Hepatic Allograft Research Articles

Changes in the serum levels of interleukin-17/interleukin-23 during acute rejection in liver transplantation

Interleukin-23 (IL-23) and T helper 17 (Th17) cells have been cast as major players in autoimmunity, but their role in transplantation immunity remains to be specified. The aim of our study was to investigate the time course of serum levels of IL-23 and IL-17 during hepatic allograft rejection. Serum levels of IL-23 and IL-17 were determined in 20 healthy subjects and 50 hepatic transplant recipients. These patients were divided into 2 groups: group I was composed of 15 patients with acute rejection, and group II was composed of 35 patients without acute rejection. Samples were collected on days 1 and 7 after liver transplantation and on the day of liver biopsy. The concentrations of IL-23 were similar for the rejection group and nonrejection group at early postoperative times. We observed a significant increase in serum IL-23 levels in the rejection group when a diagnosis of acute rejection had been established. Similarly to IL-23, at the diagnosis of acute rejection, the concentration of IL-17 was significantly higher in the rejection group versus the nonrejection group. The whole transplant group, including those with stable graft function, had higher serum levels of IL-23 and IL-17 than the controls during the entire postoperative period. In conclusion, IL-23 and IL-17 are up-regulated during acute hepatic rejection. These findings suggest a role for Th17 cells in human liver allograft rejection.

Comparison of three-dimensional rotational angiography and digital subtraction angiography for the evaluation of the liver transplants

Purpose The objective of this study is to define the role of three-dimensional (3D) rotational angiography (RA) in the evaluation of transplant hepatic arteries and compare it with digital subtraction angiography (DSA). Materials and methods The patency of the arteries and anastomoses, confidence in the ability to make a therapeutic decision, and the value of the study for the definition of the optimal projection for an intervention were graded on a scale from 0 to 10. Results Forty-three vascular segments in five patients were available for analysis. Complete concordance between 3D RA and DSA was present in 92.9% of the major (extrahepatic) segments. Three-dimensional RA demonstrated two major hepatic segments that were not visualized on DSA. There was no difference in diagnostic confidence, but 3D RA was considered superior for planning the optimal projection for intervention (10±0 vs. 6.4±1.8). Conclusion Three-dimensional RA DSA allows a more complete depiction of the hepatic allograft arterial system than DSA with comparable accuracy. Three-dimensional RA provides similar degrees of confidence in the ability to make a treatment decision, and its appropriate implementation could help reduce overall contrast and radiation dose.

Response to antiviral therapy in liver transplant recipients with recurrent hepatitis C viral infection: a single center experience

Recurrence of hepatitis C virus (HCV) in hepatic allograft is a major concern after successful liver transplant (LTx). To examine the response rate to pegylated interferon (PEG-IFN) and ribavirin in post-LTx patients with HCV recurrence. Between January 2003 and September 2006, 60 patients with biopsy proven HCV recurrence (46 males and 14 females) received PEG-IFN 2a (n = 40) or IFN 2b (n = 20) with ribavirin. All patients were followed until July 2007. Fourteen patients (23.3%) tolerated antiviral therapy for less than six months and 10 (16.7%) discontinued therapy between six and 11 months. PEG-IFN dose was reduced in 21 (35%) patients and ribavirin dose was reduced in 16 (26.7%) patients. Overall, 55% patients achieved end of treatment response (EOT) and 35% sustained virological response (SVR). Mean Hepatitis Activity Index and Fibrosis Score pre-therapy was 5.8 +/- 1.9 and 1.7 +/- 1.3 and post-therapy, it was 4.4 +/- 2.1 and 2.4 +/- 1.6, respectively. Overall, three yr patient and graft survival was 73.9% and 69.2%, respectively. The patients with SVR had significantly lower viral load compared with other groups (p = 0.028). PEG-IFN and ribavirin therapy achieved 55% EOT and 35% SVR; 60% patients tolerated therapy. Biochemical response was observed in all groups of patients irrespective of virological response.

Relevant Histopathologic Findings That Distinguish Acute Cellular Rejection From Cholangitis in Hepatic Allograft Biopsy Specimens

Relevant Histopathologic Findings That Distinguish Acute Cellular Rejection From Cholangitis in Hepatic Allograft Biopsy Specimens

Two-year observation of a randomized trial on tacrolimus-based therapy with withdrawal of steroids or mycophenolate mofetil after renal transplantation

To evaluate the safety and feasibility of steroid or mycophenolate mofetil (MMF) withdrawal from tacrolimus-based immunosuppressant regimen in renal allograft recipients. A cohort of 45 patients following cadaveric renal allograft transplantation were randomly divided into 3 groups based on the regimen of combination of tacrolimus, steroid, and MMF: triple therapy group, steroid withdrawal group, and MMF withdrawal group. During 2 years, survival of patients and allografts, clinical acute rejection, adverse events, hepatic and renal allograft function, and blood lipids were monitored to evaluate the safety and feasibility of steroid or MMF withdrawal after renal transplantation. During two-year observation, steroid or MMF was successfully withdrawn from immunosuppressant regimen based on tacrolimus without any clinical acute rejection. Patient and graft survival rates were 100% and all the renal allografts kept excellent function. Some adverse events occurred and there were no significant differences among groups. Withdrawal of steroid or MMF in low-immunological-risk renal allografts treated with tacrolimus-based immunosuppressant regimen can be achieved with no increased risk of acute rejection.

An immunohistochemical evaluation of C4d deposition in pediatric inflammatory liver diseases

C4d is a marker of the activated complement cascade used to assess the humoral component of rejection, mostly in kidney allograft transplants. The role of C4d deposition has recently been addressed in hepatic allograft but has never been tested in a series of inflammatory liver diseases without previous liver transplantation. The aim of this study was to compare the immunohistochemistry profile of C4d deposition in a pediatric population, between a cohort of patients with autoimmune hepatitis (AIH) and a series of patients with chronic viral hepatitis B or C. Immunohistochemical analysis was performed on 64 liver biopsies. C4d deposition was observed in 25 (83%) of 30 AIH biopsies examined, in 6 (40%) of 15 hepatitis C biopsies, and in 17 (89%) of 19 hepatitis B biopsies. No expression of C4d was observed in 4 noninflammatory liver specimens used as negative controls. In the AIH group, a staining of the periportal sinusoids was often observed, as well as focal periductal reinforcement. Centrolobular vein staining was observed in the 3 hepatitis groups with a higher frequency in viral hepatitis B biopsies. Regardless of the etiology, lymphoid aggregates demonstrated an accentuation of the staining. These results confirm a role for a humoral immune response in pediatric autoimmune as well as in viral hepatitis. The relative ratios of positive cases imply that this immunostaining does not represent a strong diagnostic criterion in the differentiation between viral hepatitis and AIH. However, differences in the pattern of the staining were observed, depending on the etiology of the disease. The high prevalence of C4d reactivity in viral hepatitis strongly suggests that C4d does not represent a useful marker in the differentiation between acute rejection and viral hepatitis relapse in liver transplants.

Liver eosinophilic infiltrate is a significant finding in patients with chronic hepatitis C

Eosinophilic infiltrate of liver tissue is described in primary cholestatic diseases, hepatic allograft rejection and drug-induced liver injury, but its significance and its implications in chronic hepatitis C are unknown. The aim of this study was to investigate the clinical significance of eosinophilic liver infiltrate in patients with chronic hepatitis C. We retrospectively evaluated 147 patients with chronic hepatitis C. The presence of eosinophilic infiltrate was investigated in liver biopsies, and a numeric count of eosinophilic leucocytes in every portal tract was assessed. An eosinophilic infiltrate of liver tissue (> or =3 cells evaluated in the portal / periportal spaces) was observed in 46 patients (31%), and patients who consumed drugs had an odds ratio (OR) of 4.02 (95% CI: 1.62-9.96) to have an eosinophilic infiltrate in liver biopsy. By logistic regression analysis, the presence of steatosis was independently associated with eosinophilic infiltrate (OR 5.86; 95% CI: 2.46-13.96) and homeostasis model assessment-score (OR 1.18; 95% CI: 1.00-1.39). Logistic regression analysis also showed that fibrosis staging > or = 2 by Scheuer score was associated with grading >1 by Scheuer score (OR 6.82; 95% CI 2.46-18.80) and eosinophilic infiltrate (OR 4.00; 95% CI 1.23-12.91). In conclusion, we observed that the eosinophilic infiltrate of liver tissue was significantly more frequent in patients who assumed drugs, and found a significant association between eosinophilic infiltrate, liver steatosis and liver fibrosis. These preliminary data could lead to a constant assumption of drugs as a co-factor of eosinophils-mediated liver injury in chronic hepatitis C.

Long-term outcome of human leukocyte antigen mismatching in liver transplantation: Results of the national institute of diabetes and digestive and kidney diseases liver transplantation database

A perfect or nearly perfect human leukocyte antigen (HLA) match has been associated with better immediate and long-term survival of diseased donor kidney transplants. However, the effect of HLA matching for hepatic allografts remains poorly defined. Using data from the National Institutes of Diabetes and Digestive and Kidney Diseases Liver Transplantation Database, we investigated the association between HLA mismatches and hepatic allograft survival, disease recurrence, and immunosuppression interactions. A, B, and DR loci were used to calculate total mismatch scores of 0 (no mismatches in any loci) to 6 (mismatches in all loci). Seven hundred ninety-nine adults (male, 55%; female, 45%) underwent 883 liver transplants. The 10-year graft survival according to total mismatch score was as follows: 0-2, 60%; 3-4, 54%; and 5-6, 57%. There was a negative effect of mismatching at the A locus on patient survival, with shorter survival for patients with 1 or 2 mismatches compared with 0 mismatches [P = 0.05, hazard ratio (HR) = 1.6]. Patients on tacrolimus with 1 or 2 mismatches at B or DR loci appeared to have increased rates of patient and graft survival compared to patients with 0 mismatches, with the appearance of a protective effect of tacrolimus (HR = 0.67). The effect of HLA mismatching was more pronounced on certain disease recurrences. DR-locus mismatch increased recurrence of autoimmune hepatitis (P = 0.01, HR = 4.2) and primary biliary cirrhosis (P = 0.04, HR = 2). Mismatch in the A locus was associated with more recurrence of hepatitis C virus (P = 0.01, HR = 1.6) and primary sclerosing cholangitis (P = 0.03, HR = 2.9). Mismatching at the A locus decreases patient survival in liver transplant recipients, and mismatching at the DR and A loci affects recurrence of autoimmune liver diseases and hepatitis C, respectively.

Relative contribution of direct and indirect allorecognition in developing tolerance after liver transplantation.

The interaction of donor passenger leukocytes and host leukocytes in recipient secondary lymphoid tissues during the early posttransplantation period is crucial in directing host immune reactions toward allograft rejection or acceptance. Responsible T cell clones could be activated through the direct and indirect pathways of allorecognition. We examined the role of the indirect pathway in liver transplantation (LT) tolerance by depleting host antigen-presenting cells (APC) with phagocytic activity [e.g., cluster domain (CD)68+/CD163+ macrophages, CD11c+ dendritic cells (DC)] using liposome-encapsulating clodronate (LP-CL). After Lewis rat cell or liver graft transplantation, Brown Norway (BN) rat recipients pretreated with LP-CL showed a significantly reduced type 1 helper T cell cytokine up-regulation than control-LP-treated recipients. In the LT model, LP-CL treatment and host APC depletion abrogated hepatic tolerance; Lewis liver grafts in LP-CL-treated-BN recipients developed mild allograft rejection, failed to maintain donor major histocompatibility complex (MHC) class II+ leukocytes, and developed chronic rejection in challenged donor heart allografts, while control-LP-treated BN recipients maintained tolerance status and donor MHC class II+ hepatic leukocytes. Furthermore, in the BN to Lewis LT model, LP-CL recipient treatment abrogated spontaneous hepatic allograft acceptance, and graft survival rate was reduced to 43% from 100% in the control-LP group. In conclusion, the study suggests that host cells with phagocytic activity could play significant roles in developing LT tolerance.

Late acute rejection after liver transplantation impacts patient survival

Hepatic allograft rejection still remains an important problem following liver transplantation. Early acute rejection, occurring within three months of transplant, is a common event and usually of lesser significance with respect to prognosis than other non-immune-related post-transplant morbidities. However, little is known about late acute rejection (LAR) including factors affecting its occurrence and long-term outcome. In this study, we analyzed LAR including the incidence, clinical risk factors, patient survival, and graft survival. LAR was defined as acute cellular rejection later than six months after liver transplant. Adult patients who had a minimum of 24 months of graft survival were included in this study. A total of 1604 case records of consecutive adult patients (over age 18 yr) who underwent liver transplant between 1985 and 2003 were reviewed. Of the 1604 patients, 305 (19.0%) developed LAR. Patients with primary diagnoses of autoimmune hepatitis, primary biliary cirrhosis, and primary sclerosing cholangitis had higher incidences of LAR, while patients with metabolic disease and retransplant had lower incidence of LAR (p = 0.0024). The LAR group had more female and younger recipients than the no LAR group (p = 0.0026, p = 0.0131, respectively). Patient survival as well as graft survival were significantly lower in the LAR group (p = 0.0083, p = 0.0075, respectively). PTLD was the only significant independent predictor of late rejection. The careful management and treatment of PTLD, especially immunosuppressive management, is important to prevent LAR, which is related to poorer patient survival.

Ischemic cholangiopathy following liver transplantation from donation after cardiac death donors

The use of donation after cardiac death (DCD) donor hepatic allografts is becoming more widespread; however, there have been published reports of increased graft failure from specific complications associated with this type of allograft. The complication of ischemic cholangiopathy (IC) has been reported to occur more frequently after the use of DCD hepatic allografts. We report the results of 52 liver transplants from DCD donors and the factors that influenced the development of IC. We conducted a retrospective review of all DCD and donation after brain death (DBD) donor liver recipients from September 2003 through December 2006 at a single institution. Survival and complication rates were compared between the 2 groups. The Cox proportional hazards model was then used to identify recipient and donor factors that predict the development of IC in the DCD group. There was no difference in 1-year patient or graft survival rates between the 2 groups. There was no incidence of primary nonfunction from the DCD allografts. Hepatic artery complications and anastomotic bile duct complications were comparable in the 2 groups. There was, however, an increased risk for the development of IC in the DCD group (13.7% versus 1%, P = 0.001). Donor weight >100 kg and total ischemia times > or =9 hours, in donors older than 50 years of age, predicted the development of IC in the DCD group. In conclusion, there is a higher incidence of IC in recipients receiving DCD donor livers; however, patient and graft outcomes with DCD donors remain comparable to those with DBD donors. Careful donor selection may improve utilization of these grafts.

Relevant Histopathologic Findings That Distinguish Acute Cellular Rejection From Cholangitis in Hepatic Allograft Biopsy Specimens

Background and Aim Histopathologic differential diagnosis of acute cellular rejection (ACR) and cholangitis continue to pose important problems following liver transplantation. The purpose of the present study was to evaluate the histopathologic features of ACR versus cholangitis. Methods The following variables were evaluated among 36 hepatic allograft biopsy specimens, consisting of 21 with ACR (group 1) and 15 with cholangitis (group 2) for ductal neutrophilic infiltration, presence/density of portal eosinophilia, centrilobular necrosis, central/portal vein endothelialitis, pericentral inflammation, hepatocyte ballooning, hepatocanalicular/ductular cholestasis, hepatocyte apoptosis, lobular inflammation, ductular proliferation, periductal fibrosis/edema, ductular epithelial damage, and portal inflammation. Only the first biopsy samples of the ACR group were included in this study. Results The incidences of ductal neutrophilic infiltration (93.3% vs 19%), hepatocanalicular cholestasis (86.7% vs 47.6%), ductular cholestasis (60% vs 0%), ductular proliferation (93.3% vs 4.8%), and periductal fibrosis/edema (93.3% vs 19%) were significantly greater in group 2 than group 1 ( P < .05). In contrasts the incidences of portal eosinophilia (mean ± SD, 3.37 ± 3.9 vs 0.73 ± 0.8), dense portal eosinophilia (mean ± SD, 0.33 ± 0.31 vs 0.11 ± 0.16), central vein endothelialitis (0% vs 57.1%), portal vein endothelialitis (20% vs 95.2%), apoptosis (40% vs 71.4%), and necroinflammation (0% vs 90.5%) were significantly higher in group 1 ( P < .05). The other parenchymal histopathologic changes and features of portal inflammation were similar in the 2 groups. Conclusion In the differential diagnosis, ductal changes (cholestasis, neutrophilic infiltration, proliferation, and periductal fibrosis/edema) favor cholangitis, whereas the presence and density of portal eosinophilia favor ACR. Portal inflammation is not a distinctive morphological finding.

Dendritic cells, the liver, and transplantation

Interstitial liver dendritic cells (DCs) exhibit phenotypic diversity and functional plasticity. They play important roles in both innate and adaptive immunity. Their comparatively low inherent T cell stimulatory ability and the outcome of their interactions with CD4(+) and CD8(+) T cells, as well as with natural killer (NK) T cells and NK cells within the liver, may contribute to regulation of hepatic inflammatory responses and liver allograft outcome. Liver DCs migrate in the steady state and after liver transplantation to secondary lymphoid tissues, where the outcome of their interaction with antigen-specific T cells determines the balance between tolerance and immunity. Systemic and local environmental factors that are modulated by ischemia-reperfusion injury, liver regeneration, microbial infection, and malignancy influence hepatic DC migration, maturation, and function. Current research in DC biology is providing new insights into the role of these important antigen-presenting cells in the complex events that affect liver transplant outcome.

Acute renal failure and chronic kidney disease following liver transplantation

Acute renal failure (ARF) and chronic kidney disease (CKD) are common complications after liver transplantation (LTx). The incidence of ARF post-LTx varies between 48% and 94%; 8% to 17% of patients require renal replacement therapy (RRT). The most common cause of ARF early after LTx is ischemic acute tubular necrosis, followed later by cyclosporine toxicity and sepsis. Preoperative serum creatinine >1.5 mg/dL and early hepatic allograft dysfunction are risk factors for the occurrence of postoperative ARF. Of patients with ARF due to the hepatorenal syndrome, approximately two-thirds will recover, although recovery may be delayed 3 months or longer after LTx. Mortality after LTx is affected modestly by the presence of ARF pretransplant (<2-fold increase), but increases markedly (up to 8-fold) in the face of ARF posttransplant. Mortality does not appear to be influenced by the mode of RRT used. The risk of CKD after LTx is approximately 18% at 5 years and increases to approximately 25% by 10 years after transplantation. Calcineurin inhibitor toxicity is the most common cause. Specific prognosticators for predicting CKD after LTx are presently lacking. The occurrence of CKD after LTx markedly impairs long-term survival.

Value of Soluble CD30 in Liver Transplantation

Introduction CD30 is a membrane glycoprotein that belongs to the tumor necrosis factor superfamily. It is expressed on activated T cells. After activation of CD30 + T cells, a soluble form of CD30 (sCD30) released into the bloodstream, can be measured in the serum. The aim of our study was to investigate the time course of serum levels of sCD30 during hepatic allograft rejection. Materials and methods Serum levels of sCD30 were determined in 30 healthy subjects and 50 hepatic transplant recipients. These patients were divided into two groups: group I, 35 patients without rejection; and group II, 15 patients with acute rejection. Samples were collected on day 1 and 7 after transplantation and on the day of liver biopsy. Results The concentrations of sCD30 were similar in the rejection (40.4 ± 16.5 U/mL) and nonrejection groups (43.0 ± 18.2 U/mL) on postoperative day 1. We observed a significant increase in sCD30 levels in the rejection group on postoperative day 7 (76.3 ± 61.8 U/mL vs 46.8 ± 20.5 U/mL; P = .01). The difference increased when a diagnosis of acute rejection had been established: namely 133.0 ± 113.5 U/mL versus 40.1 ± 22.0 U/mL; ( P = .001). These levels were also significantly higher during the entire postoperative period in all the patients, with or without rejection, than those observed in healthy controls (26.6 ± 5.3 U/mL; P = .005). Conclusions The release of circulating sCD30 is a prominent feature coinciding with the first episode of hepatic allograft rejection. So, monitoring of sCD30 levels may be useful for the early diagnosis of an acute rejection episode.

Prophylaxis against recurrent hepatitis B virus infection after liver transplantation

Over the past two decades, there have been significant improvements in the outcomes of liver transplantation for all indications. Liver transplantation for hepatitis B virus (HBV) infection, once considered a contraindication to transplantation, now achieves survival rates of 91% at 1 year, 81% at 5 years, and 73% at 10 years. This improvement in outcome has occurred largely with the introduction of therapies that prevent reinfection of the hepatic allograft and thus recurrent hepatitis B, cirrhosis, and graft failure. In the United States, it is estimated that 1.25 million people are chronically infected with HBV, resulting in approximately 5000 liver-related deaths and 250 liver transplantations annually. This review summarizes the important accomplishments in the successful application of liver transplantation for liver disease related to HBV infection.

Long-term survival and impact of ursodeoxycholic acid treatment for recurrent primary biliary cirrhosis after liver transplantation

The recurrence of primary biliary cirrhosis (PBC) in the hepatic allograft may impact patient and graft survival with long-term follow-up. The efficacy of ursodeoxycholic acid (UDCA) for treatment of recurrent PBC after liver transplantation (LT) remains less well known. The aims of this study were as follows: 1) to determine the significance of recurrent PBC on overall survival among PBC patients who underwent LT, and 2) to determine the efficacy of UDCA treatment after LT in patients with recurrent PBC. A retrospective cohort study was conducted of 154 PBC patients who underwent LT with at least 1 yr of follow-up after transplantation from 1985 through 2005. A total of 52 patients with recurrent PBC were identified. After adjusting for age and gender, recurrent PBC was not associated with death or liver retransplantation (hazard ratio, 0.97, 95% confidence interval, 0.41-2.31; P = 0.9). A total of 38 patients with recurrent PBC received UDCA at an average dose of 12 mg/kg/day for a mean duration of 55 months. Over a 36-month period, an estimated 52% of UDCA-treated patients experienced normalization of serum alkaline phosphatase and alanine aminotransferase compared to 22% of untreated patients. There was no significant difference in the rate of histological progression between subgroups. UDCA did not influence patient and graft survival. In conclusion, the development of recurrent PBC has little impact on long-term survival or need for retransplantation. While UDCA therapy is associated with biochemical improvement, its role in delaying histologic progression remains unknown. In this short period of treatment, UDCA was not associated with improved patient and graft survival compared to untreated patients.

World's longest surviving liver-pancreas recipient

In July 1988, the liver and pancreas of a cadaveric donor were transplanted separately into a man with type 1 diabetes with end-stage chronic hepatitis B virus. Two features of the operation may help explain the patient's current status as the longest-lived liver-pancreas recipient. One was enteric drainage of pancreatic exocrine secretions. The other was delivery of the pancreas venous effluent to the host portal system and then directly to the hepatic allograft.

Renal Disease Burden Following Liver Transplantation

Significant chronic kidney disease (CKD) occurs following orthotopic liver transplant (OLT). Since CKD is associated with increased cardiovascular events, mortality, and hepatic allograft dysfunction, early recognition of CKD and implementation of changes may improve the long-term outcome. The purpose of this study was to determine the burden of renal disease following OLT. Patients and Methods We retrospectively reviewed our OLT recipients from 1997 until 2004. We calculated glomerular filtration rates (GFR) using the Modification of Diet in Renal Disease study (MDRD) method. The GFRs were further subdivided into pre-MELD and post-MELD eras. Results During the study period, we performed 407 OLTs. We censored data from living donor liver transplants ( n = 14), combined liver-kidney transplants ( n = 12), and from patients whom we did not have complete data for 6 months after transplant ( n = 40). Mean MELD score at the time of transplant was 18 ± 7 (mean ± standard deviation). The mean GFR at 6 months following OLT was 63.7 ± 30.2 mL/min per 1.73 m 2. Only 14% ( n = 47) of our patients had normal renal function at 6 months, while 78% ( n = 266) of our patients had mild to moderate risk for renal failure. Eight percent ( n = 28) had stage 4 or 5 CKD. There were no differences between the pre-MELD and post-MELD GFRs. Conclusions The burden of renal disease is significant in our patient population at 6 months posttransplantation. It may be important to introduce CKD management as early as 6 months after transplant to impact the outcomes of OLT recipients.

Clinical evaluation (Phase I) of a human monoclonal antibody against hepatitis C virus: Safety and antiviral activity

Background/Aims: HCV-AB68, a human monoclonal antibody against the envelope protein of hepatitis C virus (HCV), neutralizes HCV in cell-culture and in the HCV-Trimera mouse model. A Phase 1 clinical trial was designed to test safety, tolerability, and antiviral activity of HCV-AB68 in patients with chronic HCV-infection. Methods/Results: Single doses of HCV-AB68, 0.25–40 mg, administered to 15 patients were well tolerated with no moderate or serious adverse events (SAEs) reported. In six patients, HCV-RNA levels transiently decreased by 2- to 100-fold immediately following infusion and rebound to baseline in 24–48 h. Multiple doses of HCV-AB68, 10–120 mg, were administered to 25 patients. Doses were given weekly for 3 weeks, then 3× a week during the fourth week, after which patients were followed for 3 months. No drug-related SAEs were reported and no specific pattern of adverse events was evident. Eight out of 25 patients had at least a 1-log reduction and 17 had at least a 0.75-log reduction in HCV-RNA levels from baseline at one or more time points following HCV-AB68 infusion. Conclusions: These data support the investigation of HCV-AB68 in the prevention of recurrent HCV-infection in patients who had received hepatic allografts for end-stage liver disease.