Ultrastructural changes and virus-like particles localized in liver hepatocytes of chimpanzees infected with non-A, non-B hepatitis

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Wilson's disease coexisting with viral hepatitis type C: a case report with histological and ultrastructural studies of the liver

Histopathological and ultrastructural findings in the liver of a female patient who suffered from Wilson's disease (WD) and viral hepatitis type C (HCV) are reported. Light and electron microscopy examinations demonstrated a variety of morphological alterations--many of them frequently seen in livers of patients with WD and others that can be found in cases presenting HCV infection. The influence of coexistence of these two diseases on morphological changes is discussed.

Detection of hepatitis C virus (HCV) RNA in paraffin embedded tissue sections of human liver of non-A, non-B hepatitis patients by in situ hybridization

Localization of hepatitis C virus (HCV) RNA was investigated by non-radioactive in situ hybridization in human liver specimens of chronic non-A, non-B (NANB) hepatitis patients who were seropositive for antibodies to HCV (anti-HCV). For in situ hybridization, T-T dimerized synthetic oligodeoxynucleotide probes were used and DNAs hybridized in situ were detected immunohistochemically using specific antibodies against T-T dimer. The data demonstrates that HCV-RNA was localized in the cytoplasm of hepatocytes in human liver biopsies obtained from the patients with chronic NANB hepatitis seropositive for anti-HCV.

Enterically transmitted non-A, non-B hepatitis in cynomolgus monkeys: morphology and probable mechanism of hepatocellular necrosis

Two cynomolgus monkeys were inoculated with a stool extract originally derived from patients suffering from enterically transmitted non-A, non-B hepatitis. Subsequently, the primates developed self-limiting acute hepatitis and their liver tissues were obtained sequentially by needle biopsy or at sacrifice. Histologically, the liver tissues exhibited necroinflammation which appeared in parallel, both in time and magnitude, with elevation in serum aminotransferases. Necroinflammation was characterized by focal dropout of hepatocytes with accumulation of lymphocytes and macrophages. These lymphocytes were positive for a cytotoxic/suppressor immunophenotype. The hepatocytes surrounding these focal necroses showed depletion of glycogen granules and decrease in glucose-6-phosphatase and succinic dehydrogenase activities. Ultrastructurally, damaged hepatocytes around the focal necroses revealed marked dilatation of both rough and smooth endoplasmic reticula, swelling and disruption of the mitochondria and leakage of nuclear materials into the cytoplasm. Frequently, direct contact between the damaged hepatocytes and lymphocytes was noted. Virus-like particles measuring about 27 nm in diameter were observed singly or in small groups within the cytoplasm of damaged hepatocytes. Primary hepatocyte culture of a cynomolgus monkey, inoculated with a transmissible stool extract did not show any cytopathic change, although similar virus-like particles were recognized ultrastructurally in the cultured hepatocytes. Morphological analysis of in vitro and in vivo transmission studies in cynomolgus monkeys strongly supported the hypothesis of immune-mediated hepatocytolysis rather than a direct cytopathic effect of this hepatitis virus.

Association of human hepatocellular membrane fusions with non-A, non-B hepatitis

Liver biopsies from patients with alcoholic hepatitis, chemical hepatitis, or viral hepatitis types A, B, or non-A, non-B were examined by electron microscopy. Circular, fused, cytoplasmic membranes were observed in hepatocytes of 17% of patients with hepatitis type B and 92% of patients with hepatitis type non-A, non-B. The membrane alterations were not observed in hepatocytes of patients with the other types of hepatitis. The greater frequency of altered cytoplasmic membranes in hepatocytes of patients with non-A, non-B hepatitis was shown to be statistically significant (p less than 0.05) when compared to that in patients with viral hepatitis type B.

[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)

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.

Electron microscopic evidence of non-A, non-B hepatitis markers and virus-like particles in immunocompromised humans

Characteristic pathological alterations of the liver in chimpanzees inoculated with non-A, non-B hepatitis sera have been described, but no corresponding findings have been reported in humans. Electron microscopic studies of the liver biopsy specimens of two homosexual patients with acquired immune deficiency syndrome, one without hepatitis (Patient 1) and one with chronic active hepatitis in remission (Patient 2), revealed the cytoplasmic tubular structures which are characteristic of chimpanzee non-A, non-B hepatitis. A cluster of 23 nm double-shelled particles was also seen in the cytoplasm of a hepatocyte in patient 1 who had received a blood transfusion 8 days before the biopsy. These particles were smaller than the Dane particles, Epstein-Barr virus, cytomegalovirus or herpes simplex virus, and different from hepatitis A virus particles; the antibodies to all of which are found in high concentration in acquired immune deficiency syndrome patients. These observations may reflect the morphologic findings for non-A, non-B hepatitis infection in humans.

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.

Experimental infection of chimpanzees with the HBsAg-associated delta (delta) agent: an ultrastructural study

Characteristic cytoplasmic membranous structures and intranuclear aggregates of particles similar to those reported in non-A, non-B hepatitis were observed by electron microscopy in the liver biopsies of chimpanzees inoculated with human serum, infectious for the delta agent. The ultrastructural changes were maximal during the intrahepatic production of the delta antigen, but were detected also independently of delta-Ag expression. The ultrastructural analogies provide further evidence that delta has properties distinct from HBV.

Intracytoplasmic inclusions in human hepatocytes in non-A, non-B hepatitis: an ultrastructural study

An ultrastructural study was carried out on 114 liver biopsies obtained for diagnostic purposes from patients with various pathological disorders of the liver including hepatitis B-related liver disease, non-A, non-B hepatitis, alcoholic liver disease, fatty change, and cryptogenic cirrhosis. The opportunity was taken to evaluate the significance of intracytoplasmic crystalline structures found in the hepatocytes of nine patients with a variety of liver disorders. The cytoplasmic inclusions varied in size up to 2 microns in length and shape and were not limited by membranes. The presence of these inclusions cannot, however, be correlated either specifically with non-A, non-B hepatitis or with other known nonviral liver disease. The functional, physiological, and pathological significance of the crystalline structures remain to be elucidated.

Are nuclear particles specific for non-A, non-B hepatitis?

This study reports the findings of an electron microscopic search for so-called non-A, non-B nuclear particles in liver biopsies from patients with mainly chronic or prolonged liver disease and from chimpanzees. In patients without hepatitis B virus or acute hepatitis A virus serological markers, non-A, non-B-like nuclear particles were seen in hepatocytes in 28 of 31 cases of presumed non-A, non-B hepatitis, but also in 11 of 12 cases of liver disease not usually attributed to hepatitis viruses. They were also seen in 22 of 24 patients with HBsAg, in 3 of 3 patients with anti-HBc and no HBsAg, in 1 of 2 patients with hepatitis A, in a case of cytomegalovirus hepatitis, and in 16 of 19 patients whose serology was not available or inconclusive. The particles were present in 1 of 8 untreated HBsAg-negative chimpanzees and in 2 of 2 HBsAg-positive chimpanzees. They appeared in 4 of 4 chimpanzees developing non-A, non-B hepatitis following exposure to various inocula. Three patterns of particle aggregates were distinguished, all of which had been shown by others in non-A, non-B hepatitis. Dense aggregates were predominant, while others have shown intermediate aggregates more often; reasons for this difference could be technical. No pattern was specific for any condition. Either non-A, non-B-like nuclear particles, although associated with non-A, non-B hepatitis, are not specific for this condition, or non-A, non-B hepatitis viruses are extremely more common than is currently appreciated.

Experimental non-A, non-B hepatitis in chimpanzees: light, electron and immune microscopical observations

Two chimpanzees (Pan troglodytes) were inoculated and cross-challenged with a fibrinogen and factor VIII preparation, respectively. Successful non-A, non-B (NANB) infection was documented by biphasic elevations of aminotransferases (ALT), concomitant hepatitic reactions and typical electron microscopic alterations, the most consistent being dilatation of the endoplasmic reticulum, as well as tubular and sponge-like cytoplasmic inclusions in the absence of nuclear virus-like particles. An anti-nuclear (anti-DNA) antibody of the IgM class in one of the chimpanzees simulating an antiviral antibody is described.

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.

Experimental infection of Tamarins with human non-A, non-B hepatitis virus

Non-A, non-B (NANB) viral hepatitis was successfully transmitted to two colony-born Tamarins following inoculation with antihaemophilic factor VIII concentrate or the "H" inoculum. Both animals showed histological and ultrastructural evidence of viral hepatitis, with raised alanine aminotransferase (ALT) levels from the second week after inoculation through to the end of follow-up, 5 months later.

Ultrastructural alterations in hepatocytes and sinus endothelia in experimental non-A, non-B hepatitis in chimpanzees with and without immunoglobulin prophylaxis

Three chimpanzees were inoculated with an infectious factor VIII preparation. Two of the chimpanzees received in addition a human immunoglobulin preparation as used for prophylaxis in humans. All three chimpanzees developed an acute limited non-A, non-B hepatitis as judged from light and electron microscopic markers after an incubation period of two weeks. The use of immunoglobulin did not prevent the infection. A prolonged incubation of 15 weeks, however, was observed in one animal when alanine aminotransferase (ALT) elevation was used as criterion of infection. In the electron microscope, non-A, non-B hepatitis was characterized by tubular structures, spongelike inclusions and attaching curved membranes, in the absence of nuclear viruslike particles. An additional finding were viruslike particles in crystalline arrays which were found in the cytoplasm of sinusoidal-lining endothelial cells and tubuloreticular complexes.

Application of electron microscopy to the study of structural changes in the liver in non-A, non-B hepatitis

Ultrastructural studies employing techniques such as alternative electron metal stain, high-angle tilting and high-voltage electron microscopy were carried out on liver biopsies obtained from chimpanzees infected with non-A, non-B hepatitis. Typical derangement of the endoplasmic reticulum leading to the formation of tubular structures in hepatocytes was observed. The use of potassium permanganate as an alternative stain revealed two features which have not been previously described. The first of these shows the wall of the tubular structures to be composed of a well-defined fibrillar-like meshwork with a periodicity of approximately 15 nm. The second feature is the demonstration of clusters of fibrin-like inclusions consisting of striated fibrils in the neighborhood of the tubular structures. The presence of intracytoplasmic fibrin may indicate non-specific morphological evidence of cell injury. Crystalline structures containing arrays of particles with an average size of 24 nm were also observed in the endoplasmic reticulum of endothelial cells of the hepatic sinusoids. Morphological differences between the crystalline lattice and the reticular arrangement, demonstrated with the use of high-angle tilting of the specimen in the electron microscopy suggest that the arrays may not be viral particules but a reflection of pathological response of the host cell.

Examination of crystalline arrays in non-A, non-B hepatitis

Individual patients within crystalline arrays found in the endothelial cells of hepatic sinusoids in experimental non-A, non-B hepatitis were examined by the Markham rotation technique. The particles appeared to possess an outer structure with 16-18 divisions. The presence of the crystalline structures is probably a reflection of host cell response to infection.