Fibrinogen inclusions in liver cells: a new type of ground-glass hepatocyte. Immune light and electron microscopic characterization

Association of the Hepatitis B Virus Large Surface Protein with Viral Infectivity and Endoplasmic Reticulum Stress-mediated Liver Carcinogenesis

Hepatitis B is the most prevalent viral hepatitis worldwide, affecting approximately one-third of the world’s population. Among HBV factors, the surface protein is the most sensitive biomarker for viral infection, given that it is expressed at high levels in all viral infection phases. The large HBV surface protein (LHBs) contains the integral pre-S1 domain, which binds to the HBV receptor sodium taurocholate co transporting polypeptide on the hepatocyte to facilitate viral entry. The accumulation of viral LHBs and its prevalent pre-S mutants in chronic HBV carriers triggers a sustained endoplasmic reticulum (ER) overload response, leading to ER stress-mediated cell proliferation, metabolic switching and genomic instability, which are associated with pro-oncogenic effects. Ground glass hepatocytes identified in HBV-related hepatocellular carcinoma (HCC) patients harbor pre-S deletion variants that largely accumulate in the ER lumen due to mutation-induced protein misfolding and are associated with increased risks of cancer recurrence and metastasis. Moreover, in contrast to the major HBs, which is decreased in tumors to a greater extent than it is in peritumorous regions, LHBs is continuously expressed during tumorigenesis, indicating that LHBs serves as a promising biomarker for HCC in people with CHB. Continuing efforts to delineate the molecular mechanisms by which LHBs regulates pathological changes in CHB patients are important for establishing a correlation between LHBs biomarkers and HCC development.

Rethinking fibrinogen storage disease of the liver: ground glass and globular inclusions do not represent a congenital metabolic disorder but acquired collective retention of proteins

Three types of intracytoplasmic inclusions immunoreactive to fibrinogen are collectively diagnosed as hepatic fibrinogen storage disease. This study aimed to better characterize ground glass (type II) and globular (type III) fibrinogen inclusions by the pathological examination of 3 cases and a literature review. Three adults (age: 32-64 years; male/female = 2:1) were unexpectedly found to have fibrinogen-positive ground glass changes (type II inclusions) by liver needle biopsy, against a background of acute hepatitis E, resolving acute cholangitis, or severe lobular hepatitis of unknown etiology. One patient also had fibrinogen-positive intracytoplasmic globules (type III inclusions) in the first biopsy, but they were not present in a second biopsy. None had coagulation abnormalities or hypofibrinogenemia. On immunostaining, both inclusions were strongly positive for not only fibrinogen but also C-reactive protein and C4d. Ultrastructurally, ground glass changes corresponded to membrane-bound cytoplasmic inclusions containing amorphous, granular material. The pathological features of type II fibrinogen inclusions were identical to those of pale bodies in hepatocellular carcinoma. The literature review suggested that type I fibrinogen inclusions characterized by a polygonal appearance are strongly associated with mutations in fibrinogen genes, coagulopathy, and family history, whereas type II/III inclusions are immunoreactive to multiple proteins and typically develop in cases of other unrelated liver diseases. In conclusion, type II and III fibrinogen inclusions do not represent a true hereditary storage disease but instead the collective retention of multiple proteins. Given the lack of clinical significance, a less specific name (e.g., pale body) may be more appropriate for those inclusions.

Hepatic fibrinogen storage disease due to the fibrinogen γ375 Arg → Trp mutation "fibrinogen Aguadilla" is present in Arabs

The mutation γ375Arg → Trp (fibrinogen Aguadilla) is one of four mutations (Brescia, Aguadilla, Angers, and AI duPont) capable of causing hepatic storage of fibrinogen. It has been observed in four children from the Caribbean, Europe, and Japan, suffering from cryptogenic liver disease. We report the first case of hepatic fibrinogen storage disease in Arabs due to a mutation in the fibrinogen γ-chain gene in a 3-year-old Syrian girl presenting with elevated liver enzymes. The finding of an impressive accumulation of fibrinogen in liver cells raised the suspicion of endoplasmic reticulum storage disease. Sequencing of the fibrinogen genes revealed a γ375Arg → Trp mutation (fibrinogen Aguadilla) in the child and in her father. In conclusion, when confronted with chronic hepatitis of unknown origin, one should check the plasma fibrinogen level and look carefully for the presence of hepatocellular intracytoplasmic globular inclusions to exclude hepatic fibrinogen storage disease.

The amazing universe of hepatic microstructure

An informal review is presented by the author of his 50 years of involvement in practice and research in hepatopathology. Some background for the author's attitude and meandering pathway into his professional career serves as introduction to a short discussion of the main topics of his interest and expertise. Histogenesis of liver cancer was the theme of early work for a Ph.D. thesis, the results of which were lost into oblivion due to local rules and circumstances, but were rescued three decades later. His conclusions about the cells of origin of liver cancer remain concordant with the newer concepts in the field after nearly half a century. Studies in the field of chronic hepatitis became a long saga, involving the first classification of this syndrome by "the Gnomes" in 1968, histochemical investigations of viral antigens, lymphocyte subsets and adhesion molecules, and a quarter century later, the creation of a new classification presently in use. Cholestasis was a broadening field in diagnostic entities and involved the study of liver lesions, comprising pathways of bile regurgitation (including reversed secretory polarity of hepatocytes) and so-called ductular reaction. The latter topic has a high importance for the various roles it plays in modulating liver tissue of chronic cholestasis into biliary cirrhosis, and as the territory of hepatic progenitor cells, crucial for liver regeneration in adverse conditions and in development of liver cancer. Study of the embryology of intrahepatic bile ducts helped to clarify the strange appearance of the ducts in "ductal plate configuration" in several conditions, including some forms of biliary atresia with poor prognosis and all varieties of fibrocystic bile duct diseases with "ductal plate malformation" as the basic morphologic lesion.

Fibrinogen angers with a new deletion (gamma GVYYQ 346-350) causes hypofibrinogenemia with hepatic storage

INTRODUCTION

This study reports a family with chronically abnormal blood liver function tests (LFT) and congenital hypofibrinogenemia. The proposita had cirrhosis initially related to alcohol abuse and chronic viral hepatitis C (HCV), but abnormal LFT persisted even when alcohol intake was stopped and despite HCV treatment was efficient based on serum RNA negative testing.

RESULTS

Needle biopsy specimens of the proposita and her brother showed eosinophilic intra-cytoplasmic inclusions that reacted strongly with fibrinogen antisera on direct immunofluorescence. Electron microscopic examination showed that the rough endoplasmic reticulum was filled with inclusions that consisted of densely packed, curved tubular structures arranged in a fingerprint-like pattern. Coagulation studies revealed low functional and antigenic fibrinogen concentrations suggestive of hypofibrinogenemia. Amplification and DNA sequencing showed a heterozygous deletion of the a7690 to g7704 nucleotides of the gamma chain gene in the 3'end of exon 8 (g 7690_7704del14; Genbank access M10014); this deletion encompassed the splicing site at position 7703 and predicts in a new putative consensus splicing sequence (AATGgtatgtt). RNA was extracted from a liver specimen from the proposita's brother. The cDNA obtained by reverse transcription polymerase chain reaction confirmed the usage of a newly generated donor site at position 7688 of the genomic sequence resulting in an in-frame heterozygous 5 amino acid deletion (GVYYQ 346-350; p.G372_Q376del) and that this mutation is responsible for a new splicing site at position 7688 of the genomic sequence.

CONCLUSION

we suggest that the molecular defect in fibrinogen Angers results in an impaired assembly and causes defective secretion and hepatic storage of fibrinogen.

Lafora-like ground-glass inclusions in hepatocytes of pediatric patients: a report of two cases

We report 2 cases of ground-glass hepatocyte inclusions occurring in pediatric patients. Case 1 had alpha-thalassaemia major and was receiving iron chelation therapy, whereas case 2 had trisomy 21 with a history of bone marrow transplantation for acute myeloid leukemia. The liver sections in both cases showed eosinophilic, periodic acid-Schiff diastase-positive intracytoplasmic inclusions that were negative for hepatitis B surface antigen. Immunohistochemically the inclusions showed positive staining with KM279, a monoclonal antibody against polyglucosan derived from Lafora inclusions. On electron microscopy, in case 1, intracytoplasmic inclusions were composed of degenerate organelles, glycogen, and irregular fibrillar structures; in case 2, they were composed of vesicular structures containing granular material. Ultrastructural changes in both cases differed from classical Lafora inclusions and ruled out hepatitis B surface antigen, glycogenosis type IV, and fibrinogen storage disease. Genetic analysis of the Lafora's disease genes performed in case 2 revealed no mutations. The development of hepatocyte cytoplasmic inclusions in both our cases could be related to medication effects, because similar inclusions were reported in patients using cyanamide. Drug-induced inclusions, mimicking Lafora's disease, should be included in the differential diagnosis of hepatocyte ground-glass inclusions.

Special stains in diagnostic liver pathology

The comprehensive histopathologic evaluation of liver tissue, including biopsy, explant, and postmortem specimens, utilizes a standard panel of special histochemical stains as well as selective immunohistochemistry. These methods provide increased accuracy in addressing common diagnostic problems such as determining the stage of fibrosis in chronic hepatitis, documenting the presence of cirrhosis or other causes of portal hypertension, iron, and copper overload, disorders of the biliary tract, and tumor histogenesis. This review discusses the indications for various staining methods and the specific uses of trichrome and reticulin connective tissue stains, periodic acid-Schiff (PAS) and diastase-pretreated PAS (DPAS), iron, and Victoria blue methods. Diagnostic applications of immunohistochemical stains are also described.

Glycogen pseudoground glass change in hepatocytes

Ground glass cytoplasmic change in hepatocytes is typically associated with chronic hepatitis B infection. We report 12 cases of glycogen pseudoground glass change that closely mimics hepatitis B inclusions. Nine individuals were immunosuppressed secondary to liver or kidney transplant (N=3), bone marrow transplant (N=2), HIV infection (N=2), kidney dialysis (N=1), or chronic inflammatory bowel disease (N=1). Medication history was available in 10 individuals and all were on multiple medications (range 2 to 33). Histologically, the pseudoground glass change was identical to the ground glass change seen in chronic hepatitis B infection, with distinct, circumscribed, gray-glassy inclusions surrounded by a rim of cytoplasm. The background livers showed mild or no inflammation and mild or no fibrosis. All cases were negative for chronic hepatitis B infection. The pseudoground glass change was PAS positive and diastase sensitive. Electron microscopy of the inclusions showed glycogen in 3/3 cases. No evidence for viral particles or significant endoplasmic reticulum proliferation was seen. Three cases had follow-up biopsies (1, 1, and 36 mo), and the pseudoground glass was persistent in 2 cases and showed partial resolution in 1 case (1 mo biopsy interval). We conclude that glycogen pseudoground glass change is typically seen in immunosuppressed individuals on numerous medications. The changes are generally seen in the background of mild chronic hepatitis with mild or no fibrosis. Glycogen pseudoground glass change can resolve, but may also persist for years.

Liver glycogen bodies: ground-glass hepatocytes in transplanted patients

Ground-glass hepatocytes have been described in Lafora's disease, fibrinogen deposition, hepatitis B, type IV glycogenosis, and alcohol aversion (cyanamide) therapy. We encountered ground-glass hepatocytes with intracytoplasmic inclusions in four liver biopsies from three transplanted patients who had none of the above-mentioned underlying diseases. One patient was a 4-year-old boy who had a kidney transplant for severe ureterovesical reflux. Patient 2 was a 52-year-old man who had two liver transplants because of hepatitis C. The third patient was a 7-month-old girl who underwent a multivisceral transplant because of necrotizing enterocolitis and liver failure induced by total parenteral nutrition. The patients developed liver abnormalities from 45 days to 4 years after their transplants. The livers showed conspicuous ground-glass hepatocytes in 90% of the children's samples and 30% of the adult liver cells. The cytoplasmic bodies stained strongly for Gomori methenamine-silver; they were positive for periodic acid-Schiff without diastase, but negative after diastase digestion. They were negative for colloidal iron and hepatitis B core and surface antigens. Electron microscopy revealed non-membrane bound aggregates of glycogen. Idiopathic ground-glass hepatocytes occur in transplanted patients and represent accumulation of altered glycogen. However, their clinical significance and cause are not entirely elucidated.

Fibrinogen Gamma375 Arg→Trp Mutation (Fibrinogen Aguadilla) Causes Hereditary Hypofibrinogenemia, Hepatic Endoplasmic Reticulum Storage Disease and Cirrhosis

Hypofibrinogenemia is a rare inherited disorder characterized by low levels of circulating fibrinogen, caused by mutations within 1 of the 3 fibrinogen genes. We report here the case of a 61-year-old man with chronic liver function test alterations. Liver biopsy examination revealed chronic hepatitis complicated by cirrhosis and weakly eosinophilic globular cytoplasmic inclusions within the hepatocytes, faintly stained with PAS-diastase. On immunohistochemistry, the inclusions reacted strongly with human antifibrinogen antibodies. Coagulation investigations of the propositus and his 2 sons showed low functional and antigenic fibrinogen concentrations that were indicative of hypofibrinogenemia. A liver biopsy performed on the 28-year-old son demonstrated the same globular cytoplasmic inclusions, albeit without associated chronic liver disease. PCR amplification followed by sequencing showed that all 3 were heterozygous for a CGG>TGG mutation at codon 375 of the fibrinogen gamma-chain gene (FGG), corresponding to an Arg>Trp substitution. This is the first in an adult male and the second published case with a discernible hepatic fibrinogen endoplasmic reticulum storage disease due to an FGG Arg375Trp (fibrinogen Aguadilla) mutation. Our results suggest that familial hypofibrinogenemia should be considered in the differential diagnosis of a progressive liver disease associated to hepatocellular intracytoplasmic globular inclusions.

A case of primary biliary cirrhosis accompanied with fibrinogen storage disease

We report the first case of primary biliary cirrhosis (PBC) accompanied by fibrinogen storage disease (FSD). A 50-year-old Japanese woman had been treated for numbness of her right-side extremities for 5 years. Mildly elevated serum levels of alkaline phosphatase and gamma-glutamyl transferase were detected. The titers of both anti-mitochondrial (x 320) and anti-mitochondrial M2 (x 84) antibodies were elevated. The biopsied liver specimen showed mononuclear cell infiltrate densely encircling the bile ducts, poorly developed epithelioid cell granuloma, and loss of integrity of bile duct organization, which permitted a diagnosis of stage I PBC according to Scheuer's histologic classification. In addition, round to oval, eosinophilic, homogenous intracytoplasmic inclusions, several microm in average size, with a surrounding halo were found in the vast majority of hepatocytes. These inclusions were negative for the periodic acid-Schiff reaction. In immunohistochemistry, the inclusions were positive for fibrinogen and complement C3c, but not for HBs antigen and alpha1-antitrypsin. These findings were identical to FSD. To investigate the mechanism(s) of abnormal fibrinogen storage, immunostaining for heat shock protein 70 and ubiquitin was performed. The former was detected in all intracytoplasmic inclusions, whereas the latter was detected in only some inclusions, suggesting a partial loss of ubiquitin expression.

Novel fibrinogen gamma375 Arg-->Trp mutation (fibrinogen aguadilla) causes hepatic endoplasmic reticulum storage and hypofibrinogenemia

The proposita and her sister had chronically elevated liver function test results, and needle biopsy specimens showed scattered eosinophilic inclusions within the hepatocytes. On immunoperoxidase staining, the inclusions reacted strongly with anti-fibrinogen antisera; on electron-microscopic (EM) examination, the material appeared confined to the endoplasmic reticulum (ER) and was densely packed into tubular structures with a swirling fingerprint appearance. Coagulation investigations showed low functional and antigenic fibrinogen concentrations that were indicative of hypofibrinogenemia. Amplification and DNA sequencing showed a heterozygous CGG-->TGG mutation at codon 375 of the fibrinogen gamma chain gene. This novel gamma375 Arg-->Trp substitution segregated with hypofibrinogenemia in 3 family members and was absent from 50 normal controls. When purified plasma fibrinogen chains were examined by sodium dodecyl sulfate/polyacrylamide gel electrophoresis, reverse-phase chromatography, electrospray ionization mass spectrometry, and isoelectric focusing, only normal gamma chains were detected. In conclusion, we propose that this nonconservative mutation causes a conformational change in newly synthesized molecules and that this provokes aggregation within the ER and in turn causes the observed hypofibrinogenemia. Whereas the mutation site, gamma375, is located in the gammaD domain at the jaws of the primary E-to-D polymerization site, purified plasma fibrinogen showed normal polymerization, supporting our contention that molecules with variant chains never reach the circulation but accumulate in the ER.

The role of immunohistochemistry in diagnosis

Immunohistochemistry is a strong tool in hepatopathologic diagnosis: the technique is relatively simple and inexpensive. New and very sensitive detection methods have been recently developed (e.g., the EnVision technique and the microwave antigen retrieval method). This article discusses the role of immunohistochemistry in differentiating chronic cholestatic diseases from chronic hepatitis and in characterizing infectious agents. Algorythms for the typing of lymphomas and for the differentiation of primary tumors versus metastases are proposed as well. The immunohistochemical criteria for the diagnosis of premalignant lesions are discussed.

Ground-glass hepatocytes in fibrinogen storage disease in Japanese Black calves

This paper reports the occurrence of large intracytoplasmic inclusions observed in the hepatocytes of six Japanese Black calves showing clinical illness. These inclusions were round to elongated polyhedral in shape, with a consistently homogeneous glassy appearance. Hepatocytes with the inclusions had a ground-glass appearance. The inclusions were negative for the periodic acid-Schiff reaction and methenamine silver stain. Immunohistochemically, they were strongly positive for fibrinogen. Electron microscopy revealed that the inclusions consisted of granular material, showing moderate electron density and bounded by a unit membrane. On the external surface of the unit membrane, there were direct connections to cellular organelles, including the ribosomes and rough-surfaced endoplasmic reticulum. The results showed these inclusions to be entirely consistent with fibrinogen inclusions described in man. Hepatocellular fibrinogen storage disease, as identified in this study, has not previously been described in animals.

Fibrinogen brescia: hepatic endoplasmic reticulum storage and hypofibrinogenemia because of a gamma284 Gly-->Arg mutation

The proposita suffered from liver cirrhosis and biopsy showed type 1 membrane-bound fiberglass inclusions. The hepatic inclusion bodies were weakly periodic acid-Schiff diastase-positive, and on immunoperoxidase staining reacted specifically with anti-fibrinogen antisera. Coagulation investigations revealed low functional and antigenic fibrinogen together with a prolonged thrombin time of 37 seconds (normal, 17 to 22 seconds) suggestive of a hypodysfibrinogenemia. DNA sequencing of all three fibrinogen genes showed a single heterozygous mutation of GGG (Gly)-->CGG (Arg) at codon 284 of the gamma-chain gene. However, examination of purified fibrinogen chains by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, reverse-phase high-performance liquid chromatography, ion-exchange high-performance liquid chromatography, and isoelectric focusing, failed to show any evidence of the mutant gamma(Br) chain in plasma fibrinogen. This finding was substantiated by electrospray ionization mass spectrometry, which showed only a normal gamma (and Bbeta) chain mass, but a large increase in the portion of their disialo isoforms. We speculate that misfolding of the variant protein causes hepatic retention and the subsequent hypofibrinogenemia, and that the functional defect (dysfibrinogenemia) results from hypersialylation of otherwise normal Bbeta and gamma chains consequent to the liver cirrhosis. These conclusions were supported by studies on six other family members with hypofibrinogenemia, and essentially normal clotting times, who were heterozygous for the gamma284 Gly-->Arg mutation.

Liver injury in alpha 1-antitrypsin deficiency

Alpha 1-antitrypsin deficiency is the most common genetic cause of liver disease in children. It is also associated with chronic liver disease, hepatocellular carcinoma, and pulmonary emphysema in adults. Liver injury is caused by hepatotoxic effects of retention of the mutant alpha 1-antitrypsin molecule within the endoplasmic reticulum of liver cells, and emphysema is caused by uninhibited proteolytic damage to elastic tissue in the lung parenchyma. Recent studies of the biochemistry and cell biology of the mutant alpha 1-antitrypsin molecule have led to advances in understanding susceptibility to liver injury and in developing new strategies for prevention of both liver and lung disease.

Oncocytic hepatocellular carcinoma with numerous globular hyaline bodies

Two well circumscribed tumors, oncocytic and non-oncocytic, were removed from the non-cirrhotic liver of a 67 year old male. The large oncocytic tumor (OCT), occupying the entire left lobe, was multilobulated with focal coagulation necrosis and areas of hemorrhage. Light microscopy revealed that it consisted of exclusively large, granular oxyphilic cells with moderate nuclear atypia and occasional mitotic figures, which were trabecular and/or pseudoglandular in structure, but no lamellar fibrosis was seen. Characteristically, the OCT cells included numerous globular hyaline bodies (GHB) of various sizes which were stained red with acid fuchsin and deep blue or magenta with phosphotungstic acid hematoxylin (PTAH), but negative for periodic acid Schiff (PAS), orcein, rhodamine and Grimelius methods. Immunohistochemically, alpha-fetoprotein (AFP), alpha-1-antitrypsin, alpha-1-antichymotrypsin, fibrinogen and ferritin were all negative. On ultrastructural examination, tumor cells were mitochondria-rich, including electron dense, ovoid or polyhedral inclusions, with the delineated membrane identical with that of the GHB. In contrast, the small tumor in the right lobe (Segment 7) was a solid adenoma with no oncocytic transition. Based on these findings, it was postulated that OCT consists of heterogenous proliferation of mitochondria-rich hepatocytes which tend to induce lysosomal GHB closely associated with mitochondrial abnormalities.

Characterization of a chicken hepatoma cell line with a specific defect in fibrinogen secretion

This study characterizes plasma protein synthesis and its hormonal regulation in a chicken hepatoma cell line, with particular emphasis on fibrinogen. Whereas virtually all aspects of hemopexin, transferrin and albumin production in these cells corresponded to those of cultured primary hepatocytes, fibrinogen was not secreted. Analysis of fibrinogen subunit synthesis revealed a specific defect in synthesis of one subunit, gamma, correlating with a lack of its mRNA. Pulse-chase and electron microscopic studies demonstrate that, despite the inability of these cells to secrete the A alpha and B beta subunits produced, there is no long-term accumulation of unsecreted fibrinogen. The B beta fibrinogen subunits are largely degraded 2 hr after synthesis. During this time, approximately half of the A alpha subunits are degraded; the rest are converted to the glycosylated form. The implications of this type of defect with respect to the pathogenesis of fibrinogen storage disease are discussed.

Ground glasslike hepatocytes produced by glycogen-membrane complexes ("glycogen bodies")

A 54-year-old man developed liver disease 11 months after renal transplantation. Liver biopsy demonstrated hepatitis with numerous periodic acid-Schiff-positive, diastase-sensitive ground glass inclusions in parenchymal cells. Electron microscopy revealed that the inclusions consisted of parallel arrays of smooth surfaced cisternae separated by glycogen rosettes ("glycogen bodies"). The differential diagnosis of ground glass hepatocytes, the occurrence of glycogen bodies, and the possible etiological factors in the patient's liver disease are discussed.

Pathomorphologic study of pale bodies in hepatocellular carcinoma

Pathomorphological and immunohistochemical studies were conducted on cases of hepatocellular carcinoma (HCC) with pale bodies (PB). HCC containing PBs was seen in 6 (5.7%) of 106 consecutively resected HCC cases. It was of interest that varying degrees of sclerotic change were found in 4 of the 6 cases and a certain correlation between PBs and sclerotic change of HCC tissue was suggested. Histologically, PBs were identified as a pale amorphous substance with a distinct margin and most of PBs occupied the entire cytoplasm of the cancer cells. PBs were practically negative for periodic-acid Schiff, and were also negative for phosphotungstic acid hematoxylin and orcein stains. Ultrastructurally, PBs were found to be a mass of granular or fibrillar materials having a single-layered limiting membrane, and dilated rough endoplasmic reticular (rER) were also found in the vicinity of PBs, suggesting the presence of a close relationship between rough endoplasmic reticula and PBs. Most PBs were found to be strongly positive for anti-fibrinogen antibody and some of them were weakly positive for anti-albumin, but were solely negative for other antibodies such as anti-HBs antigen, anti-alpha-1-antitrypsin, and anti-ferritin. According to those findings, PBs were thought to be fibrinogens accumulating in cystic rER due to a defective intracellular transport or an excretion disturbance.

Ground-glass hepatocytes with Lafora body like inclusions--histochemical, immunohistochemical and electronmicroscopic characterization

We report two adult patients whose liver biopsy specimens revealed numerous ground-glass hepatocytes due to inclusions resembling Lafora bodies. The inclusions were large, intracytoplasmic, pale, eosinophilic and kidney-shaped and were periodic acid-Schiff positive and HBsAg negative. Immunoperoxidase studies showed that the inclusions were positive for cytokeratins and alpha 1-antitrypsin. In case 1, the inclusions were not membrane-bound and consisted of secondary lysosomes and degenerate organelles including rough and smooth endoplasmic reticulum. In case 2, electronmicroscopy showed the inclusions were not membrane-bound, but consisted of dense granules, fibrils and vacuoles, with appearances very similar to Lafora bodies. Neither patient had myoclonus or epilepsy. Electronmicroscopy is important in differentiating the type of Lafora body like inclusions found in liver biopsies.

Co-existence of hepatocyte ground-glass inclusions from several causes

Two patients with two and three types respectively of ground-glass hepatocyte inclusions are described. Both were hepatitis B surface antigen (HBsAG) positive and received cyanamide for alcohol aversion therapy. In addition, one of them had taken benzodiazepines and barbiturates. In one patient, cyanamide and HBsAg inclusions co-existed in the same hepatocytes.

Endoplasmic storage disease of liver: characterization of intracytoplasmic hyaline inclusions

Two cases of endoplasmic storage disease of liver are described. The liver tissue in each case showed numerous intracytoplasmic hyaline inclusions of varying sizes with formation of ground-glass hepatocytes. These inclusions were pale eosinophilic in hematoxylin & eosin stained sections, and were periodic acid-Schiff and HBsAg negative. Immunoperoxidase studies revealed strong positivity for fibrinogen and complement components C3 and C4 in case 1 and exclusive positivity for fibrinogen in case 2. On electron microscopy, the inclusions appeared as granular or fibrillar material within dilated cisternae of rough endoplasmic reticulum.

Specific intracellular hyaluronic acid binding to isolated rat hepatocytes is membrane-associated

Intact isolated rat hepatocytes show a small amount of specific 125I-labeled hyaluronic acid (HA) binding. However, in the presence of digitonin, a very large increase in the specific binding of 125I-HA is observed. Chondroitin sulfate, heparin and dextran sulfate were as effective as unlabeled HA in competing for 125I-HA binding to permeabilized hepatocytes, indicating that the binding sites may have a general specificity for glycosaminoglycans. After rat hepatocytes had been homogenized in a hypotonic buffer, more than 98% of the 125I-HA binding activity could be pelleted by centrifugation at 100,000 x g for 1 h. Mild alkaline treatment of hepatocyte membranes did not release 125I-HA binding activity, suggesting that the HA binding site is an integral membrane molecule. Furthermore, trypsin treatment of deoxycholate-extracted membranes destroyed the binding activity, as assessed by a dot-blot assay. This suggests that a protein component in the membrane is necessary for 125I-HA binding activity. Rat fibrinogen could be a possible candidate for the HA binding activity because HA binds specifically to human fibrinogen (LeBoeuf et al. (1986) J. Biol. Chem. 261, 12 586). Also, fibrinogen can be found in a quasi-crystalline form in rat hepatocytes and could be pelleted with the membranes. Rat fibrinogen was not responsible for the 125I-HA binding activity, since (1) purified rat fibrinogen did not bind to 125I-HA, and (2) immunoprecipitation of rat fibrinogen from hepatocyte extracts did not decrease the 125I-HA binding of these extracts. We conclude that the internal HA binding sites are membrane- or cytoskeleton-associated proteins and are neither cytosolic proteins nor fibrinogen.

Immunohistochemical techniques for the demonstration of viral antigens in liver tissue

Liver biopsy specimens from patients positive for serum HBsAg reveal various expression patterns when properly stained by immunohistochemical techniques for the demonstration of HBsAg, HBcAg and HDAg. A negative staining for these three antigens seems to be associated with two conditions, i.e., self-limiting acute lobular hepatitis (ALH) or low amounts of intrahepatic antigens. The discrepancy between serum positivity and tissue negativity for HBsAg can be explained either by sampling error or by the higher sensitivity of the radioimmunoassay as compared with immunohistochemical methods. The use of amplification systems such as the avidin-biotin-peroxidase complex enhances the sensitivity of immunohistochemical peroxidase-antiperoxidase (PAP) techniques and makes it possible to detect very small amounts of both HBsAg and HBcAg in liver cells from paraffin-embedded tissue sections which had been negative with the conventional PAP technique. In cases with a positive staining for viral antigens, two main expression patterns (non-aggressive and aggressive) can be distinguished. The non-aggressive pattern is reflected in the HBcAg-free HBsAg-positive type (HBsAg carrier) or the generalized type of nuclear core (HBcAg carrier), while the aggressive pattern is reflected in the presence of HDAg, the presence of HDAg and HBcAg, the focal type of nuclear core or the cytoplasmic HBcAg. Superinfection of HBsAg carriers or switching from generalized to focal core, with or without cytoplasmic expression of HBcAg, results in transition from non-aggressive to aggressive pattern. The aggressive pattern occurs in association with histological features of chronic active hepatitis (CAH). When it occurs in ALH cases or in milder forms of chronic hepatitis, an evolution into CAH has to be expected. Features of severe CAH, eventually with cirrhosis, are found in association with two new expression patterns: the cytoplasmic core and the simultaneous presence of HBcAg and HDAg. When features of CAH are observed in liver tissue specimens with HBcAg-free HBsAg-positive type, the liver disease may be due to viral superinfection or to non-viral etiology, e.g., alpha 1-antitrypsin deficiency.

Cyanamide hepatotoxicity. Incidence and clinico-pathological features

Ground-glass hepatocytes resembling those seen in HBsAg carriers on hematoxylin and eosin and on trichrome stained sections, but giving a negative reaction to orcein and a positive one to PAS, were found in liver biopsy specimens from nine asymptomatic former alcoholics who were on treatment with cyanamide, in one of four who had been treated with cyanamide several months before the liver biopsy procedure, in none of 15 treated with disulfiram, and in one of eight who had apparently not received aversive drugs. Portal and periportal inflammatory changes and fibrosis were more frequently observed in biopsy specimens containing PAS-positive ground-glass hepatocytes than in those without, but cirrhosis was found with a similar frequency. It is concluded that periportal PAS-positive ground-glass hepatocytes are a histological marker of cyanamide treatment.