Long-term results after conversion from cyclosporine to tacrolimus in pediatric liver transplantation for acute and chronic rejection

Clinical outcomes of Omicron infection and vaccine acceptance among pediatric liver transplant recipients: insights from a cross-sectional survey

OBJECTIVES

Our study aims to explore the clinical characteristics of Omicron infection in pediatric liver transplant recipients (PLTRs), after the national COVID-19 outbreak. Additionally, we will investigate changes in vaccine coverage and parental attitudes towards vaccinating their children after this current outbreak.

METHODS

We conducted a web-based questionnaire survey to gather information on Omicron infection, vaccination status, and guardian attitude among PLTRs. Besides, utilized valid questionnaire and long-term follow-up information processing techniques, and performed statistical analysis of relevant parameters.

RESULTS

528 valid questionnaires were collected, among which, 251 responses replied Omicron infection status. The Omicron infection rate in Chinese PLTRs was 56.2% (141/251), similar to the report in the normal population (around 60%). 99.3% of infected PLTRs presented mild symptoms, mostly with fever (78.0%), followed by Cough (76.6%), with a mean RTPCR conversion time of 7 days; the overall PLTRs' vaccination rate in this study was 13.3%, similar to that of our previous study (9.4%). Besides, we found no significant differences of either infection rate or clinical symptoms between the vaccinated and unvaccinated groups. Moreover, the study showed 61.6% of guardians supported COVID-19 inoculation despite the outbreak of Omicron status.

CONCLUSIONS

The symptoms of Omicron infection in Chinese PLTRs were relatively mild, vaccine immunization had a limited effect on PLTRs' defense against Omicron infection, besides, their guardians supported the inoculation policy with a caution.

CLINICAL TRIAL REGISTRATION

http://www.chictr.org.cn , identifier ChiCTR2200055968.

Fecal Microbiome Data Distinguish Liver Recipients With Normal and Abnormal Liver Function From Healthy Controls

Emerging evidence suggests that altered intestinal microbiota plays an important role in the pathogenesis of many liver diseases, mainly by promoting inflammation via the “intestinal microbiota-immunity-liver” axis. We aimed to investigate the fecal microbiome of liver recipients with abnormal/normal liver function using 16S rRNA gene sequencing. Fecal samples were collected from 90 liver recipients [42 with abnormal liver function (Group LT_A) and 48 with normal liver function (Group LT_N)] and 61 age- and gender-matched healthy controls (HCs). Fecal microbiomes were analyzed for comparative composition, diversity, and richness of microbial communities. Principal coordinates analysis successfully distinguished the fecal microbiomes of recipients in Group LT_A from healthy subjects, with the significant decrease of fecal microbiome diversity in recipients in Group LT_A. Other than a higher relative abundance of opportunistic pathogens such as Klebsiella and Escherichia/Shigella in all liver recipients, the main difference in gut microbiome composition between liver recipients and HC was the lower relative abundance of beneficial butyrate-producing bacteria in the recipients. Importantly, we established a fecal microbiome index (specific alterations in Staphylococcus and Prevotella) that could be used to distinguish Group LT_A from Group LT_N, with an area under the receiver operating characteristic curve value of 0.801 and sensitivity and specificity values of 0.771 and 0.786, respectively. These findings revealed unique gut microbial characteristics of liver recipients with abnormal and normal liver functions, and identified fecal microbial risk indicators of abnormal liver function in liver recipients.

Donor CYP3A5 genotype influences tacrolimus disposition on the first day after paediatric liver transplantation

AIM

The aim of the present study was to investigate the influence of the cytochrome P450 (CYP) 3A4/5 genotype in paediatric liver transplant recipients and donors, and the contribution of age and gender to tacrolimus disposition on the first day after transplantation.

METHODS

The contribution of the CYP3A4/5 genotype in paediatric liver transplant recipients and donors to the tacrolimus blood trough concentrations (C₀ ) and the tacrolimus concentration/weight-adjusted dose ratio on day 1 was evaluated in 67 liver-transplanted children: 33 boys and 34 girls, mean age 4.5 years.

RESULTS

Donor CYP3A5 genotype appears to be significantly associated with tacrolimus disposition on the first day after liver transplantation (P < 0.0002). Other physiological factors, such as recipient age and donor gender may also play a role and lead to significant differences in tacrolimus C₀ and tacrolimus concentration/weight-adjusted dose ratio on day 1. However, according to the general linear model, only recipient age appears to be independently associated with tacrolimus disposition on the first day after liver transplantation (P < 0.03). Indeed, there was a faster tacrolimus metabolism in children under 6 years of age (P < 0.02).

CONCLUSIONS

Donor CYP3A5 genotype, recipient age and, to a lesser extent, donor gender appear to be associated with tacrolimus disposition on day 1 after transplant. This suggests that increasing the starting tacrolimus doses in paediatric patients under 6 years of age who receive a graft from a male extensive metabolizer may enhance the possibility of their tacrolimus levels reaching the therapeutic range sooner.

Management of acute rejection in paediatric liver transplantation

The success of paediatric liver transplantation is attributed to improved surgical techniques and the advent of calcineurin inhibitor-based immunosuppression. Acute rejection (AR) rarely results in graft loss with calcineurin inhibitor immunosuppressive regimens, and the advent of newer agents like interleukin (IL)-2 receptor antibodies. The latter have the benefit of reducing the incidence of AR further and may be of use in patients who are susceptible to recurrent AR, were retransplanted for graft rejection or are in a steroid-sparing regimen. A total of 60 % of all paediatric liver transplants result in AR; however, there is a 75 % response rate to initial steroid therapy. Steroid therapy remains the mainstay of initial AR management, coupled with an increase in baseline immunosuppression. Steroid-resistant rejection (SRR), previously an immediate indication for potent anti-lymphocyte preparations, is now effectively treated with chimeric or humanised IL-2 receptor monoclonal antibodies. Recurrent AR can be treated by adding adjuvant immunosuppressive agents such as mycophenolate mofetil (MMF) or sirolimus. Studies have also demonstrated the efficacy of MMF as rescue therapy for SRR. Anti-lymphocyte preparations such as anti-thymocyte globulin (ATG) and OKT3 are rarely used in SRR but may be of use as rescue therapy for severe SRR. The challenges of the management of AR remain in the management of recurrent AR and SRR. We discuss the pathogenesis, diagnosis and management of AR, including prevention, and specific management of AR and SRR based on current evidence and our own experience at the King's College Paediatric Liver, Gastroenterology and Nutrition Centre in London.

Posttransplant metabolic syndrome in children and adolescents after liver transplantation: a systematic review

During long-term follow-up, 18% to 67% of pediatric liver transplant recipients are overweight or obese, with rates varying by age and pretransplant weight status. A similar prevalence of posttransplant obesity has been seen in adults. Adults also develop posttransplant metabolic syndrome and, consequently, cardiovascular disease at rates that exceed the rates in age- and sex-matched populations. Posttransplant metabolic syndrome has never been studied in pediatric liver transplant recipients, and this population is growing as transplant outcomes continue to improve. Here we systematically review the literature for each component of metabolic syndrome-obesity, hypertension, dyslipidemia, and glucose intolerance-in pediatric liver transplant recipients. Their rates of obesity are similar to the rates in children in the general U.S. population. However, hypertension, dyslipidemia, and diabetes are more common than would be expected in transplant recipients according to age, sex, and obesity severity. Immunosuppressive medications are major contributors. The limitations of previous studies, including heterogeneous methods of diagnosis, follow-up times, and immunosuppressive regimens, hinder the analysis of risk factors. Importantly, no studies have reported graft or patient outcomes associated with components of metabolic syndrome after pediatric liver transplantation. However, if the trends in children are similar to the trends seen in adults, these conditions may lead to significant long-term morbidity. Further research on the prevalence, causes, and consequences of posttransplant metabolic syndrome in pediatric liver transplant recipients is needed and will ultimately help to improve long-term outcomes.

Pharmacology of immunosuppressive medications in solid organ transplantation

The multitude of immunosuppressants available for solid organ transplantation allows for many combinations of immunosuppressive therapies that can be tailored to a patient’s specific lifestyle and immunosuppression needs. Newer agents currently being studied offer even more possibilities for the future to further reduce the incidence of acute rejection and prolong graft and patient survival.

One thousand consecutive primary liver transplants under tacrolimus immunosuppression: a 17- to 20-year longitudinal follow-up

BACKGROUND

Tacrolimus has proven to be a potent immunosuppressive agent in orthotopic liver transplantation (OLT). The aim of this study is to examine its long-term efficacy and safety.

METHODS AND RESULTS

One thousand consecutive primary OLTs performed between August 1989 and December 1992 and maintained under tacrolimus-based immunosuppression were followed up until January 2009. Patient and graft survivals with corresponding causes of death and retransplantation, maintenance immunosuppression, and adverse effects were examined. The study population includes 600 males and 400 females comprising 166 children, 630 adults, and 204 seniors. The mean follow-up was 17.83 (range, 16.1-19.50) years. The overall 20-year actuarial patient and graft survivals were 35.8% and 32.6%, respectively. At the last follow-up, 442 patients were alive; 133 (77.1%) children, 265 (34.5%) adults, and 44 (16.1%) seniors (P=0.0001). After the first post-OLT year, cardiopulmonary events, recurrence of primary disease, and malignancy were the main causes of death. Overall, 183 recipients underwent retransplants; mainly for primary nonfunction, hepatic artery thrombosis, and recurrent primary disease, 180 required dialysis, and 45 underwent kidney transplant. A total of 97.7% of the survivors were on tacrolimus and 26.2% were also receiving adjunctive immunosuppressants at the last follow-up.

CONCLUSIONS

The overall 20-year actuarial patient and graft survivals were 35.8% and 32.6%, respectively, with significantly better survival among children. Age-related complications, recurrence of primary disease, and malignancy were the major causes of late graft loss. Graft loss related to immunologic reasons was rare. The prevention of recurrent disease and newer immunosuppressive regimen will further improve these results.

Adverse effects of immunosuppression in pediatric solid organ transplantation

Solid organ transplantation is a life-saving treatment for end-stage organ failure in children. Immunosuppressant medications are used to prevent rejection of the organ transplant. However, these medications are associated with significant adverse effects that impact growth and development, quality of life (QOL), and sometimes long-term survival after transplantation. Adverse effects can differ between the immunosuppressants, but many result from the overall state of immunosuppression. Strategies to manage immunosuppressant adverse effects often involve minimizing exposure to the drugs while balancing the risk for rejection. Early recognition of immunosuppressant adverse effects may help to reduce morbidities associated with solid organ transplantation, improve QOL, and possibly increase overall patient survival.

Long-term evaluation of cyclosporine and tacrolimus based immunosuppression in pediatric liver transplantation

Both calcineurin inhibitors (CNIs), cyclosporine and tacrolimus, are widely used in pediatric liver transplant recipients and currently data are limited with regards to long-term results using the one drug or the other in comparable low doses. We conducted the present study to assess the advantages and disadvantages of both drugs in children at least five yr post-liver transplantation. A total of 129 children were enrolled in the study. Thirty-eight of the children were switched to tacrolimus monotherapy for different reasons [steroid resistant graft rejection (n = 15), chronic rejection (n = 5), severe acute rejection (n = 4), repetitive acute graft rejection (n = 5), dysfunction of the transplant (n = 3), insufficient CsA metabolism (n = 3), hypertrichosis (n = 2), and CsA toxicity (n = 1)], four patients had primary tacrolimus therapy, and 87 patients are receiving cyclosporine. Mean trough levels were 5.3 +/- 2.3 ng/mL (tacrolimus) and 73.6 +/- 44.5 micro/L (cyclosporine), respectively at least five yr post-orthotopic liver transplantation (OLT). There was no significant difference in the calculated glomerular filtration rate between children on cyclosporine and tacrolimus (142.7 + 39.5 mL/min/1.73 m(2) vs. 151.1 +/- 44.1 mL/min/1.73 m(2)). The incidence of arterial hypertension was 7.1% vs. 9.2%, that of hepatotoxicity was 0% vs. 2.3%. Cosmetic changes were found in more than one-third of the patients on cyclosporine and in 4.8% of the patients receiving tacrolimus. Quality of life was excellent in both groups (self assessment). The impact of CNIs on chronic graft dysfunction cannot be assessed by our present study. We conclude from the results that cyclosporine and tacrolimus are both excellent drugs for maintenance immunosuppression in the long-term course following pediatric liver transplantation. However, this retrospective analysis is limited by the bias between children on CsA as compared with patients receiving tacrolimus. A prospective randomized controlled trial is needed in order to assess which CNI is the best for children following OLT.

Current issues in pediatric transplantation

Pediatric solid organ transplantation is so successful that >80% of children will survive to become teenagers and adults. Therefore, it is essential that these children maintain a good quality life, free of significant long-term side effects. While intensive immunosuppressive regimens (containing CsA, tacrolimus, MMF, and steroids) effectively reduce acute or chronic rejection, they can produce long-term side effects including viral infection, renal dysfunction, hypertension, and stunting. The development of effective methods of diagnosis, prevention, and treatment of CMV means that this is no longer a significant cause of mortality, but morbidity remains high. In contrast, infection rates of EBV remain high in EBV-negative pre-transplant patients. However, pre-emptive reduction of immunosuppression or treatment with rituximab or adoptive T-cell therapy is effective in preventing/treating post-transplant lymphoproliferative disease. Recent protocols have concentrated on reducing CsA immunosuppression, to prevent unacceptable cosmetic effects, and to reduce the hypertension, hyperlipidemia, and nephrotoxicity. Both CsA and tacrolimus cause a 30% reduction in renal function, with 4-5% of patients developing severe chronic renal failure. The use of IL-2 inhibitors for induction therapy with low-dose calcineurin inhibitors, in combination with renal-sparing drugs such as MMF or sirolimus for maintenance immunosuppression, should prevent significant renal dysfunction in the future. The concept of steroid-free immunosuppression with IL-2 inhibitors, tacrolimus, and MMF is an attractive option, which may reduce stunting and renal dysfunction. However, these regimens may be associated with the increased development of de-novo autoimmune hepatitis in 2-3% of children. The most important challenge to long-term survival in transplanted children is the management of non-adherence and other adolescent issues, particularly when transferring to adult units, as this is the time when many successful transplant survivors lose their grafts.

Antiinflammatory effects of Tacrolimus in a mouse model of pleurisy

INTRODUCTION

Tacrolimus is an antibiotic macrolide with immunosuppressant properties isolated from Streptomyces tsukubaensis.

OBJECTIVES

This study evaluated whether the acute and systemic administration of Tacrolimus significantly interfered in leukocyte migration, exudation, myeloperoxidase and adenosine-deaminase and nitric oxide levels, as well as Interleukin-1 (IL-1beta) and tumor necrosis factor alpha (TNFalpha) levels in a mouse model of pleurisy in comparison to those obtained with dexamethasone.

MATERIALS AND METHODS

Pleurisy was induced by carrageenan (Cg, 1%), bradykinin (BK, 10 nmol), histamine (HIS, 1 micromol) or substance P (PS, 20 nmol) administered by intrapleural route (ipl.) and the inflammatory parameters (cell migration and exudation) were analyzed 4 h after. In the model of pleurisy induced by carrageenan, other markers in the pleural fluid, such as cytokines (TNFalpha and Il-1beta), nitrite/nitrate (NOx), myeloperoxidase (MPO) and adenosine-deaminase (ADA) levels, were also studied. Dexamethaseone (0.5 mg/kg, i.p., 0.5 h before) was also analyzed in all protocols.

RESULTS

In the pleurisy induced by carrageenan, Tacrolimus (1 mg/kg, i.p.) and dexamethasone (0.5 mg/kg, i.p.) administered 0.5 h before caused a significant decrease in leukocytes, neutrophils and exudation (P < 0.01). Under the same conditions, Tacrolimus and dexamethasone did not modify the blood's white or red cells (P > 0.05). Tacrolimus showed a long lasting antiinflammatory effect, inhibiting leukocytes and neutrophils for up to 24 h (P < 0.01), whereas the inhibition of exudation was less marked (up to 2 h) (P < 0.01). These drugs caused a marked reduction in MPO activity, as well as IL-1beta and TNFalpha levels (P < 0.01), but only Tacrolimus inhibited ADA activity (P < 0.01). On the other hand, dexamethasone, but not Tacrolimus, inhibited NOx levels (P < 0.01). In the same conditions, Tacrolimus significantly inhibited cell migration induced by either bradykinin, histamine or substance P (P < 0.05). In a similar manner, dexamethasone inhibited leukocyte influx induced by bradykinin and histamine (P < 0.05). Regarding exudation effects, dexamethasone markedly inhibited this parameter induced by BK, HIS or SP, whereas Tacrolimus only inhibited exudation caused by HIS (P < 0.05).

CONCLUSIONS

The results of the present work indicate that Tacrolimus showed important antiinflammatory properties against pleurisy in mice that are different from those caused by dexamethasone. The inhibition of proinflammatory cytokine (TNFalpha, IL-1beta), enzyme (myeloperoxidase, adenosine-deaminase) and mediator (bradykinin, histamine, substance P) release and/or action appears to account for Tacrolimus's actions.

Diagnosis and management of allograft failure

The article focuses on diagnosis and management of allograft failure in four main categories: (1) ischemic-reperfusion injury (primary nonfunction), (2) technical complications (hepatic artery and portal vein thrombosis), (3) chronic rejection, and (4) recurrent disease. It also discusses the complex problems involved in retransplantation for allograft failure.

Posttransplantation Quality of Life: More Than Graft Function

Whereas newer immunosuppressive therapies have increased patient and graft survival, long-term treatment with these drugs has been linked to medical and physical complications that may impact on posttransplantation quality of life. Immunosuppression-related physical side effects that can alter appearance--including hirsutism, gingival hyperplasia, weight gain, cushingoid facies, hand tremors, alopecia, and skin disorders--are among the most bothersome to patients and may have serious psychosocial implications. In addition, physical side effects may influence patient adherence to their prescribed treatment regimens and result in more serious complications, such as acute rejection, graft loss, rehospitalization, and even mortality. Therefore, strategies for minimizing side effects of immunosuppressive therapy and improving medication adherence are integral to better long-term transplant recipient management.

Tacrolimus (FK506) Versus Cyclosporine Microemulsion (Neoral) as Maintenance Immunosuppression Therapy in Kidney Transplant Recipients

The effects of the calcineurin inhibitors tacrolimus (FK506) and cyclosporine (Neoral) on graft survival, function, and metabolic profile were evaluated in 69 patients receiving Neoral (group 1) and 54 patients receiving FK506 (group 2) for maintenance immunosuppression following kidney transplantation. Recipient and donor demographics and induction therapy were comparable, except for a higher number of sensitized patients in group 2 (n = 13). Acute rejection timing, severity, and infection rates and types were similar in both groups. During hospitalization, at 6 months, and at 1 year following transplantation, no significant differences were noted between groups in fasting glucose, serum cholesterol levels, triglyceride levels, or need for insulin or antihypertensive therapy. Mean serum creatinine levels on discharge (1.42 mg/dL +/- 0.14 vs 1.68 mg/dL +/- 0.3), at 1 month (1.45 mg/dL +/- 0.1 vs 1.39 mg/dL +/- 0.11), 3 months (1.46 mg/dL +/- 0.09 vs 1.32 mg/dL +/- 0.14), and 1 year (1.29 mg/dL +/- 0.08 vs 1.19 mg/dL +/- 0.09), but not at 6 months (1.42 +/- 0.37 vs 1.10 +/- 0.07; P = .001), were comparable between groups. The 1-year patient and graft survival rates were 98.3% for group 1 and 94.5% for group 2. When evaluated for acute rejection, infection, and metabolic differences, we conclude that both tacrolimus and cyclosporine are effective and safe calcineurin inhibitors for short-term use in kidney transplantation. A similar study is proposed to evaluate the long-term effects of both agents.

A comparison of tacrolimus and cyclosporine in liver transplantation: effects on renal function and cardiovascular risk status

A retrospective chart review of 1065 consecutive liver allograft recipients in 11 centers from January 1997 to September 1998 was performed. Patients were followed for 3 years or until graft loss. Patients received either tacrolimus (n = 594), cyclosporine (n = 450) or no calcineurin inhibitor (n = 21). Model for end-stage liver disease (MELD) scores at time of transplant were similar between the two groups. During follow-up, more patients switched from cyclosporine to tacrolimus (26.7%) than from tacrolimus to cyclosporine (12.8%; p < 0.0001). Patient and graft survival were equivalent. Corticosteroid use was more common in cyclosporine-treated patients (p < 0.00001). Patients receiving tacrolimus experienced lower serum creatinine levels at months 3 through 36 (p < 0.0001). Systolic blood pressure was lower in patients receiving tacrolimus (p < 0.001) despite a reduced requirement for anti-hypertensive agents (p < 0.0001). In addition, tacrolimus was associated with lower total cholesterol and triglyceride levels for months 3 through 24 and 3 through 12, respectively (p < 0.01), despite a reduced requirement for anti-hyperlipidemic agents. The incidence of new-onset diabetes mellitus was similar in both groups. While both calcineurin inhibitors were associated with excellent patient and graft survival, renal function, blood pressure and serum lipid levels were significantly better with tacrolimus treatment.

Tacrolimus for Primary Liver Transplantation: 12 to 15 Years Actual Follow-Up With Safety Profile

BACKGROUND

Tacrolimus has been increasingly used for liver transplantation during the last decade. The drug has immunological advantages in short- to medium-term follow-up. However, data on longitudinal follow-up are lacking.

AIM

The aim of the present report was to examine the impact of tacrolimus in primary adult and pediatric liver transplantation (LTx) patients.

MATERIAL AND METHOD

One thousand consecutive primary LTx patients were performed under tacrolimus between August 1989 and December 1992 were followed up until August 2004. Mean follow-up was 13.4 +/- 0.92 (range, 11.7-15) years. There were 600 males and 400 females with a mean age of 42.6 +/- 20.2 years. There were 166 children (age 18 years or younger) and 834 adults, of whom 204 were older than 60 years (seniors).

RESULTS

Four hundred ninety-seven (49.7%) patients died in the follow-up period. The overall 15-year actuarial patient survival rate was 51.4%. The survival rate for children was significantly better (81.3%) compared with adults (47.5%) and seniors (36.4%) (P = .0001). One hundred fifty-one patients received a second LTx, 22 patients received a third LTx, and 4 patients received a fourth LTx. Over all 15 years the actuarial graft survival rate was 46.1%. At last follow-up, 69.1% of patients were off steroids. The majority of late deaths were due to age-related complications, recurrence of disease, and De novo cancers.

CONCLUSION

The data on longitudinal follow-up have shown actuarial survival for children to be significantly better than in adults and seniors. Graft loss from immunological causes are rare even with long-term follow-up.

Clinical pharmacokinetics and pharmacodynamics of tacrolimus in solid organ transplantation

The aim of this review is to analyse critically the recent literature on the clinical pharmacokinetics and pharmacodynamics of tacrolimus in solid organ transplant recipients. Dosage and target concentration recommendations for tacrolimus vary from centre to centre, and large pharmacokinetic variability makes it difficult to predict what concentration will be achieved with a particular dose or dosage change. Therapeutic ranges have not been based on statistical approaches. The majority of pharmacokinetic studies have involved intense blood sampling in small homogeneous groups in the immediate post-transplant period. Most have used nonspecific immunoassays and provide little information on pharmacokinetic variability. Demographic investigations seeking correlations between pharmacokinetic parameters and patient factors have generally looked at one covariate at a time and have involved small patient numbers. Factors reported to influence the pharmacokinetics of tacrolimus include the patient group studied, hepatic dysfunction, hepatitis C status, time after transplantation, patient age, donor liver characteristics, recipient race, haematocrit and albumin concentrations, diurnal rhythm, food administration, corticosteroid dosage, diarrhoea and cytochrome P450 (CYP) isoenzyme and P-glycoprotein expression. Population analyses are adding to our understanding of the pharmacokinetics of tacrolimus, but such investigations are still in their infancy. A significant proportion of model variability remains unexplained. Population modelling and Bayesian forecasting may be improved if CYP isoenzymes and/or P-glycoprotein expression could be considered as covariates. Reports have been conflicting as to whether low tacrolimus trough concentrations are related to rejection. Several studies have demonstrated a correlation between high trough concentrations and toxicity, particularly nephrotoxicity. The best predictor of pharmacological effect may be drug concentrations in the transplanted organ itself. Researchers have started to question current reliance on trough measurement during therapeutic drug monitoring, with instances of toxicity and rejection occurring when trough concentrations are within 'acceptable' ranges. The correlation between blood concentration and drug exposure can be improved by use of non-trough timepoints. However, controversy exists as to whether this will provide any great benefit, given the added complexity in monitoring. Investigators are now attempting to quantify the pharmacological effects of tacrolimus on immune cells through assays that measure in vivo calcineurin inhibition and markers of immunosuppression such as cytokine concentration. To date, no studies have correlated pharmacodynamic marker assay results with immunosuppressive efficacy, as determined by allograft outcome, or investigated the relationship between calcineurin inhibition and drug adverse effects. Little is known about the magnitude of the pharmacodynamic variability of tacrolimus.

Role of tacrolimus in the evolution of liver transplantation

Once regarded as a last-resort therapy for patients with end-stage liver disease, liver transplantation has become a viable therapeutic option because of sweeping improvements in surgical techniques and the development of more powerful immunosuppressive agents. The addition of tacrolimus to the immunosuppression regimen represents a highly potent therapy and a powerful defense against acute rejection. In the decade since tacrolimus was approved for use in the United States, it has become a widely used immunosuppressant in the field of liver transplantation.

LONG-TERM EFFECTS OF TRANSPLANTATION ON QUALITY OF LIFE

Identifying predictors of noncompliance and initiating preventive strategies, including education and support services, can lessen the occurrence of noncompliance. Selection of immunosuppression protocols that involve fewer adverse effects and fewer medications can help increase patient satisfaction, improve compliance, maintain graft function, and enrich the long-term quality of life for transplant recipients.

Low-dose immunosuppression reduces the incidence of post-transplant lymphoproliferative disease in pediatric liver graft recipients

OBJECTIVES

In pediatric solid organ transplantation, the Epstein-Barr virus (EBV)-related lymphoproliferative disorders (PTLD) still play a major role in post-transplant morbidity and mortality. The aim of the study was to determine the incidence of PTLD in pediatric patients with liver transplant who receive low-dose immunosuppression protocols.

METHODS

All pediatric patients (n = 269) received a dual immunosuppression therapy consisting of cyclosporine A (initial trough levels, 170-200 microg/L; trough levels for maintenance immunosuppression after 1 year, 80-100 microg/L) and prednisolone (starting dose, 60 mg/m2). Steroids were reduced to 30 mg/m2 after 1 week, followed by a weekly tapering to 5 mg/m2. Seventy-seven of 269 patients were switched to tacrolimus therapy. The authors evaluated the significance of EBV-DNA monitoring by quantitative polymerase chain reaction in identifying patients at risk for PTLD.

RESULTS

Patient survival was 90.3%; graft survival was 85.9%. Eight patients lost their grafts because of chronic rejection. The incidence of PTLD was low (0.7%), although a significant EBV viral load was found in 42.4% of the patients. One third of the patients with a viral load of 3,000 genomes/10(5) cells or greater had clinical signs of EBV infection.

CONCLUSIONS

The authors conclude that low-dose immunosuppressive protocols significantly reduce the incidence of PTLD. In patients treated with that regimen, the monitoring of EBV viral load seems not to be helpful. It can be assumed that low-dose immunosuppression does not suppress EBV-specific cytotoxic CD8+ T cells, thus allowing the host to control EBV infection without the risk of PTLD. Our low-dose immunosuppression protocol did not increase the risk of chronic rejection.

Tacrolimus: a further update of its use in the management of organ transplantation

Extensive clinical use has confirmed that tacrolimus (Prograf) is a key option for immunosuppression after transplantation. In large, prospective, randomised, multicentre trials in adults and children receiving solid organ transplants, tacrolimus was at least as effective or provided better efficacy than cyclosporin microemulsion in terms of patient and graft survival, treatment failure rates and the incidence of biopsy-proven acute and corticosteroid-resistant rejection episodes. Notably, the lower incidence of rejection episodes after renal transplantation in tacrolimus recipients was reflected in improved cost effectiveness. In bone marrow transplant (BMT) recipients, the incidence of tacrolimus grade II-IV graft-versus-host disease was significantly lower with tacrolimus than cyclosporin treatment. Efficacy was maintained in renal and liver transplant recipients after total withdrawal of corticosteroid therapy from tacrolimus-based immunosuppression, with the incidence of acute rejection episodes at up to 2 years' follow-up being similar with or without corticosteroids. Tacrolimus provided effective rescue therapy in transplant recipients with persistent acute or chronic allograft rejection or drug-related toxicity associated with cyclosporin treatment. Typically, conversion to tacrolimus reversed rejection episodes and/or improved the tolerability profile, particularly in terms of reduced hyperlipidaemia. In lung transplant recipients with obliterative bronchiolitis, conversion to tacrolimus reduced the decline in and/or improved lung function in terms of forced expiratory volume in 1 second. Tolerability issues may be a factor when choosing a calcineurin inhibitor. Cyclosporin tends to be associated with a higher incidence of significant hypertension, hyperlipidaemia, hirsutism, gingivitis and gum hyperplasia, whereas the incidence of some types of neurotoxicity, disturbances in glucose metabolism, diarrhoea, pruritus and alopecia may be higher with tacrolimus treatment. Renal function, as assessed by serum creatinine levels and glomerular filtration rates, was better in tacrolimus than cyclosporin recipients at up to 5 years' follow-up.

CONCLUSION

Recent well designed trials have consolidated the place of tacrolimus as an important choice for primary immunosuppression in solid organ transplantation and in BMT. Notably, in adults and children receiving transplants, tacrolimus-based primary immunosuppression was at least as effective or provided better efficacy than cyclosporin microemulsion treatment in terms of patient and graft survival, treatment failure and the incidence of acute and corticosteroid-resistant rejection episodes. The reduced incidence of rejection episodes in renal transplant recipients receiving tacrolimus translated into a better cost effectiveness relative to cyclosporin microemulsion treatment. The optimal immunosuppression regimen is ultimately dependent on balancing such factors as the efficacy of the individual drugs, their tolerability, potential for drug interactions and pharmacoeconomic issues.

Strategies for optimizing immunosuppression in adolescent transplant recipients: a focus on liver transplantation

Adolescence is a difficult time for transplant recipients; they must learn to take responsibility for their own behavior and medication, and to balance their developing sexuality in a body that has been transformed by the adverse effects of immunosuppression. More than 80% of children survive transplantation to adolescence and adulthood, thus long-term outcome and tailoring of immunosuppression is of great importance. To date, the most experience with long-term immunosuppression regimens is cyclosporine, which is well tolerated and effective. Long-term adverse effects include hypertension, nephrotoxicity, and post-transplant lymphoproliferative disease (PTLD). The recent development of tacrolimus has improved the cosmetic adverse effects related to cyclosporine, but has similar rates of hypertension and nephrotoxicity, and possibly a higher rate of PTLD. There has been a recent, welcome development in renal sparing drugs, such as mycophenolate mofetil, which has no cosmetic adverse effects, does not require drug level monitoring and is thus particularly attractive to teenagers. Recent surveys demonstrate recovery of renal function with mycophenolate mofetil, if started prior to irreversible renal dysfunction. There are currently little published data on the use of sirolimus (rapamycin) in the pediatric population, but preliminary studies suggest that the future use of interleukin-2 receptor antibodies may be beneficial for immediate post-transplant induction of immunosuppression. It is important when planning immunosuppression for adolescents to consider the effects of drug therapy on both males and females in order to maintain fertility and to ensure safety in pregnancy. Noncompliance is a problem in this age group, but adequate practical measures and support should reduce noncompliance, and allow good, long-term graft function.

Limitations of EBV-PCR monitoring to detect EBV associated post-transplant lymphoproliferative disorder

Post-transplant lymphoproliferative disorder (PTLD) represents a significant threat to the survival of pediatric transplant recipients. Epstein-Barr (EBV) viral load monitoring using polymerase chain reaction (PCR) has been reported to have a variable sensitively with relatively higher specificity as in an indicator of the development of PTLD. We report two cases of pathologically confirmed PTLD in children who failed to develop sustained increases in their EBV-PCR determined viral loads. We suggest that clinicians should be aware of the potential for false-negative results of EBV-PCR in pediatric transplant recipients.

Sirolimus in pediatric transplant recipients

The side effects of calcineurin inhibitors (CI) have a unique spectrum in pediatric recipients of organ transplants. These include a lifelong risk of mortality due to sepsis, a nearly 5% risk of renal failure from protracted exposure to CI, and a significantly higher risk of posttransplant lymphoproliferative disorder (PTLD) when compared with adults (10% versus 2%). This led us to explore the use of the new antiproliferative immunosuppressant sirolimus (SRL) for rescue and primary immunosuppression in recipients of pediatric abdominal and thoracic organs at the Children's Hospital of Pittsburgh. Following initial success with SRL in 50 such children, we also explored its use for the elimination of tacrolimus (TAC) in patients experiencing toxicity and for maintenance immunosuppression in steroid-sparing regimens in liver transplantation. These early results suggest that sirolimus may hold promise as a primary immunosuppressive agent under defined protocol conditions. The salient features of our experience with SRL in over 85 children are summarized here.

Use of tacrolimus in rescue therapy of acute and chronic rejection in liver transplantation

PURPOSE

To study the indications and results of tacrolimus as rescue therapy for acute cellular or chronic rejection in liver transplantation.

PATIENTS AND METHODS

Eighteen liver transplant recipients who underwent rescue therapy with tacrolimus between March 1995 and August 1999 were retrospectively studied. The treatment indication, patients, and graft situation were recorded as of October 31st, 1999. The response to tacrolimus was defined as patient survival with a functional graft and histological reversal of acute cellular, or for chronic rejection, bilirubin serum levels decreasing to up to twice the upper normal limit.

RESULTS

Fourteen cases (77.8%) presented a good response. The response rate for the different indications was: (1) acute cellular + sepsis - 0/1 case; (2) recurrent acute cellular - 1/1 case; (3) OKT3-resistant acute cellular - 2/2 cases; (4) steroid-resistant acute cellular + active viral infection - 3/3 cases; (5) chronic rejection - 8/11 cases (72.7% response rate). The 4 patients who did not respond died.

CONCLUSION

Tacrolimus rescue therapy was successful in most cases of acute cellular and chronic rejection in liver transplantation.

The absence of chronic rejection in pediatric primary liver transplant patients who are maintained on tacrolimus-based immunosuppression: a long-term analysis

BACKGROUND

Although the outcome of liver transplantation has improved significantly during the past two decades, graft loss caused by chronic rejection after liver transplantation still occurs in 2% to 20% of recipients. The overall incidence of chronic rejection is also reported to be low in adult recipients, and risk factors have been identified. Chronic rejection is associated with the inability to maintain baseline immunosuppression. Additionally, the diagnoses of primary biliary cirrhosis, primary sclerosing cholangitis, autoimmune hepatitis, hepatitis B virus, and hepatitis C virus, common indications for liver transplantation in adults, are associated with a higher incidence of chronic rejection. Fortunately, these diagnoses are rarely seen in children. Little is known about chronic rejection in long-term pediatric liver transplant survivors. The purpose of this longitudinal study was to examine the incidence of biopsy-proven chronic rejection in long-term survivors of primary pediatric liver transplantation under tacrolimus-based immunosuppression.

METHODS

From October 1989 to December 1992, 166 children (boys=95, girls=71; mean age=5.0+/-2.9 years) received a primary liver transplant. These patients were followed until March 2000 with a mean follow-up of 9+/-0.8 (range, 7.4-10.4) years. All liver biopsy specimens and explanted grafts were evaluated for evidence of chronic rejection using the International Banff Criteria.

RESULTS

The mortality rate during the follow-up period was 15% (n=25). Retransplantation was required in 11% (n=18) of recipients. Actuarial patient and graft survival rates at 10 years were 84.9% and 80.1%, respectively. There were 535 liver biopsy samples available for evaluation, including the 18 explanted allografts. Biopsy specimens of three other functioning allografts showed evidence of chronic rejection. Immunosuppression had been discontinued or drastically reduced in these recipients because of life-threatening infections, noncompliance, or both. On restoring baseline immunosuppression, all three children had normalized liver function and the allografts were maintained; the liver transplant patients who are alive currently have normal liver functions.

CONCLUSION

The findings of this study suggest that chronic rejection does not occur in pediatric liver transplant recipients receiving tacrolimus-based immunosuppression, provided baseline immunosuppression is maintained.

Optimal immunosuppression in teenagers

Adolescence is a difficult time for transplant recipients, who need to cope with the challenges of becoming independent from their parents, as well as taking responsibility for their own behavior and medication. They need to balance their developing sexuality with a body image which may be affected by the side-effects of immunosuppression. It is now anticipated that more than 80% of children will survive their transplant to become teenagers and adults, and it is therefore important to ensure that immunosuppressive medication is acceptable, convenient for drug level monitoring and free of significant long-term side-effects.

Pediatric Liver Transplantation

Pediatric liver transplantation is a fast-growing and challenging field. Healthcare providers must stay informed of advancements in the management of liver transplant candidates and recipients. The goal of this paper is to provide nurses who care for pediatric liver transplant candidates and recipients with a review of the basic medical management of these patients, from the preoperative evaluation to postoperative care.

Efficacy of tacrolimus rescue therapy in refractory acute rejection after lung transplantation

BACKGROUND

Encouraging results in transplantation of other solid organs led to investigation of the use of tacrolimus in lung transplantation as a salvage immunosuppressant in persistent acute rejection.

METHODS

The incidence and severity of acute rejection and the number of steroid pulses were analyzed in 20 lung recipients who were converted from a cyclosporine- to a tacrolimus-based immunosuppressive regimen because of refractory biopsy-proven acute rejection.

RESULTS

Tacrolimus was started 12.0 +/- 13.0 months after transplantation, and the mean follow-up was 25.0 +/- 13.7 months. After shifting to tacrolimus, a significant decline was observed in both the number of acute rejections per patient (3.0 +/- 1.56 to 0.85 +/- 1.14, p < 0.0001), and the incidence of acute rejection per 100 patient-days (1.52 +/- 0.99 to 0.14 +/- 0.21, p < 0.0001). Furthermore, the average histologic grade of rejection decreased from 1.9 +/- 0.8 to 0.4 +/- 0.5 (p < 0.0001). Methylprednisolone pulses similarly decreased from 1.9 +/- 1.3/patient to 0.3 +/- 0.7/patient (p < 0.0001). During cyclosporine immunosuppression, the mean forced expiratory volume in 1 second decreased to 84.4% +/- 13.3% of individual best value. The average lung function parameters were stable 3 months after the change of medication, and then began to improve. After an average follow-up of 36.5 +/- 19.2 months, 2 patients have developed bronchiolitis obliterans syndrome (one has Stage 1 and one has Stage 3).

CONCLUSION

Conversion to a tacrolimus-based immunosuppressive regimen for refractory acute lung rejection is associated with reduced incidence and severity of acute rejection episodes, steroid sparing, and stabilization or improvement of pulmonary function.

Pediatric liver transplantation. A single center experience spanning 20 years

BACKGROUND

Survival after liver transplantation has improved significantly over the last decade with pediatric recipients faring better than adults. The 20-year experience of pediatric liver transplantation at Children's Hospital of Pittsburgh is reported in terms of patient survival; graft survival in relation to age, gender, and immunosuppressive protocols; causes of death; and indications for retransplantation.

METHOD

From March 1981 to April 1998, 808 children received liver transplants at Children's Hospital of Pittsburgh. All patients were followed until March 2001, with a mean follow-up of 12.2+/-3.9 years (median=12.6; range=2.9-20). There were 405 female (50.2%) and 403 male (49.8%) pediatric recipients. Mean age at transplant was 5.3+/-4.9 years (mean=3.3; range 0.04-17.95), with 285 children (25.3%) being less than 2 years of age at transplant. Cyclosporine (CsA)-based immunosuppression was used before November 1989 in 482 children (50.7%), and the subsequent 326 recipients (40.3%) were treated with tacrolimus-based immunosuppression. Actuarial survival was calculated using the Kaplan-Meier statistical method. Differences in survival were calculated by log-rank analysis.

RESULTS

Overall patient survival at 1, 5, 10, 15, and 20 years was 77.1%, 72.6%, 69.4%, 65.8%, and 64.4%, respectively. There was no difference in survival for male or female patients at any time point. At up to 10 years posttransplant, the survival for children greater than 2 years of age (79.5%, 75.7%, and 71.6% at 1, 5, and 10 years, respectively) was slightly higher than those at less than 2 years of age (72.6%, 66.9%, and 65.3% at 1, 5, and 10 years, respectively). However, at 15 and 20 years posttransplant, survival rates were similar (>2 years=67.3% and 65.8%; <2 years=64.1% and 64.1%). A significant difference in survival was seen in CsA-based immunosuppression (71.2%, 68.1%, 65.4%, and 61%) versus tacrolimus-based immunosuppression (85.8%, 84.7%, 83.3%, and 82.9%) at 1, 3, 5, and 10 years, respectively (P=0.0001). The maximum difference in survival was noted in the first 3 months between CsA and tacrolimus; thus, indicating there may have been other factors (nonimmunological factors) involved in terms of donor and recipient selection and technical issues. The mean annual death rate beyond 2 years posttransplant was 0.47%, with the mean annual death rate for patients who received tacrolimus-based immunosuppression being significantly lower than those who received CsA-based immunosuppression (0.14% vs. 0.8%; P=0.001). The most common etiologies of graft loss were hepatic artery thrombosis (33.4%), acute or chronic rejection (26.6%), and primary nonfunction (16.7%). Of note, retransplantation for graft loss because of acute or chronic rejection occurred only in those patients who received CsA-based immuno-suppression.

CONCLUSION

The overall 20-year actuarial survival for pediatric liver transplantation is 64%. Survival has increased by 20% in the last 12 years with tacrolimus-based immunosuppression. Although this improvement may be the result of several factors, retransplantation as a result of acute or chronic rejection has been completely eliminated in patients treated with tacrolimus.

Conversion from cyclosporin to tacrolimus in paediatric liver transplant recipients

Substitution of cyclosporin with tacrolimus should be considered for paediatric liver transplant recipients with cyclosporin-associated complications such as hypertension, gum hyperplasia, hirsutism, gynaecomastia and growth retardation, as well as recurrent or refractory acute rejection, chronic duct injury or chronic rejection. Continued experience with well tolerated drug administration and careful monitoring during drug substitution has limited drug toxicity associated with tacrolimus to a level comparable to or less than that associated with cyclosporin. Successful outcome with long term graft salvage has been reported in up to 80% of patients converted to tacrolimus because of acute rejection and 50% of patients converted because of chronic rejection. Nearly all children converted because of cyclosporin-related complications have a successful outcome. Additional benefits of conversion to tacrolimus include improvement in growth and resolution of hypertension, hirsutism and cushingoid facies. Complete corticosteroid withdrawal is possible in up to 78% of children post-conversion. Long term outcome in these patients may be optimised by conversion to tacrolimus at an early stage of acute or chronic transplant rejection in order to minimise the cumulative amount of immunosuppression. Avoidance of cyclosporin-related toxicity and minimisation of corticosteroid therapy may further improve patient compliance to drug therapy.

Recent advances in pediatric liver transplantation

Pediatric liver transplantation has matured into a well-established, highly successful treatment for advanced pediatric liver disease. Recent 1-year success rates range from 85% to 95%. This unprecedented achievement is the result of careful selection criteria and optimal timing of transplantation, technical advances in surgical technique, and improved treatment following transplant. This report highlights many recent published findings representing advances that have led to current successful approaches.

Post-transplant lymphoproliferative disease in children

Epstein-Barr virus (EBV)-driven post-transplant lymphoproliferative disease (PTLD) is an important cause of morbidity and mortality following transplantation, and it occurs more frequently in children than in adults. Of 22 (5%) children at our institution who developed tissue-proven PTLD 1-60 months (mean 16.5 months) following organ transplant, 11 died: nine of these 22 patients developed PTLD between 1989 and 1993, and seven (78%) died; the remaining 13 developed PTLD between 1994 and 1998, and four (31%) died (p = 0.08). All nine patients who developed PTLD < 6 months after transplant died, but 11 of 13 patients who manifested disease > or = 6 months after transplant survived (p = 0.0002). Ten of 11 (91%) survivors, but only two of eight (25%) children who died, had serologic evidence of EBV infection at the time of PTLD diagnosis (p = 0.04). EBV seroconversion identified patients at risk for developing PTLD, but also characterized patients with sufficient immune function to survive EBV-related lymphoid proliferation. In situ hybridization for EBER1 mRNA was diagnostically helpful because it detected EBV in tissue sections of all 20 patients with B-cell PTLD, including those with negative serology.

Liver transplantation

Continued discussion over organ allocation and distribution remained a focal point in the field of liver transplantation in the year 2000. Despite the ongoing debate, no significant changes were implemented in the current allocation system. By far, the most widely discussed topic in liver transplantation this year was live donor adult-to-adult liver transplantation. Several authors reported on their initial experience, with both recipient and donor outcomes appearing excellent. As the number of transplant centers performing this procedure increases we look forward to further studies regarding the safety and long-term outcome of this innovative procedure. Studies on viral hepatitis after liver transplantation again focused on the problem of recurrent hepatitis B and hepatitis C. Several small studies found benefit in patients with hepatitis B treated with intramuscular hepatitis B immunoglobulin and lamivudine after transplantation. Although breakthrough replication remains a problem in some patients, these studies offer hope that combination therapy for hepatitis B may provide improved long-term graft survival in these patients. In patients with hepatitis C, several studies focused on identifying risk factors to predict graft recurrence of the virus after liver transplantation. Both cellular rejection and level of viral replication may be important predictors of recurrent hepatitis C virus in the graft. Early treatment reports using interferon and ribavirin suggest that some patients may have a viral response during therapy; however, it is short lived, and tolerance of medication is difficult. Certainly, we look forward to further studies looking at means of prevention and treatment of viral hepatitis in patients undergoing liver transplantation.