Non-adherence to post-transplant care: prevalence, risk factors and outcomes in adolescent liver transplant recipients

This study examined the prevalence, demographic variables and adverse outcomes associated with non-adherence to post-transplant care in adolescent liver transplant recipients. We conducted a retrospective chart review of 111 adolescent patients (age 12-21 yr) greater than six months post-transplantation and defined non-adherence as not taking the immunosuppressive(s) or not attending any clinic visit in 2005. Fifty subjects (45.0%) were non-adherent and 61 (55.0%) were adherent. Twenty percent of the subjects did not attend clinic and 10.9% did not complete laboratory tests. Non-adherence was significantly associated with fewer completed laboratory tests (p < 0.0001), single parent status (p < 0.0186), and older age and greater years post-transplantation by both univariate and multivariate analyses (p < 0.008, p < 0.0141 and p < 0.0012, p < 0.0174, respectively). Non-adherence to medication was significantly associated with a rejection episode in 31 patients (p < 0.0069) but not in the subgroup of seven patients who stopped their immunosuppression completely. Non-adherence to post-transplant care is a prevalent problem in adolescents particularly of an older age and greater years post-transplantation. Rejection was a significant consequence of medication non-adherence except in a subgroup with presumed graft tolerance who discontinued their immunosuppression. These results emphasize the need for strict monitoring of adherence to post-transplant care to improve long-term survival and quality of life in adolescent transplant patients.

Alloimmunization to red blood cell antigens affects clinical outcomes in liver transplant patients

Transfusion therapy of liver transplant patients remains a challenge. High volumes of intraoperative blood transfusion have been shown to increase the risk of poor graft or patient survival. We conducted a retrospective study of 209 consecutive liver transplant cases at our institution. Only patients receiving their first liver transplant, with no other simultaneous organ transplants, were included. Cox proportional hazard modeling was used to identify clinical variables correlated with postoperative patient mortality. Statistically significant variables for poor patient survival were the number of red blood cell and plasma units transfused, a history of red blood cell alloantibodies, and the immunosuppressive regimen used. History of pregnancy also approached statistical significance but was less robust than the other 3 variables. Our findings suggest that blood transfusion and immune modulation greatly affect the survival of patients after liver transplantation.

Liver allografts are toleragenic in rats conditioned with posttransplant total lymphoid irradiation

BACKGROUND

Posttransplant total lymphoid irradiation (TLI) treatment has been applied to tolerance induction protocols in heart and kidney transplantation models.

METHODS

We examined the efficacy and mechanism of posttransplant TLI treatment in the induction and maintenance of tolerance in a rat orthotopic liver transplantation model.

RESULTS

Posttransplant TLI prolonged ACI (RT1(a)) liver allograft survival in Lewis (RT1(b)) hosts, with 50% long-term engraftment without immunosuppression and without evidence of chronic rejection. Injection of donor-type liver mononuclear cells (LMCs) facilitated the prolongation of graft survival, with more than 70% of grafts in LMC recipients surviving more than 100 days without chronic rejection. Recipients with long-term liver allograft survival accepted ACI but not PVG skin grafts. In TLI-conditioned recipients with accepted grafts, apoptosis occurred predominantly in graft-infiltrating leukocytes. In contrast, there were few apoptotic leukocytes in rejecting grafts. Recipients with long-term graft acceptance (>100 days of survival) demonstrated evidence of immune deviation; mixed lymphocyte reaction to ACI stimulator cells was vigorous, but secretion of interferon-gamma and interleukin-2 was reduced. In tolerant recipients, the number of Foxp3(+) CD25(+) CD4(+) regulatory T cells was increased in the liver allograft as well as in the peripheral blood.

CONCLUSION

We conclude that posttransplant TLI induces tolerance to liver allografts via a mechanism involving apoptotic cell-deletion and immunoregulation.

Mutations to bid cleavage sites protect hepatocytes from apoptosis after ischemia/reperfusion injury

BACKGROUND

Apoptosis of hepatocytes contributes to many forms of liver pathology and can compromise liver function. Hepatocytes have been shown to require mitochondrial disruption to execute apoptosis, a process that is controlled by members of the Bcl-2 family. Bid is a proapoptotic Bcl-2 family member that is cleaved to its active form, tBid, by caspase 8 and granzyme B. Studies in the Bid-deficient mouse have established that hepatocytes require Bid to undergo apoptosis.

METHODS

We generated aspartic acid to glutamic acid mutations in the rat Bid protein, at the caspase 8 and granzyme B cleavage sites, and utilized recombinant adenoviruses to express this protein in hepatoma cells and in the livers of rats.

RESULTS

Cells transduced with recombinant adenoviruses encoding Bid containing mutations to the caspase 8 and granzyme B cleavage sites are significantly protected from both tumor necrosis factor-alpha-induced and cell-mediated apoptosis. Protection occurs through a mechanism that includes decreased Bid cleavage, caspase activation, and mitochondrial membrane damage. Further, after warm ischemia/reperfusion injury, we show that rats expressing cleavage-resistant Bid in the liver display significantly less hepatocyte apoptosis as compared to control rat livers and this results in improved liver function and survival.

CONCLUSION

Our results suggest that reagents that prevent the cleavage of Bid would be an effective strategy to inhibit hepatocyte apoptosis and decrease liver injury.

Outcomes of transplantation in children with primary hepatic malignancy

HBL and HCC are the most common hepatic malignancies in children. The role of OLT in children with HCC is still a matter of debate. The aim of this study was to review our experience of OLT for HCC. Medical records of patients (<18 yr) who underwent OLT for HCC were reviewed and compared to children who underwent OLT for HBL and for indications other than malignancy. There were 25 patients: HCC (10 cases) and HBL (15 cases). The actuarial patient survival for HCC at one and five yr was 100% and 83.3%, for the HBL group the survival was 86.7% at both one and five yr, and for indications (n=377) other than malignancy the patient survival for pediatric OLT at our center was 87.7% and 84.7% at one and five yr, respectively. The actuarial recurrence free survival at five yr was 83.3% for HCC and 66.8% for HBL. In conclusion, OLT is a good therapeutic modality for children with HCC and HBL.

Mutations to Bid cleavage sites protect hepatocytes from apoptosis following ischemia/reperfusion injury (102.23)

Apoptosis of hepatocytes occurs during graft rejection, and ischemia/reperfusion injury (IRI). Hepatocytes require mitochondrial disruption to execute apoptosis, a process that is controlled by proteins of the Bcl-2 family. Bid is a proapoptotic Bcl-2 family member that is cleaved to its active form, tBid, by caspase 8 and granzyme B.

We demonstrate that FaO hepatoma cells, transduced with recombinant adenoviruses expressing Bid with mutations to the caspase 8 (D60E) and granzyme B (D76E) cleavage sites (AdBidEE), are significantly protected from both TNF-induced and cell-mediated apoptosis. Furthermore, rats expressing cleavage-resistant Bid in the liver display significantly less hepatocyte apoptosis and improved liver function as compared to control (AdLacZ) rat livers following warm IRI. All untreated and LacZ-expressing animals died within the first 24 hours post-IRI. In marked contrast, rats expressing AdBidEE (n=8) had significantly improved survival following IRI compared with AdLacZ-expressing rats (p = 0.0079, n=6), and have normal liver function at seven days.

We demonstrate that administration of AdBidEE protects hepatocytes from apoptosis and preserves liver function. Moreover, we propose that administration of AdBidEE may be useful in preventing apoptosis associated with warm ischemia in donors after cardiac death and thus increase the pool of deceased donors for transplantation.

EBV can protect latently infected B cell lymphomas from death receptor-induced apoptosis

The relationship between EBV infection and sensitivity to death receptor (DR)-induced apoptosis is poorly understood. Using EBV- and EBV+ BJAB cells, we provide the first evidence that EBV can protect latently infected B cell lymphomas from apoptosis triggered through Fas or TRAIL receptors. Caspase 8 activation was impaired and cellular FLIP recruitment was enriched in death-inducing signaling complexes formed in EBV-infected BJAB cells relative to parent BJAB cells. Furthermore, latent membrane protein 1 expression alone could reduce caspase activation and confer partial resistance to DR apoptosis in BJAB cells. This protective effect was dependent on C-terminal activating region 2-driven NF-kappaB activation, which in turn up-regulated cellular FLIP expression in latent membrane protein 1+ BJAB cells. Thus, the ability of latent EBV to block DR apoptosis may help to ensure the survival of host cells during B cell differentiation, and contribute to the development of B cell lymphomas, especially in immunocompromised individuals.

Pediatric intestinal transplantation at Packard Children's Hospital/Stanford University Medical Center: report of a four-year experience

We report a 4-year experience of a new program in pediatric intestinal transplantation. Among 50 children referred for evaluation, 27 were listed for transplantation. Two children originally listed for combined liver/small bowel transplant were changed to isolated intestinal transplant as rehabilitation efforts resulted in full recovery of hepatic function. Eighteen children received 18 grafts: 12 liver/intestine, 5 isolated intestine, and 1 multivisceral. Mean age at transplant was 3.6 year with 75% of patients aged 0 to 2 years. Five listed children died while waiting and four were still on the list. Immunotherapy included antithymocyte globulin induction and tacrolimus, sirolimus, and prednisone maintenance. At 1 year, patient and graft survivals were 75% and 67%, respectively. For isolated intestine, 1 year survivals were 100% and 75%, while for combined liver/intestine, they were 71% for both. Enteral autonomy is 100% with total parenteral nutrition stopping by 35.8 days (mean). We had two patients develop posttransplant lymphoproliferative disorder and three, exfoliative rejection, one of whom recovered completely. In conclusion, our program in pediatric intestinal transplantation has become well established with a high proportion of smaller/younger children receiving grafts. Outcomes achieved levels expected based on The Intestinal Transplant Registry and UNOS criteria, which were better than expected for isolated intestinal transplants and achievement of enteral autonomy.

Adolescent non-adherence: prevalence and consequences in liver transplant recipients

Few studies have examined the prevalence, demographic variables and adverse consequences associated with non-adherence to immunosuppressive therapy in the adolescent liver transplant population. Our hypothesis is that a significant proportion of adolescent liver transplant recipients exhibit non-adherence to medical regimens and that certain demographic and medical condition-related characteristics can be identified as potential predictors of non-adherent behavior. Furthermore, non-adherence leads to a greater incidence of morbidity and mortality in this population as compared with the adherent subset of adolescent patients. We reviewed the charts of 97 patients from 1987 to 2002 who by December of 2002 had survived at least 1 yr post-transplant and were followed by the Pediatric Liver Transplant Service at any point during their adolescent period (ages of 12-21). Non-adherence was defined as documentation of a report of non-adherence by a patient, parent or healthcare provider that was recorded in the patient's legal medical record. Descriptive statistics were used to determine the prevalence, demographic variables and adverse outcomes associated with non-adherence to immunosuppressive therapy. Categorical variables were analyzed using the chi-square test or the Fisher exact probability test. The unpaired Student's t-test was used to analyze the continuous variable of age at transplant. Using the inclusion criteria, a total of 97 patients represented the study sample of whom 37 subjects (38.1%) were defined as non-adherent and 60 (61.8%) were adherent. Non-adherent subjects were more likely to be female, older (>18 yr) and from a single-parent household. There was no significant difference in immunosuppressive regimen between non-adherent and adherent patients. Non-adherence was significantly (p<0.025) associated with lower socioeconomic status (SES), older age at transplant (p<0.005, 95% CI: -5.5 to -.99, Student's t-test) and episodes of late acute rejection (p<.001). Non-adherence was also significantly associated with re-transplantation and death secondary to chronic rejection by the Fisher exact test (p<0.006 and p<0.05, respectively). Non-adherence to immunosuppressive therapy is a prevalent problem that is correlated with certain demographic and medical condition-related risk factors and more frequent adverse consequences in the adolescent liver transplant population. The greater incidence of late acute rejection, death and re-transplantation owing to chronic rejection in non-adherent patients suggests that non-adherence is significantly associated with an increased risk of morbidity and mortality. Further investigation to identify patients at greatest risk for non-adherence is necessary to design the most effective intervention to increase patient survival and well being.

IFN-gamma, produced by NK cells that infiltrate liver allografts early after transplantation, links the innate and adaptive immune responses

The role of NK cells following solid organ transplantation remains unclear. We examined NK cells in acute allograft rejection using a high responder model (DA-->Lewis) of rat orthotopic liver transplantation. Recipient-derived NK cells infiltrated liver allografts early after transplantation. Since chemokines are important in the trafficking of cells to areas of inflammation, we determined the intragraft expression of chemokines known to attract NK cells. CCL3 was significantly increased in allografts at 6 h post-transplant as compared to syngeneic grafts whereas CCL2 and CXCL10 were elevated in both syngeneic and allogeneic grafts. CXCL10 and CX3CL1 were significantly upregulated in allografts by day 3 post-transplant as compared to syngeneic grafts suggesting a role for these chemokines in the recruitment of effector cells to allografts. Graft-infiltrating NK cells were shown to be a major source of IFN-gamma, and IFN-gamma levels in the serum were markedly increased, specifically in allograft recipients, by day 3 post-transplant. Accordingly, in the absence of NK cells the levels of IFN-gamma were significantly decreased. Furthermore, graft survival was significantly prolonged. These data suggest that IFN-gamma-producing NK cells are an important link between the innate and adaptive immune responses early after transplantation.

Keratins as susceptibility genes for end-stage liver disease

BACKGROUND & AIMS

Keratins 8 and 18 protect the liver from stress. Keratin 8 and 18 variants in 17 of 467 liver disease explants and 2 of 349 blood bank controls were previously reported in 5 analyzed exonic regions. We asked whether mutations were present in the remaining 10 exons of keratins 8 and 18.

METHODS

Exonic regions were polymerase chain reaction-amplified from genomic DNA, isolated from the above-mentioned 2 cohorts, and analyzed for the presence of mutations. Mutant keratins were also studied biochemically.

RESULTS

We identified 10 novel keratin 8 and 18 heterozygous variants in 44 of 467 explants and 11 of 349 controls: keratin 18 deletion (delta64-71), a keratin 8 frameshift that truncates the last 14 amino acids; 8 missense keratin 8 and 18 alterations; and several new polymorphisms. The most common variant, keratin 8 R340H, at the highly conserved R340 was found in 30 of 467 explants and 10 of 349 controls (P = .02) and was confirmed in the diseased livers by generation of an R340H-specific antibody. Germline transmission and variant protein expression were verified. The mutations involved a variety of liver diseases, and some variants had an ethnic background preponderance. Mutations that introduced disulfide bonds (keratin 8 G61C or R453C) decreased keratin solubility, particularly after oxidative stress, whereas others decreased keratin 8 phosphorylation (keratin 8 G433S).

CONCLUSIONS

The overall frequency of keratin 8 and 18 variants was 12.4% in 467 liver disease explants and 3.7% in 349 blood bank controls (P < .0001). Variants can alter keratin solubility or phosphorylation and may render individuals susceptible to end-stage liver disease, depending on their genetic background and exposure to other insults, such as alcohol or viral infection.

Complete immunosuppressive withdrawal as a uniform approach to post-transplant lymphoproliferative disease in pediatric liver transplantation

Epstein-Barr virus (EBV)-associated post-transplant lymphoproliferative disease (PTLD) in pediatric liver transplant recipients is associated with a high mortality (up to 60%) and the younger age groups, who are predominantly EBV-naïve, are at highest risk for development of this disease. The aim of this study is to assess, in this high-risk group, patient outcome and graft loss to rejection when complete withdrawal of immunosuppressive agents (IMS) is instituted as the mainstay of treatment in addition to the use of standard therapy. A retrospective analysis of 335 pediatric patients whose liver transplants were performed by our team between September 1988 and September 2002, was carried out through review of computer records, database and patient charts. Fifty patients developed either EBV or PTLD; 80% were < or =2 yr of age. Of these 50 patients, 19 had a positive tissue diagnosis for PTLD and 31 were diagnosed with EBV infection, 14 of whom had positive tissue for EBV. Fifty-eight percent of patients who developed PTLD and 51.6% of patients with EBV received antibody for induction or treatment of rejection prior to onset of disease. Forty-six patients (92%) received post-transplant antiviral prophylaxis with ganciclovir or acyclovir. Antiviral treatment included ganciclovir in 76%, acyclovir in 20% and Cytogam (in addition to one of the former agents) in 44%. In those with PTLD, treatment included chemotherapy (n = 1), Rituximab (n = 2), and ocular radiation (n = 1). IMS was stopped in all patients with PTLD and in 19 with EBV infection and was held as long as there was no allograft rejection. Eight patients have remained off IMS for a mean of 1535.5 +/- 623 days. Of the 21 patients who were restarted on IMS for acute rejection, 18 responded to steroids and/or reinstitution of low-dose calcineurin inhibitors. The mean time to rejection while off IMS in this group was 107.43 +/- 140 days (range: 7-476). Two patients were re-transplanted for chronic rejection; one had chronic rejection that existed prior to discontinuing IMS. The mortality rate in our series was 31.6% in those with PTLD and 6% in those with EBV disease. The cause of death was related to PTLD or sepsis in all cases; no deaths were due to graft loss from acute or chronic rejection. PTLD is associated with high mortality in the pediatric population. Based on this report, we advocate aggressive management of PTLD that is composed of early cessation of IMS, the use of antiviral therapy, and chemotherapy when indicated. Episodes of rejection that occur after stopping IMS can be successfully treated with standard therapy without graft loss to acute rejection.

One hundred percent patient and kidney allograft survival with simultaneous liver and kidney transplantation in infants with primary hyperoxaluria: a single-center experience

BACKGROUND

Combined liver-kidney transplantation is the definitive treatment for end-stage renal disease caused by primary hyperoxaluria type I (PH1). The infantile form is characterized by renal failure early in life, advanced systemic oxalosis, and a formidable mortality rate. Although others have reported on overall results of transplantation for PH1 covering a wide age spectrum, none has specifically addressed the high-risk infantile form of the disease.

METHODS

Six infants with PH1 underwent simultaneous liver-kidney transplantation at our center between May 1994 and August 1998. Diagnosis was made at 5.2+/-3.3 months of age, they were on dialysis for 11.8+/-2.3 months, and they underwent transplantation at 14.8+/-3.0 months of age when they weighed 10.6+/-1.7 kg.

RESULTS

At a mean follow-up of 6.4+/-1.7 years (range, 3.9-8.1 years), we report 100% patient and kidney allograft survival. There were no cases of acute tubular necrosis. Long-term kidney allograft function remained stable in all patients, with serum creatinine values of less than 1.1 mg/dL and a mean creatinine clearance of 99 mL/min/1.73 m2 at follow-up. Those who received combined hemodialysis and peritoneal dialysis pretransplant had lower posttransplant urinary oxalate values than those receiving peritoneal dialysis alone. There was improvement in growth and psychomotor and mental developmental scores after transplantation.

CONCLUSIONS

Combined liver-kidney transplantation for the infantile presentation of PH1 is associated with excellent outcome when the approach includes early diagnosis and early combined transplantation, aggressive pretransplant dialysis, and avoidance of posttransplant renal dysfunction.

A patient with hepatitis C-related cirrhosis and hepatocellular carcinoma who was cured with an orthotopic liver transplantation and interferon therapy

A patient with hepatitis C virus (HCV)-related liver cirrhosis and hepatocellular carcinoma (HCC) was treated successfully with an orthotopic liver transplantation (OLT) followed by interferon therapy. The 36-year-old Japanese man was diagnosed as having liver cirrhosis in 1983. HCC was detected in 1991, and by 1994, jaundice and ascites had developed. The patient underwent OLT in June 1995, after which hepatitis C recurred, with elevated aminotransferases. His liver biopsy specimen showed chronic active hepatitis. He was given interferon-alpha three times weekly for 24 weeks in 1999. Six months after the end of the interferon treatment, the patient's serum HCV RNA became negative, with normalization of aminotransferases, and his liver histology exhibited amelioration of fibrosis and inflammation. At the present time, he remains free of HCC (more than 6.5 years after the OLT) and free of HCV RNA (more than 2.5 years since interferon therapy was completed). This is the first Japanese patient whose HCC was cured by OLT and HCV was eradicated by interferon therapy.

Keratin 8 and 18 mutations are risk factors for developing liver disease of multiple etiologies

Keratin 8 and 18 (K8K18) mutations are found in patients with cryptogenic cirrhosis, but the role of keratin mutations in noncryptogenic cirrhosis and the incidence of keratin mutations in the general population are not known. We screened for K8K18 mutations in genomic DNA isolated from 314 liver explants of patients who primarily had noncryptogenic cirrhosis, and from 349 blood bank volunteers. Seven unique K8K18 mutations were found in 11 independent patients with biliary atresia, hepatitis BC, alcohol, primary biliary cirrhosis, and fulminant hepatitis. Seven of the 11 patients had mutations previously described in patients with cryptogenic cirrhosis: K8 Tyr-53 --> His, K8 Gly-61 --> Cys, and K18 His-127 --> Leu. The four remaining patients had mutations at one K8 and three other K18 new sites. Of the 349 blood bank control samples, only one contained the Tyr-53 --> His and one the Gly-61 --> Cys K8 mutations (P < 0.004 when comparing cirrhosis versus control groups). Two additional mutations were found in both the liver disease and blood bank groups and, hence, likely represent polymorphisms. Livers with keratin mutations had cytoplasmic filamentous deposits that were less frequent in livers without the mutations (P = 0.03). Therefore, K8K18 are likely susceptibility genes for developing cryptogenic and noncryptogenic forms of liver disease.

Liver transplantation for fulminant hepatitis at Stanford University

BACKGROUND

To review the clinical characteristics and outcomes of 26 patients evaluated for liver transplantation for fulminant hepatic failure at Stanford University and Lucile Packard Children's Hospital in an attempt to identify risk factors and prognostic predictors of survival.

METHODS

A retrospective review of the records of 26 consecutive patients who were evaluated for possible liver transplantation for acute liver failure from May 1, 1995, to January 1, 2000. Pretransplant patient demographics and clinical characteristics were collected, and the data were analyzed by univariate and multivariate analysis.

RESULTS

Clinical assessment of encephalopathy did not predict outcome. Patients with abnormal computed tomography (CT) of the brain had a twofold increase in mortality compared with those patients with normal studies (p = 0.03). Patients requiring mechanical ventilation and continuous venovenous hemofiltration (CVVH) also had a poor prognosis.

CONCLUSION

Predictors of poor outcome after fulminant hepatic failure include abnormal CT scan, mechanical ventilation, and requirement for hemofiltration.

Identification of Epstein-Barr virus-specific CD8+ T lymphocytes in the circulation of pediatric transplant recipients

BACKGROUND

Pediatric transplant recipients are at increased risk for Epstein Barr virus (EBV)-related B cell lymphomas. In healthy individuals, the expansion of EBV-infected B cells is controlled by CD8+ cytotoxic T cells. However, immunosuppressive therapy may compromise antiviral immunity. We identified and determined the frequency of EBV-specific T cells in the peripheral blood of pediatric transplant recipients.

METHODS

HLA-B*0801 and HLA-A*0201 tetramers folded with immunodominant EBV peptides were used to detect EBV-specific CD8+ T cells by flow cytometry in peripheral blood mononuclear cells from 24 pediatric liver and kidney transplant recipients. The expression of CD38 and CD45RO on EBV-specific, tetramer-binding cells was also examined in a subset of patients by immunofluorescent staining and flow cytometry.

RESULTS

Tetramer-binding CD8+ T cells were identified in 21 of 24 transplant recipients. EBV-specific CD8+ T cells were detected as early as 4 weeks after transplant in EBV seronegative patients receiving an organ from an EBV seropositive donor. The frequencies (expressed as a percentage of the CD8+ T cells) of the tetramer-binding cells were HLA-B8-RAKFKQLL (BZLF1 lytic antigen peptide) tetramer, range=0.96 to 3.94%; HLA-B8-FLRGRAYGL (EBNA3A latent antigen peptide) tetramer, range=0.03 to 0.59%; and HLA-A2-GLCTLVAML (BMLF1 lytic antigen peptide) tetramer, range=0.06 to 0.76%. The majority of tetramer reactive cells displayed an activated/memory phenotype.

CONCLUSIONS

Pediatric transplant recipients receiving immunosuppression can generate EBV-specific CD8+ T cells. Phenotypic and functional analysis of tetramer cells may prove useful in defining and monitoring EBV infection in the posttransplant patient.

Epstein-Barr virus infection is associated with endothelial Bcl-2 expression in transplant liver allografts

INTRODUCTION

In liver transplant recipients with Epstein-Barr virus (EBV) disease, we reported a low rate of acute rejection after stopping or markedly lowering immunosuppression. This observation led to the hypothesis that EBV, as a means of viral persistence, induces expression of antiapoptotic factors and these factors, in turn, confer protection to the transplanted organ. Bcl-2, an antiapoptotic factor induced by EBV in various host cells, is not normally expressed in the liver. We questioned whether bcl-2 is expressed in the transplanted liver and whether its expression is modified by EBV.

MATERIALS AND METHODS

Retrospective liver biopsy specimen from liver transplant patients diagnosed with EBV (n=12) were examined for the presence of bcl-2 by immunohistochemistry and compared with EBV (-) transplant (n=15), and nontransplant (n=13) livers.

RESULTS

The most significant finding was the presence of endothelial bcl-2 expression in the majority of EBV (+) transplant samples examined (67%) and its relative absence in the other two groups (P<0.005). There was also bcl-2 expression in the hepatocytes and lymphocytes of the majority of transplant liver samples, irrespective of EBV status.

DISCUSSION

We have identified a strong association between EBV infection and endothelial bcl-2 expression in transplant livers. We also found that transplantation, in itself, was associated with bcl-2 expression in the hepatocytes and lymphocytes of liver allografts.