-B hepatitis. NaDodSO4/PAGE of the glycoprotein revealed a single major band at Mr approximately 77,000. Antibodies to this glycoprotein were shown to possess the following immunoreactivity: (i) they reacted by radioimmunoassay with sera obtained at the time of diagnosis from 17 of 42 patients with non-A, non-B hepatitis and with only 2 of 58 sera from either matched controls or patients with hepatitis A or hepatitis B, (ii) they reacted with sucrose gradient fractions from a proven infectious non-A, non-B hepatitis serum at a peak density of 1.14 g/ml and in the soluble protein fractions on top of the gradient, and (iii) they reacted in ELISA with disrupted human T-cell lymphocytotropic virus type III (HTLV-III), and (iv) they reacted in immunoblots with a protein of Mr 74,000 derived from HTLV-III.

Recommended precautions for patients undergoing hemodialysis who have AIDS or non-A, non-B hepatitis

Precautions used for dialysis patients who have acquired immunodeficiency syndrome or non-A, non-B hepatitis are based on infection control strategies developed for the control of hepatitis B in dialysis centers. Specifically, these recommendations include identifying infected patients; isolating (except for non-A, non-B hepatitis patients) patients, and separating staff, and equipment; applying blood precautions and aseptic techniques; and using good environmental control procedures. AIDS patients can be safely dialyzed by either hemodialysis or peritoneal dialysis in hospital-based or free-standing centers, or at home without risk of AIDS transmission to other patients or to staff members, if precautions that have been developed for the control of hepatitis B infection in dialysis units are employed. Further, the type of dialysis treatment, or modality, should be based on the needs of the patient and not on a fear of risk of disease transmission.

[Hepatitis non-A, non-B: epidemiologic, clinical, serologic and morphologic aspects]

Hepatitis non-A, non-B (HNANB) is due to one or more transmissible agents, probably viruses. Epidemiologically, HNANB is transmitted predominantly by transfusion of blood or plasma derivatives, and percutaneous inoculation, but a non-percutaneous transmission by the fecal-oral route is also established. However, despite 10 years of intense world-wide research, the transmissible agent, or agents, have not been identified and there are no serological assays for either an antigen or an antibody that can be used to detect this infection. The clinical diagnosis of HNANB remains, therefore, a diagnosis of exclusion mainly of hepatitis A and B, Epstein-Barr virus, cytomegalovirus and drug-induced liver disease. In contrast to hepatitis A and B, the clinical and biochemical course of HNANB tends to be less severe and the proportion of asymptomatic and anicteric cases is higher, but fulminant hepatitis and fatalities also occur. Typically, there is a fluctuating waxing and waning pattern of the serum aminotransferase activities in HNANB. HNANB has a relative high tendency to progress to a chronic stage. The exact frequency of HNANB-induced liver cirrhosis and convincing evidence for an association with hepatocellular carcinoma cannot be assessed, although the persistence of the infectious agent in chronic HNANB and the existence of a chronic asymptomatic carrier state have been proved. By light microscopy there is a broad morphologic spectrum of acute and chronic viral hepatitis, but no single pathognomonic lesion exists that allows a reliable distinction to be made of HNANB from hepatitis A and B. Electron microscopy of liver biopsy specimens of chimpanzees, experimentally infected with HNANB agents, permits the visualisation of cytoplasmic changes, which appear to be specific for infection with HNANB viruses. In human liver biopsy specimens from patients with HNANB, identical ultrastructural cytoplasmic changes could not consistently be demonstrated. In contrast, intranuclear aggregates of spherical and tubular particles measuring 20-29 nm, first described in experimental HNANB in chimpanzees, have been repeatedly demonstrated in acute and chronic HNANB in man. These nuclear particles have been considered as compelling evidence of human HNANB infection. The specificity has been challenged, however, by the demonstration of identical particles in other viral and non-viral hepatopathies and in liver biopsies of healthy volunteers. By immune electron microscopy, a multiplicity of virus-like particles are described in association with HNANB.(ABSTRACT TRUNCATED AT 400 WORDS)

Epidemic outbreak of non-A, non-B hepatitis in a plasmapheresis center. I: Epidemiological observations

An epidemic outbreak of non-A, non-B hepatitis occurred in 1977/78 involving 30 donors at a plasmapheresis center. A chimpanzee inoculated with serum of one donor developed non-A, non-B hepatitis with characteristic tubular alterations in the endoplasmatic reticulum. Infections were detected over a period of several months, with two well defined peaks in December 1977 and between the end of January and the beginning of February 1978. Epidemiological data suggested a spread within the center. The most probable mode of transmission was contamination with serum from plastic bags used for reinfusing erythrocytes. The estimated mean incubation time was 41 days (range 27 to 59 days).

Epidemic outbreak of non-A, non-B hepatitis in a plasmapheresis center. II: Clinical observations and a four-year follow-up of patients

An epidemic outbreak of non-A, non-B hepatitis occurred in 1977/78 involving 30 donors at a plasmapheresis center. Of 27 hospitalized patients with peak ALT values between 334 and 1736 (mean 831) IU/l, only 16 had subjective symptoms like fatigue and lack of appetite, 11 had nausea, 11 were jaundiced and one developed transient arthritis. Patients with jaundice became chronically ill significantly less frequently than those without jaundice. Nineteen of 26 patients followed up had elevated ALT values after 12 months (73%) and 11 after 46 months (42%). Needle liver biopsies performed in 18 of the 19 patients with elevated ALT after 12 months revealed chronic persistent hepatitis in 14 and chronic active hepatitis in three. Follow-up biopsies always showed improvement (nine patients) or complete recovery (eight patients).

Detection of reverse transcriptase activity in association with the non-A, non-B hepatitis agent(s)

Particle-associated reverse transcriptase activity was detected in four human serum specimens and in two plasma-derived products, all of which had been shown to transmit non-A, non-B hepatitis (NANBH) to other human beings and/or chimpanzees. Reverse transcriptase activity was also detected in all twelve sera from patients with acute or chronic NANBH. In contrast, reverse transcriptase activity was found in only 2 of 49 serum specimens from healthy plasma donors and laboratory workers. Sucrose density gradient fractions of two of the infectious human sera (peak reverse transcriptase activity at 1.14 g/ml) transmitted NANBH to chimpanzees. Biochemical and enzymatic data indicate that the NANBH agent(s) is a retrovirus or is retrovirus-like.

Long-term sequelae of non-A, non-B hepatitis in experimentally infected chimpanzees

We have observed the development of long-term sequelae in four cases of experimentally induced non-A, non-B (NANB) hepatitis in chimpanzees. These sequelae were characterized by the following manifestations: nonprotection against challenge with autologous infectious plasma following acute disease and subtle histopathological alterations typical of long-lasting viral hepatitis. These manifestations were observed in animals infected with either of two human inocula. Whether or not these inocula represent sources of single or multiple etiologic agents is not known. However, our studies suggest that these inocula share at least one common etiologic agent. Further, these results may represent an atypical chronology of convalescence from viral hepatitis infection. For example, the convalescent stage of a type B hepatitis infection may be expected to occur within 6 to 8 months following exposure, whereas true convalescence in NANB hepatitis may be protracted over several months to several years. Thus, future efforts to identify the causative agent(s) of NANB hepatitis, and efforts to define the immune response in NANB, must take into consideration these studies.

Hepatitis B viral nucleotide sequences in non-A, non-B or hepatitis B virus-related chronic liver disease

The presence of serological markers of hepatitis B virus (HBV) infection and of hepatocellular HBV DNA were investigated in 19 HBsAg-negative patients with clinically and histologically significant chronic liver disease. Four cases negative for antibodies to HBsAg (anti-HBs), to the core antigen (anti-HBc), and to the e antigen (anti-HBe) were classified as non-A, non-B hepatitis. The remainder, positive for one or more of the three antibodies, were classified as hepatitis B. Histologic diagnosis was chronic active hepatitis in five, chronic persistent hepatitis in 11, micronodular cirrhosis in two, and fatty liver in one patient. The DNA extracted from limited amounts of liver biopsies, without cleavage by restriction endonucleases, was analyzed by the Southern blot technique for the presence of episomal HBV DNA. Autoradiographs showed a single band of less than 4.0 kilobase (kb) corresponding to the monomeric form of HBV DNA in five patients, several bands of larger forms (4.0 to 18.0 kb) in three patients, both the monomeric and the larger forms in eight patients, and no HBV DNA in three patients. While HBV DNA was detected in the hepatocellular DNA of six patients who underwent splenectomy, hybridization was negative with the DNA extracted from their spleens. The episomal viral DNA larger than 4.0 kb may represent concatemeric forms or free oligomers which could not be distinguished from rearranged and/or integrated viral DNA in the limited analyses of the hepatocellular DNA hydrolyzed with HindIII or EcoRI. Our observations suggest the presence of HBV-like agents in the liver of serologically HBsAg-negative patients with chronic liver disease.

Nuclear particles of non-A, non-B type in healthy volunteers and patients with hepatitis B

In an electron microscopic study, nuclear aggregates of virus-like spherical and tubular particles measuring 20 to 29 nm in diameter were found in 5 of 7 clinically healthy volunteers with normal liver histology, 6 of 10 patients with hepatitis B and 17 of 18 patients with hepatitis non-A, non-B. The incidence of hepatocytes containing nuclear particles was approximately 0.5 to 2% in all three groups. We conclude that these nuclear particles are not specific ultrastructural markers of hepatitis non-A, non-B in man as originally claimed for experimental hepatitis non-A, non-B in chimpanzees.

Detection of non-A, non-B hepatitis antigen by immunocytochemical staining

Liver tissue obtained from a chimpanzee during the acute phase of an experimental non-A, non-B (NANB) hepatitis virus infection was studied by a sensitive immunocytochemical staining procedure for the presence of NANB viral antigens. Initial investigations were conducted with a model system of hepatitis B virus (HBV) antigens for purposes of comparing two immunocytochemical staining methods. Of these two procedures, an immunoperoxidase procedure, utilizing an avidin-biotinylated enzyme complex, was at least 40-fold more sensitive than a conventional immunoperoxidase technique for the detection of HBV-specific tissue antigens. Utilization of the avidin-biotin-amplified immunoperoxidase staining procedure, in conjunction with four primary convalescent antisera obtained from NANB hepatitis-implicated donors, resulted in the observation of NANB virus-associated antigen in the cytoplasm of hepatocytes from an infected chimpanzee liver. These same human antisera were not reactive with a number of uninfected control cells nor with cells infected with HBV, hepatitis A virus, or cytomegalovirus. Preincubation of one of these convalescent NANB sera, or IgG derived thereof, with an acute-phase serum obtained from a NANB hepatitis virus-infected chimpanzee abolished the antibody reactivity. We conclude from these observations that selected convalescent sera from NANB hepatitis virus-infected patients contain low levels of antibody that specifically react with a cytoplasmic antigen associated with NANB virus-infected hepatocytes.

Ultrastructural alterations in serial liver biopsy specimens from chimpanzees experimentally infected with a human non-A, non-B hepatitis agent

Four chimpanzees experimentally infected with an agent of human non-A, non-B hepatitis were studied to determine the sequence of ultrastructural alterations in hepatocytes during infection. Three of the four types of cytoplasmic alterations previously described in association with non-A, non-B hepatitis were observed in the hepatocytes. Sponge-like cytoplasmic inclusions (designated C-I) were detected at or near the time of peak serum aminotransferase elevations in two of the four chimpanzees. Undulating membranes (designated C-II) were observed in all four chimpanzees, at the time of the first elevation of serum aminotransferase levels. Cytoplasmic tubules (designated C-III) were first observed four, eight, and twelve weeks, respectively, after inoculation in three of the chimpanzees. Four weeks after the peak of serum aminotransferase elevations, cytoplasmic alterations could no longer be detected in hepatocytes of the four chimpanzees. Intranuclear inclusions consisting of 20-27 nm granules and vermicular particles were observed in hepatocytes from preinoculation liver biopsy specimens, as well as biopsies obtained during non-A, non-B hepatitis. The number of these particles was greatest near the time of peak elevation of serum aminotransferase levels, however. Tubulo-crystalline inclusions were noted as well in the endothelial cells from both preinoculated and infected chimpanzees. Cytoplasmic alterations in hepatocytes of chimpanzees experimentally infected with an agent of non-A, non-B hepatitis appear characteristic of infection with this agent. In contrast, intranuclear particles were not specifically related to the non-A, non-B hepatitis infection.

Community-acquired non-A, non-B hepatitis: clinical characteristics and chronicity

The characteristics of 86 patients with acute non-A, non-B hepatitis were compared to 23 patients with acute hepatitis A and 76 with acute hepatitis B by medical record reviews of patients seen at 5 hospitals in Baltimore, Maryland, as part of case-control study of viral hepatitis. Results of serum aminotransferase levels, bilirubin, albumin, and prothrombin times alone could not distinguish the type of viral hepatitis because of extensive overlap. The alanine aminotransferase range for non-A, non-B hepatitis was 56 to 1819 IU/liters, for hepatitis A 250 to 1995 IU/liters, and for hepatitis B 203 to 2120 IU/liters. The ranges of aspartate aminotransferase and bilirubin for the types of hepatitis also overlapped. Fewer patients with non-A, non-B hepatitis or hepatitis A had a prolonged prothrombin time compared to patients with hepatitis B. Hepatic encephalopathy was seen only in two patients with hepatitis B. Forty-two percent of non-A, non-B hepatitis patients followed for 6 months or longer continued to have elevated alanine aminotransferase levels. Chronic alanine aminotransferase elevation was independent of the source of infection: transfusion, parenteral drug use, or all other sources. Prolonged follow-up is necessary to evaluate chronicity in patients with non-A, non-B hepatitis.

Primary hepatocellular carcinoma following non-A, non-B posttransfusion hepatitis

In 1964 a 42-year-old woman was hospitalized with clinical and laboratory signs of posttransfusion hepatitis five weeks after administration of six whole blood transfusions. During the following 17 years anicteric chronic liver disease was repeatedly documented by elevations of serum aspartate aminotransferase (SGOT) and alkaline phosphatase enzymes. In 1981 hepatomegaly, progressive jaundice, and a serum alphafetoprotein level of 516,000 ng/ml were observed. Percutaneous liver biopsy showed a primary hepatocellular carcinoma (PHC). Serologic examinations failed to reveal markers for hepatitis B virus including HBsAg, anti-HBs, and anti-HBc by radioimmunoassay; antibody to hepatitis A virus was also absent. This sequence of events demonstrates a presumptive association of PHC and the agent(s) of non-A, non-B viral hepatitis.

Diseases transmitted by blood transfusion

Except for post-transfusion hepatitis (PTH), the transmission of disease by blood transfusion appears to be very limited. There are only a few case reports documenting the transmission of malaria and other parasitic diseases, syphilis, or bacterial infections. The ability to eradicate PTH will depend on the development of sensitive-specific tests for the non-A, non-B agent(s). In the interim, two important steps that might be taken to reduce the incidence of PTH are the careful recruitment of blood donors and, most important, the judicious use of blood and its components.

Ultrastructural changes in human hepatocytes in acute non-A, non-B hepatitis

Ultrastructural findings in the liver of a 52-year-old man with acute non-A, non-B (NANB) post-transfusion hepatitis are described. Apart from non-specific alterations also known to occur in hepatocytes in hepatitis A and B--such as proliferation of membranes of smooth endoplasmic reticulum, formation of membrane-bound cytoplasmic vacuoles containing electron-dense material, and accumulation of distorted peroxisomes--unique cytoplasmic changes were observed that have not previously been described in man. A few hepatocytes contained in their cytoplasm tightly packed, bent, parallel structures and small clusters of virus-sized particles. No virus-like material was found in the nucleus of liver cells or in Kupffer and endothelial cells. Closely similar structures have been reported earlier in the acute-phase hepatocytic cytoplasm of chimpanzees with NANB hepatitis. These alterations may represent an ultrastructural hallmark of acute human NANB hepatitis.

A case of acute non-A, non-B sporadic hepatitis with evolution of liver cirrhosis on serial histologic follow-up

Progression of acute non-A, non-B (NANB) posttransfusion hepatitis to liver cirrhosis has been well recognized as in hepatitis B infection, whereas no progression of acute NANB sporadic hepatitis to liver cirrhosis has yet been documented. We reported a 29-year-old male with prolonged transaminase elevations in whom acute NANB sporadic hepatitis progressed to histologically confirmed cirrhosis during follow-up of about 3 years. It is suggested that some of the cryptogenic cirrhosis of non-B type may develop from acute NANB sporadic hepatitis and long-term observation is also needed in patients with acute hepatitis of this category.

Detection and transmission in chimpanzees of hepatitis B virus-related agents formerly designated "non-A, non-B" hepatitis

Four chimpanzees have been infected with three different inocula containing "non-A, non-B" hepatitis virus(es). After inoculation, serial studies established the presence of antigenemia or viremia (or both) by radioimmunoassay with high-affinity monoclonal antibodies directed toward separate and distinct determinants on hepatitis B surface antigen (HBsAg) and by molecular hybridization analysis using a cloned hepatitis B virus (HBV) DNA probe. In contrast to results observed during HBV infection, elevations in serum alanine aminotransferase values indicate that liver injury preceded antigenemia by several weeks. Thus, the time between inoculation and development of antigenemia (incubation period) varied from 64 to 190 days and, in some cases, single or multiple episodes of antigenemia or viremia occurred in the absence of elevated aminotransferase levels. In this study, two chimpanzees were high-titer positive for antibodies to HBsAg (anti-HBs) from previous infection with HBV, suggesting that the antigenic composition of HBV-related virus(es) is substantially different from that of HBV, since naturally occurring anti-HBs antibodies were not protective. Demonstration of HBV-related virus(es) by the methods used in this study of experimental hepatitis infection in chimpanzees should now permit detection, isolation, and characterization of these previously elusive agents.

Reducing the incidence of non-A,non-B post-transfusion hepatitis by testing donor blood for alanine aminotransferase: economic considerations

Recent studies have established a relation between elevated alanine aminotransferase levels in donor blood and the incidence of non-A, non-B hepatitis in recipients of such blood. Routine testing of donor blood for alanine aminotransferase activity in order to reduce hepatitis is not currently supported, largely because the results of such testing are unknown. We assessed the potential economic benefits of screening donor blood for alanine aminotransferase as a means to reduce post-transfusion hepatitis. Benefits, defined as the expected costs of hepatitis potentially avoided, ranged from $898 to $31,629 per 1000 blood units collected. This wide range reflected lack of information about the natural history of non-A, non-B hepatitis. Costs were defined as the direct costs of testing and the indirect costs associated with loss of blood product, additional donor recruitment, and informing donors of their abnormal aminotransferase levels; costs ranged from $3,151 to $4,003 per 1000 units. Our results suggest that if prospective studies demonstrate that exclusion of blood with elevated aminotransferase levels decreases non-A, non-B hepatitis in recipients, the net economic impact may be positive. However, because of major uncertainties about the medical consequences of non-A, non-B hepatitis, the benefit estimates are so broad that they preclude a definitive policy decision.

Hepatitis A and non-A, non-B viral hepatitis in São Paulo, Brazil: epidemiological, clinical and laboratory comparisons in hospitalized patients

During a 33-month period, 295 patients with acute viral hepatitis were admitted to a state hospital for civil servants and their dependents in São Paulo, Brazil. Seventy-nine per cent (232) were HBsAg negative. To define the contribution of non-A, non-B viral hepatitis to hepatitis morbidity in this population, further serological studies were performed in 147 confirmed HBsAg-negative patients. One hundred and twelve (76%) were serologically classified as hepatitis A based on identification of IgM antibody to hepatitis A virus. Thirty patients (20%) without IgM antibody to hepatitis A virus, HBsAg, or anti-HBc were categorized as the non-A, non-B hepatitis group. The remaining five patients had probable hepatitis B (IgM antibody to hepatitis A virus negative, HBsAg negative, anti-HBs negative but anti-HBc positive). These data suggest that all three etiological forms of viral hepatitis are endemic in São Paulo. Epidemiological, clinical, and laboratory features were compared to the hepatitis A and non-A, non-B hepatitis groups. Patients with non-A, non-B hepatitis were significantly older than patients with hepatitis A (mean age +/- S.D.: 30 +/- 22 years vs. 9 +/- 9 years, p less than 0.001). Contact with hepatitis or jaundice was recognized in 26 (23%) of 112 hepatitis A patients and 3 (10%) of 30 non-A, non-B patients, a difference which was not statistically significant. Parenteral exposures were identified in 13 (43%) of 30 patients with non-A, non-B hepatitis and 23 (21%) of the 112 hepatitis A patients. Blood transfusion in the 2 months preceding onset of illness was reported in 5 (17%) of the 30 non-A, non-B patients and in none of the hepatitis A group (p less than 0.001). Although prodromal symptoms and fever were more common in patients with hepatitis A, neither these nor other clinical features appeared to be distinguishing characteristics. Similarly, mean peak SGPT levels, peak SGPT levels of greater than or equal to 1,000 IU/per liter, and the mean duration of SGPT elevations for each group were not significantly different. Mean peak serum bilirubin levels were slightly higher in the non-A, non-B group than in the hepatitis A group (7.6 +/- 8.0 mg per dl vs. 5.1 +/- 2.7, p less than 0.01) and peak bilirubin levels greater than or equal to 10 mg per dl were found in 27% of the non-A, non-B group and 5% of the hepatitis A group (p less than 0.001). Whether the higher bilirubin levels reflect an agent-related phenomenon or an older population of affected patients is uncertain.