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1.
Braz J Med Biol Res ; 56: e12671, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36995875

RESUMO

In biliary atresia (BA), efforts to prevent premature liver transplantation (LT) are aimed at early diagnosis, timing of Kasai-portoenterostomy (KPE), and centralization of care. This report presents the clinical picture, treatment strategies, and outcomes of BA patients with no previous treatment. A retrospective cohort study (Jan/2001 to Jan/2021) was conducted to evaluate the outcome of patients with BA referred to a single team. Study groups were: 1) Kasai-only group (K-only) n=9), 2) LT-only group (n=7), and 3) Kasai+LT group (K+LT) (n=23). Survival with native liver and overall survival were 22.9 and 94.8%, respectively, at 120 months of follow-up. There was no difference in age at KPE in the K-only group (46.8±21.8 days) vs K+LT (52.1±22 days), P=0.4. Ten (25.6%) patients were babies conceived through in vitro fertilization (IVF). Four IVF patients (40%) presented associated congenital heart disease vs 5 patients (17%) in the remaining group (P=0.14). Two of the IVF patients were premature (<37 weeks). Median maternal age at birth was 35 years (33 to 41 years). Excellent patient survival is expected for patients with BA with the available treatment strategies. IVF+BA was an unexpected prevalent association in this cohort, and further studies are required to better understand these findings.


Assuntos
Atresia Biliar , Nascimento Prematuro , Lactente , Recém-Nascido , Feminino , Humanos , Adulto , Atresia Biliar/cirurgia , Atresia Biliar/complicações , Atresia Biliar/diagnóstico , Portoenterostomia Hepática/efeitos adversos , Estudos Retrospectivos , Resultado do Tratamento , Fertilização in vitro
2.
Braz. j. med. biol. res ; 56: e12671, 2023. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1430017

RESUMO

In biliary atresia (BA), efforts to prevent premature liver transplantation (LT) are aimed at early diagnosis, timing of Kasai-portoenterostomy (KPE), and centralization of care. This report presents the clinical picture, treatment strategies, and outcomes of BA patients with no previous treatment. A retrospective cohort study (Jan/2001 to Jan/2021) was conducted to evaluate the outcome of patients with BA referred to a single team. Study groups were: 1) Kasai-only group (K-only) n=9), 2) LT-only group (n=7), and 3) Kasai+LT group (K+LT) (n=23). Survival with native liver and overall survival were 22.9 and 94.8%, respectively, at 120 months of follow-up. There was no difference in age at KPE in the K-only group (46.8±21.8 days) vs K+LT (52.1±22 days), P=0.4. Ten (25.6%) patients were babies conceived through in vitro fertilization (IVF). Four IVF patients (40%) presented associated congenital heart disease vs 5 patients (17%) in the remaining group (P=0.14). Two of the IVF patients were premature (<37 weeks). Median maternal age at birth was 35 years (33 to 41 years). Excellent patient survival is expected for patients with BA with the available treatment strategies. IVF+BA was an unexpected prevalent association in this cohort, and further studies are required to better understand these findings.

3.
Am J Transplant ; 16(2): 497-508, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26663361

RESUMO

T cell suppression prevents acute cellular rejection but causes life-threatening infections and malignancies. Previously, liver transplant (LTx) rejection in children was associated with the single-nucleotide polymorphism (SNP) rs9296068 upstream of the HLA-DOA gene. HLA-DOA inhibits B cell presentation of antigen, a potentially novel antirejection drug target. Using archived samples from 122 white pediatric LTx patients (including 77 described previously), we confirmed the association between rs9296068 and LTx rejection (p = 0.001, odds ratio [OR] 2.55). Next-generation sequencing revealed that the putative transcription factor (CCCTC binding factor [CTCF]) binding SNP locus rs2395304, in linkage disequilibrium with rs9296068 (D' 0.578, r(2) = 0.4), is also associated with LTx rejection (p = 0.008, OR 2.34). Furthermore, LTx rejection is associated with enhanced B cell presentation of donor antigen relative to HLA-nonidentical antigen in a novel cell-based assay and with a downregulated HLA-DOA gene in a subset of these children. In lymphoblastoid B (Raji) cells, rs2395304 coimmunoprecipitates with CTCF, and CTCF knockdown with morpholino antisense oligonucleotides enhances alloantigen presentation and downregulates the HLA-DOA gene, reproducing observations made with HLA-DOA knockdown and clinical rejection. Alloantigen presentation is suppressed by inhibitors of methylation and histone deacetylation, reproducing observations made during resolution of rejection. Enhanced donor antigen presentation by B cells and its epigenetic dysregulation via the HLA-DOA gene represent novel opportunities for surveillance and treatment of transplant rejection.


Assuntos
Apresentação de Antígeno/imunologia , Linfócitos B/imunologia , Epigenômica , Rejeição de Enxerto/etiologia , Antígenos HLA/genética , Isoantígenos/imunologia , Transplante de Fígado/efeitos adversos , Western Blotting , Células Cultivadas , Criança , Imunoprecipitação da Cromatina , Feminino , Seguimentos , Genótipo , Rejeição de Enxerto/patologia , Sobrevivência de Enxerto , Humanos , Técnicas Imunoenzimáticas , Hepatopatias/cirurgia , Masculino , Polimorfismo de Nucleotídeo Único/genética , Complicações Pós-Operatórias , Prognóstico , Estudos Prospectivos , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Risco , Doadores de Tecidos
4.
Am J Transplant ; 9(1): 179-91, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18976293

RESUMO

Antigen-specific T cells, which express CD154 rapidly, but remain untested in alloimmunity, were measured with flow cytometry in 16-h MLR of 58 identically-immunosuppressed children with liver transplantation (LTx), to identify Rejectors (who had experienced biopsy-proven rejection within 60 days posttransplantation). Thirty-one children were sampled once, cross-sectionally. Twenty-seven children were sampled longitudinally, pre-LTx, and at 1-60 and 61-200 days after LTx. Results were correlated with proliferative alloresponses measured by CFSE-dye dilution (n = 23), and CTLA4, a negative T-cell costimulator, which antagonizes CD154-mediated effects (n = 31). In cross-sectional observations, logistic regression and leave-one-out cross-validation identified donor-specific, CD154 + T-cytotoxic (Tc)-memory cells as best associated with rejection outcomes. In the longitudinal cohort, (1) the association between CD154 + Tc-memory cells and rejection outcomes was replicated with sensitivity/specificity 92.3%/84.6% for observations at 1-60 days, and (2) elevated pre-LTx CD154 + Tc-memory cell responses were associated with significantly increased incidence (p = 0.02) and hazard (HR = 7.355) of rejection in survival/proportional hazard analysis. CD154 expression correlated with proliferative alloresponses (r = 0.835, p = 7.1e-07), and inversely with CTLA4 expression of allospecific CD154 + Tc-memory cells (r =-0.706, p = 3.0e-05). Allospecific CD154 + T-helper-memory cells, not CD154 + Tc-memory, were inhibited by increasing Tacrolimus concentrations (p = 0.026). Collectively, allospecific CD154 + T cells provide an estimate of rejection risk in children with LTx.


Assuntos
Ligante de CD40/imunologia , Rejeição de Enxerto/imunologia , Transplante de Fígado/imunologia , Linfócitos T/imunologia , Antígenos CD/imunologia , Antígeno CTLA-4 , Criança , Pré-Escolar , Estudos de Coortes , Feminino , Humanos , Memória Imunológica , Masculino
5.
Am J Transplant ; 7(9): 2165-71, 2007 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-17608834

RESUMO

Late graft loss (LGL) and late mortality (LM) following liver transplantation (LT) in children were analyzed from the studies of pediatric liver transplantation (SPLIT) database. Univariate and multivariate associations between pre- and postoperative factors and LGL and LM in 872 patients alive with their primary allografts 1 year after LT were reviewed. Thirty-four patients subsequently died (LM) and 35 patients underwent re-LT (LGL). Patients who survive the first posttransplant year had 5-year patient and graft survival rates of 94.2% and 89.2%, respectively. Graft loss after the first year was caused by rejection in 49% of the cases with sequelae of technical complications accounting for an additional 20% of LGL. LT for tumor, steroid resistant rejection, reoperation in the first 30 days and >5 admissions during the first posttransplant year were independently associated with LGL in multivariate analysis. Malignancy, infection, multiple system organ failure and posttransplant lymphoproliferative disease accounted for 61.8% of all late deaths after LT. LT performed for FHF and tumor were associated with LM. Patients who are at or below the mean for weight at the time of transplant were also at an increased risk of dying. Frequent readmission was also found to be associated with LM.


Assuntos
Rejeição de Enxerto/epidemiologia , Transplante de Fígado/mortalidade , Adolescente , Canadá/epidemiologia , Criança , Pré-Escolar , Feminino , Seguimentos , Sobrevivência de Enxerto , Humanos , Lactente , Recém-Nascido , Masculino , Análise Multivariada , Estudos Prospectivos , Fatores de Risco , Taxa de Sobrevida/tendências , Fatores de Tempo , Transplante Homólogo , Estados Unidos/epidemiologia
6.
Am J Transplant ; 6(3): 557-64, 2006 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-16468966

RESUMO

An 8.5-year-old girl with classical maple syrup urine disease (MSUD) required liver transplantation for hypervitaminosis A and was effectively cured of MSUD over an 8-year clinical follow-up period. We developed a collaborative multidisciplinary effort to evaluate the effects of elective liver transplantation in 10 additional children (age range 1.9-20.5 years) with classical MSUD. Patients were transplanted with whole cadaveric livers under a protocol designed to optimize safe pre- and post-transplant management of MSUD. All patients are alive and well with normal allograft function after 106 months of follow-up in the index patient and a median follow-up period of 14 months (range 4-18 months) in the 10 remaining patients. Leucine, isoleucine and valine levels stabilized within 6 hours post-transplant and remained so on an unrestricted protein intake in all patients. Metabolic cure was documented as a sustained increase in weight-adjusted leucine tolerance, normalization of plasma concentration relationships among branched-chain and other essential and nonessential amino acids, and metabolic and clinical stability during protein loading and intercurrent illnesses. Costs and risks associated with surgery and immune suppression were similar to other pediatric liver transplant populations.


Assuntos
Procedimentos Cirúrgicos Eletivos/métodos , Transplante de Fígado , Doença da Urina de Xarope de Bordo/cirurgia , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Seguimentos , Humanos , Lactente , Leucina/sangue , Doença da Urina de Xarope de Bordo/sangue , Fatores de Tempo , Resultado do Tratamento
7.
Transplant Proc ; 35(3 Suppl): 113S-114S, 2003 May.
Artigo em Inglês | MEDLINE | ID: mdl-12742479

RESUMO

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.


Assuntos
Sirolimo/uso terapêutico , Imunologia de Transplantes , Transplante de Medula Óssea/imunologia , Criança , Creatinina/sangue , Transplante de Coração/imunologia , Humanos , Imunossupressores/uso terapêutico , Intestinos/transplante , Transplante de Rim/imunologia , Transplante de Fígado/imunologia , Estudos Retrospectivos , Resultado do Tratamento
9.
Transplantation ; 72(5): 851-5, 2001 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-11571449

RESUMO

AIMS: The role of sirolimus (SRL) as a rescue agent (n=42) and as a component of primary immunosuppression (n=8) was evaluated in a mixed population of 50 transplanted children receiving tacrolimus (liver: 26, heart: 5, intestinal: 5, liver-intestine: 9, lung: 1, bone marrow: 1, liver-kidney: 1, multivisceral: 1). Rescue indications for tacrolimus (TAC) failure were recurrent acute rejection and acute rejection complicating withdrawal of immunosuppression in posttransplant lymphoproliferative disorder (PTLD). Rescue indications for TAC toxicity were nephrotoxicity, pancreatitis, seizures, hypertrophic cardiomyopathy, and graft-versus-host disease. RESULTS: Mean age at rescue was 11.5 years and mean follow-up was 204 (range 18-800) days. As primary immunosuppression, SRL+TAC prevented early acute rejection in 7/8 children. The indication for rescue resolved in 33/42 children. In children with TAC toxicity, this was associated with decrease in TAC doses by 50%, significant improvements in renal function, and continuing decline in Epstein-Barr virus (EBV) viral load in PTLD patients. Serious adverse events led to discontinuation of SRL in 9/42 rescue patients, 3 of them also experienced acute rejection. Three additional children also experienced acute rejection on SRL therapy (overall incidence 6/50, 12%). Pharmacokinetic analysis in the first week of SRL administration suggested a short half-life (11.8+/-5.5 hr, n=21). CONCLUSIONS: SRL and reduced-dose TAC may achieve adequate immunosuppression without compromising renal function or enhancing EBV viremia significantly.


Assuntos
Rejeição de Enxerto/tratamento farmacológico , Rejeição de Enxerto/prevenção & controle , Imunossupressores/uso terapêutico , Sirolimo/uso terapêutico , Tacrolimo/uso terapêutico , Imunologia de Transplantes , Doença Aguda , Adolescente , Adulto , Criança , Pré-Escolar , Infecções por Vírus Epstein-Barr/tratamento farmacológico , Infecções por Vírus Epstein-Barr/virologia , Herpesvirus Humano 4/efeitos dos fármacos , Herpesvirus Humano 4/isolamento & purificação , Humanos , Terapia de Imunossupressão/métodos , Imunossupressores/efeitos adversos , Imunossupressores/farmacocinética , Lactente , Rim/efeitos dos fármacos , Rim/fisiopatologia , Transtornos Linfoproliferativos/tratamento farmacológico , Transtornos Linfoproliferativos/virologia , Recidiva , Sirolimo/efeitos adversos , Sirolimo/farmacocinética , Tacrolimo/efeitos adversos
10.
J Interferon Cytokine Res ; 21(7): 507-14, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11506745

RESUMO

Targets of cyclosporine (CsA) were identified from an array of stimulated lymphocyte responses (sLR) comprising 34 stimulation conditions in whole blood from 3 normal human volunteers (NHV) containing clinically relevant CsA concentrations (0-1200 ng/ml) in vitro. In whole blood from 5 additional NHV, selected targets (intracellular interleukin-2 [IL-2], tumor-necrosis factor-alpha [TNF-alpha], and interferon-gamma [IFN-gamma]) were measured in phorbol myristate acetate (PMA)-ionomycin-stimulated T lymphocytes. Effect:concentration relationships were analyzed with E(max) pharmacodynamic (PD) equations and expressed as the concentration associated with one-half maximal inhibitory effect (EC(50)). CsA demonstrated a rich matrix of inhibitory effects on T cells (CD3(+)), B cells (CD19(+)), dendritic cells (DC) (CD11c(+)), and basophils (CD123(+)) but not on monocytes (CD14(+)) (n = 3). PD analyses suggested that the EC(50) of CsA (1) for IL-2 in CD3(+) cells in NHV (n = 8) was similar to the EC(50) demonstrated by us previously in CD4(+) cells from transplanted patients (n = 13) (EC(50) = 260 ng/ml vs. 249 ng/ml), (2) for each cytokine was different under identical stimulation conditions (TNF-alpha, 324 ng/ml; IFN-gamma, 504 ng/ml), and (3) was relatively constant for a given cytokine under different stimulation conditions (e.g., PMA-ionomycin or the staphylococcal enterotoxin B [SEB] superantigen). In conclusion, inhibition of cytokine targets by CsA is concentration dependent. Further, a given CsA concentration may produce similar inhibitory effects across different stimulation conditions. Measurement of cytokine target expression may, therefore, allow effect-controlled administration of CsA during clinical transplantation.


Assuntos
Antígenos de Diferenciação de Linfócitos B/análise , Ciclosporina/farmacologia , Citocinas/análise , Imunossupressores/farmacologia , Adulto , Linfócitos B/efeitos dos fármacos , Linfócitos B/imunologia , Linfócitos B/metabolismo , Basófilos/efeitos dos fármacos , Basófilos/imunologia , Basófilos/metabolismo , Biomarcadores/análise , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Humanos , Ativação Linfocitária/efeitos dos fármacos , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia , Linfócitos T/metabolismo
11.
Ann Surg ; 234(3): 404-16; discussion 416-7, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11524593

RESUMO

OBJECTIVE: To assess the long-term efficacy of intestinal transplantation under tacrolimus-based immunosuppression and the therapeutic benefit of newly developed adjunct immunosuppressants and management strategies. SUMMARY BACKGROUND DATA: With the advent of tacrolimus in 1990, transplantation of the intestine began to emerge as therapy for intestinal failure. However, a high risk of rejection, with the consequent need for acute and chronic high-dose immunosuppression, has inhibited its widespread application. METHODS: During an 11-year period, divided into two segments by a 1-year moratorium in 1994, 155 patients received 165 intestinal allografts under immunosuppression based on tacrolimus and prednisone: 65 intestine alone, 75 liver and intestine, and 25 multivisceral. For the transplantations since the moratorium (n = 99), an adjunct immunosuppressant (cyclophosphamide or daclizumab) was used for 74 transplantations, adjunct donor bone marrow was given in 39, and the intestine of 11 allografts was irradiated with a single dose of 750 cGy. RESULTS: The actuarial survival rate for the total population was 75% at 1 year, 54% at 5 years, and 42% at 10 years. Recipients of liver plus intestine had the best long-term prognosis and the lowest risk of graft loss from rejection (P =.001). Since 1994, survival rates have improved. Techniques for early detection of Epstein-Barr and cytomegaloviral infections, bone marrow augmentation, the adjunct use of the interleukin-2 antagonist daclizumab, and most recently allograft irradiation may have contributed to the better results. CONCLUSION: The survival rates after intestinal transplantation have cumulatively improved during the past decade. With the management strategies currently under evaluation, intestinal transplant procedures have the potential to become the standard of care for patients with end-stage intestinal failure.


Assuntos
Terapia de Imunossupressão/métodos , Intestinos/transplante , Adulto , Anticorpos Monoclonais/uso terapêutico , Anticorpos Monoclonais Humanizados , Criança , Pré-Escolar , Ciclofosfamida/uso terapêutico , Daclizumabe , Sobrevivência de Enxerto , Doença Enxerto-Hospedeiro/etiologia , Humanos , Imunoglobulina G/uso terapêutico , Transplante de Fígado , Monitorização Imunológica , Prednisona/uso terapêutico , Prognóstico , Tacrolimo/uso terapêutico , Doadores de Tecidos , Condicionamento Pré-Transplante/métodos , Transplante Homólogo , Viroses/etiologia
13.
Transplantation ; 69(3): 432-6, 2000 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-10706056

RESUMO

BACKGROUND: Clinically, cyclosporine (CSA, Neoral) is titrated to concentrations, and not to pharmacological effect. METHODS: Intracellular interleukin- (IL) 2 was measured in phorbol myristic acid-ionomycin-stimulated peripheral lymphocytes by flow cytometry, after isolation from 14 renal transplant recipients receiving CSA+prednisone, and double-blind rapamycin (rapamycin:placebo=4:1). RESULTS: The proportion (%) of CD4+IL-2+ lymphocytes corresponding to CSA levels (mean+/-SD ng/ml) measured preoperatively (TO=O), and on postoperative day 8, before (356+/-63), and 2 hr after the morning dose (Cmax=1567+/-669), decreased from 39+/-16 to 15+/-8 and 3+/-1.6, respectively. Reciprocally, unresponsive lymphocytes (%CD4+IL-2-) increased with increasing CSA levels and predicted an EC50 of 249 ng/ml (CSA concentration at which CD4+IL-2- cells increased by 50% over baseline) in an Emax pharmacodynamic model. CONCLUSIONS: Clinically, the pharmacological effect of CSA is quantifiable, and lies in the upper end of the predicted range. In our Neoral-treated sample population, Cmax was associated with the least variable "cyclosporine effect." Such information could potentially individualize immunosuppression, and lead to rational dosing strategies.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Ciclosporina/administração & dosagem , Rejeição de Enxerto/prevenção & controle , Imunossupressores/administração & dosagem , Transplante de Rim , Sirolimo/administração & dosagem , Método Duplo-Cego , Rejeição de Enxerto/imunologia , Humanos , Ativação Linfocitária
14.
J Pediatr Surg ; 35(2): 283-9; discussion 289-90, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10693682

RESUMO

BACKGROUND/PURPOSE: The expanding applicability of liver transplantation as treatment for end-stage liver disease has fostered a disproportionate increase in liver transplant candidates in the face of an unchanging pool of donor organs. This has resulted in disparities in pretransplant waiting times and deaths. The splitting of a liver allograft allows for the transplantation of 2 recipients, usually an adult and a child, thus providing a means to expand the cadaveric donor pool. METHODS: The authors present their results on the performance of an ex vivo (back table) split and in situ (in a hemodynamically stable cadaveric donor) split to evaluate safety, applicability, and effectiveness. Between November 1989 through April 1998, 54 split-liver transplant recipient operations were performed (24 pediatric and 30 adult). Thirty donors were procured: the ex vivo splitting yielded 25 grafts from 13 donors (donor age, 24.6+/-11 years), and the in-situ technique yielded 29 grafts from 17 donors (mean donor age of 25.5+/-10.4 years). Five donors involved interinstitutional sharing for which the left side of the graft was kept at the host hospital and the right side grafts were utilized at our center. RESULTS: Overall 1-year patient survival was 85%, with a graft survival of 72%. Patient survival was similar with ex vivo (74%) as compared with the in situ splitting group (96%; P = .06), as was graft survival in ex vivo (61 %) versus in situ (81%) splitting (P = .15). The pediatric population benefited most from the in situ technique, with a 1-year patient survival rate of 100% with the in situ technique versus the ex vivo technique survival rate of 64% at 1 year (P = .02). The 1-year graft survival comparing these 2 techniques was 83% for the in situ group versus 45% for the ex vivo group. Analysis of the program evolution of split-liver transplantation suggested a time-dependent learning curve, which was applicable to surgical splitting technique, implantation, and recipient selection. CONCLUSIONS: The principle of splitting livers from cadaveric donors is fundamentally sound and technically feasible. The authors' outcomes analysis using 2 different procurement techniques suggests that the in situ technique is clinically efficacious, can be used alternatively with the ex vivo technique, and is comparable to whole-liver allograft transplantation.


Assuntos
Hepatopatias/cirurgia , Transplante de Fígado/métodos , Obtenção de Tecidos e Órgãos , Adulto , Cadáver , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento
15.
BioDrugs ; 14(1): 31-48, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18034554

RESUMO

The current management of hepatic allograft rejection after liver transplantation in children requires effective baseline immunosuppression to prevent rejection and rapid diagnosis and treatment to manage acute rejection episodes. The subsequent impact on chronic rejection is dependent on the combination of adequate prevention and the treatment of acute rejection. Tacrolimus is a macrolide lactone that inhibits the signal transduction of interleukin-2 (IL-2) via calcineurin inhibition. Introduced in 1989, tacrolimus was first used in the salvage of refractory acute or chronic rejection under cyclosporin or to rescue patients with significant cyclosporin-related complications. The majority of paediatric transplant centres use a combination of steroids with tacrolimus as a basic immunosuppressant regimen following paediatric liver transplantation. This combination has allowed the acute cellular rejection-free rate to increase to between 30 and 60%, while lowering the rate of refractory rejection to less than 5%. Corticosteroid-resistant rejection is commonly treated with monoclonal (muromonab CD3) or polyclonal preparations. Although most episodes of acute cellular rejection occur during the first 6 weeks after liver transplant, the appearance of late acute liver allograft rejection must raise the question of noncompliance, especially in the adolescent population. Chronic rejection is becoming increasingly rare under tacrolimus-based immunosuppression. Tacrolimus is effective in reversing refractory acute cellular rejection or early chronic rejection in patients initially treated with cyclosporin-based regimens. Patients with a history of noncompliance as well as children with autoimmune liver disease are at risk of chronic rejection. Retransplantation therapy for chronic rejection has, fortunately, become more rare in the tacrolimus era with only 3% of retransplants being performed for this indication. Newer immunosuppressive agents are further modifying the long term management of liver allograft rejection. These include mycophenolate mofetil, rapamycin and IL-2 antibodies such as daclizumab. The development of these agents is allowing patient-specific immunosuppressive management to minimise rejection as well as the complications related to immunosuppression.

16.
J Pediatr Surg ; 34(1): 107-10; discussion 110-1, 1999 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10022153

RESUMO

PURPOSE: The aim of this study was to assess the relative impact of segmental grafts from cadaveric and living donors on outcomes in 3,409 pediatric transplants (<18 years) between 1990 and 1996. METHODS: Analysis of the United Network for Organ Sharing (UNOS) Scientific registry data from 1990 to 1996 was performed. RESULTS: Liver grafts consisted of 2,636 whole grafts (WLG), 246 liver donor grafts (LDG), 89 split liver graft (SLG), and 438 reduced-size grafts (RSG). Although the number of pediatric transplants were unchanged between 1990 and 1996, segmental grafts made up an increasing proportion from 14.5% to 29.2%, and WLG decreased proportionately. The increase among segmental grafts occurred for LDG (threefold), followed by SLG (53%) and RSG (50%). One-year graft and patient survival rates for 3,409 transplants were 69.7% and 81.9%, respectively and were significantly higher (P<.001) in nonhospitalized patients than in hospitalized patients (79.8% and 91.3% v 61.0% and 73.7%). LDG graft survival (75.9%) was comparable with WLG(70.9%) but significantly better at 1 year than SLG (60.3%, P = .007) and RSG (61.1%, P = .001), even after excluding retransplants and ICU patients. Patient survival rates were not different statistically between groups. A separate analysis of outcomes in recipients less than 1 year of age suggested significantly better graft and patient survivals for LDG (83.3% and 89.4%) than for WLG (62.3% and 76.5%) and RSG (62.7% and 75%). CONCLUSIONS: Segmental liver grafts from cadaveric and living donors constitute an increasing proportion of pediatric transplants. Survival rates of cadaveric segmental graft are inferior to those of live donor segmental grafts even after adjustment for medical condition. Live donor grafts demonstrate consistently superior graft and patient outcomes in pediatric recipients less than 1 year of age, and should be promoted aggressively as a solution to the critical shortage of size matched grafts in small recipients.


Assuntos
Sobrevivência de Enxerto , Transplante de Fígado/métodos , Fatores Etários , Cadáver , Humanos , Lactente , Hepatopatias/cirurgia , Transplante de Fígado/estatística & dados numéricos , Doadores Vivos , Sistema de Registros , Resultado do Tratamento , Estados Unidos
17.
Ann Clin Lab Sci ; 28(5): 280-2, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9784828

RESUMO

The development of a high-titer factor V inhibitor is described in a patient who underwent orthotopic liver transplantation followed by porcine xenoperfusion after an acute rejection episode. The inhibitor showed no cross-reactivity to either porcine or bovine factor V, nor was it accessible to human platelet factor V. The limitations of treatment modalities including intravenous immunoglobulin, steroids, cytotoxic therapy, intense plasmapheresis and platelet transfusions are discussed.


Assuntos
Fator V/antagonistas & inibidores , Imunoglobulinas/análise , Transplante de Fígado/imunologia , Adulto , Animais , Fator V/imunologia , Rejeição de Enxerto/imunologia , Rejeição de Enxerto/terapia , Humanos , Fígado Artificial , Masculino , Plasmaferese , Diálise Renal , Reoperação , Suínos , Falha de Tratamento
20.
Clin Transplant ; 11(2): 104-9, 1997 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-9113445

RESUMO

UNLABELLED: Whole organ pancreaticoduodenal transplantation with bladder drainage by the duodenal segment technique is currently the preferred method of vascularized pancreas transplantation but is associated with a finite risk of surgical complications. Meticulous bench reconstruction of the pancreaticoduodenal allograft may minimize complications following transplantation. Over a 6.5-yr period, 192 pancreas transplants were performed in 181 diabetic patients by the same transplant team. A retrospective review was performed in order to describe a stepwise approach to bench preparation of the pancreaticoduodenal allograft that has developed from this experience. In this series of 192 consecutive pancreaticoduodenal reconstructions, no procured pancreas was deemed non-usable solely from an anatomic standpoint. The mean backtable pancreas preparation time was 2 h. The operative complication rate 19%, the incidence of technical graft loss was 6.8%, and there was no mortality related to technical problems. CONCLUSIONS: Using a standardized approach, meticulous bench reconstruction of the pancreaticoduodenal allograft: 1) can be performed in virtually any anatomic setting; 2) decrease complications following transplantation; 3) improves initial allograft function; and 4) minimizes organ wastage.


Assuntos
Transplante de Pâncreas/métodos , Diabetes Mellitus/cirurgia , Duodeno/transplante , Humanos , Transplante de Pâncreas/efeitos adversos , Estudos Retrospectivos
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