Early hepatocyte, endothelial, and bile duct cell injury after pediatric liver transplantation from cadaveric or living-related donors

Superior Outcomes and Reduced Wait Times in Pediatric Recipients of Living Donor Liver Transplantation

Background

Living donor liver transplantation (LDLT) is increasingly used to bridge the gap between the current supply and demand imbalance for deceased donor organs to provide lifesaving liver transplantation.

Methods

Outcomes of 135 children who underwent LDLT were compared with 158 recipients of deceased donor liver transplantation (DDLT) at the largest pediatric liver transplant program in Canada.

Results

Recipients of LDLT were significantly younger than deceased donor recipients (P ≤ 0.001), less likely to require dialysis pretransplant (P < 0.002) and had shorter wait time duration when the primary indication was cholestatic liver disease (P = 0.003). The LDLT donors were either related genetically or emotionally (79%), or unrelated (21%) to the pediatric recipients. One-, 5-, and 10-year patient survival rates were significantly higher in LDLT (97%, 94%, and 94%) compared with DDLT (92%, 87%, and 80%; log-rank P = 0.02) recipients, as were graft survival rates (96%, 93%, and 93% for LDLT versus 89%, 81.4%, and 70%, respectively, for DDLT; log-rank P = 0.001). Medical and surgical complications were not statistically different between groups. Graft failure was higher in recipients of DDLT (odds ratio, 2.60; 95% confidence interval, 1.02, 6.58) than in the LDLT group after adjustment for clinical characteristics and propensity score.

Conclusions

Living donor liver transplantation provides superior outcomes for children and is an excellent and effective strategy to increase the chances of receiving a liver transplant.

Clinical outcomes and risk factors of hepatocellular carcinoma treated by liver transplantation: A multi-centre comparison of living donor and deceased donor transplantation

BACKGROUND

The different outcomes of deceased donor liver transplantation (DDLT) and living donor liver transplantation (LDLT) for hepatocellular carcinoma (HCC) are currently being debated. We aimed to retrospectively compare the outcomes following LDLT and DDLT and to analyse the factors influencing this.

METHODS

We compared the overall survival (OS) and disease-free survival (DFS) rates of HCC patients after LDLT (n=389) and DDLT (n=6471) from 81 centres over a 10-year period. OS and DFS rates were calculated with the Kaplan-Meier method. And univariate and multivariate Cox proportional hazards regressions were performed on the entire cohort to identify predictors.

RESULTS

Of 6860 patients, the 1-, 3-, and 5-year OS rates were 86.79%, 70.16%, and 66.31% after LDLT, respectively, and 74.2%, 54.21%, and 46.97% after DDLT, respectively (P<0.001). The 1-, 3-, and 5-year DFS rates were 78.46%, 63.68%, and 61.63% after LDLT, respectively, and 65.65%, 48.61%, and 41.87% after DDLT, respectively (P<0.001). The multivariate Cox regression model determined that the DFS and OS of HCC patients post-liver transplantation (LT) were strongly associated with tumour morphology and biology, but not graft type.

CONCLUSIONS

With regards to OS and DFS, there were no disadvantages to LDLT as compared with DDLT; tumour morphology and biology may affect the prognosis of LT.

Hepatic IL-8 release during graft procurement is associated with impaired graft function after human liver transplantation

In experimental models, brain death induces inflammatory cascades, leading to reduced graft survival. Thus far, factors prior to graft preservation have gained less attention in clinical setting. We studied pre-preservation inflammatory response and its effects on graft function in 30 brain dead liver donors and the respective recipients. Before donor graft perfusion, portal and hepatic venous blood samples were drawn for phagocyte adhesion molecule expression and plasma cytokine determinations. Donor intensive care unit stay correlated with donor C-reactive protein (R = 0.472, p = 0.013) and IL-6 (R = 0.419, p = 0.026) levels, and donor (R = 0.478, p = 0.016) and recipient gamma-glutamyl transferase (R = 0.432, p = 0.019) levels. During graft procurement, hepatic IL-8 release was observed in 17/30 donors. Grafts with hepatic IL-8 release exhibited subsequently higher alkaline phosphatase [319 (213-405) IU/L vs. 175 (149-208) IU/L, p = 0.006] and bilirubin [101 (44-139) micromol/L vs. 30 (23-72) micromol/L, p = 0.029] levels after transplantation. Our findings support the concept that inflammatory response in the brain dead organ donor contributes to the development of graft injury in human liver transplantation.

Living-related versus deceased donor pediatric liver transplantation: a multivariate analysis of technical and immunological complications in 235 recipients

Timely access to a living donor (LD) reduced pretransplant mortality in pediatric liver transplantation (LT). We hypothesized that this strategy may provide better posttransplant outcome. Between July 1993 and April 2002, 235 children received a primary LT from a LD (n = 100) or a deceased donor (DD) (n = 135). Demographic, surgical and immunological variables were compared, and respective impact on posttransplant complications was studied using a multivariate analysis. Five-year patient survival rates were 92% and 85% for groups LD and DD, respectively (p = 0.181), the corresponding graft survival rates being 89% and 77% (p = 0.033). At multivariate analysis: (1) type of donor (DD) was correlated with higher rate of artery thrombosis (p < 0.012); (2) biliary complication rate at 5 years was 29% and 23% for groups LD and DD, respectively (p = 0.451); (3) lower acute rejection incidence could be correlated with type of donor (DD) (p = 0.001), and immunosuppressive therapy (tacrolimus) (p < 0.001). We conclude that (1) according to the multivariate analysis, LT with LD provided similar patient and graft outcome, when compared to DD; (2) a higher rate of artery thrombosis and a lower rate of rejection were observed in group DD; (3) this study confirms the efficacy of tacrolimus for immunoprophylaxis, whatever the type of organ donor is.

The incidence and management of acute and chronic rejection after living donor liver transplantation

Living donor liver transplantation (LDLT) is a good alternative to cadaveric liver transplantation for end-stage liver disease. Herein we report the outcome of 132 LDLTs performed between 1999 and 2005, with special emphasis on the incidence and management of acute and chronic rejection. Among the LDLT population a first acute rejection episode (ARE) was clinically suspected in 24% and proven by liver biopsy in 11%. According to the Banff classification, 50% of AREs were grade 1, and 50%, grade 2. There was no grade 3 AREs. The first ARE occurred between 7 days and 23 months posttransplantation (mean 97 days, median 70 days). Ninety-seven percent (31/32) of the AREs occurred within the first year after transplantation and 3% (1/32) in the second year. Among the patients with ARE, 23% developed a second ARE between 4 and 11 months. A third ARE was detected in 8% of patients after month 18. All AREs responded to adjustment of immunosuppressive doses or steroid boluses. Chronic rejection (CR) was detected in 2%. In conclusion, the incidences of ARE and CR are consistent with the previously reported data. Acute and chronic rejections seem to be mild and easily manageable clinical conditions. Our results also showed a significant difference between clinically suspected and biopsy-proven ARE emphasizing the importance of indicated liver biopsies in the management of the LDLT population.

Is blood eosinophilia an effective predictor of acute rejection in living donor liver transplantation?*

Summary The association of blood eosinophilia with acute cellular rejection (ACR) after living donor liver transplantation has not been examined yet. The subjects were the 167 recipients who underwent liver biopsy (314 times). The blood eosinophil counts in the preoperative period (n = 167), 3 days before (n = 314) and on the day of biopsy (n = 314) were compared among the groups stratified by severity of ACR. Among 314 biopsy specimens, the 140 biopsy specimens were diagnosed with ACR. In the 140 ACR episodes, eosinophil counts before and after therapy was compared between the episodes that responded to therapy (n = 80) and those not (n = 60). The sensitivity and specificity of preoperative eosinophilia (eosinophil counts >130 mm(3)) to predict ACR was 33% and 65%, respectively. The eosinophil counts >400 mm(3) 3 days before and on the day of biopsy was associated with the severity of ACR (P < 0.0001). The sensitivity to predict ACR was 26% and 33%, and the specificity, 94% and 93%, respectively. There was no significant difference in changes of eosinophil counts between the steroid-responders versus the nonresponders. The present results suggested the limited role of eosinophilia as a predictor of ACR after living donor liver transplantation.

Impact of surgical and immunological parameters in pediatric liver transplantation: a multivariate analysis in 500 consecutive recipients of primary grafts

OBJECTIVE

To assess the respective impact of surgical and immunologic factors on patient/graft outcome and rejection after pediatric liver transplantation.

SUMMARY BACKGROUND DATA

Orthotopic liver transplantation (OLT) constitutes a validated therapeutic modality for acute liver failure and end-stage liver disease in children. Only a few large studies of factors influencing outcome of pediatric OLT are available in the literature. Studies considering the impact of rejection on graft outcome are scarce in adult OLT and are not even available for pediatric recipients.

METHODS

Five hundred consecutive pediatric recipients (<15 years) of a primary OLT performed between March 1984 and July 2000 were retrospectively reviewed. The main indication was biliary atresia (n = 328). A living related donor graft was used from July 1993 onwards in 82 children (16%). Survival was calculated and multivariate analysis was performed.

RESULTS

Actuarial survival rates at 1, 5, and 10 years were 85%, 81%, and 79% for patients, and 76%, 71%, and 70% for grafts, respectively. At the multivariate analysis, only 3 factors were found to be independently correlated with better patient survival: year of transplantation (P = 0.001), pretransplant diagnosis (P < 0.001, worst results for liver tumors), and ABO matching (P < 0.001, worst results for ABO incompatibility). Similarly, 3 factors were independently correlated with better rejection-free graft survival: tacrolimus as primary immunosuppressant (P < 0.001), a negative T-cell crossmatch (P = 0.016), and younger age of the donor (P < 0.001).

CONCLUSIONS

Pediatric OLT constitutes a complex undertaking with multifactorial impact on results: (1). a strong learning curve effect was shown to impact on overall results; (2). pediatric liver tumors still represent a challenging indication for OLT; (3). primary immunoprophylaxis with tacrolimus provided a lower rejection incidence; (4). the younger donor age effect deserves further immunologic investigations.

Cadaveric versus living-donor livers: differences in inflammatory markers after transplantation

BACKGROUND

Prolonged cold storage of organs for transplantation may lead to inflammatory damage upon reperfusion. The aim of this study was to investigate whether organs from living donors experience less damage upon reperfusion than those retrieved from cadaver donors, where cold ischemia times are significantly longer.

METHODS

Biopsies were obtained from cadaveric (n=23) and living-related donor (LRD) (n=10) liver transplants before and 2 hours after reperfusion. Cryosections were stained with antibodies against neutrophils, platelets, activated platelets, and endothelium.

RESULTS

LRD liver allografts showed minimal changes postreperfusion. In contrast, after reperfusion of cadaver allografts, neutrophil infiltration was detected in 22% and increased expression of von Willebrand factor (vWF), CD41, and P-selectin in 48%, 30%, and 13% of allografts, respectively. In cadaver allografts with deposition of activated platelets expressing either P-selectin or vWF, the cold ischemia time was significantly longer (885 +/- 123 min vs. 608 +/- 214 min, P=0.04; 776.8 +/- 171 min vs. 559.3 +/- 216 min, P=0.01, respectively). Increases in neutrophils and platelets after reperfusion were not significantly associated with clinical events posttransplant. However, in cadaver transplants that experienced early acute rejection, the mean cold ischemia time was significantly longer than in allografts with no rejection (732 +/- 174 min vs. 480 +/- 221 min, P=0.006).

CONCLUSIONS

This study demonstrates that in the clinical situation, cold ischemia causes platelet deposition and neutrophil infiltration after reperfusion of cadaveric liver allografts. These early inflammatory events may contribute to make the graft more susceptible to acute rejection.

Leukocyte infiltration and inflammatory antigen expression in cadaveric and living-donor livers before transplant

BACKGROUND

There is evidence to indicate that organs obtained from cadaveric donors may be injured as a result of inflammatory events occurring at around the time of brain death. The aim of this study was to investigate whether there are differences in the expression of proinflammatory molecules between cadaveric and living-donor livers before transplant and to determine whether there is any association with donor factors and posttransplant graft function.

METHODS

A comparison of biopsies obtained before implantation from cadaveric (n=22) and living-related donor (LRD) (n=10) livers was performed. Cryostat tissue sections were stained with antibodies to leukocyte subpopulations, adhesion molecules, and human leukocyte antigen class II antigens.

RESULTS

Significantly higher levels of CD3+ lymphocytes (1.5%+/-0.8% vs. 0.5%+/-0.3%; P=0.00004), CD68+ monocytes and macrophages (4.0%+/-1.2% vs. 2.7%+/-0.6%; P=0.0003), and Fas-ligand staining (4.2%+/-2.6% vs. 1.5%+/-1.1%; P=0.0003) were detected in cadaveric livers compared with LRD livers before transplantation. Furthermore, higher levels of intercellular adhesion molecule-1 expression were detected in cadaveric donor livers and found to be associated with longer periods of ventilation (P=0.01), infection in the donor (P=0.013), and administration of dopamine (P=0.03). Although there were no differences in neutrophil infiltration between cadaveric and LRD livers, significantly higher levels were found in cadaveric donors with infection (P=0.01).

CONCLUSION

This study demonstrates that inflammatory changes occur in cadaveric donor livers and are associated with events occurring during the period of intensive care. These proinflammatory changes did not seem to affect the short-term clinical outcome of cadaveric liver allografts but may contribute to alloimmune responses and impairment of graft function in the long term.

In vitro effects of ciprofloxacin and roxithromycin on apoptosis of jurkat T lymphocytes

Ciprofloxacin (CPFX) and roxithromycin (RXM) induced apoptosis of activated Jurkat T cells in vitro. CPFX showed concentration-dependent acceleration of apoptosis of activated Jurkat T cells by enhancing the expression of FasL and activities of caspase-3 and -8. RXM accelerated cell death, enhanced expression of FasL and caspase-3 but not caspase-8, and did not show the concentration dependency.

Allograft rejection in pediatric liver transplantation: Comparison between cadaveric and living related donors

The aim of this study was to determine whether living related liver transplantation has an immunological advantage compared with cadaveric liver transplants in children. The records of 100 pediatric primary liver transplant recipients performed between January 1992 and December 1998 at the University of California, San Francisco Medical Center, were reviewed retrospectively. Ten children who died or required a second graft within the first 14 post-operative days were excluded from this study group. Two children with combined kidney-liver transplants were also excluded. As a result, the study group included 51 children in the cadaveric liver transplantation (CLT) group and 37 children in the living-related liver transplantation (LRLT) group. Until 1995, primary immunosuppression consisted of cyclosporin A, azathioprine and steroids. Since 1995, primary immunosuppression consisted of cyclosporin A, mycophenolate mofetil and steroids. Actuarial graft survival rates at 1, 2 and 5 yrs were 90%, 80.9% and 80.9% in the CLT group vs. 94.6%, 91.6% and 78.5% in the LRLT group, respectively (NS). Rejection was diagnosed in 40 of 51 cadaveric first grafts (78.4%) and 25 of 37 living-related primary grafts (67.6%). Rejection episodes were diagnosed greater than 1 yr post-transplantation in 11 of 51 cadaveric first grafts (21.6%) and none of 37 living-related primary grafts (0%) (p < 0.05). LRLT succeeded in reducing the immunosuppressive therapy compared with CLT at 24 months after transplantation (p < 0.05). The overall incidence of rejection and graft survival rate were comparable in CLT and LRLT; however, rejection episodes in LRLT recipients diagnosed greater than 1 yr post-transplant were significantly fewer than CLT recipients. LRLT have a partial immunological advantage compared with CLT.

Early graft function after pediatric liver transplantation: comparison between in situ split liver grafts and living-related liver grafts

BACKGROUND

The systematic application of living-related and cadaveric, in situ split-liver transplantation has helped to alleviate the critical shortage of suitable-sized, pediatric donors. Undoubtedly, both techniques are beneficial and advantageous; however, the superiority of either graft source has not been demonstrated directly. Because of the potential living-donor risks, we reserve the living donor as the last graft option for pediatric recipients awaiting liver transplantation. Inasmuch as no direct comparison between these two graft types has been performed, we sought to perform a comparative analysis of the functional outcomes of left lateral segmental grafts procured from these donor sources to determine whether differences do exist.

METHODS

A retrospective analysis of all liver transplants performed at a single institution between February 1984 and January 1999 was undertaken. Only pediatric (<18 years) recipients of left lateral segmental grafts procured from either living-related (LRD) or cadaveric, in situ split-liver (SLD) donors were included. A detailed analysis of preoperative, intraoperative, and postoperative variables was undertaken. Survival was estimated using the Kaplan-Meier method, and comparison of variables between groups was undertaken using the t test of Wilcoxon rank sum test.

RESULTS

There were no significant differences in the preoperative variables between the 39 recipients of SLD grafts and 34 recipients of LRD grafts. The donors did differ significantly in mean age, ABO blood group matching, and preoperative liver function testing. Postoperative liver function testing revealed significant early differences in aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, prothrombin time, and alkaline phosphatase, with grafts from LRD performing better than those from SLD. SLD grafts also had significantly longer ischemia times and a higher incidence of graft loss owing to primary nonfunction and technical complications (9 vs. 2, P<0.05). However, six of these graft losses in the SLD group were because of technical or immunologic causes, which, theoretically, should not differ between the two groups. Furthermore, these graft losses did not negatively impact early patient survival as most patients were successfully rescued with retransplantation (30-day actuarial survival, 97.1% SLD vs. 94.1% LRD, P=0.745). In the surviving grafts, the early differences in liver function variables normalized.

CONCLUSIONS

Inherent differences in both donor sources exist and account for differences seen in preoperative and intraoperative variables. Segmental grafts from LRD clearly performed better in the first week after transplantation as demonstrated by lower liver function variables and less graft loss to primary nonfunction. However, the intermediate function (7-30 days) of both grafts did not differ, and the early graft losses did not translate into patient death. Although minimal living-donor morbidity was seen in this series, the use of this donor type still carries a finite risk. We therefore will continue to use SLD as the primary graft source for pediatric patients awaiting liver transplantation.

Living donor liver transplantation for children with liver failure and concurrent multiple organ system failure

Liver transplantation for pediatric patients in liver failure and multiple organ system failure (MOSF) often results in poor patient survival. Progression of organ failure occurs while awaiting a cadaveric allograft. Therefore, we considered living donor liver transplantation (LDLT) in this critically ill group of children and report our initial results with comparison to a similar group who received cadaveric donation (CAD). A retrospective chart review was performed on all pediatric liver transplant recipients who met criteria for MOSF at the time of transplantation. Data collection involved pretransplantation patient profiles, as well as postoperative complications and patient survival. Eight patients in MOSF received living donor transplants and 11 patients received a cadaveric allograft. Mean wait time was 3.5 days in the LDLT group and 6.5 days in the CAD group. Pretransplantation patient profiles and postoperative complications were similar between groups. Mean cold ischemia times were 3.8 hours in the LDLT group and 7.9 hours in the CAD group (P = .0002). Thirty-day and 6-month survival rates of the LDLT group were 88% and 63% compared with 45% and 27% in the CAD group, respectively. Living donor transplant recipients in MOSF had decreased wait times to transplantation, as well as decreased cold ischemia times, compared with cadaveric transplant recipients. Patients in the LDLT group had markedly improved survival compared with the CAD group. Timely transplantation before worsening organ failure may account for these findings.

Effect of treatment with prostaglandin E1 and N-acetylcysteine on pediatric liver transplant recipients: a single-center study

Prostaglandin E1 (PGE1) and N-acetylcysteine (NAC) have been used as single agents to decrease reperfusion injury and improve outcome after solid-organ transplantation (Tx). We hypothesized that combined treatment with NAC and PGE1 would be safe and reduce reperfusion injury. We therefore carried out a pilot study to assess the safety of this drug combination and gain information regarding the efficacy of treating pediatric liver transplant recipients with NAC and PGE1. The pilot study took the form of an open-label study incorporating 25 pediatric liver transplant recipients (12 children in the treatment group and 13 children as controls). NAC (70 mg/kg) was given intravenously over 1 h following reperfusion and then every 12 h for 6 days. PGE1 (0.4 mg/kg/h) was given as a continuous intravenous infusion for 6 days, starting after the first NAC dose. The primary outcome was the safety of combined treatment with NAC and PGE1. Patient survival, graft survival, allograft rejection within the first 90 days after Tx, peak post-transplant serum alanine aminotransferase (ALT) concentration, post-transplant length of hospitalization, and post-operative complications were secondary outcomes. Post-operative complications occurred at similar rates in both control and treated groups. No complications or adverse events occurred in the treated group as a result of study drugs. The 3-month patient survival rate was 100% for both groups. For the group treated with NAC and PGE1, peak serum ALT was lower and median length of stay was shorter but the differences did not reach statistical significance. The proportion of patients with allograft rejection was not significantly different between the two groups. However, rejection was more severe in the control group than in the treated group. In summary, infusions of NAC and PGE1 were safely administered to pediatric liver transplant recipients. However, a randomized controlled study is needed to determine the efficacy of treatment with NAC and PGE1.

Long-term results of living-related donor liver graft transplantation: a single-center analysis of 110 transplants

BACKGROUND

Difficulties of cadaveric donation and serious donor shortage have led to the development and popularization of living-related donor liver graft transplantation (LRLT). Because the history of this procedure is rather short, important aspects specific to this procedure have not been sufficiently documented. The objective of this study was to analyze a single center's 10-year experience with 110 LRLT in pediatric and adult patients with end-stage liver diseases.

METHODS

The medical records of 110 consecutive patients who underwent LRLT were reviewed. The recipients were comprised of 72 children and 38 adults. The graft volume corresponded to 26-192% of the recipient's standard liver volume. The relationship between pretransplant covariates and patient and graft survival was analyzed. Actuarial patient/graft survival rates were determined at 1, 3, and 5 years. The type and incidence of posttransplant complications were analyzed, as was long-term graft function.

RESULTS

The 1-, 3-, and 5-year actuarial patient and graft survival rates were 88%, 85%, and 85%, respectively. Log-rank test demonstrated that ABO-compatibility predicted patient survival rate, whereas patient age, underlying disease, patient's clinical status, donor-recipient relation, donor age, and graft volume/standard liver volume ratio did not. Long-term liver function remains excellent. All the donors have returned to normal daily lives with an uneventful course.

CONCLUSIONS

LRLT is an efficacious procedure that provides excellent short-term and long-term survival. The indication criteria for both recipient and donor were legitimate in this series, except for transplant across ABO-incompatibility. Cautious expansion of this procedure may be justified under the situation of serious shortage of cadaveric donor.

Bronchiolitis obliterans is not the primary cause of death in pediatric living donor lobar lung transplant recipients

BACKGROUND

Obliterative bronchiolitis (OB) is the chief cause of mortality in cadaveric lung transplant patients (CL). But, is OB the primary cause of mortality for living donor lobar recipients? To answer this question, we reviewed the causes of mortality in our pediatric patients who underwent living donor lobar lung transplantation (LD) and compared them with our pediatric patients who received whole cadaveric lungs (CL).

METHODS

Data collected included demographics, transplant type, hospital days, immunosuppression regimen, and cause of death. Statistical analysis was done using Fisher's Exact test and Student's t-test (mean +/- SD).

RESULTS

From May 1993 to December 1999, 53 patients underwent lung transplantation (21 males, 32 females; mean age 12.4 +/- 5.4 years). Twenty-nine patients had LD procedures (12 males, 17 females; mean age 14.4 +/- 3.6 years) and 24 patients had CL surgery (9 males, 15 females; p = .78 [not significant]; mean age 9.8 +/- 6.3 years; p =.001). All patients received triple immunosuppression without induction. During the study period, 9 LD (6 males, 3 females; mean age 15.7 +/- 5.0 years) and 14 CL (3 males, 11 females; mean age 11.3 +/- 6.9 years) patients died. There was no significant difference between patients in the LD and CL groups who died with regard to gender (p = .08), age at the time of death (p = .12), mortality rate (p = .06), number of hospital days (p = .09), immunosuppressive medications (p > .08), incidence of non-specific graft failure (p = .26), or incidence of infection (p = .18). However, there was a significant difference in the incidence of OB between LD and CL recipients (p = .002).

CONCLUSIONS

OB was not found to be the chief cause of mortality in pediatric LD recipients. We speculate that prevention of infections, possibly by a modest reduction in immunosuppressive therapy and aggressive antimicrobial therapy, may improve long-term survival in pediatric living donor lobar lung transplant recipients.

Liver transplantation. The pediatric challenge

Successful liver transplantation in a child is often a hard-won victory, requiring all the combined expertise of a dedicated pediatric transplant team. This article outlines the considerable challenges still facing pediatric liver transplant physicians and surgeons. In looking to the future, where should priorities lie to enhance the success already achieved? First, solutions to the donor shortage must be sought aggressively by increasing the use of from split-liver transplants, judicious application of living-donor programs, and increasing the donation rate, perhaps by innovative means. The major immunologic barriers, to successful xenotransplantation make it unlikely that this option will be tenable in the near future. Second, current immunosuppression is nonspecific, toxic, and unable to be individually adjusted to the patient's immune response. The goal of achieving donor-specific tolerance will require new consideration of induction protocols. Developing a clinically applicable method to measure the recipient's immunoreactivity is of paramount importance, for future studies of new immunosuppressive strategies and to address the immediate concern of long-term over-immunosuppression. The inclusion of pediatric patients in new protocols will require the ongoing insistence of pediatric transplant investigators. Third, the current immunosuppressive drugs have a long-term morbidity and mortality of their own. These long-term effects are particularly important in children who may well have decades of exposure to these therapies. There is now some understanding of their long-term renal toxicity and the risk of malignancy. New drugs may obviate renal toxicity, whereas the risk of malignancy is inherent in any nonspecific immunosuppressive regimen. Although progress is being made in preventing and recognizing PTLD, this entity remains an important ongoing concern. The global effect of long-term immunosuppression on the child's growth, development, and intellectual potential is unknown. Of particular concern is the potential for neurotoxicity from the calcineurin inhibitors. Fourth, recurrent disease and new diseases, perhaps potentiated by immunosuppressive drugs, must be considered. Already the recurrence of autoimmune disease and cryptogenic cirrhosis have been documented in pediatric patients. Now, a new lesion, a nonspecific hepatitis, sometimes with positive autoimmune markers, that may progress to cirrhosis has been recognized. It is not known whether this entity is an unusual form of rejection, an unrecognized viral infection, or a response to immunosuppressive drugs themselves. Finally, pediatric transplant recipients, like any other children, must be protected and nourished physically and mentally if they are to fulfill their potential. After liver transplantation the child's growth, intellectual functioning, and psychologic adaptation may all require special attention from parents, teachers, and physicians alike. There is limited understanding of how the enormous physical intervention of a liver transplantation affects a child's cognitive and psychologic function as the child progresses through life. The persons caring for these children have the difficult responsibility of providing services to evaluate these essential measures of children's health over the long term and to intervene if necessary. Part of the transplant physician's our duty to protect and advocate for children is to fight for equal access to health care. In most of the developing world, economic pressures make it impossible to consider liver transplantation a health care priority. In the United States and in other countries with the medical infrastructure to support liver transplantation, however, health care professionals must strive to be sure that the policies governing candidacy for transplantation and allocation of organs are applied justly and uniformly to all children whose lives are threatened by liver disease. In the current regulatory climate that increasingly takes medical decisions out of the hands of physicians, pediatricians must be even more prepared to protect the unique and often complicated needs of children both before and after transplantation. Only in this way can the challenges of the present and the future be met.

A 12-day course of FK506 allows long-term acceptance of semi-identical liver allograft in inbred miniature swine

BACKGROUND

Spontaneous tolerance to liver allograft has been reported previously in outbred pig models, but the lack of genetic background did not allow to analyze the impact of the major histocompatibility complex (MHC) on tolerance induction. A model of semi-identical liver allograft was therefore developed in inbred miniature swine in order to mimic the clinical situation of living related liver transplant (parent into infant) and to study a protocol for inducing tolerance to liver allograft.

METHODS

SLAdd (class Id/d, class IId/d) pigs received orthotopic liver allograft from heterozygous SLAcd (class Ic/d, class IIc/d) miniature swine. Eight animals did not receive immunosuppression. Fourteen SLAdd animals had a 12-day course of FK506 and were divided in two subgroups. In subgroup FK-1, six pigs received a daily intramuscular injection of FK506 at 0.1-0.4 mg/kg, in order to reach daily trough levels between 7 and 20 ng/ml; in subgroup FK-2, eight additional animals received two daily injections of FK506 at 0.05 mg/kg regardless of the daily trough levels. Graft survival, liver biological tests, histology, cellular and humoral immune responses, as well as detection of microchimerism were assessed in all groups.

RESULTS

All untreated animals rejected their allograft and died within 28.1 +/- 9.5 days. These rejector animals developed a significant anti-donor cellular and humoral immune response. No peripheral or lymphoid tissue microchimerism was detected in this group. In contrast, long-term survival was obtained in five FK-treated animals (112, 154, 406, 413, and 440 days), whereas several pigs died with a normal allograft function from either overimmunosuppression or intercurrent causes. All FK-treated pigs developed a specific anti-donor unresponsiveness in both cell mediated lymphocytotoxicity and mixed lymphocyte reaction and did not develop anti-donor alloantibodies. The study of the anti-donor immune response by mixed lymphocyte reaction, during the first postoperative week, demonstrated a specific anti-donor unresponsiveness in the peripheral blood from the first posttransplant day. Although microchimerism was detectable in the peripheral blood for several postoperative weeks (maximum 10 weeks) in FK-treated animals, donor cells or DNA were not detected during the long-term follow-up in peripheral blood or lymphoid tissues.

CONCLUSIONS

Spontaneous tolerance to semi-identical orthotopic liver allograft did not occur, whereas a 12-day course of FK506 allowed long-term graft acceptance. All FK-treated animals developed in vitro signs of specific immune unresponsiveness and transient peripheral microchimerism. The specific anti-donor cellular unresponsiveness occurred on the first postoperative day after surgery and was of long-term duration. The study of the early immunological events in this model could be of major importance regarding clinical living related liver transplantation.

Different time course of circulating adhesion molecules and hyaluran during hepatic allograft rejection

BACKGROUND

Inducible adhesion molecules are involved in cell-mediated allograft rejection. In addition, the endothelium is the main target of this process. This study investigated, whether soluble (s) forms of vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) are elevated during cellular rejection and whether hyaluran is a useful marker of endothelial function in liver transplantation.

METHODS

Serum levels of sICAM-1, sVCAM-1, and hyaluran were determined in 24 controls and 27 hepatic transplant recipients. These patients were divided in two groups: group I, 14 patients without rejection; and group II, 13 patients with rejection. Samples were collected on day 1 and 7 after transplantation, on the day of liver biopsy, and after treatment of the rejection.

RESULTS

We found a significant increase in sICAM-1 levels in the postoperative period in the rejection group compared with the non rejection group. It persisted significantly elevated until the diagnosis of rejection was made. In contrast, sVCAM-1 was only significantly elevated in the rejection group when diagnosis of rejection was evident. Hyaluran levels were also significantly elevated in the rejection group at diagnosis of rejection. We noticed a significant decline in sICAM-1, sVCAM-1, and hyaluran levels after successful treatment of rejection. In addition, we observed in the non-rejection group a stable lower levels of hyaluran during the entire postoperative period.

CONCLUSIONS

The release of circulating adhesion molecules is a prominent feature coinciding with the first episode of hepatic rejection. Differential patterns of sICAM-1 and sVCAM-1 exist during rejection. In addition, hyaluran levels may be a sensitive marker of liver endothelial cell function in the postoperative period of liver transplantation.

Pediatric liver transplantation with cadaveric or living related donors: comparative results in 90 elective recipients of primary grafts

STUDY DESIGN

Between July 1993 and March 1997, 110 children were listed for primary elective liver transplantation with cadaveric (Cad: n = 68) or living-related (LR: n = 42) donors. Pregraft mortality, post-transplant survival, and surgical and immunologic complications were retrospectively compared in both groups.

RESULTS

The pregraft mortality rate was 10 (15%) of 68 versus 1 (2%) of 42 in the Cad and LR groups, respectively (P =.049). Postliver transplantation 1-year patient and graft survival rates were 87% and 75% in the Cad group (n = 49) versus 92% and 90% in the LR group (n = 41), respectively (NS). The incidence of post-transplant complications was as follows: hepatic artery thrombosis (Cad: 16%; LR: 0%, P =.020), portal vein thrombosis (Cad: 8%; LR: 2%, NS), and biliary complications (Cad: 14%; LR: 34%, P =.044). The overall incidence of acute rejection was similar in both groups; however, a lower incidence of acute rejection occurred in LR graft recipients treated with tacrolimus.

CONCLUSIONS

The introduction of an LR donor liver transplantation program allowed a significant decrease in the pretransplant mortality rate, with a consequent overall improvement in patient survival compared with the Cad series. The incidence of biliary complications was higher in the LR series, whereas better human leukocyte antigen matching in this subgroup did not result in a lower rejection incidence.