Apoptosis and allograft rejection in the absence of CD8+ T cells

BACKGROUND

The requirement for cytotoxic T lymphocytes during allograft rejection is controversial. We previously demonstrated that CD8+ T cells are not necessary for allograft rejection or for the induction of apoptosis in rat small intestinal transplantation. In this study, we examined the mechanisms of apoptosis and rejection after liver transplantation in the absence of CD8+ T cells.

METHODS

Either Lewis or dark agouti rat liver grafts were transplanted into Lewis recipients to create syngeneic and allogeneic combinations. CD8+ T cells were depleted in an additional allogeneic group by treatment with OX-8 mAb on day -1 and day 1 after liver transplant.

RESULTS

Apoptosis and rejection were observed in both the CD8+ T cell-depleted allogeneic and allogeneic grafts by hematoxylin and eosin staining, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining, and radiolabeled-annexin V in vivo imaging. Granzyme B and FasL were expressed in all allogeneic transplants, including those depleted of CD8+ T cells, indicating that a mononuclear cell other than a CD8+ T cell can be the source of these molecules during allograft rejection. Activation of the caspase cascade was detected in all rejecting allografts. Caspases 3, 8, and 9 were activated at similar significantly elevated levels in both allogeneic and CD8+ T cell-depleted liver grafts.

CONCLUSION

These data indicate that in the absence of CD8+ T cells an alternative pathway, associated with granzyme B and FasL expression and activation of the caspase cascade, can mediate apoptosis and graft rejection.

Orthotopic liver transplantation for carcinoid tumour metastatic to the liver: anesthetic management

PURPOSE

To report the anesthetic management of a patient with carcinoid tumour metastatic to the liver who presented for orthotopic liver transplantation. Anesthetic implications of metastatic carcinoid tumour on liver transplantation and the use of octreotide are discussed.

CLINICAL FEATURES

A 51-yr-old woman with intestinal carcinoid tumour metastatic to the liver presented for orthotopic liver transplantation, a recent treatment option for patients with extensive hepatic carcinoid metastases and disabling symptoms unresponsive to conventional therapy. Despite continuous administration of the somatostatin analogue octreotide via a hepatic artery infusate pump, the patient suffered from daily break through symptoms, which included flushing, palpitations, paroxysmal hypertension, and dyspnea. The patient presented to the operating room with sinus tachycardia and severe arterial hypertension. Octreotide and phentolamine were used to prevent further mediator release and to control the paroxysmal hypertension. Midazolam, fentanyl, thiopental, succinylcholine, vecuronium, and isoflurane were used to induce and maintain anesthesia safely. An intravenous octreotide infusion was initiated after induction and continued throughout the case. Infrequent and non-threatening peaks in arterial blood pressure were readily treated with small intravenous doses of vasoactive drugs and octreotide. No other manifestations of the carcinoid syndrome occurred. The patient had an uneventful recovery and was discharged on postoperative day #6.

CONCLUSION

The patient safely underwent orthotopic liver transplantation for treatment of symptomatic carcinoid tumour metastatic to the liver. The anesthetic management followed recent recommendations favouring the use of octreotide to prevent patients from becoming symptomatic. Outlined dosing regimen for octreotide provided satisfactory hemodynamic stability.

Radiolabeled annexin V imaging: diagnosis of allograft rejection in an experimental rodent model of liver transplantation

PURPOSE

To assess the value of imaging rejection-induced apoptosis with technetium 99m and annexin V, a human protein-based radiopharmaceutical used in the diagnosis of acute rejection of a liver transplant, in a well-characterized rodent model of orthotopic liver transplantation.

MATERIALS AND METHODS

99mTc-radiolabeled annexin V was intravenously administered to six allografted (immunologically mismatched) and five isografted (immunologically matched) recipient rats on days 2, 4, and 7 after orthotopic liver transplantation. Animals were imaged 1 hour after injection of 0.2-2.0 mCi (8.0-74.0 MBq) of radiolabeled annexin V by use of clinical nuclear scintigraphic equipment.

RESULTS

All animals in the allografted group demonstrated marked increases of 55% and 97% above the activity in the isografted group in hepatic uptake of annexin V on days 4 and 7, respectively. Severe acute rejection was histologically detected in all allografted livers on day 7. There was no histologic evidence of acute rejection in isografted animals. Dynamic hepatobiliary imaging with 99mTc and mebrofenin, an iminodiacetic acid derivative, demonstrated no correlation with the presence or absence of acute rejection or with annexin V uptake.

CONCLUSION

Noninvasive imaging with radiolabeled annexin V is more sensitive and specific than imaging with 99mTc-mebrofenin in the diagnosis of acute rejection of a liver transplant.

Significance of detecting Epstein-Barr-specific sequences in the peripheral blood of asymptomatic pediatric liver transplant recipients

Pediatric allograft recipients are at increased risk for Epstein-Barr virus (EBV)-associated illnesses. The early identification and diagnosis of EBV-associated disorders is critical because disease progression can often be curtailed by modification of immunosuppression. We have previously shown that detection of EBV-specific sequences in the circulation by polymerase chain reaction (PCR) correlated well with the clinical symptoms of EBV infection. The purpose of the current study is to determine the significance of detecting EBV-specific sequences by PCR in asymptomatic pediatric liver transplant recipients. Peripheral-blood DNA was analyzed for the EBV genes, coding from the nuclear antigen 1 (EBNA-1) and the viral capsid antigen (gp220) by PCR. Samples from asymptomatic pediatric liver transplant recipients were analyzed from the immediate postoperative period and at 2- to 4-month intervals thereafter. We followed up 13 of these asymptomatic recipients who tested positive for EBV compared with 7 asymptomatic recipients who tested negative for EBV during the early posttransplantation period. Follow-up ranged from 1.5 to 4 years posttransplantation. Nine patients (69%) initially positive for EBV and asymptomatic ultimately developed symptoms of EBV infection, including fever, lymphadenopathy, rash, respiratory and gastrointestinal symptoms, and/or hepatitis. Five of these patients (56%) went on to develop posttransplant lymphoproliferative disorder based on histological examination of biopsied tissue and immunohistochemical identification of the EBV antigen/DNA in tissue. This is the first report suggesting that detection of EBV-specific sequences in the absence of symptoms may herald impending EBV-associated disorders. Thus, routine monitoring for circulating EBV sequences in asymptomatic recipients may be useful in the early identification of those at risk for developing EBV-associated disease and its ultimate prevention.

Liver transplantation at Stanford University Medical Center

Because of the unique demographics of our patient population, we have had the opportunity to dedicate further studies of the management of hepatitis B and hepatitis C. We have experienced a very low HBV recurrence rate with the use of HBIG in patients transplanted for hepatitis B. Investigations, including the use of new antiviral agents, and the development of approaches to minimize or abrogate disease recurrence such as lower levels of immunosuppression are ongoing. Using a standardized approach to the proper evaluation and selection of patients for liver transplantation with alcoholic liver disease or other liver diseases with coexistent alcohol abuse, we report favorable long-term results in these patients. We have reviewed our results and our approach to the management of EBV and posttransplant lymphoproliferative disorder. There is a firm commitment in our laboratories and outpatient clinics to the investigation of disease prevention, reliable detection and screening methods, and treatment modalities for EBV-related disease. We have addressed specific technical considerations to pediatric liver transplant and have discussed unique aspects of postoperative management in these patients. One-third of the transplants performed at Stanford are in children, 42% of whom are less than one year old. Results with our pediatric transplant recipients compare favorably with those of our adult recipients with patient and graft survival rates approaching 90% at one year and exceeding 80% at 46 months for both groups. As a response to the limited organ supply, we have extended our criteria for suitable donors. Most notably, we have utilized older donors and grafts with significant microsteatosis and have observed good results with these grafts as long as ischemia time is minimized. We have also successfully used reduced size grafts for our pediatric patients with good results and are continuing to expand the use of living-related partial grafts and split allografts.

Major hepatic resection without blood transfusion: experience with total vascular exclusion

Thirty consecutive, major liver resections performed with total vascular exclusion in both non-cirrhotic and cirrhotic patients were analysed retrospectively. The patients' ages ranged from 6 months to 80 years. Ten were Asians and five had cirrhosis associated with chronic hepatitis B or C. There was no perioperative death and the mean hospital stay was 6 days for adults and 9.2 days for children. The average vascular exclusion or warm ischaemia time was 25 min (range 10-55 min) and the average intraoperative blood volume given was 275 mL (range 0-3000 mL) packed red blood cells. Sixty per cent required no intraoperative blood transfusion. The mean total bilirubin and aspartate aminotransferase were 1.0 mg/dL (range 0.3-2.3 mg/dL) and 84 IU/L (range 14-306 IU/L) when measured prior to discharge at postoperative day 4-7. In our experience, total vascular exclusion is invaluable in major or difficult liver resections, especially lesions adjacent to the hepatic veins and vena cava. It is associated with a low blood transfusion requirement and a low incidence of complications. It further obviates the need for dissection of the porta hepatis and its associated risks. Total vascular exclusion time of 30 min appears to be well tolerated, even in patients with compensated cirrhosis.

Does Asian race affect hepatitis B virus recurrence or survival following liver transplantation for hepatitis B cirrhosis?

To assess whether Asian race is an independent variable affecting survival and hepatitis B virus (HBV) recurrence after liver transplantation, the results of 27 consecutive liver transplants performed between June 1994 and April 1997 for HBV cirrhosis were analysed. In the group of 13 Asians, 38% had associated hepatocellular carcinoma and 62% had positive hepatitis B virus early antigen (HBeAg) or elevated HBV-DNA before transplant. Prophylactic hepatitis B immunoglobulin (HBIG) was administered perioperatively and long term at 4-6 weekly interval. Four patients with elevated HBV-DNA received lamivudine before transplantation. The 3 year actuarial patient survival rate was 100% in both Asian and non-Asian patients. Twenty-six patients remained seronegative for hepatitis B virus surface antigen after transplantation. The incidence of post-transplant HBV recurrence was similar: 0% in Asians compared with 7% in non-Asians. There was no recurrence in the group of 12 patients who were HBV-DNA or HBeAg negative pretransplant.

Resection versus transplantation for hepatocellular carcinoma

Hepatocellular carcinoma is responsible for more than 1 million deaths per year worldwide and thus remains a challenging medical problem. It causes few or no symptoms and the tumour frequently reaches an enormous size by the time of diagnosis in countries where screening is seldom used. It is generally resistant to commercially available anti-neoplastic agents and radiation therapy. The principal treatment continues to be resection, either partial or complete, with liver transplantation. However, less than one-third of patients are surgical candidates for either resection or transplantation at the time of clinical presentation. This review will address the results observed following resection or transplantation for hepatocellular carcinoma.

Long-term outcomes in pediatric liver recipients: comparison between cyclosporin A and tacrolimus

In recent years, tacrolimus (FK506, TAC) has been increasingly utilized in liver transplantation. However, long-term risks and benefits as compared with conventional cyclosporin A (CsA) have not been fully elucidated. This retrospective study examined the potential outcome differences between TAC- and CsA-based immunosuppressive therapy in pediatric liver transplant recipients. From March 1988 to December 1996, 218 children (aged 0.1-17 yr) underwent 238 orthotopic liver transplantations; 58.7% (128/218) were under 2 yr of age at time of transplant. Initially, the maintenance immunosuppressive regimen consisted of CsA and prednisone, with antilymphocytic preparations (MALG, ATGAM, and OKT3) as induction therapy. Subsequently, TAC was used first as rescue therapy for steroid refractory rejection in CsA patients and then as maintenance immunosuppression. Fifty-seven out of the 147 CsA patients were converted to TAC for various reasons while 71 patients were placed on TAC as primary maintenance immunosuppression. 62.6 per cent (92/147) of liver recipients on CsA experienced at least one biopsy-proven acute rejection episode as compared to 50.7% (36/71) for TAC patients (p = 0.09); likewise, 34% (50/147) of CsA patients had more than one episode of rejection vs. 18.3% (13/71) for patients on TAC (p < 0.02). Rejection was the reason for conversion from CsA to TAC in 29 of 57 patients. Conversely, 19.0% (28/147) of CsA patients had to be switched to TAC for reasons not related to rejection (i.e. side-effects). The overall incidence of histologically proven chronic rejection was 7.8% (17/218). 10.9 per cent (16/147) of the children who were on CsA initially developed chronic rejection, which was significantly higher compared with one of 71 TAC recipients (p < 0.02). Of these 16 CsA patients with chronic rejection, 50.0% (8/16) underwent retransplantation for graft failure (mean interval from time of diagnosis of chronic rejection to re-transplant, 4.0 months; range 1-8 months), whereas the TAC patient has remained clinically stable with normal liver function tests after 23 months of follow-up. One year after liver transplantation, 72.8% (107/147) of CsA patients were still on steroids (mean dosage 0.20 mg/kg/d), as compared to 42.3% (30/71) of the TAC patients (mean dosage 0.14 mg/kg/d). The incidence of post-transplant lymphoproliferative disorder (PTLD) in Epstein-Barr virus (EBV)-infected patients was 2.2% (2/90), 7.0% (5/71) and 12.3% (7/57) for CsA, primary and TAC-converted groups, respectively. The overall incidence of PTLD was 6.9% (15/218). In summary, pediatric liver transplant recipients treated with TAC as primary maintenance immunosuppressive medication experienced significantly fewer episodes of rejection; especially chronic rejection, which lead to graft loss. However, the trade-off is a potential increased incidence of EBV-related PTLD in these patients.

Effect of intraoperative blood transfusion on patient outcome in hepatic transplantation

OBJECTIVE

To evaluate the effect of intraoperative transfusion of red blood cells (RBCs) on patient and graft survival.

DESIGN

A retrospective study.

SETTING

A tertiary care referral center.

PATIENTS

Between January 1, 1992, and December 31, 1994, medical records from 225 adult patients who underwent primary liver transplantations were analyzed.

RESULTS

Overall patient survival was 90% at 1 year and 86% at 3 years, while graft survival was 89% at 1 year and 85% at 3 years. The following factors were associated with patient and graft survival: age, sex, medical condition at the time of transplantation, and intraoperative transfusion of RBCs. When these factors were subjected to a multivariate analysis, all were independently associated with survival. Fifty-four recipients (24%) underwent transplantation without intraoperative transfusion of RBCs, while 171 recipients (76%) received at least 1 U of RBCs intraoperatively. Recipients who did not receive transfusion of RBCs had higher patient and graft survival rates than patients who did receive RBCs. By multivariate analysis, transplantation without intraoperative transfusion of RBCs no longer remained statistically significant, and only sex and the patient's medical condition were independently associated with patient and graft survival. Patient and graft survival decreased if 5 or more U were transfused, but transfusion of 5 or more U was not independently associated with survival by multivariate analysis.

CONCLUSIONS

Increased transfusion requirement for RBCs was independently associated with patient and graft survival. While transplantation without transfusion of intraoperative RBCs was associated with superior patient and graft survival, these effects were overridden by patient sex and medical condition at the time of transplantation.

Posttransplant lymphoproliferative disorders and gastrointestinal manifestations of Epstein-Barr virus infection in children following liver transplantation

BACKGROUND

Epstein-Barr virus (EBV) infection is common after liver transplantation in children and is associated with the risk of posttransplant lymphoproliferative disorders (PTLD).

METHODS

This retrospective study examined the frequency of gastrointestinal (GI) symptoms and the risk of PTLD in pediatric liver recipients who developed symptomatic EBV infection. We reviewed 172 children who received orthotopic liver transplants between March 1988 to December 1994. Twenty-two cases were retransplants. The mean age at transplantation was 3.7 years (range, 0.1-17 years). The immunosuppressive regimens consisted of induction therapy with Minnesota antilymphocyte globulin/antithymocyte globulin/OKT3 in most cases and maintenance therapy with prednisone and either cyclosporine or tacrolimus (FK506).

RESULTS

After 1 year of minimum follow-up, 54 of 172 patients had symptomatic EBV infections (confirmed by serology, histology, or whole blood polymerase chain reaction. At the time of infection, 38.5% (21/54) had either diarrhea or GI bleeding or both. PTLD developed in 11 patients (6.4%). The incidence of PTLD was 42.9% (9/21) when GI bleeding or diarrhea was associated with EBV infections, compared with 6.1% (2/33) when EBV infection was not associated with GI symptoms. Seven of 10 (70%) patients with GI bleeding and 2 of 11 (18.2%) with diarrhea developed PTLD. Of seven patients examined by endoscopy for GI bleeding, two had biopsy-proven PTLD of the GI tract, whereas one of two patients examined by endoscopy for diarrhea had biopsy-proven PTLD.

DISCUSSION

In summary, a high incidence of PTLD was found in patients who developed GI bleeding or diarrhea associated with EBV infection after pediatric liver transplantation. In these patients, endoscopy and biopsy may lead to early diagnosis of PTLD.

Liver transplantation in the first three months of life

BACKGROUND

Pediatric liver transplant recipients have traditionally been grouped according to age. Age-based classification schemes are useful in identifying clinical problems in selected age groups and also for developing solutions to these problems. Although infants in the first 3 months of life have not traditionally been considered a distinct age group, several features of these infants may distinguish them from other pediatric liver transplant recipients.

METHODS

The experience with liver transplantation in infants during the first 3 months of life in three large pediatric liver transplant programs (University of Chicago, Stanford University, and UCLA) was analyzed in order to characterize this group.

RESULTS

A total of 23 liver transplants were performed at these three centers in children younger than 3 months of age. This group of patients comprised approximately 37% of the U.S. experience between 1988 and 1994 according to United Network for Organ Sharing statistics. Age distribution at the time of transplantation included the following: <1 month, 28%; 1-2 months, 35%; and 2-3 months, 36%. Median age at the time of transplantation was 37 days (range, 7-90 days), and mean age was 57+/-30 days. Mean weight at the time of transplantation was 3.8+/-1.0 kg. Etiology of liver disease included idiopathic hepatitis, 52%; iron storage disease, 17%; and other causes, 31%. Types of liver allografts used included cadaveric, 85% (reduced size, 60%, and full-size, 25%); living donor, 15%; ABO-identical, 65%; and ABO-compatible, 35%. Actuarial patient and graft survival rates were 60% and 60% at 1 year and 60% and 42% at 2 years, respectively. Median follow-up was 1.5 years. Rejection occurred in 42% of patients, with a median time to first rejection of 13 days. Of these patients, 28% required steroids only and 14% required OKT3. Three patients (14%) were retransplanted at a median time to retransplantation of 1.6 years. Vascular thrombosis occurred in three patients (14%).

CONCLUSIONS

Liver transplantation performed in infants younger than 3 months of age (1) provides acceptable short- and long-term patient and graft survival, (2) is associated with significant rates of rejection, and (3) is not associated with excessive rates of vascular thrombosis. The etiology of end-stage liver disease occurring in the first 3 months of life is distinct from that in other pediatric liver transplant recipient age groups. These infants should be referred promptly for liver transplantation as reasonable survival can be expected.

Characterization of allograft rejection in an experimental model of small intestinal transplantation

Graft rejection continues to be a major barrier to the success of clinical small intestinal transplantation. The objective of this study was to characterize histopathologic and immune parameters of allograft rejection in an experimental model of small intestinal transplantation. Heterotopic intestinal transplants were performed in allogeneic and isogeneic rat strain combinations. An additional group of allogeneic recipients was treated with tacrolimus (1 mg/kg/day) for 7 days beginning on posttransplant day 1. Recipients of allografts and isografts were killed on days 1 to 7 following transplantation, and tacrolimus-treated allograft recipients were killed on days 4 and 7. Grafts and native intestines were examined for histopathology and cytokine gene expression. Very early rejection was observed on posttransplant day 3 and severe rejection was apparent by day 7. The key histopathologic features of acute graft rejection including apoptosis, crypt epithelial cell injury, and an inflammatory infiltrate were uniformly identifiable on day 4 and progressed in severity through day 7. Interleukin (IL)-2, IL-4, IL-5, IL-6, interferon-gamma (IFN-gamma), and tumor necrosis factor-alpha mRNA were readily detectable in allografts on days 1 to 7. However, only IFN-gamma mRNA showed a significant early and sustained increase in allografts as compared to isografts and native intestine. Treatment of allograft recipients with tacrolimus abrogated the major histopathologic features of rejection and markedly inhibited IFN-gamma gene expression. These results indicate that graft rejection in small intestinal transplantation is characterized by a local and specific immune response marked by IFN-gamma production that results in crypt epithelial cell injury and apoptosis. Tacrolimus abrogates the histopathologic features of rejection in association with a marked inhibition of IFN-gamma gene expression.

CD30 expression identifies a functional alloreactive human T-lymphocyte subset

BACKGROUND

CD30 is a member of the tumor necrosis factor/nerve growth factor receptor family and has been proposed as a marker of specific cytokine-producing subsets in humans. Previous studies have examined the expression of CD30 on established T helper type 1 and T helper type 2 cell clones and the function of CD30+ cells after mitogenic stimulation. In this study, we examined the development and function of CD30+ T cells generated in response to alloantigen.

METHODS

Primary one-way mixed lymphocyte reactions were established, and the expression of CD30 on T lymphocytes was determined by immunofluorescence and flow cytometry. Fluorescence-activated cell sorting was utilized to define the cytokine profile of alloactivated CD30+ cells after restimulation with anti-CD3 monoclonal antibodies or alloantigen. The effect of cyclosporine on the development of CD30+ cells, and on cytokines produced by CD30+ T lymphocytes, in response to alloantigen was determined.

RESULTS

CD30+ T lymphocytes could be detected on day 2 of mixed lymphocyte reactions and continued to increase in number and proportion through day 6. Both CD4 and CD8 T cells expressed CD30 after primary alloantigenic stimulation. CD30+ T cells are a subset of alloactivated T cells and are the major source of interferon-gamma and interleukin-5 produced in response to alloantigen. Cyclosporine partially, but not completely, inhibits the development of CD30+ cells, and has a greater effect on interferon-gamma production than on interleukin-5 production.

CONCLUSIONS

CD30+ T lymphocytes may constitute an important immunoregulatory subset in human allograft rejection.

Effect of cyclosporine and tacrolimus on the growth of Epstein-Barr virus-transformed B-cell lines

BACKGROUND

Transplant patients receiving immunosuppressive drugs are at increased risk for Epstein-Barr virus (EBV)-associated disorders including posttransplant lymphoproliferative disorder. The function of T lymphocytes, which are critical to preventing the expansion of EBV-infected B cells, is inhibited by immunosuppressive drugs. The purpose of this study was to determine whether immunosuppressive drugs have direct effects on EBV-infected B cells.

METHODS

The growth and proliferation of EBV-infected spontaneous lymphoblastoid cell lines (SLCLs), cultured in the presence or absence of cyclosporine (CsA) and tacrolimus (TAC), were measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and [3H]thymidine incorporation assays. The effect of CsA and TAC on the viability of SLCLs was determined by cell counts with trypan blue. Apoptosis of SLCLs was induced with an anti-Fas agonist monoclonal antibody in the presence or absence of CsA and TAC and measured by flow cytometry after terminal deoxynucleotidyl transferase end-labeling and propidium iodide staining.

RESULTS

CsA and TAC, but not sirolimus, increased the growth of SLCLs. The increased growth in the presence of CsA and TAC was attributable to enhanced cell viability and not increased cell division of SLCLs. In addition, CsA and TAC inhibited Fas-mediated apoptosis of SLCLs.

CONCLUSIONS

CsA and TAC enhance the survival of EBV-transformed B-cell lines. CsA and TAC promote or augment SLCL growth through protection from cell death but do not affect cell division. The inhibition of cell death by CsA and TAC may contribute to the expansion of EBV-infected cells in immunosuppressed individuals.

Allograft rejection after liver transplantation for autoimmune liver diseases

Autoimmune liver diseases (AILD) may progress to liver failure, requiring liver transplantation as definitive therapy, and these immune-mediated disorders may predispose the patient to more frequent graft rejection. The objective of this study was to determine the effect of preexisting AILD on the incidence of allograft rejection after liver transplantation. Sixty-three patients who underwent liver transplantation between March 1988 and December 1994 for AILDs that included autoimmune hepatitis (AIH; n = 33) and primary biliary cirrhosis (PBC; n = 30) were retrospectively compared with 47 patients who underwent liver transplantation for alcoholic cirrhosis during the same time period. There was a lower incidence of acute allograft rejection in patients with AILD who received tacrolimus-based compared with cyclosporine-based immunosuppression (50% v 85.5%; P = .02). However, patients with AILDs overall had a higher incidence of acute rejection than patients with alcoholic cirrhosis (81% v 46.8%; P < .001), regardless of the type of immunosuppression. In addition, steroid-resistant rejection occurred more frequently in patients with AILDs than in patients with alcoholic cirrhosis (38.1% v 12.8%; P = .003). There was also a trend toward a higher incidence of chronic rejection in patients with AILDs compared with patients with alcoholic cirrhosis (11.1% v 2.1%), but this difference did not reach statistical significance. Patient and graft survivals at 1 and 3 years were similar between patients with AILDs and alcoholic liver disease. Compared with alcoholic cirrhosis, preexisting AILDs are associated with a higher incidence of acute allograft rejection and a trend toward more frequent chronic rejection.

CD8+ cells are not necessary for allograft rejection or the induction of apoptosis in an experimental model of small intestinal transplantation

Allospecific CTL can function as cellular effectors of solid organ graft rejection; however, the specific mechanisms of cell damage remain undetermined. In this study we examined the role of CD8+ T cells in apoptosis and rejection of small intestinal allografts. ACI rat intestinal grafts transplanted into Lewis rat recipients showed apoptosis of epithelial crypt cells on day 3 posttransplant as determined by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling staining. By day 7 numerous apoptotic crypt cells were detected in allografts, but were rarely observed in FK506-treated allograft recipients, isografts, or native intestine of allograft recipients. To further investigate the mechanism of rejection, recipient rats were depleted of CD8+ cells by treatment with OX-8 mAbs the day before and the day after transplantation of rat small intestinal allografts. Depletion of CD8+ cells from allograft recipients did not alter the tempo or the histologic features of rejection compared with those in the control (IgG-treated) group. Moreover, there was no difference in the number of apoptotic crypt epithelial cells in the grafts of control and CD8-depleted rats. Reverse transcriptase-PCR analyses determined there were similar levels of transcripts for Fas, Fas ligand, perforin, and granzyme B in control and CD8-depleted allograft recipients. By Western blot it was determined that the levels of Fas ligand protein were increased in the CD8-depleted group compared with those in control and FK506-treated allograft recipients. These data suggest that CD8 cells are not required for tissue injury or apoptotic cell death in small intestine allograft rejection.

CD8+ Cells Are Not Necessary for Allograft Rejection or the Induction of Apoptosis in an Experimental Model of Small Intestinal Transplantation

Allospecific CTL can function as cellular effectors of solid organ graft rejection; however, the specific mechanisms of cell damage remain undetermined. In this study we examined the role of CD8+ T cells in apoptosis and rejection of small intestinal allografts. ACI rat intestinal grafts transplanted into Lewis rat recipients showed apoptosis of epithelial crypt cells on day 3 posttransplant as determined by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling staining. By day 7 numerous apoptotic crypt cells were detected in allografts, but were rarely observed in FK506-treated allograft recipients, isografts, or native intestine of allograft recipients. To further investigate the mechanism of rejection, recipient rats were depleted of CD8+ cells by treatment with OX-8 mAbs the day before and the day after transplantation of rat small intestinal allografts. Depletion of CD8+ cells from allograft recipients did not alter the tempo or the histologic features of rejection compared with those in the control (IgG-treated) group. Moreover, there was no difference in the number of apoptotic crypt epithelial cells in the grafts of control and CD8-depleted rats. Reverse transcriptase-PCR analyses determined there were similar levels of transcripts for Fas, Fas ligand, perforin, and granzyme B in control and CD8-depleted allograft recipients. By Western blot it was determined that the levels of Fas ligand protein were increased in the CD8-depleted group compared with those in control and FK506-treated allograft recipients. These data suggest that CD8 cells are not required for tissue injury or apoptotic cell death in small intestine allograft rejection.

New approaches to supporting the failing liver

With the continued, growing disparity between the numbers of organ donations and patients waiting for liver transplantation, various efforts have been made to optimize the allocation of organs, as well as to devise means to support the failing liver. Over the years, the development of bioartificial liver-assist devices has aimed at replacing the three main functions of hepatocytes, which are synthetic, metabolic, and excretory. The application of porcine hepatocytes in humans to carry out biotransformation, as well as other metabolic functions and refinement of the membrane separator, have yielded some promising results in supporting patients with acute liver failure. Further advances will need to be made before these bioartificial devices can be considered for routine application in clinical settings.

Human hepatocytes produce an isoform of FAS that inhibits apoptosis

BACKGROUND

Fas (Apo-1/CD95), a member of the tumor necrosis factor receptor family, can mediate apoptosis when engaged by its ligand or by anti-Fas antibody. Fas is expressed by cells of the immune system and by some nonlymphoid tissues. Numerous studies have suggested that the Fas pathway may play a role in the rejection of allografts. Functional, soluble forms of the Fas receptor are produced by activated peripheral blood mononuclear cells and some transformed cell lines. The purpose of this study was to determine if soluble variants of Fas are produced in the liver and to determine if blockade of the Fas pathway, by liver-derived soluble Fas, inhibits Fas-mediated apoptosis.

METHODS

Liver and purified hepatocyte specimens were analyzed for Fas transcripts by reverse transcriptase-polymerase chain reaction with primers that span the transmembrane region of the molecule. Bile and cell lysates were analyzed for soluble Fas by specific enzyme-linked immunosorbent assay. Lysates were prepared from normal liver and hepatocytes and utilized to block Fas-mediated apoptosis of Jurkat cells as determined by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling and flow cytometry.

RESULTS

A variant form of Fas is abundantly expressed in normal liver and purified hepatocytes. This variant form of Fas is expressed in all normal liver specimens but only in half of the liver specimens obtained during allograft rejection. The levels of soluble Fas diminish in patients undergoing liver allograft rejection in contrast to patients with stable grafts. Importantly, a soluble form of Fas is produced in the liver by hepatocytes and can specifically inhibit Fas-mediated apoptosis.

CONCLUSION

These data raise the possibility that soluble Fas, produced by hepatocytes, may influence the immune response by blocking Fas-mediated apoptosis and, thus, may have a role in liver transplantation.

Current status of living-related liver transplantation

Living-related liver transplantation has come of age. This manuscript addresses the most important facets of the living-related liver transplant procedure including selection of the donor, the recipient operation, immunosuppression and rejection as well as the most common surgical complications. It also describes the results in terms of patient and graft survival, retransplantation and quality of life. Although living-related liver transplantation has not solved the problem of organ shortage, it has provided many children with an opportunity to live and enjoy life.

Experience with the piggyback technique without caval occlusion in adult orthotopic liver transplantation

BACKGROUND

To assess the feasibility and outcome of a piggyback technique without caval occlusion or veno-venous bypass (VB), we retrospectively reviewed 131 consecutive adult orthotopic liver transplantation (OLT) performed in 129 patients between May 1993 and February 1995. Six were second transplants, and six were combined liver-kidney transplants. The piggyback technique was attempted in all cases.

METHODS

We were able to perform the piggyback technique in 98 OLTs (75%). The remaining 33 OLTs (25%) were converted to the standard technique; of these, 20 (15%) required VB. The reasons for conversion to the standard technique were: anatomical (22 transplants), severe portal hypertension requiring VB (8 transplants), tumor (1 transplant), and other reasons (2 transplants). Six retransplantations were performed (four piggyback, two standard).

RESULTS

There was no significant difference in age, United Network for Organ Sharing status, Child's classification, and diagnosis between the patients in whom piggyback was possible or not. The actuarial patient and graft survival at 1 year were similar between the piggyback group and the group of patients converted to standard technique (87/85% vs. 86/86%, respectively). No death was related to either technique. With piggyback, the average operative time was 8.6+/-1.9 hr, median amount of blood transfused intraoperatively was 2 U (33% did not require transfusion), and median intensive care unit and hospital stays were 3 and 11 days, respectively. With the piggyback technique, the mean preoperative and maximum postoperative serum creatinine levels were 1.4+/-1.0 and 1.8+/-1.5 mg/dl.

CONCLUSION

The piggyback technique without caval occlusion is possible in the majority of patients. It is safe and has reduced the use of VB to 15% of our adult OLTs. The piggyback technique avoids retrocaval dissection, facilitates retransplantation, and is associated with a short anhepatic phase, low blood product usage, and short intensive care unit stay.