Gut microbiota and its implications in small bowel transplantation / 医学前沿

The gut microbiota is mainly composed of a diverse population of commensal bacterial species and plays a pivotal role in the maintenance of intestinal homeostasis, immune modulation and metabolism. The influence of the gut microbiota on solid organ transplantation has recently been recognized. In fact, several studies indicated that acute and chronic allograft rejection in small bowel transplantation (SBT) is closely associated with the alterations in microbial patterns in the gut. In this review, we focused on the recent findings regarding alterations in the microbiota following SBTand the potential roles of these alterations in the development of acute and chronic allograft rejection. We also reviewed important advances with respect to the interplays between the microbiota and host immune systems in SBT. Furthermore, we explored the potential of the gut microbiota as a microbial marker and/or therapeutic target for the predication and intervention of allograft rejection and chronic dysfunction. Given that current research on the gut microbiota has become increasingly sophisticated and comprehensive, large cohort studies employing metagenomic analysis and multivariate linkage should be designed for the characterization of host-microbe interaction and causality between microbiota alterations and clinical outcomes in SBT. The findings are expected to provide valuable insights into the role of gut microbiota in the development of allograft rejection and other transplant-related complications and introduce novel therapeutic targets and treatment approaches in clinical practice.

Comparative Analyses of Signature Genes in Acute Rejection and Operational Tolerance

Using biomarkers as prediction tools or therapeutic targets can be a valuable strategy in transplantation. Recent studies identified biomarkers of acute rejection (AR) and operational tolerance (TOL) through the application of meta-analysis. In this study, we comparatively analyzed the signature genes in acute rejection and operational tolerance seen in human allogeneic transplantations using massive bioinformatical meta-analysis. To identify the signature genes in opposite immunological conditions, AR and TOL, we first collected the 1,252 gene expression data specifically intended for those circumstances. Then we excluded based on biological cut-values, Principal Component Analysis (PCA) as well as Multi-Dimensional Scaling (MDS). Using differentially expressed genes (DEGs) from meta-analysis, we then applied a ranked scoring system to identify the signature genes of AR and TOL. We identified 53 up-regulated and 32 down-regulated signature genes in acute rejection condition. Among them, ISG20, CXCL9, CXCL10, CCL19, FCER1G, PMSE1, UBD are highly expressed in AR condition. In operational tolerance, we identified 110 up-regulated and 48 down-regulated signature genes. TCL1A, BLNK, MS4A1, EBF1, IGHM are up-regulated in TOL condition. These genes are highly representative of AR or TOL across the different organs such as liver, kidney and heart. Since immune response is the sum of complex biological and molecular dynamics, these signature genes as well as pathway analysis using a systems biology approach could be used to catch the insights of the certain pathways that would be overlooked with the conventional gene-level comparative analysis.

Association of Foxp3 Polymorphism With Allograft Outcome in Kidney Transplantation

BACKGROUND: Forkhead box P3 (Foxp3) is the most reliable marker for regulatory T cells, which play an important role in maintaining renal allograft tolerance. Recently, Foxp3 polymorphisms have been reported to be associated with graft outcome in kidney transplantation. We analyzed the association of Foxp3 polymorphisms with renal allograft outcome. METHODS: Foxp3 polymorphisms (rs3761548 A/C, rs2280883 C/T, rs5902434 del/ATT, and rs2232365 A/G) were tested by PCR with sequence-specific primers (PCR-SSP) in 231 adult kidney transplantation recipients from 1996-2004 at Seoul National University Hospital. RESULTS: Patients with the rs3761548 CC genotype showed better graft survival than those with the AC or AA genotype (log rank test, P=0.03). Patients with the rs3761548 CC genotype also showed a lower rate of recurrence of the original glomerular disease than those with the AC or AA genotype (P=0.01). The frequency of acute rejection (AR) in patients with the rs2280883 TT genotype was lower than that in patients with the rs2280883 CT or CC genotype (26.9% vs 53.3%, P=0.038). Patients with the rs2280883 TT genotype also showed better graft survival than those with the CT or CC genotype (P=0.03). CONCLUSIONS: Foxp3 rs3761548 CC and rs2280883 TT genotypes were associated with superior graft outcome of kidney transplantation. Further studies involving a larger number of patients are needed.

Inducción de tolerancia en modelo de autotrasplante / Induction of tolerance in allogeneic transplant model

Introduction: Vascularized composite allotransplantation (VCA) involves the transplantation of complex anatomical structures including different kinds of tissue. The aim was to study the effect of a treatment with immature dendritic cells in a model of VCA. Materials and Methods: The rat hind limb allotransplantation model was used. Due to the high antigenic mistmatch Brown Norway rats were used as donors and Lewis rats as recipients. The bone marrow derived immature dendritic cells were cultured under GM-CSF stimuli and donor tissue. The rejection grade and the survival of the graft were assessed. Experimental groups: group I (n = 3): no treatment; Group II (n = 6): tacrolimus 10 mg/kg one day before the transplantation (day -1); Group III (n = 3): tacrolimus 10 mg/kg on day -1 and 6 mg/kg from day 0 to 14, plus intravenous saline infusion on days 7 and 14; Group IV (n = 3): tacrolimus 10 mg/kg on day -1 and 6 mg/kg from day 0 to 14, plus intravenous immature dendritic cells on days 7 and 14. Results: All 15 allografts developed rejection. The mean allograft survival was 14 days in group I, 15 days in group II, 34 days in group III and 58 days in groups IV (p < 0.05). Conclusions: In the rat hind limb allotransplantation model under tacrolimus monotherapy, the treatment with immature bone marrow derived dendritic cells pulsed with alloantigens increases the survival of the graft.

Introducción: El alotrasplante compuesto vascularizado (ACV) involucra el trasplante de estructuras anatómicas complejas que pueden contener distintos tipos de tejidos. El objetivo de este estudio fue evaluar el efecto del tratamiento con células dendríticas inmaduras derivadas de médula ósea del receptor y cargadas con aloantígenos como potencial inductor de tolerancia en un modelo de ACV. Animales y Métodos: Para realizar el modelo de alotrasplante de extremidad posterior de la rata, se utilizaron como donantes ratas Brown Norway y como receptoras ratas Lewis. Las células dendríticas se diferenciaron a partir de precursores de médula ósea que se cargaron con lisado de tejido del donante. Grupos experimentales: Grupo I (n = 3): sin tratamiento; Grupo II (n = 6): tacrolimus 10 mg/kg vía oral el día previo al trasplante (día -1); Grupo III (n = 3): tacrolimus 10 mg/kg el día -1 y 6 mg/kg desde el día 0 al 14 post operatorio como mantención; Grupo IV (n = 3): mismo esquema de tacrolimus que grupo III, pero además infusión intravenosa de células dendríticas los días 7 y 14. Se evaluó la sobrevida de los implantes y el grado de rechazo. Resultados: Los 15 animales trasplantados presentaron rechazo. La sobrevida media del ACV fue de 14 días en el grupo I, 15 días en el grupo II, 34 días en el grupo III y 58 días en el grupo IV (p < 0,05). Conclusión: En un modelo de ACV bajo tratamiento con tacrolimus, la infusión de células dendríticas inmaduras derivadas de médula ósea y pulsadas con aloantígeno aumentan la sobrevida del implante.

Validation of the content of the prevention protocol for early sepsis caused by Streptococcus agalactiaein newborns / Validação de conteúdo do protocolo de prevenção da sepse precoce porStreptococcus agalactiae em recém-nascidos / Validación de contenido del protocolo de prevención de la sepsis precoz por Streptococcus agalactiaeen recién nacidos

AbstractObjective: to validate the content of the prevention protocol for early sepsis caused by Streptococcus agalactiaein newborns.Method: a transversal, descriptive and methodological study, with a quantitative approach. The sample was composed of 15 judges, 8 obstetricians and 7 pediatricians. The validation occurred through the assessment of the content of the protocol by the judges that received the instrument for data collection - checklist - which contained 7 items that represent the requisites to be met by the protocol. The validation of the content was achieved by applying the Content Validity Index.Result: in the judging process, all the items that represented requirements considered by the protocol obtained concordance within the established level (Content Validity Index > 0.75). Of 7 items, 6 have obtained full concordance (Content Validity Index 1.0) and the feasibility item obtained a Content Validity Index of 0.93. The global assessment of the instruments obtained a Content Validity Index of 0.99.Conclusion: the validation of content that was done was an efficient tool for the adjustment of the protocol, according to the judgment of experienced professionals, which demonstrates the importance of conducting a previous validation of the instruments. It is expected that this study will serve as an incentive for the adoption of universal tracking by other institutions through validated protocols.

ResumoObjetivo:validar o conteúdo do protocolo de prevenção da sepse precoce porStreptococcus agalactiaeem recém-nascidos.Método:estudo transversal, descritivo, do tipo metodológico, com abordagem quantitativa. A amostra foi composta por 15 juízes, oito médicos obstetras e sete pediatras. A validação ocorreu por intermédio da avaliação de conteúdo do protocolo pelos juízes, os quais receberam o instrumento de coleta de dados - checklist - contendo sete itens, que representam requisitos a serem contemplados no protocolo. A validação de conteúdo foi atingida mediante aplicação do Índice de Validade de Conteúdo.Resultado:no processo de julgamento, todos os itens que representam requisitos contemplados no protocolo obtiveram concordância dentro do nível estabelecido (Índice de Validade de Conteúdo >0,75). Dos sete itens, seis obtiveram concordância total, (Índice de Validade de Conteúdo 1.0) e o item exequibilidade obteve Índice de Validade de Conteúdo de 0,93. A avaliação global dos instrumentos obteve Índice de Validade de Conteúdo de 0,99.Conclusão:a validação de conteúdo realizada foi ferramenta eficaz para adequação do protocolo, de acordo com o julgamento de profissionais experientes, demonstrando a importância em se realizar validação prévia de instrumentos. Espera-se que, este estudo incentive a adoção do rastreio universal por outras instituições, mediante protocolos validados.

ResumenObjetivo:validar el contenido del protocolo de prevención de la sepsis precoz porStreptococcus agalactiaeen recién nacidos.Método:estudio transversal, descriptivo, del tipo metodológico, con un enfoque cuantitativo. La muestra fue conformada por 15 jueces, ocho obstetras y siete pediatras. La validación se dio a través de la evaluación de contenido del protocolo por los jueces, los cuales recibieron el instrumento de recolección de datos - checklist - conteniendo siete ítems, que representan los requisitos para ser incluidos en el protocolo. La validación de contenido se logró a través de la aplicación del Índice de Validez de Contenido.Resultado:en el proceso de evaluación, todos los ítems que representan los requisitos contemplados en el protocolo obtuvieron una concordancia dentro del nivel establecido (Índice de Validez de Contenido > 0,75). De los siete ítems, seis obtuvieron una concordancia total (Índice de Validez de Contenido 1,0), y el ítem viabilidad obtuvo un Índice de Validez de Contenido de 0,93. La evaluación global de los instrumentos obtuvo un Índice de Validez de Contenido de 0,99.Conclusión:la validación de contenido realizada fue una herramienta eficaz para la adecuación del protocolo, según la evaluación de profesionales expertos, demostrando así la importancia de realizar la validación previa de los instrumentos. Se espera que este estudio fomente la adopción del cribado (screening) universal por otras instituciones, mediante protocolos validados.

Risk behaviors for sexually transmitted diseases among crack users / Comportamentos de risco para doenças sexualmente transmissíveis em usuários de crack / Conductas de riesgo para enfermedades de transmisión sexual entre usuarios de crack

AbstractObjectives: to investigate the prevalence and risk behaviors by means of reporting of sexually transmitted diseases among crack users.Method: cross-sectional study carried out with 588 crack users in a referral care unit for the treatment of chemical dependency. Data were collected by means of face-to-face interview and analyzed using Stata statistical software, version 8.0.Results: of the total participants, 154 (26.2%; 95% CI: 22.8-29.9) reported antecedents of sexually transmitted diseases. Ages between 25 and 30 years (RP: 2.1; 95% CI: 1.0-4.0) and over 30 years (RP: 3.8; 95% CI: 2.1-6.8), alcohol consumption (RP: 1.9; 95% CI: 1.1-3.3), antecedents of prostitution (RP: 1.9; 95% CI: 1.3-2.9) and sexual intercourse with person living with human immunodeficiency virus/AIDS (RP: 2.7; 95% CI: 1.8-4.2) were independently associated with reporting of sexually transmitted diseases.Conclusion: the results of this study suggest high risk and vulnerability of crack users for sexually transmitted diseases.

ResumoObjetivos:investigar a prevalência e comportamentos de risco através do relato de doenças sexualmente transmissíveis em usuários de crack.Método:estudo transversal, realizado com 588 usuários de crack, de uma unidade de referência para tratamento de dependência química. Os dados foram obtidos por meio de entrevista face a face e analisados em programa estatístico Stata, versão 8.0.Resultados:do total de participantes, 154 (26,2%; IC 95%: 22,8-29,9) referiram antecedentes de doenças sexualmente transmissíveis. Idade entre 25 e 30 anos (RP: 2,1; IC 95%: 1,0-4,0) e superior a 30 anos (RP: 3,8; IC 95%: 2,1-6,8), consumo de álcool (RP: 1,9; IC 95%: 1,1-3,3), antecedentes de prostituição (RP: 1,9; IC 95%: 1,3-2,9) e relação sexual com pessoa vivendo com o vírus da imunodeficiência humana/aids (RP: 2,7; IC 95%: 1,84,2) foram independentemente associados ao relato de doenças sexualmente transmissíveis.Conclusão:os resultados deste estudo sugerem elevado risco e vulnerabilidade dos usuários de crackpara as doenças sexualmente transmissíveis.

ResumenObjetivos:investigar la prevalencia y las conductas de riesgo a través del informe de las enfermedades de transmisión sexual entre los usuarios de crack.Método:estudio transversal con 588 usuarios de crack, de una unidad de referencia para el tratamiento de la dependencia química. Los datos fueron obtenidos a través de entrevista cara a cara y se analizaron utilizando el programa estadístico Stata, versión 8.0.Resultados:del total de participantes, 154 (26,2%; IC 95%: 22,8-29,9) informaron antecedentes de enfermedades de transmisión sexual. Edad entre 25 y 30 años (RP: 2,1; IC9 5%: 1,0-4,0) y superior a 30 años (RP: 3,8; IC 95%: 2,1-6,8), consumo de alcohol (OR: 1,9; IC 95%: 1,1-3,3), antecedentes de prostitución (RP: 1,9; IC 95%: 1,3-2,9) y relaciones sexuales con persona viviendo con el virus de inmunodeficiencia humana/ SIDA (RP: 2,7; IC 95%: 1,8-4,2) se asociaron de forma independiente con la notificación de las enfermedades de transmisión sexual.Conclusión:los resultados de este estudio sugieren alto riesgo y la vulnerabilidad de los usuarios de crackpara las enfermedades de transmisión sexual.

Tolerancia operacional en un receptor pediátrico de trasplante hepático: Caso clínico / Operational tolerance in a pediatric liver transplant recipient: Case report

La tolerancia operacional (ausencia de rechazo del injerto y buena evolución sin inmunosupresión) ha sido objeto de intensa investigación en trasplante hepático pediátrico en los últimos años. La morbimortalidad relacionada con la exposición a drogas inmunosupresoras a largo plazo en estos pacientes es bien conocida. Reportamos un caso de tolerancia operacional de nuestro centro en un receptor pediátrico de trasplante hepático libre de inmunosupresión desde los 16 meses postrasplante luego de una progresiva disminución a partir de su primoinfección asintomática por virus de Epstein-Barr, con buena evolución histológica y clínico-humoral en 22 meses de seguimiento. De acuerdo con nuestro conocimiento, este es el primer caso de tolerancia operacional en un receptor pediátrico de trasplante hepático reportado en nuestro país y creemos que debería profundizarse el estudio de estos pacientes para detectar características que permitan identificar una población potencialmente tolerante en la cual es posible disminuir y suspender la inmunosupresión.

Operational tolerance (absence of allograft rejection and good outcome without immunosuppression) has been object of intense research in pediatric liver transplant in the last years. The morbidity and mortality related to long-term immunosuppressive treatment of these patients are well known. We report a case of operational tolerance of our unit in a pediatric liver transplant recipient who is immunosuppressant-free since 16 month after transplant after progressive withdrawal related to asymptomatic Epstein-Barr virus first infection. He has good histological, clinical and serological outcome after 22 month of follow-up. To our knowledge, this is the first operational tolerance reported case in our country after liver transplant in a pediatric recipient and we believe that the study of these patients is important in order to detect characteristics that allow to identify a potentially tolerant group in which it is possible to withdraw immunosuppressive drugs.

Comparación de resultados entre el retrasplante y el trasplante renal primario en el Hospital Hermanos Ameijeiras de 1984 a 2012 / Comparison of results between retransplantation and primary kidney transplantation on Hermanos Ameijeiras Hospital from 1984 to 2012

Introducción: el retrasplante constituye la mejor opción terapéutica para los enfermos que pierden un primer trasplante renal y vuelven a diálisis, existen disímiles criterios en cuanto a sus resultados al compararlos con los trasplantes renales primarios. Objetivo: analizar el porcentaje de retrasplantes, revisar la supervivencia del injerto y del enfermo, el comportamiento de variables que pueden incidir en los resultados y compararlos con los de los enfermos que reciben un primer trasplante renal. Métodos: se realizó un estudio analítico, descriptivo, retrospectivo, de los trasplante renales realizados en el Hospital Hermanos Ameijeiras desde 1984 hasta diciembre de 2012; quedaron excluidos, los terceros trasplante, dobles (2 riñones a un mismo receptor), combinados (páncreas-riñón e hígado-riñón) y aquellos en los que no fue posible obtener la información requerida para la investigación. Se compararon (entre los grupos retrasplantes y primeros trasplantes) variables de índole general: edad de los receptores y donantes, sexo del receptor, enfermedad que ocasionó la insuficiencia renal, porcentaje de reactividad ante un panel de linfocito (PRA), compatibilidades HLA, tipo de donante (vivo o cadáver), tiempos de isquemia, presencia y duración de necrosis tubular aguda (donante cadáver), rechazo y supervivencia del injerto y el paciente. Resultados: los retrasplantes constituyeron el 5,4 por ciento de la muestra. No existieron diferencias entre edades, sexo, PRA, compatibilidades ni tipo de donante entre los segundos y primeros injertos. Los enfermos que llegaron a la insuficiencia renal por riñones poliquísticos nunca han recibido en nuestro centro un segundo trasplante. Resultó significativamente estadístico el uso de terapia cuádruple secuencial como inmunosupresión de inducción en los retrasplantes (55,9 por ciento vs. 9,7 por ciento de los primarios...

Introduction: retransplant constitutes the best therapeutic choice for patients who lose a first renal transplant and return to dialysis, existing dissimilar criteria as to its results when ranking them with renal primary transplant. Objective: to analyze the percentage of retransplantation, to revise graft and patient survival, to review the behavior of variables that can affect the results and to compare them with patients receiving a first renal transplant. Methods: an analytic, descriptive, retrospective study was accomplished, including all renal transplant performed at the Hermanos Ameijeiras Hospital from 1984 to December of 2012. Third transplants, double transplants (two kidneys to the same receptor), combined transplants (pancreas-kidney and liver-kidney) and those where it was not possible to obtain the information required for this research were excluded. Variables of general nature were compared between retransplantation groups and first transplants, such as: age of recipient and donor, sex of the recipient, a disease that caused kidney failure, percentage of reactivity to a lymphocyte panel (PRA), HLA compatibility, donor type (living or dead), ischemia time, presence and duration of acute tubular necrosis (dead donor), rejection and graft and patient survival. Results:rRetransplant constituted only 5.4 percent of the sample (34 patients). There were no differences in age, sex, PRA, donor type or compatibilities between the second and first grafts. Patients who reached the renal failure due to polycystic kidneys have never had a second transplant in our institution. The use of sequential quadruple therapy as induction immunosuppression, retransplantation (55.9 percent vs. 9.7 percent of primary) was statistically significant...

Long-term outcomes of children after solid organ transplantation

Solid organ transplantation has transformed the lives of many children and adults by providing treatment for patients with organ failure who would have otherwise succumbed to their disease. The first successful transplant in 1954 was a kidney transplant between identical twins, which circumvented the problem of rejection from MHC incompatibility. Further progress in solid organ transplantation was enabled by the discovery of immunosuppressive agents such as corticosteroids and azathioprine in the 1950s and ciclosporin in 1970. Today, solid organ transplantation is a conventional treatment with improved patient and allograft survival rates. However, the challenge that lies ahead is to extend allograft survival time while simultaneously reducing the side effects of immunosuppression. This is particularly important for children who have irreversible organ failure and may require multiple transplants. Pediatric transplant teams also need to improve patient quality of life at a time of physical, emotional and psychosocial development. This review will elaborate on the long-term outcomes of children after kidney, liver, heart, lung and intestinal transplantation. As mortality rates after transplantation have declined, there has emerged an increased focus on reducing longer-term morbidity with improved outcomes in optimizing cardiovascular risk, renal impairment, growth and quality of life. Data were obtained from a review of the literature and particularly from national registries and databases such as the North American Pediatric Renal Trials and Collaborative Studies for the kidney, SPLIT for liver, International Society for Heart and Lung Transplantation and UNOS for intestinal transplantation.

Issues in solid-organ transplantation in children: translational research from bench to bedside

In this review, we identify important challenges facing physicians responsible for renal and cardiac transplantation in children based on a review of the contemporary medical literature. Regarding pediatric renal transplantation, we discuss the challenge of antibody-mediated rejection, focusing on both acute and chronic antibody-mediated rejection. We review new diagnostic approaches to antibody-mediated rejection, such as panel-reactive antibodies, donor-specific cross-matching, antibody assays, risk assessment and diagnosis of antibody-mediated rejection, the pathology of antibody-mediated rejection, the issue of ABO incompatibility in renal transplantation, new therapies for antibody-mediated rejection, inhibiting of residual antibodies, the suppression or depletion of B-cells, genetic approaches to treating acute antibody-mediated rejection, and identifying future translational research directions in kidney transplantation in children. Regarding pediatric cardiac transplantation, we discuss the mechanisms of cardiac transplant rejection, including the role of endomyocardial biopsy in detecting graft rejection and the role of biomarkers in detecting cardiac graft rejection, including biomarkers of inflammation, cardiomyocyte injury, or stress. We review cardiac allograft vasculopathy. We also address the role of genetic analyses, including genome-wide association studies, gene expression profiling using entities such as AlloMap®, and adenosine triphosphate release as a measure of immune function using the Cylex® ImmuKnow™ cell function assay. Finally, we identify future translational research directions in heart transplantation in children.

Blood transfusion-related immunomodulation

The phenomenon of transfusion-related immunomodulation (TRIM) has been studied since the observation of a higher kidney allograft survival in patients who had received a higher number of transfusions. Conversely, it has been suggested as one of the possible causes related to the development of infections in patients with multiple blood transfusions and/or after a major surgery, and has been also associated with a decreased function of natural killer cells (NK) and antigen-presenting cells (APCs), reduced cell-mediated immunity, and increased regulatory T cells (Tregs). This review aimed to conceptualize TRIM and discuss some aspects related to its mechanisms and the prevention of immunomodulatory events.

Sirolimus Conversion Efficacy for Graft Function Improvement and Histopathology in Renal Recipients with Mild to Moderate Renal Insufficiency

This study was designed to evaluate whether sirolimus (SRL) conversion effectively improves renal function and histopathology in calcineurin inhibitor (CNI)-treated renal recipients with mild to moderate renal insufficiency. SRL conversion from CNI was performed in patients who underwent kidney transplantation from 6 months to 5 yr prior to screening. Forty-five patients were enrolled. The effect of SRL conversion on graft function was evaluated, and protocol biopsies were performed preconversion and 1 yr after conversion. Overall graft function after SRL conversion gradually improved, and the improvement in renal function was closely associated with the shorter duration of CNI exposure. When we divided the patients by the duration of CNI exposure, the patients with less than 1 yr of CNI exposure demonstrated significant improvement, but patients with a greater than 1 yr CNI exposure did not exhibit significant improvement. In contrast, protocol biopsies demonstrated no significant improvements in the modified "ah" score or other Banff scores after SRL conversion. Furthermore, the duration of CNI treatment prior to SRL conversion was not associated with histological findings 1 yr after SRL conversion. SRL conversion improved graft function in renal recipients with mild to moderate renal insufficiency, but this effect is not accompanied by histological improvement.

Utilización de Eculizumab en un receptor de trasplante renal con altos títulos de anticuerpos preformados anti-HLA donante específico / Use of Eculizumab in a kidney transplant receptor with high levels of donor-specific anti-HLA preformed antibodies

Presentamos un caso en el que, por primera vez en América latina, se utilizó eculizumab, un anticuerpo que inhibe la activación terminal del complemento, para la prevención de rechazo mediado por anticuerpos (RMA) en un receptor de trasplante renal con títulos altos de anticuerpos anti-HLA específico de donante preformados. El paciente, un hombre de 51 años de edad, trasplantado por segunda vez, receptor de un injerto de donante vivo relacionado, recibió, antes del trasplante, cuatro sesiones de plasmaféresis y terapia con tacrolimus y micofenolato sódico hasta el día del trasplante. La terapia de inducción fue con inmunoglobulina antitimocítica e inmunoglobulina intravenosa(IVIg). La administración de eculizumab fue del siguiente modo: 1200 mg. dos horas antes del trasplante; 600mg dentro de las primeras 24 horas posteriores al trasplante; durante un mes, una vez por semana, 600 mg. Al día 30, una dosis de 1200 mg. A un mes del trasplante, el paciente muestra buena función del injerto.

Imunoproteção de ilhotas pancreáticas microencapsuladas em biomateriais inovadores e seu potencial terapêutico no diabetes mellitus tipo 1 / Immunoprotection of pancreatic islets microencapsulated in inovative biomaterials and its therapeutic potential in type 1 Diabetes Mellitus

O transplante de ilhotas microencapsuladas constitui uma alternativa terapêutica interessante para o Diabetes Mellitus tipo 1, permitindo um melhor controle glicêmico e eliminando a necessidade de imunossupressão. Entretanto, a manutenção a longo prazo da viabilidade das células-β ainda é um desafio. No isolamento, a perda da matriz extracelular e as condições hipóxicas subsequentes afetam decisivamente a sobrevivência e funcionalidade das ilhotas. Objetivo Para diminuir o estresse sobre o enxerto, levando a um sucesso prolongado do transplante, propôs-se a adição de perfluorocarbono (PFC) ou laminina (LN), moléculas associadas respectivamente à oxigenação e interações célula-célula, ao biomaterial baseado em alginato, Biodritina, adequado ao encapsulamento celular. Metodologia Para testar a estabilidade das formulações PFC-Biodritina e LN-Biodritina, microcápsulas foram submetidas a diferentes estresses (rotacional, osmótico, temperatura e cultura) por 7 e 30 dias. A pureza do biomaterial foi avaliada pela coincubação com macrófagos murinos RAW264.7, por 3, 9 e 24h, quando a ativação dos macrófagos foi observada pela expressão gênica de IL- 1β e TNFα. Microcápsulas implantadas i.p. em camundongos foram recuperadas após 7 ou 30 dias, para análises de biocompatibilidade. A expressão de níveis de mRNA (bax, bad, bcl-2, bcl-XL, xiap, caspase 3, mcp1/ccl2, hsp70, ldh, insulina 1 e 2), proteínas (Bax, Bcl-XL e Xiap) e a atividade de Caspase3 foram avaliadas em ilhotas microencapsuladas com PFC- e LN-Biodritina, após cultura de 48h em condições de normóxia e hipóxia (<2% O2). Camundongos diabéticos foram transplantados com ilhotas encapsuladas nas diferentes formulações e os animais foram monitorados pelas variações de massa corporal, glicêmicas e pela funcionalidade do enxerto (TOTGs). As ilhotas foram recuperadas de animais normo ou hiperglicêmicos e uma análise de biocompatibilidade das cápsulas foi realizada, assim como a avaliação funcional das células-β...

Transplantation of microencapsulated islets represents an attractive therapeutical approach to treat type 1 Diabetes Mellitus, accounting for an improved glycemic control and the abolishment of immunosuppressive therapies. However, maintenance of long-term β-cell viability remains a major problem. During islet isolation, the loss of extracellular matrix interactions and the hypoxic conditions thereafter dramatically affect β-cell survival and function. Objective To lessen the burden of islet stress and achieve a better outcome in islet transplantation we tested the addition of perfluorocarbon (PFC) or laminin (LN), molecules associated respectively with oxygenation and cell-cell interaction, to Biodritin, an alginate-based material suitable for cell microencapsulation. Methodology To test the stability of PFC-Biodritin and LN-Biodritin composites, microcapsules were subjected to different stresses (rotational, osmotic, temperature and culture) for 7 and 30 days. To assess biomaterial purity microcapsules were co-incubated with RAW264.7 murine macrophage cell line for 3, 9 and 24h and macrophage activation was detected through mRNA levels of IL-1β and TNFα. Microcapsules were implanted i.p. in mice and retrieved after 7 or 30 days, for biocompatibility analyses. Gene expression at mRNA (bax, bad, bcl-2, bcl-XL, xiap, caspase 3, mcp1/ccl2, hsp70, ldh, insulin 1 and 2) and protein (Bax, Bcl-XL and Xiap) levels, together with Caspase3 activity, were evaluated in islets microencapsulated in PFC- or LN-Biodritin, upon culturing for 48h in normoxic or hypoxic (<2% O2) conditions. Diabetic mice were transplanted with PFC- or LN-Biodritin microencapsulated islets, followed by assessments of body weight, glycemia and graft function by oral glucose tolerance tests (OGTTs). Microencapsulated islets were retrieved from normoglycemic or hyperglycemic mice and biocompatibility analyses of the beads together with a functional assessment of the graft followed. After graft...

Induction of Donor-Specific Tolerance: Is This Achievable?

No abstract available.

Tolerancia inmune y trasplante hepático: introducción para clínicos / Immune tolerance and liver transplant: introduction for clinicians

Immunologic tolerance is the absence of immune response to an allograft, which is specific to graft and, therefore, implies an appropriate immune response to a third party. In clinical practice, a related concept is more frequently used: operational tolerance. Although its frequency is unknown in most of solid organ transplants it is present in the 20 percent of hepatic receptors. This means that tolerant receptors are able to maintain a normal graft function in complete absence of immunosuppressive drugs, avoiding the frequent –and sometimes severe– adverse effects related to its use. In this paper we aim to present physicians who are familiar to liver transplantation to basic concepts related to immune tolerance and operational tolerance in humans.

La tolerancia inmune es la ausencia de una respuesta efectora dirigida al injerto, la cual es específica y, por lo tanto, implica una apropiada respuesta inmune a una tercera parte. En la práctica clínica, un concepto relacionado, es frecuentemente utilizado: la tolerancia operacional. Su frecuencia es desconocida en el trasplante de la mayor parte de órganos sólidos, pero se estima que se desarrolla en el 20 por ciento de los receptores hepáticos. Estos receptores son capaces de mantener una función normal del injerto en ausencia completa e indefinida de inmunosupresores, lo cual les permite evitar los frecuentes y algunas veces graves efectos adversos relacionados con el uso de inmunosupresores. Este artículo pretende introducir a los médicos dedicados al trasplante hepático, a los conceptos básicos relacionados con la tolerancia inmune y la tolerancia operacional en humanos.

Innate immunity and transplantation tolerance: the potential role of TLRs/NLRs in GVHD / 대한혈액학회지

Graft-versus-host disease (GVHD) is a serious complication of allogeneic hematopoietic cell transplantation (HCT) and this occurs as donor T lymphocytes, activated by recipient antigen presenting cells (APC), attack the host tissues or organs. This APC activation is a crucial initial step of influencing the outcome of GVHD and is mediated by innate immune signaling. Toll-like receptors (TLRs) and nucleotide binding oligomerization domain (NOD)-like receptors (NLRs) are important components of innate immunity; both families of receptors are known for sensing various microbial ligands or danger signals. Signaling through TLRs/NLRs regulate activities of APCs, through phagocytosis, cytokine and chemokine release, delivery of APCs from peripheral tissues to draining lymph nodes, and antigen presentation. Several TLRs/NLRs have been identified and their ligands and signaling pathways have been described. Recent findings suggest a significant association of TLR/NLR polymorphisms with the increased risk for severe GVHD. Therefore, these TLR/NLR pathways likely contributing to immune response for GVHD may serve as novel therapeutic targets to facilitate allograft tolerance. This review summarizes the role of TLRs/NLRs innate immune receptors and signaling in GVHD pathophysiology.

Issues on Long-term Management after Liver Transplantation in Children / 대한이식학회지

With advancements of liver transplantation, the patient's survival improved remarkably. Thus the long-term survivors are increasing especially for the pediatric liver transplantation recipients. Consequently they are facing the challenge of maintaining graft function while minimizing long-term complications. In this review, I will discuss calcineurin inhibitor toxicity, problems with steroid, adherence to medical regimen, posttransplant growth, chronic graft dysfunction, tolerance.