Immunofluorescence tests in non-A, non-B hepatitis.
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Biomedical subjects
Publications and source records attributed to A Alberti.
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The long-term outcome of non-A, non-B post-transfusion hepatitis was evaluated in 21 patients who developed the illness after open-heart surgery and could be followed thereafter up to five years. Histological chronic sequelae were documented in 13 patients, and consisted of chronic persistent hepatitis in one case, chronic lobular hepatitis in two and chronic active hepatitis in 10, five of whom also developed superimposed cirrhosis. Progression to these chronic states was in most cases symptomless, independently of the severity of liver lesions; one patient, however, died of gastrointestinal bleeding due to cirrhosis of the liver. During follow-up the biochemical pattern of chronic non-A, non-B hepatitis was unique, while striking fluctuations of transaminase levels. Liver histology proved essential to identify the severity of chronic liver lesions, as clinical and biochemical features were uniform and not indicative of it. Our results suggest that cirrhosis may develop, often with an asymptomatic course, in a significant number of patients who do not recover after acute post-transfusion non-A, non-B hepatitis.
Sera from 71 patients with acute liver injury have been tested for antibodies to hepatocyte membrane lipoprotein complex (LSP) using a sensitive radioimmunoassay. Two main patterns of anti-LSP response were seen. In the first, seen in patients with type A and B viral hepatitis, anti-LSP antibodies were detectable at presentation, with the highest titres two to 10 days before the peak in serum aminotransferases and, in the hepatitis B patients, when viral DNA polymerase concentrations were still high, indicating active viral replication. These findings are consistent with the anti-LSP response being consequent on an interaction between T cells and neoantigens on the liver cell surface. A similar pattern was found in halothane hepatitis where immune responses to a halothane-altered liver membrane antigen are present early in the course of the disease. In the second type of response, exemplified by cases with paracetamol-induced hepatic necrosis, anti-LSP was only occasionally detectable at presentation, although present in very low titre later in the clinical course. This may be due to the release of altered antigen at the time of hepatocellular injury. The same pattern was found in a selected group of patients with uncomplicated acute alcoholic hepatitis, suggesting that in both these groups of patients the liver damage may have been due to a direct toxic effect on liver cells.
8 children, known to have been hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) positive for more than 6 months and with chronic active hepatitis on biopsy, received 2.5 mg levamisole/kg/day, 2 days a week for 6-18 months. In 6 of the 8 children transaminases normalized within 4-18 months of therapy, with seroconversion to antibody to HBeAg (anti-HBe) and disappearance of HBV-DNA polymerase from serum and of hepatitis B core antigen (HBcAg) from liver. In these cases liver biopsies taken after treatment showed histological regression to chronic persistent hepatitis. Two distinct patterns of response to levamisole were noted: patients having higher pretreatment transaminase levels and lower expression of HBcAg in the liver showed an early transaminase normalization and anti-HBe seroconversion with therapy, while in patients with less active disease and more diffuse HBcAg positivity in pretreatment liver biopsies, longer treatment periods were necessary to achieve these effects. Our results suggest that long-term levamisole therapy may be beneficial in HBeAg-positive chronic hepatitis type B.
Peripheral blood T lymphocytes from 21 patients with chronic HBV infection were incubated with autologous hepatocytes in a microcytotoxicity assay. Cytotoxicity was significantly increased in 13 cases, and in 12 of these the cytotoxic effect of the T lymphocytes was inhibited by preincubating the liver cells with IgG containing antibodies to the hepatitis B core antigen (HBcAg). Normal human IgG and IgG containing antibodies to the hepatitis B surface antigen (HBsAG) were without effect. Control experiments using autologous fibroblasts as target cells showed low levels of T cell cytotoxicity and no blocking effect of anti-core antibody. All patients in whom it was possible to demonstrate HBcAg in liver tissue had significantly increased T cell cytotoxicity to autologous hepatocytes. These studies suggest that T cell cytotoxicity in patients with chronic HBV infection is directed against determinants resembling the hepatitis B core antigen on the plasma membrane of hepatocytes.
The antibody specificity of immunoglobulin G bound to the liver cell membrane during hepatitis B virus infection and chronic liver disease has been studied in 8 patients after antibody elution with high molar urea. Eluted immunoglobulin G showed antibody specificity for hepatitis B core antigen by radioimmunoassay and by indirect immunofluorescence on positive liver tissue. On the contrary, no reaction could be detected against other viral antigens (i.e., hepatitis B surface antigen and hepatitis B e antigen) or against liver-specific proteins. Furthermore, in 5 selected cases, after urea removal of cytophilic antibody, hepatitis B core antigen could be demonstrated by direct immunofluorescence in a granular pattern on the liver cell surface, thus suggesting a masking effect of immunoglobulin G on membranous hepatitis B core antigen in patients with persistent virus replication in the liver.
The morphological alteration and disintegration test (MADT) as a key indicator for Hepatitis B Virus (HBV) inactivation was compared with the chimpanzee infectivity test using three suspensions of HBV differing in the degree of inactivation as judged by electronmicroscopic studies. The results of the MADT and the chimpanzee studies correlated well. Thus, the MADT, evidently, can replace the laborious, costly and time-consuming animal studies for the evaluation of chemical disinfectants for hepatovirucidal activity.
Electron microscopy examination of liver biopsies from 8 patients with chronic non-A, non-B hepatitis revealed ultrastructural changes similar to those previously described in chimpanzees with experimentally induced acute non-A, non-B hepatitis. These changes consisted of intranuclear clusters of electron-dense, 15-27-nm particles that were detected in five out of the eight patients and of circular cytoplasmic structures that were present in seven cases. Other cytoplasmic abnormalities found in our patients related to the presence of curved membranes apparently developing from apposition of two cisternae of endoplasmic reticulum. In contrast with what has been reported in infected chimpanzees, the nuclear and cytoplasmic changes were not mutually exclusive in our patients, but coexisted in four of them.
Levels of serum hepatitis B virus DNA-polymerase (HBV-DNAP) were studied longitudinally over variable periods of time in 16 HBV chronic carriers using a modified assay procedure developed to increase reproducibility. Ten patients were tested on a short-term basis at 3- to 6-hr intervals for 48 hr or at 24- to 48-hr intervals for 15 consecutive days, and all showed marked vacillations in enzyme levels although hospitalized and untreated. Patients with chronic active hepatitis on liver biopsy had larger fluctuations compared to cases of chronic persistent hepatitis. Six patients were longitudinally tested over a period of 12-32 months and those three receiving immunosuppressive drugs showed a progressive increase in DNAP levels during therapy, but two returned to pretreatment levels after therapy was withdrawn and one even cleared permanently the complete virus with seroconversion to anti-HBe. Such outcome was also observed in one patient with chronic active hepatitis who remained untreated.
The presence of hepatitis B 'e' antigen (HBeAg) and its antibody (anti-HBe was evaluated by radioimmunoassay (RIA) in various groups of HBsAg-positive patients. HBeAg was present in the majority of the sera from patients with acute viral hepatitis at onset of clinical symptoms and disappeared after 1 year. Almost all hemodialysis patients had HBeAg in their sera. 40% of the patients who had chronic active hepatitis and 50% with chronic persistent hepatitis had HBeAg with no relationship to the inflammatory activity of the disease evaluated by the presence of mononuclear infiltration in liver biopsy. The comparison between the presence of HBeAg and Dane particle-associated DNA-polymerase activity showed that HBeAg was consistently found in almost all the sera which presented DNA-polymerase activity. HBeAg, as determined by RIA, may therefore be useful in the screening of highly infective patients with elevated viral replication.
An antigen-antibody system has been identified by immunofluorescence in patients with non-A, non-B hepatitis. The non-A, non-B antigen was localized in the hepatocyte nuclei of liver biopsies from patients with acute post-transfusion or sporadic non-A, non-B hepatitis and in those from patients with chronic post-transfusion non-A, non-B hepatitis, the percentage of positive cells being most prominent in patients receiving immunosuppressive treatment. Absence of the antigen in normal livers and in livers from patients with type B hepatitis infection indicated its specific association with non-A, non-B infection. Antibody reacting with the nuclear antigen became detectable in serum during post-transfusion acute non-A, non-B hepatitis in 11 out of 15 cases; it was absent before transfusion. Six out of 12 cases of sporadic acute non-A, non-B hepatitis were also found to produce the antibody, which was repeatedly found to be absent during the acute phase in five patients with type A and in eight with type B hepatitis. The non-A, non-B antibody, mainly an IgM antibody, persisted in serum for prolonged periods of time after onset, both in patients showing biochemical resolution of their illness and in those who continued to have liver damage after the acute phase. Accordingly, eight out of nine patients with chronic non-A, non-B hepatitis were found positive for the antibody in serum, seven at the time the non-A, non-B antigen was detected in their liver. Thus this non-A, non-B associated antigen-antibody system shares remarkable similarities of behaviour with the "core" system of the hepatitis B virus.
Clinical, virological, and histological features of hepatitis B virus infection have been examined in 35 children, aged 1 to 11 years, known to be hepatitis B surface antigen (HBsAg) carriers for at least six months when entering the study. Only 10 patients had a history of acute unresolved hepatitis: in the remaining cases the detection of HBsAg had been an occasional finding. Although 77% of the patients were asymptomatic, all had evidence of hepatic involvement and liver history showed the features of chronic persistent hepatitis in 18 cases and of chronic active hepatitis in 16 cases, with associated cirrhosis in two of them. One patient had only minimal histological changes. A high percentage of children with both chronic persistent and chronic active hepatitis had evidence of active virus replication throughout the observation period. During the follow-up study of one to eight years (mean 3.1 +/- 1.7 years), transaminase levels became consistently normal in five patients with chronic persistent hepatitis, and inflammatory infiltrates disappeared in three of them. However, only one of these children cleared HBsAg from serum. Eleven of 16 patients with chronic active hepatitis received immunosuppressive treatment but only one of them achieved a complete and protracted remission, although active viral replication persisted. On the other hand, two of five untreated patients reached complete remission after two and three years of follow-up respectively and one of them cleared HBsAg three years later. These results would suggest the possibility of a spontaneous complete remission of HBsAg positive chronic active hepatitis in children but also raise doubts about the usefulness of immunosuppressive therapy in such patients.
Sera from 42 patients with acute viral hepatitis (AVH), 97 patients with chronic active liver disease (CALD) and 89 controls were tested by radioimmunoprecipitation for the presence of antibodies against human liver-specific protein (LSP). Anti-LSP were found in all but one patient with AVH type A (93%) and in a smaller percentage of AVH type B (55%). In non-A, non-B cases, anti-LSP were found in low percentages: 27% in acute cases, 10% in chronic cases. Furthermore, in CALD, a significant difference was found between HBsAg-positive CAH and 'autoimmune' CAH, a significant difference was found between HBsAg-positive CAH and 'autoimmune' CAH, both in anti-LSP prevalence (21%, 67%; P less than 0.005) and in anti-LSP titre (1:154 +/- 170, 1:316 +/- 186; P less than 0.005). In HBsAg-negative/anti-HBc-positive CAH, three of 15 patients were anti-LSP positive. Anti-LSP were found only in three of 57 patients with various non-hepatic diseases with autoimmune features. None of the 12 healthy HBsAg carriers was positive. Hence there is evidence for a considerable heterogeneity in anti-LSP response in acute and in chronic inflammatory HBsAg-negative liver diseases. These data suggest that anti-LSP antibodies do not play a prominent role in the process of transition to chronicity of acute viral hepatitis particularly in non-A, non-B cases, whereas these antibodies may be important in the mechanism of ongoing liver cell injury in patients with 'autoimmune' CAH, and can represent a useful diagnostic marker of this type of hepatitis.
Circulating antibodies reacting specifically with the cell membrane of hepatocytes isolated from halothane-anesthetized rabbits were detected in nine of 11 patients with fulminant hepatic failure after helothane-induced anesthesia. The immunoglobulin deposition, as revealed by immunofluorescence, showed a granular pattern on the hepatocyte surface membrane. Preincubation of halothane-pretreated, but not of control, hepatocytes with serum containing this antibody rendered them susceptible to cytotoxic effects of normal lymphocytes in vitro. Control studies using serum from subjects repeatedly exposed to halothane without the development of liver damage, and from patients with viral and toxic liver injury have confirmed the specificity of these findings to serve halothane-associated liver injury. These results provide further evidence of an immunologic component in this condition.
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Serum levels of hepatitis B virus specific DNA polymerase and hepatitis B e antigen were studied serially in 34 patients with hepatitis B virus infection--20 who had the acute illness and recovered, seven who died with fulminant disease, three who died as a result of subacute hepatic necrosis, and four who went on to develop chronic active hepatitis. DNA polymerase activity was present in 16 (80%) and HBeAg in 13 (65%) of the uncomplicated cases at presentation and in all of those patients from whom the initial sample was obtained before the peak in aminotransferase. Both markers disappeared after 30 days from the onset but DNAP remained persistently positive during a follow-up period of four to 10 months in the four patients who progressed to chronic hepatitis. These results indicate that DNAP and HBeAg are transiently present in all cases of acute hepatitis B. Only their persistence after the acute episode could represent a useful prognostic marker of chronically. In this respect, DNAP was more reliable in our patients than HBeAg. In uncomplicated acute hepatitis, the peak in DNAP levels, which defines the time of maximum virus replication in the liver, preceded the peak in aminotransferase levels. Among the 10 patients who developed massive liver damage after hepatitis B infection, DNAP was detected in five of the seven with fluminant hepatitis, with enzyme levels that were comparable with those observed in uncomplicated acute hepatitis and presentation, but not in the cases of subacute hepatic necrosis. These findings are consistent with the hypothesis that in hepatitis B infection, liver damage, whatever the severity, is not directly related to the degree of virus replication.
In an attempt to define further the significance of immunoglobulin G (IgG) fixed in vivo to the hepatocyte membrane in hepatitis B virus (HBV) infection, we have studied the relationship between presence of membrane-bound IgG and that of intracellular hepatitis B surface (HBsAg) and core (HBcAg) antigens in hepatocytes from 25 HBsAg chronic carriers. For this purpose, we have used a double immunofluorescence technique that is able to detect IgG and viral antigens within the same liver cell. In 15 patients with HBsAg-positive chronic active hepatitis, we found a statistically significant association between detection of membrane-bound IgG and that of intranuclear HBcAg within the same liver cells. On the contrary HGsAg containing hepatocytes generally did not show IgG fixed on their surface. IgG was not detected on the liver cell surface in 10 other HBsAg carriers without active disease and with large amounts of HBsAg containing hepatocytes. These results suggest that in HBsAg-positive chronic active hepatitis membrane-bound IgG is directed against viral antigens or virus-induced neoantigens that appear on the surface of infected cells at the time of active virus replication. Modulation of virus expression by this IgG could play a role in the pathogenesis of the disease.