Krzysztof Krawczynski

The Natural History of Community-Acquired Hepatitis C in the United States

BACKGROUND Chronic liver disease develops in more than half of patients with post-transfusion hepatitis C, but little is known about the natural history of community-acquired hepatitis C. METHODS In 1985 and 1986 we identified adults with acute non-A, non-B hepatitis in four counties in the United States and followed them prospectively. We used three markers to detect hepatitis C virus (HCV) infection in stored samples of serum: antibody to HCV (anti-HCV) detected by second-generation serologic assays; HCV RNA detected by polymerase-chain-reaction assay; and antibody to HCV antigen (anti-HCVAg) detected by fluorescent-antibody-blocking assay. RESULTS Of 130 patients with non-A, non-B hepatitis, 106 (82 percent) had HCV infection, 93 were positive for anti-HCV, and 13 were positive only for HCV RNA or anti-HCVAg. Chronic hepatitis developed in 60 (62 percent) of 97 HCV-infected patients followed for 9 to 48 months, with no relation to the risk factors for infection. Ten of the 30 patients who had liver biopsies had chronic active hepatitis. In samples collected 42 to 48 months after the onset of hepatitis, HCV RNA was detected in 12 of 13 tested patients with chronic hepatitis and in all 15 tested patients with hepatitis that had resolved. Anti-HCV persisted in all but two of the initially positive patients, for a rate of antibody loss of 0.6 per 100 person-years. CONCLUSIONS Patients with community-acquired hepatitis C have a high rate of chronic hepatitis. HCV may be a major cause of chronic liver disease in the United States, and in most patients HCV infection seems to persist for at least several years, even in the absence of active liver disease.

Molecular Cloning and Disease Association of Hepatitis G Virus: A Transfusion-Transmissible Agent

An RNA virus, designated hepatitis G virus (HGV), was identified from the plasma of a patient with chronic hepatitis. Extension from an immunoreactive complementary DNA clone yielded the entire genome (9392 nucleotides) encoding a polyprotein of 2873 amino acids. The virus is closely related to GB virus C (GBV-C) and distantly related to hepatitis C virus, GBV-A, and GBV-B. HGV was associated with acute and chronic hepatitis. Persistent viremia was detected for up to 9 years in patients with hepatitis. The virus is transfusion-transmissible. It has a global distribution and is present within the volunteer blood donor population in the United States.

Acute non-A-E hepatitis in the United States and the role of hepatitis G virus infection

BACKGROUND Little is known about the relation of the newly discovered hepatitis G virus (HGV) to the cause and clinical course of acute and chronic viral hepatitis. METHODS We selected patients from a surveillance study of acute viral hepatitis in four U.S. counties who had acute disease during 1985 to 1986 or 1991 to 1995. Serum samples were tested for HGV RNA by the polymerase chain reaction. RESULTS HGV RNA was detected in 4 of 45 patients with a diagnosis of non-A-E hepatitis (9 percent), 23 of 116 patients with hepatitis C (20 percent), 25 of 100 patients with hepatitis A (25 percent), and 32 of 100 patients with hepatitis B (32 percent) (P<0.05 for the comparison of hepatitis B with hepatitis non-A-E or C). The clinical characteristics of the acute illness were similar for patients with HGV alone and those with hepatitis A, B, or C with or without HGV infection. During a follow-up period of one to nine years, chronic hepatitis did not develop in any of the patients with HGV alone, but 75 percent were persistently positive for HGV RNA, as were 87 percent of those with both hepatitis C and HGV infection. The rates of chronic hepatitis were similar in patients with hepatitis C alone (60 percent) and those with both hepatitis C and HGV infection (61 percent). CONCLUSIONS The evidence from this surveillance study does not implicate HGV as an etiologic agent of non-A-E hepatitis. Persistent infection with HGV was common, but it did not lead to chronic disease and did not affect the clinical course in patients with hepatitis A, B, or C.

Hepatitis E: An overview and recent advances in clinical and laboratory research

Hepatitis E virus (HEV) is a non‐enveloped RNA (7.5 kb) virus that is responsible for large epidemics of acute hepatitis and a proportion of sporadic hepatitis cases in southeast and central Asia, the Middle East, parts of Africa and Mexico. Hepatitis E virus infection spreads by the faecal–oral route (usually through contaminated water) and presents after an incubation period of 8–10 weeks with a clinical illness resembling other forms of acute viral hepatitis. Clinical attack rates are the highest among young adults. Asymptomatic and anicteric infections are known to occur. Chronic HEV infection is not observed. Although the mortality rate is usually low (0.07–0.6%), the illness may be particularly severe among pregnant women, with mortality rates reaching as high as 25%. Recent isolation of a swine virus resembling human HEV has opened the possibility of zoonotic HEV infection. Studies of pathogenetic events in humans and experimental animals reveal that viral excretion begins approximately 1 week prior to the onset of illness and persists for nearly 2 weks; viraemia can be detected during the late phase of the incubation period. Immunoglobulin M antibody to HEV (anti‐HEV) appears early during clinical illness but disappears rapidly over a few months. Immunoglobulin G anti‐HEV appears a few days later and persists for at least a few years. There is no specific treatment available for hepatitis E virus infection. Ensuring a clean drinking water supply remains the best preventive strategy. Recombinant vaccines are being developed that may be particularly useful for travellers to disease‐endemic areas and for pregnant women.

Acute Hepatitis E by a New Isolate Acquired in the United States

OBJECTIVE To report the first case of acute hepatitis E by a novel isolate acquired in the United States and confirmed by nucleotide sequencing. MATERIAL AND METHODS We describe the clinical manifestations and the results of associated laboratory studies in a man who was found to have acute hepatitis E infection. RESULTS A 62-year-old man was hospitalized because of fever, abdominal pain, and jaundice. After an initial evaluation did not provide a cause, his serum was found to be positive for IgG anti-hepatitis E virus (HEV) by three antibody assays. Serum was also positive for HEV RNA by reverse transcriptase polymerase chain reaction (PCR). Sequencing results from the PCR products demonstrated substantial differences at the nucleotide level between this strain and the known Mexican and Burmese strains. CONCLUSION On the basis of this initial report, HEV should be considered an etiologic agent in patients with acute non-ABC hepatitis in the United States.

GLOMERULONEPHRITIS ASSOCIATED WITH HEPATITIS-B SURFACE ANTIGEN IMMUNE COMPLEXES IN CHILDREN

Abstract Immunoglobulins and complement were identified by immunofluorescence in 32 of 52 unselected kidney-biopsy specimens from children with clinical nephrosis and/or glomerulonephritis (G.N.). Deposits with the composition and characteristics of viral hepatitis type B surface antigen (HB s Ag)/antibody complexes were identified in 18 of these 32 specimens (56·2%). HB s Ag immune complexes were found in endocapillary proliferative G.N. (2 of 13 cases), membranoproliferative G.N. (12 of 15 cases), membranous G.N. (2 of 2 cases), and endocapillary and extracapillary proliferative G.N. (2 of 2 cases). HB s Ag was detected by immunoelectro-osmophoresis in the sera of 16 of these patients and antibody to hepatitis-B core antigen (anti-HB c ) was detected by indirect immunofluorescence in all 18. The remaining 20 kidney-biopsy specimens were devoid of immunoglobulins, complement, and HB s Ag or contained only trace amounts of immunoglobulins and complement. They all showed minimal glomerular lesions. Neither HB s Ag nor anti-HB c were found in the sera of these patients. These findings strongly suggest that HB s Ag immune complexes may play a primary pathogenic role in a significant number of glomerulonephritides in children subclinically infected with viral hepatitis type B.

Hepatitis C virus antigen in hepatocytes: immunomorphologic detection and identification.

Hepatitis C virus (HCV) antigen was detected immunohistochemically using fluorescein isothiocyanate-labeled immunoglobulin G fractions from chimpanzee and human sera strongly reactive with recombinant hepatitis C virus structural and non-structural proteins. The antigen was localized in the cytoplasm of hepatocytes in all 9 chimpanzees with acute hepatitis C, in 5 of 10 chimpanzees with chronic HCV infection, and in 11 of 12 patients with chronic hepatitis C. The specificity of the hepatocellular HCV and FITC-labeled probes for HCV was ascertained by blocking studies with paired serum samples obtained from 8 infected and uninfected chimpanzees or from 14 patients during the acute and chronic phases of HCV infection. Absorption experiments on FITC-labeled probes with selected host proteins (normal liver homogenate, plasma proteins, red blood cells) did not indicate cross reactivity of the probes with these antigens. Direct immunomorphologic evidence for the HCV specificity of hepatocellular HCV antigen deposits and the FITC-labeled polyclonal anti-HCVAg probe was established in absorption experiments using recombinant HCV nonstructural proteins. The putative HCV NS3 protein was the most prominent component of hepatocellular HCV antigen.

Duration of viraemia and faecal viral excretion in acute hepatitis E.

Data on duration of viral excretion and viraemia during hepatitis E virus (HEV) infection are limited. We tested serial stool and serum samples from 20 patients with acute hepatitis E for HEV RNA. Faecal excretion and viraemia in these patients were found to be short lived. In 19 patients, all samples obtained after biochemical resolution of hepatitis tested negative; in the remaining patient, HEV RNA was detected in the serum samples but not in stool after biochemical resolution. Long-term persistence of HEV in body fluids of infected individuals seems to be an unlikely reservoir for transmission of HEV.

CELLULAR LOCALISATION OF AUSTRALIA ANTIGEN IN THE LIVER OF PATIENTS WITH LYMPHOPROLIFERATIVE DISORDERS

Abstract Australia (Au) antigen was detected by means of immunofluorescence in the liver taken at necropsy of six patients with lymphoproliferative disorders who were seropositive for this antigen. Specific fluorescence was observed in the nuclei and/or the cytoplasm of hepatic parenchymal cells. Aggregations of virus-like particles of about 20 mμ in diameter were identified by electron microscopy in the nuclei of hepatocytes of these patients. The particles were morphologically identical with particles precipitated out of the sera of all Au-positive patients by anti-Au antibody. Au antigen or virus-like particles were not detected in the liver of six patients with lymphoproliferative disorders who were seronegative for Au antigen. None of these patients had any clinical or biochemical evidence of hepatitis. In two of the Au-positive patients histological changes were compatible with most of those characteristic for a mild form of chronic (persistent) hepatitis. These findings confirm and extend previous reports on the cellular localisation and the virus-like nature of Au antigen. They furthermore suggest that in some patients with lymphoproliferative disorders a state of specific tolerance may develop prerequisite for an apparently harmless proliferation of Au antigen in hepatocytes.

Experimental Studies on Subclinical Hepatitis E Virus Infection in Cynomolgus Macaques

Serial subclinical transmission among susceptible humans may serve as a reservoir of hepatitis E virus (HEV) in areas in which HEV is endemic. This hypothesis was investigated in an experimental primate model. Four groups of 4 cynomolgus macaques each were inoculated intravenously with 10(4)-10(5) (group 1), 10-100 (group 2), and 1-10 (group 3) cynomolgus macaque HEV infectious doses. All 4 animals in group 1 had clinical disease marked by alanine aminotransferase (ALT) elevation, fecal virus excretion, viremia, and seroconversion. Of the animals in groups 2 and 3, only 1 had evidence of biochemical hepatitis, although most had virus excretion and viremia (3 animals each in groups 2 and 3), and evidence of seroconversion (1 animal in group 2 and 3 animals in group 3). Viral genomic titers in stool specimens of animals with or without ALT elevation were similar. Infectivity studies confirmed the viability and transmission potential of the virus excreted by animals without ALT elevation. These data suggest that subclinical HEV infection may represent an HEV reservoir.