James D. Eason

Mixed allogeneic chimerism and renal allograft tolerance in cynomolgus monkeys.

We have developed a nonmyeloablative preparative regimen that can produce mixed chimerism and renal allograft tolerance between MHC-disparate nonhuman primates. The basic regimen includes ATG, nonmyeloablative total-body irradiation (TBI, 300 rads), thymic irradiation (TI, 700 rads), and donor bone marrow infusion. Kidney allografts from MHC-mismatched donors were transplanted with various manipulations of the preparative regimen. Monkeys treated with the basic regimen alone (n = 2) rejected allografts by day 15. With the addition of cyclosporine (CsA) for one month (n = 3), one monkey developed multilineage mixed chimerism and renal allograft tolerance thereafter (> 430 days). To reduce the toxicity of the preparative regimen, TBI was fractionated to 150 rads on two successive days in subsequent studies. All monkeys receiving this modified regimen (n = 4) developed multilineage chimerism with fewer side effects and accepted renal allografts long-term with no further immunosuppression (196 days, 198 days, > 150 days, and > 40 days). In long-term survivors, donor-specific nonreactivity was confirmed by MLR and skin transplantation. Three monkeys treated with the basic regimen plus CsA but with only 150 rads of TBI (n = 1) or no TBI (n = 2) did not develop multilineage chimerism and grafts were rejected (day 40-50) soon after the CsA discontinuation. Monkeys treated with the same regimen, but without DBM (n = 2), rejected kidney allografts by day 52. Therefore, at least transient engraftment of DBM appears to be essential for induction of donor specific tolerance in this monkey model.

Steroid-free liver transplantation using rabbit antithymocyte globulin and early tacrolimus monotherapy.

Background. In 2001, we published early results of a prospective randomized trial of 71 patients who received either steroids or rabbit antithymocyte globulin (RATG) for orthotopic liver transplantation (OLT). We now report follow-up on these patients and additional patients undergoing steroid-free OLT. Methods. A total of 119 adult OLT recipients were prospectively randomized to receive either methylprednisolone 1,000 mg followed by a 3-month steroid taper or a steroid-free regimen of RATG 1.5 mg/kg during the anhepatic phase followed by a 1.5 mg/kg dose on posttransplant day 1. Maintenance immunosuppression consisted of tacrolimus and mycophenolate mofetil in both groups. Mycophenolate mofetil was weaned over 3 months in the first 71 patients and over 2 weeks in the last 48 patients, achieving tacrolimus monotherapy by 2 weeks posttransplant. Subsequently, a group of 24 sequential OLT recipients received the steroid-free (RATG) protocol. Endpoints of the study were survival, rejection, infectious complications, posttransplant diabetes, and recurrent hepatitis C virus. Results. One-year patient survival was 85% in each group of the prospective randomized trial with a mean follow-up of 18.5 months. One-year graft survival was 82% in the RATG group and 80% in the steroid group (P =not significant). Patient and graft survival of the 24 nonrandomized RATG patients was 96% with a mean follow-up of 3 months. The incidence of rejection was not significantly different; however, 50% of the patients in the steroid group required pulse steroids to reverse the rejection compared with only one patient (1.6%) in the RATG group (P =.03). The incidence of cytomegalovirus infection (P <.05) and posttransplant diabetes was higher in the steroid group (P =.03). There was a trend toward decreased severity of hepatitis C virus in the RATG group. Conclusions. Steroid-free liver transplantation using RATG and early tacrolimus monotherapy effectively reduces immunosuppression-related complications with excellent survival.

Tolerance: Is it worth the risk?

Background. The success of orthotopic liver transplantation (OLT) has been limited by the adverse effects of immunosuppression. The purpose of this study was to determine the safety and feasibility of withdrawing immunosuppression in OLT recipients to achieve tolerance. Methods. Eighteen adult OLT recipients in our steroid-free protocol without rejection were selected for this protocol. All patients chosen for this trial were on tacrolimus monotherapy with normal liver function tests (LFTs). Tacrolimus was weaned as long as LFTs remained stable. Weaning was halted for elevations of liver enzymes and tacrolimus was increased to the last dosage at which the patients had normal LFTs. Rejection was treated by increasing tacrolimus to levels of 10–15 ng/ml. Mycophenolate mofetil (MMF) or sirolimus was added if there was severe rejection by biopsy. Steroids were used if there was no improvement. Results. One patient has been weaned off immunosuppression. Three additional patients were weaned completely off but had tacrolimus resumed because of mild elevations in LFTs. Eleven of 18 (61%) patients had rejection. Two patients required steroid therapy and one required rabbit antithymocyte globulin in addition to MMF and steroids. One of the patients with rejection developed diabetes and one patient had renal failure, which subsequently resolved. One patient died following a stroke. Conclusions. Clinical tolerance can be achieved in a minority of patients, even when being maintained on minimum immunosuppression. The potential benefit of achieving tolerance must be weighed against the risks of rejection therapy in patients doing well on low-dose immunosuppression.

Early Postoperative Hepatic Sonography as a Predictor of Vascular and Biliary Complications in Adult Orthotopic Liver Transplant Patients

OBJECTIVE Our objective was to quantitatively assess the value of early posttransplantation hepatic artery resistive indexes in predicting vascular and nonvascular complications in adult orthotopic liver transplant (OLT) patients. MATERIALS AND METHODS Between 1999 and 2001, 110 consecutive adults received grafts. Doppler sonographic graft evaluations measured main, right, and left resistive indexes within 24 to 48 hr after surgery (normal resistive index cutoff, 0.6). Clinical, operative, procedural, and radiologic reports were reviewed for vascular and biliary complications. Frequency, Students t test, logistic, and regression statistical analyses were performed. RESULTS even patients (6.4%) had vascular complications, including two (1.8%) hepatic artery and two (1.8%) hepatic vein stenoses, one (0.9%) hepatic vein thrombosis, two (1.8%) portal vein thromboses, and one (0.9%) thrombosis and two (1.8%) stenoses of the inferior vena cava (IVC). In 19 patients (17.3%), biliary complications included anastomotic strictures and leaks 1 week to 18 months after transplantation. In 11 patients (10%), sonographically large hematomas required surgical evacuation. In grafts with vascular complications or large hematomas, the mean early posttransplant main, right, and left indexes were significantly lower (< or = 0.6) than without these complications (p < 0.01). In grafts with and without biliary complications, mean early posttransplant main, right, and left indexes did not differ significantly. CONCLUSION In adult OLT patients, low early posttransplant hepatic artery resistive indexes were sensitive (100%) and specific (80%) predictors for vascular complications (e.g., hepatic artery, portal vein, hepatic vein, and IVC) but not for biliary complications. All patients with indexes less than 0.6 within 24-48 hr after surgery should be monitored closely for vascular complications.

Evaluation of recombinant human soluble dimeric tumor necrosis factor receptor for prevention of OKT3-associated acute clinical syndrome

Tumor necrosis factor alpha (TNFa) has been shown to be the primary cytokine responsible for the OKT3-induced acute clinical syndrome (OKT3-ACS). Recombinant human soluble tumor necrosis factor receptor (TNFR:Fc) is a dimer of the p80 TNF receptor, which binds both TNFa and lymphotoxin (LT). Renal allograft recipients undergoing OKT3 therapy for steroid-resistant rejection were randomized to receive OKT3 alone or in combination with TNFR:Fc to determine its safety and efficacy in decreasing the severity of OKT3-ACS and in restoring renal function. Six of 12 patients were given TNFR:Fc prior to each of the first two injections of OKT3. All patients were monitored for manifestations of OKT3-ACS and changes in renal function. In addition, serial serum samples were assayed for TNFa and TNFR:Fc levels (ELISA) and TNFa bioactivity (L929). No adverse side effects were identified in patients receiving TNFR:Fc. Patients treated with TNFR:Fc had significantly fewer symptoms by day 2 of OKT3, and had a lower overall incidence of chills and arthralgias. Renal dysfunction reversed within 24 hr in the TNFR:Fc-treated group in contrast to the 48-72-hr delay in the control group. Antigenic TNFa levels increased in the control group from < 10 pg/ml pre OKT3 to a mean peak level of 30 +/- 13 pg/ml on day 1 and decreased to pretreatment levels by day 2. TNFR:Fc-treated patients had a mean peak TNFa level of 235 +/- 135 pg/ml, suggesting a carrier effect of TNFR:Fc. In contrast, bioactivity was barely detectable (mean 20 +/- 14 pg/ml) in the day 1 samples from TNFR:Fc-treated patients, whereas significant bioactivity (peak mean 60 +/- 35 pg/ml) was detected in sera from control patients. TNF receptor levels reached 600 ng/ml in treated patients and remained elevated for up to 18 days confirming the long half-life of TNFR:Fc. This phase 1 trial demonstrates that TNFR:Fc is well tolerated and may limit the severity of OKT3-ACS. The most significant observation was a more rapid improvement in renal function in the TNFR:Fc-treated patients. The absence of TNFa bioactivity indicates that TNFR:Fc functions as a TNF antagonist. Further evaluation of higher doses of TNFR:Fc in OKT3-treated patients is currently in progress.

Inhibition of the effects of TNF in renal allograft recipients using recombinant human dimeric tumor necrosis factor receptors

Tumor necrosis factor alpha (TNFa) and lymphotoxin (LT) or TNF beta are closely linked cytokines produced by macrophages and activated T lymphocytes, which play important regulatory roles in the immune response to allografts. They have also been implicated as mediators of the adverse reactions observed during OKT3 therapy. Therefore, anti-TNF agents could be useful both for immunosuppression and for limiting the systemic response observed in patients receiving OKT3. Recombinant TNFR:Fc is a fusion protein that binds TNFa and LT, thereby neutralizing their effects in vitro. The present study investigates the potential clinical application of TNFR:Fc in a nonhuman primate renal allograft model. Cynomolgus renal allograft recipients were treated with TNFR:Fc induction therapy alone or in combination with subtherapeutic doses of cyclosporine. Control animals received no immunosuppression or subtherapeutic cyclosporine. TNFR:Fc, administered as the only immunosuppressive agent, successfully prolonged renal allograft survival in the majority of treated animals. The prolongation of allograft survival was even more impressive when TNFR:Fc was combined with subtherapeutic doses of cyclosporine. Onset of rejection was significantly delayed as well in the TNFR:Fc treated groups. No adverse side effects were observed in any of the TNFR:Fc treated animals. Precursor cytotoxic T cells were detected in peripheral blood samples of treated recipients but the level of effector CTLs in vivo was below the threshold of detection. These results demonstrate that TNFR:Fc can be safely administered and is effective in prolonging renal allograft survival and in delaying the onset of rejection when administered alone or in combination with cyclosporine.

Induction with rabbit antithymocyte globulin versus induction with corticosteroids in liver transplantation : Impact on recurrent hepatitis C virus infection

This study compares the clinical course of recurrent hepatitis C virus (HCV) infection between 64 patients, who were randomized to receive either rabbit antithymocyte globulin (RATG) or steroids as induction therapy with tacrolimus for maintenance. The HCV recurrence was assessed by HCV RNA levels, peak ALT at 3–6 months, the grade of inflammation at biopsy at 3–6 months posttransplant, progression of fibrosis, and survival. All patients had also received antiviral therapy with interferon alpha 2b and ribavirin, if there were no contraindications. There was no statistically significant difference between the two groups in terms of inflammation at 3 months, peak ALT, or HCV RNA. The survival between the two groups of patients was similar. It appears that steroid-free liver transplantation with RATG induction does not have any negative influence on HCV recurrence in hepatitis C patients after liver transplantation.

Transplantation of livers from HBc Ab positive donors into HBc Ab negative recipients : a strategy and preliminary results

Here we describe a strategy for using livers from hepatitis B core antibody (anti‐HBc) positive donors in anti‐HBc negative recipients and report our preliminary results. Adult anti‐HBc negative recipients were immunized against hepatitis B virus (HBV) prior to transplantation. Liver biopsies from anti‐HBc positive, HBs Ag negative donors were performed at the time of procurement to rule out acute hepatitis or chronic liver disease. Donor serum and liver samples were collected for HBV DNA analysis by PCR.

Should liver transplantation be performed for patients with hepatitis B

Because of the almost universal recurrence of hepatitis B surface antigenemia (HBsAg) after liver transplantation, some centers have questioned whether these patients are appropriate allograft candidates. Since January 1984, 51 patients with hepatitis B (HBV) underwent OLT at our center. No therapy was given to prevent reinfection. Three patients underwent retransplantation. The indications for transplant included fulminant HBV (13 patients), chronic HBV (33 patients), and hepatocellular carcinoma (HCCA) in addition to HBV (5 patients). Incidental HCCA was found in 2 of the 33 patients thought to have only chronic HBV. Actuarial survival for the entire group was 57% at 1 year and 54% at 3 years. Of the 23 patients who died, only 4 deaths were attributable to recurrent HBV liver disease. Four patients survived less than 4 days due to primary graft nonfunction. Ten patients died in the first 3 months from sepsis. Although all patients who died beyond 30 days had recurrent HBsAg, only 4 deaths were attributable to recurrent HBV. The remaining 5 deaths were caused by portal vein thrombosis, bile leak, lymphoma, pancreatitis, and sepsis occurring at 15 months. Excluding the 4 patients who died from primary graft nonfunction, actuarial survival was 63% at 1 year and 60% at 3 years. Of the 28 survivors, 24 are HBsAg positive; however, only 5 have recurrent HBV

Transjugular portosystemic shunts in pediatric patients awaiting liver transplantation

Three pediatric patients from 6 to 11 years of age awaiting liver transplantation for end stage liver disease underwent transjugular intrahepatic portosystemic shunt (TIPS) placement for control of variceal bleeding. Two of the three procedures were performed emergently after endoscopic sclerotherapy failed to stop active bleeding. One procedure was performed electively after multiple prior bleeding episodes. The shunts were created from the middle or left hepatic vein to the left portal vein, and none of the subsequent transplant surgeries was complicated by the presence of the stents. No major or minor complications were related to TIPS placement. Two patients underwent concomitant variceal embolization. Bleeding was successfully controlled in each patient. We conclude that TIPS placement in children is technically feasible, does not complicate subsequent surgery, and is useful treating acute variceal hemorrhage in pediatric patients awaiting liver transplantation.