Reinfection of liver graft by hepatitis C virus after liver transplantation.

We have investigated hepatitis C virus (HCV) viremia before and after orthotopic liver transplantation (OLT). 38 patients were examined; 16 were anti-HCV positive and 22 anti-HCV negative pre-OLT in a RIBA-2 test (Ortho Diagnostic Systems Inc., Westwood, MA). HCV-RNA was detected using a modified nested polymerase chain reaction in 14/38 and 10/38 patients before and after OLT, respectively. 7 of these 14 subjects who were HCV-RNA positive before OLT were also positive for serum hepatitis B surface antigen. After OLT, six patients became HCV-RNA positive, likely as a result of transfusions, while four developed a probable recurrence of HCV infection. Infection of the liver graft by the same strain of HCV was indeed demonstrated by sequence analysis of a hypervariable domain (in the envelope region) in two cases. This establishes the possibility of HCV recurrence and shows the usefulness of polymerase chain reaction as the only assay currently capable of identifying HCV infection after OLT.

Fulminant non--A-G viral hepatitis leading to liver transplantation.

BACKGROUND: All hepatotropic viruses are known to cause fulminant hepatic failure (FHF). However, in 30% to 40% of patients with FHF, the precise cause remains unknown. We aimed to better define this subgroup. METHODS: We evaluated the clinical course and outcome of 7 patients admitted during a 22-month period with fulminant viral hepatitis leading to liver transplantation; none had serologic or molecular evidence of hepatitis A, B, C, D, E, or G viral infection, thus the term non-A-G viral hepatitis. All known etiologies of FHF were excluded. RESULTS: All patients had prodromal symptoms suggestive of viral causes. Mean age was 30 years. The interval between onset of jaundice and appearance of encephalopathy was 23 days (range, 4-50 days). Five patients had grade III/IV encephalopathy. Serum alanine aminotransferase levels showed a single peak of activity. The duration between first symptoms and liver transplantation was 28 days (range, 12-71 days). Results of histological study of the explanted liver showed submassive (4 patients) or massive (3 patients) hepatocyte necrosis. In all patients, results of polymerase chain reaction analysis did not detect hepatitis B virus DNA, hepatitis C virus RNA, or hepatitis G virus RNA in the explanted liver. After transplantation, 2 patients showed (6 months later) increased liver enzyme levels of undetermined cause, and results of a liver biopsy showed mild lobular hepatitis; 1 patient had lymphoproliferative disorder (Epstein-Barr virus-originated); and 1 patient, aplastic anemia, which is known to be associated with seronegative viral hepatitis. The latter patient died, whereas the other 6 patients are alive (survival rate, 86%). CONCLUSIONS: Our patients with non-A-G viral hepatitis had a severe acute onset with progressive FHF requiring liver transplantation. There is some suggestion of recurrent viral disease after transplantation implicating other unknown viruses in the etiology.

Spontaneous long-term acceptance of RT-1-incompatible liver allografts in inbred rats. Analysis of the immune status.

In several combinations of inbred rats, liver allografts are spontaneously tolerated, and after a few weeks liver tolerant rats are in a state of donor-specific transplantation tolerance. In vivo and in vitro experiments were conducted to analyze the immunological status of LEW or BN rats with spontaneously tolerated (LEW X BN) F1 liver allografts several months after transplantation. Acute rejection of secondary donor-specific heart allografts retransplanted from liver-tolerant rats to normal syngeneic hosts suggests that the state of tolerance in liver-tolerant rats is related to an active modification of the immune system of the rat and not to a reduced immunogenicity of the graft. No cytotoxic antibodies or cells were found in liver-tolerant rats. Reactivity in mixed lymphocyte culture was normal or slightly reduced. Arguments for the presence of splenic suppressor cells were found in LEW tolerant rats using a local graft-versus-host assay, but these could not be found in BN rats, or when attempting to transfer or to break the tolerance state. A nonspecific humoral blocking factor was found in vitro in liver-tolerant rats but transfer of serum from liver-tolerant rats to normal syngeneic hosts did not permit a significant prolongation of donor-specific heart allografts. These results suggest that more than one mechanism may be involved at the maintenance phase of liver allograft tolerance.

Specific absorption of lymphocytotoxic alloantibodies by the liver in inbred rats.

It has been suggested that liver allografts are less sensitive to lymphocytotoxic antibodies than other organ allografts. In this experimental study in sensitized inbred rat recipients, we have used extracorporeal liver hemoperfusion to study interactions between the liver and lymphocytotoxic antibodies. Donor-specific liver hemoperfusion can delay hyperacute rejection of heart allografts and reduce the level of lymphocytotoxic antibodies. Immunofluorescence examination of the hemoperfused liver revealed deposits of C3 on Kupffer cells and of IgG on sinusoidal cells. In control rats in which a third-party liver, a donor-specific splenic or renal hemoperfusion was performed, heart allograft survival was less prolonged. The decrease in antibody levels was not significant and the deposit of C3 and IgG was much less evident. Similarly, previous blockade of the Kupffer cells of the donor-specific hemoperfused liver by dextran sulfate suppressed the effect of liver hemoperfusion. These results support the hypothesis that resistance of the liver to hyperacute rejection might be due to a massive and nontoxic absorption of lymphocytotoxic antibodies onto nonparenchymal liver cells.

Delayed rejection of heart allografts after extracorporeal donor-specific liver hemoperfusion. Role of Kupffer cells.

Liver allografts have a privileged status in regard to acute rejection. In this experimental study, we have analyzed the immunosuppressive effects of an extracorporeal liver hemoperfusion. In the LEW-to-BN combination of inbred rats, donor-specific liver hemoperfusion can significantly delay acute rejection of heart allografts. Analysis of the immunological status of these animals revealed a significant decrease in donor-specific lymphocytotoxic antibodies and in cytotoxic T lympholysis. Reactivity in mixed lymphocyte culture was normal. After third-party (DA) liver hemoperfusion or after donor-specific (LEW) splenic hemoperfusion, prolongation of heart allograft survival was moderate. Previous blockade of Kupffer cells suppressed the effects of donor-specific liver hemoperfusion. These results suggest that the sequestration by Kupffer cells of a clone of cytotoxic T cells and/or lymphocytotoxic antibodies may explain the immunosuppressive effects of donor-specific liver hemoperfusion.

Relationship between the liver and lymphocytotoxic alloantibodies in inbred rats. Specific absorption by nonparenchymal liver cells.

Liver allografts have a privileged status with regard to hyperacute rejection. In this experimental study, we have used extracorporeal liver hemoperfusion in sensitized rats in order to analyze reactions between lymphocytotoxic antibodies and the liver. In sensitized BN rats, a donor-specific (Lewis) extracorporeal liver hemoperfusion can delay hyperacute rejection of heart allografts and reduce the level of lymphocytotoxic antibodies. The decrease in the level of antibodies could be due to massive absorption of antibodies by the liver or to release of major histocompatibility complex antigens in a soluble form. Immunofluorescent examination of the hemoperfused liver revealed important deposits of C3 on Kupffer cells and of IgG on sinusoidal cells. On the contrary, in control rats in which a third-party (DA) liver hemoperfusion was performed, heart allograft survival was less prolonged, the decrease in the level of lymphocytotoxic antibodies was not significant, and the deposits of IgG and C3 were much less evident. The level of circulating immune complexes was unchanged after a donor-specific or a third-party liver hemoperfusion. These results support the hypothesis that resistance of the liver to hyperacute rejection might be due to a massive and nontoxic absorption of lymphocytotoxic antibodies on nonparenchymal liver cells.

Portal hypertension after bile duct obstruction: effect of bile diversion on portal pressure in the rat.

Biliary obstruction of 14 and 28 days induced in the rat an increase of portal pressure (PP) and wedge hepatic vein pressure (WHVP); the higher these were, the longer was the obstruction. Occurrence of portal hypertension seemed related to portal and periportal fibrosis. Relief of obstruction after 14 days by bilioduodenal anastomosis brought back to normal PP and WHVP. In rats with longer obstruction periods, bilioduodenal anastomosis failed to lower PP and WHPV although biological signs of cholestasis returned to normal levels. These results suggest that portal hypertension may arise very shortly after biliary obstruction in rats and that it may persist in animals with a prolonged biliary obstruction despite an efficient bile drainage. In clinical conditions, such results would favor early treatment of lesions that usually cause prolonged bile duct obstruction, such as postoperative bile duct stenosis.

Temporary liver transplantation in acute liver failure.

The ability of a heterotopic graft to prolong life in animals dying in hepatic coma due to liver necrosis has never been definitely established. Acute hepatic failure was produced in 15 dogs by an hour of total interruption of the hepatic blood supply. Nine dogs received an intrathoracic hepatic homograft concurrently. Nontransplanted dogs died within 21 hours in hepatic coma, while transplanted dogs survived significantly longer (P less than .001). In all transplanted dogs, biological signs of hepatic failure were corrected in 24 hours. In four animals, the graft was removed on the fifth postoperative day. Two of those survived for 10 and 15 days respectively with normal hepatic function. These results demonstrate that a temporary heterotopic liver transplant is able to support life during the acute, normally lethal phase in dogs with massive liver necrosis.

Delaying rejection in discordant heart xenografts in the rat: efficacy of cyclosporin, prostaglandin I2 and exchange transfusion.

If effective modes of prevention of hyperacute rejection were available, the problem of the absence of enough suitable donors could be solved by the use of organ xenografts. Organ xenograft rejection is principally mediated by preformed antibodies which are responsible for the hyperacute pattern of rejection. We decided therefore to study various methods of prevention of rejection in the guinea pig to Lewis rat combination (donor-recipient discordant species) in which hyperacute rejection is particularly intense. Three series of experiments were performed. In the first series immunosuppression of the recipient was induced using an oral solution of cyclosporin A. In the second series antiplatelet-aggregation therapy was administered to the recipient, using intravenous prostacyclin (PGI2). In the third series antibody depletion of the recipient was attempted using exchange transfusion with or without prostacyclin perfusion. The most significant (p less than 0.01) prolongation of graft survival time was observed when combining exchange transfusion (8 ml) and PGI2 infusion (620 ng/kg/min). This observation suggests that, if antibody depletion in the recipient is the primary goal, measures aiming at reducing the consequences of the antigen-antibody reaction are also necessary to improve the results of organ xenografting.

[Compartmental distribution of hepatitis C virus quasispecies in mononuclear cells and liver].

OBJECTIVE: To explore the role of the infection of monouclear cells by hepatitis C virus(HCV) in the chronicity of HCV infection. METHODS: Direct sequencing of the amplified hypervariable region (HVR) gene of HCV was used to distinguish main HCV quasispecies infecting non-hepatocytes from those infecting hepatocytes and circulating virions. The main HCV quasispecies in peripheral blood mononuclear cells(PBMC), liver-associated mononuclear cells (LAMC), serum and liver samples from 6 patients with chronic hepatitis C and from 6 patients with HCV-related cirrhosis were analysed and compared. RESULTS: The main HCV qusispecies in the livers were different from those in PBMC in 3 transplanted cirrhotic patients and 5 patients with chronic hepatitis C. Different substitutions existed between PBMC and LAMC in 3 of 6 patients analysed. Mutations were observed within the first 50 amino acids of E2 gene, which induced amino acid change in 6 of 9 patients analysed. CONCLUSION: In chronically infected patients, the detection of HCV RNA in mononuclear cells is not due to the adsorption of circulating virions but a significant infection. The compartmental distribution of HCV quasispecies in hepatocytes and mononuclear cells could be involved in the chronicity of HCV infection.

[Cyclosporin, toxicity and efficacy in rejection of liver allografts in the rat]. / Ciclosporine, toxicité et efficacité dans le rejet des allogreffes hépatiques chez le rat.

52 orthotopic liver transplants were performed in DA to lewis rat strain combination, in order to appreciate cyclosporine toxicity, and efficacy at doses of 10 mg/kg day (G II) and 20 mg/kg/day (GIII) compared to liver allografts in DA/lewis rats. The first signs of cyclosporine hepatotoxicity are biological (increased plasma level of bilirubine and transaminase) that were noticed at the dose of 20 mg/kg/day. Histological signs (cells inclusion, hepatocytic necrosis) appeared late and were less constant as well as difficult to assert creatinine plasma level was the best reflect of cyclosporine nephrotoxicity. Renal toxicity was practically constant at the dose of 20 mg/kg/day. In spite of renal and hepatic toxicity, cyclosporin by itself, allows the abolition of the acute rejection of liver allografts in the rat.