RESUMEN
Donor criteria for liver grafts have been expanded because of organ shortage. Currently, no exact definitions for extended donor grafts have been established. The aim of this study was to analyze the impact of donor-specific risk factors, independent of recipient characteristics. In collaboration with Eurotransplant and European Liver Transplant Register, solely donor-specific parameters were correlated with 1-year survival following liver transplantation. Analyses of 4701 donors between 2000 and 2005 resulted in the development of a nomogram to estimate graft survival for available grafts. Predictions by nomogram were compared to those by Donor Risk Index (DRI). In the multivariate analysis, cold ischemic time (CIT), highest sodium, cause of donor death, γ-glutamyl transferase (γ-GT), and donor sex (female) were statistically significant factors for 3 months; CIT, γ-GT, and cause of donor death for 12-month survival. The median DRI of this study population was 1.45 (Q1: 1.17; Q3: 1.67). The agreement between the nomogram and DRI was weak (kappa = 0.23). Several donor-specific risk factors were identified for early survival after liver transplantation. The provided nomogram will support quick organ quality assessment. Nevertheless, this study showed the difficulties of determining an exact definition of extended criteria donors.
Asunto(s)
Trasplante de Hígado/métodos , Trasplante de Hígado/normas , Donantes de Tejidos , Obtención de Tejidos y Órganos/normas , Adulto , Isquemia Fría , Europa (Continente) , Femenino , Supervivencia de Injerto , Humanos , Fallo Hepático/mortalidad , Fallo Hepático/terapia , Masculino , Persona de Mediana Edad , Análisis Multivariante , Nomogramas , Sistema de Registros , Factores de Riesgo , Factores Sexuales , Resultado del Tratamiento , Listas de Espera , gamma-Glutamiltransferasa/metabolismoRESUMEN
In an earlier study, we were able to show that Tac monotherapy following 2 × 20 mg alemtuzumab induction is at least as effective as Tac-based triple-drug immunosuppression in cadaveric renal transplantation. We were interested to learn whether 1 × 30 mg of alemtuzumab is as effective as 2 × 20 mg. Patients of the initial study group (group A) received 20 mg alemtuzumab on days 0 and 2, and tac monotherapy from day 2 on. This group acted as control group for the new arm (group C), where patients were given only 1 × 30 mg alemtuzumab on day 0 followed by Tac monotherapy from day 2 on with the same target levels as in the control group. Frequency of rejection at 6 months was 15% in the control group compared to 6% in the study group and 20% at 12 months in group A versus 6% in group C (P = 0.034). Time to rejection was 4.9 months in group A and 0.8 in group C. One-year patient survival was 98.5% in both groups, graft survival 96.9% in group A, and 98.5% in group C. Safety profile was similar in both groups apart from more viral and bacterial infections in group C. Single shot alemtuzumab induction of 30 mg is as effective as 2 × 20 mg in cadaveric renal transplantation.
Asunto(s)
Anticuerpos Monoclonales Humanizados/administración & dosificación , Anticuerpos Antineoplásicos/administración & dosificación , Inmunosupresores/administración & dosificación , Trasplante de Riñón/efectos adversos , Adolescente , Adulto , Anciano , Alemtuzumab , Infecciones por Citomegalovirus , Femenino , Rechazo de Injerto , Supervivencia de Injerto/efectos de los fármacos , Humanos , Terapia de Inmunosupresión/métodos , Masculino , Persona de Mediana Edad , Terapia Neoadyuvante , Tacrolimus/uso terapéutico , Resultado del TratamientoRESUMEN
The aim of the present study was to describe the current situation of donation after circulatory death (DCD) in the Council of Europe, through a dedicated survey. Of 27 participating countries, only 10 confirmed any DCD activity, the highest one being described in Belgium, the Netherlands and the United Kingdom (mainly controlled) and France and Spain (mainly uncontrolled). During 2000-2009, as DCD increased, donation after brain death (DBD) decreased about 20% in the three countries with a predominant controlled DCD activity, while DBD had increased in the majority of European countries. The number of organs recovered and transplanted per DCD increased along time, although it remained substantially lower compared with DBD. During 2000-2008, 5004 organs were transplanted from DCD (4261 kidneys, 505 livers, 157 lungs and 81 pancreas). Short-term outcomes of 2343 kidney recipients from controlled versus 649 from uncontrolled DCD were analyzed: primary non function occurred in 5% vs. 6.4% (P = NS) and delayed graft function in 50.2% vs. 75.7% (P < 0.001). In spite of this, 1 year graft survival was 85.9% vs. 88.9% (P = 0.04), respectively. DCD is increasingly accepted in Europe but still limited to a few countries. Controlled DCD might negatively impact DBD activity. The degree of utilization of DCD is lower compared with DBD. Short-term results of DCD are promising with differences between kidney recipients transplanted from controlled versus uncontrolled DCD, an observation to be further analyzed.
Asunto(s)
Muerte Encefálica , Muerte , Donantes de Tejidos/estadística & datos numéricos , Obtención de Tejidos y Órganos/estadística & datos numéricos , Europa (Continente) , Supervivencia de Injerto , Humanos , Trasplante de Riñón/estadística & datos numéricos , Trasplante de Hígado/estadística & datos numéricos , Trasplante de Pulmón/estadística & datos numéricos , Trasplante de Páncreas/estadística & datos numéricosRESUMEN
Distinct lymphocyte populations have been identified that either promote or impede the establishment of chimerism and tolerance through allogeneic bone marrow transplantation (BMT). Natural killer T (NKT) cells have pleiotropic regulatory properties capable of either augmenting or downmodulating various immune responses. We investigated in this study whether NKT cells affect outcome in mixed chimerism models employing fully mismatched nonmyeloablative BMT with costimulation blockade (CB). The absence of NKT cells had no detectable effect on chimerism or skin graft tolerance after conditioning with 3Gy total body irradiation (TBI), and a limited positive effect with 1Gy TBI. Stimulation of NKT cells with alpha-galactosylceramide (alpha-gal) at the time of BMT prevented chimerism and tolerance. Activation of recipient (as opposed to donor) NKT cells was necessary and sufficient for the alpha-gal effect. The detrimental effect of NKT activation was also observed in the absence of T cells after conditioning with in vivo T-cell depletion (TCD). NKT cells triggered rejection of BM via NK cells as chimerism and tolerance were not abrogated when NKT cells were stimulated in the absence of both NK cells and T cells. Thus, activation of NKT cells at the time of BMT overcomes the effects of CB, inhibiting the establishment of chimerism and tolerance.
Asunto(s)
Células Asesinas Naturales/citología , Linfocitos T/citología , Animales , Trasplante de Médula Ósea , Quimerismo , Femenino , Galactosilceramidas/farmacología , Sistema Inmunológico , Tolerancia Inmunológica , Inmunosupresores/uso terapéutico , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C3H , Ratones Endogámicos C57BL , Trasplante de Piel/métodos , Irradiación Corporal TotalRESUMEN
BACKGROUND: In an attempt to monitor the pharmacodynamics of mycophenolate mofetil (MMF) we investigated the association of inosine monophosphate dehydrogenase (IMPDH) activity in peripheral blood mononuclear cells with the expression of lymphocyte activation markers in stable cardiac transplant recipients treated with MMF. METHODS: Twenty-four study patients were switched from azathioprine to MMF 7.2+/-4.1 years after heart transplantation. RESULTS: While the MPA trough level remained unchanged, the mean activity of IMPDH declined from 890 to 462 pmol/10(6)PBMC/h three months after onset of MMF therapy, was almost completely inhibited at six months and partially restored to 160 pmol/10(6)PBMC/h 12 months after switch to MMF (p< .0001). We detected also significant changes in a number of activated lymphocyte subsets: CD4+/25+, CD8+/38+, CD19+/69+, CD3+/16+/56+, natural killer (NK) cells, and monocytes. Moreover, the IMPDH activity profile correlated positively with the number of CD8+/38+ T cells (correlation coefficient (CC) +0.53), and inversely with NK cells (CC -0.52) and CD19+/69+ cells (CC -0.61). CONCLUSIONS: We revealed a close association of IMPDH baseline activity in mononuclear cells with the expression of lymphocyte activation markers in stable heart transplant patients after introduction of MMF therapy. This supports the assumption of a rather immunomodulatory than immunosuppressive effect of MMF.
Asunto(s)
IMP Deshidrogenasa/metabolismo , Activación de Linfocitos/efectos de los fármacos , Activación de Linfocitos/inmunología , Ácido Micofenólico/análogos & derivados , Adulto , Femenino , Trasplante de Corazón , Humanos , Masculino , Persona de Mediana Edad , Ácido Micofenólico/farmacologíaRESUMEN
BACKGROUND: The purpose of this study was to analyze the impact of extended donor criteria (EDC) and of changes in the Model for End-Stage Liver Disease (MELD) score while waiting for liver-transplantation (Delta-MELD) on patient survival and initial graft function. METHODS: We included 386 consecutive patients with end-stage liver disease who underwent orthotopic liver transplantation at the Medical University Vienna between 1997 and 2003. Primary outcome was patient survival and secondary outcome was initial graft function. EDC included: age >60 years, >4 days intensive medical care, cold ischemia time >10 hr, need for noradrenalin >0.2 microg/kg/min or doputamin >6 microg/kg/min, a donor peak serum sodium >155 mEq/L, a donor serum creatinine >1.2 mg/100 mL, and a body mass index >30. RESULTS: Delta-MELD was significantly higher in the nonsurvivor population (P=0.01) and EDC showed a significant influence on initial graft function (P=0.01). Worsening in either Delta-MELD or the presence of at least two EDC was not associated with an increased risk of primary graft dysfunction and death. Worsening in Delta-MELD and the presence of at least two EDC was significantly associated with primary graft dysfunction (P=0.01) and death (P=0.008). CONCLUSION: The combination of a liver recipient with worsening Delta-MELD and a potential donor with at least two EDC should be avoided.
Asunto(s)
Fallo Hepático/cirugía , Trasplante de Hígado/fisiología , Donantes de Tejidos , Colestasis Intrahepática/cirugía , Estudios de Seguimiento , Hepatitis B/cirugía , Hepatitis C , Humanos , Cirrosis Hepática Alcohólica/cirugía , Fallo Hepático/clasificación , Trasplante de Hígado/efectos adversos , Trasplante de Hígado/mortalidad , Oportunidad Relativa , Selección de Paciente , Complicaciones Posoperatorias/epidemiología , Estudios Retrospectivos , Análisis de Supervivencia , Sobrevivientes , Factores de Tiempo , Listas de EsperaRESUMEN
Bone marrow transplantation (BMT) under costimulation blockade induces mixed chimerism and tolerance in rodent models. Recent data, predominantly from in vitro studies, suggest that in addition to blocking the CD28 costimulation pathway CTLA4Ig also acts through upregulating the tryptophan-catabolizing enzyme indoleamine-2,3-dioxygenase (IDO). Here we demonstrate that even though CTLA4Ig is critically required for the induction of chimerism and tolerance in a murine model of nonmyeloablative BMT, IDO activity is not. No significant differences were detectable in the kynurenine to tryptophan ratios (indicative of IDO activity) in sera of BMT recipients treated with CTLA4Ig (tolerant group) versus BMT recipients treated without CTLA4Ig (nontolerant group) versus naïve controls. In vivo inhibition of IDO immediately after BMT with CTLA4Ig or several months thereafter did not block achievement of chimerism and tolerance. Thus, IDO does not play a critical role in the induction or maintenance of chimerism and tolerance in a CTLA4Ig-based BMT model.
Asunto(s)
Trasplante de Médula Ósea/inmunología , Tolerancia Inmunológica/inmunología , Inmunoconjugados/uso terapéutico , Indolamina-Pirrol 2,3,-Dioxigenasa/metabolismo , Abatacept , Animales , Tolerancia Inmunológica/efectos de los fármacos , Inmunosupresores/uso terapéutico , Ratones , Ratones Endogámicos BALB C , Quimera por Trasplante , Trasplante Homólogo/inmunología , Irradiación Corporal TotalRESUMEN
BACKGROUND: Induction of mixed chimerism and tolerance usually requires cytoreduction or transplantation of high numbers of bone marrow cells (BMC). However, such protocols have only a suboptimal success rate and, more importantly, equivalent numbers of BMC cannot be routinely obtained in the clinical setting. The authors therefore evaluated whether a short-course of immunosuppression (IS) given in addition to co-stimulation blockade would facilitate chimerism induction and allow reduction of the minimally required number of BMC without cytoreduction. METHODS: B6 mice received 200, 100, or 50 x 10 unseparated BMC from Balb/c donors plus an anti-CD40L monoclonal antibody (mAb) and CTLA4Ig (without irradiation or cytotoxic drugs). Some groups were treated additionally with IS (rapamycin, methylprednisolone, and mycophenolate mofetil for 4 weeks after bone marrow transplantation), donor-specific transfusion (DST), or anti-OX40L mAb, as indicated. RESULTS: IS led to long-term multilineage chimerism in 9 of 10 mice receiving 200 x 10 BMC (without IS, 1 of 4; P<0.05), in all mice (n=10) receiving 100 x 10 (without IS, 6 of 9; P<0.05), and notably in 9 of 10 mice treated with 50 x 10 BMC (without IS, 4 of 10; P<0.05). With transient IS, donor skin grafts were accepted longer than 170 days in 9 of 10 mice receiving 200 x 10 (without IS, 0 of 5 mice; P<0.05), all mice receiving 100 x 10 (without IS, 6 of 9; P<0.05), and 6 of 11 mice receiving 50 x 10 BMC (without IS, 4 of 10). The use of DST or anti-OX40L mAb had no beneficial effect. CONCLUSIONS: Transient IS significantly improves rates of chimerism and donor skin graft survival, and allows lasting mixed chimerism after transplantation of only 50 x 10 BMC. Thus, IS might help in the further development of noncytoreductive chimerism protocols.
Asunto(s)
Trasplante de Médula Ósea/inmunología , Supervivencia de Injerto/fisiología , Terapia de Inmunosupresión/métodos , Trasplante de Piel/inmunología , Quimera por Trasplante , Tolerancia al Trasplante , Abatacept , Animales , Anticuerpos Monoclonales/uso terapéutico , Humanos , Inmunoconjugados/uso terapéutico , Ratones , Ratones Endogámicos C57BL , Acondicionamiento Pretrasplante/métodos , Trasplante HomólogoAsunto(s)
Conservadores de la Densidad Ósea/administración & dosificación , Difosfonatos/administración & dosificación , Fracturas Óseas/prevención & control , Imidazoles/administración & dosificación , Trasplante de Hígado , Anciano , Densidad Ósea/efectos de los fármacos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Ácido ZoledrónicoRESUMEN
The transplantation of donor hematopoietic stem cells has been used successfully in numerous experimental settings to induce donor-specific tolerance. After appropriate host conditioning, hematopoietic stem-cell transplantation leads to a lasting state of donor macrochimerism that is associated with a robust form of tolerance. One of the key factors in the success of this approach is its reliance on intrathymic clonal deletion to ensure lifelong tolerization of newly developing T cells. Evidence for ongoing central deletion comes from studies following superantigen-reactive T cells and from experiments using mice transgenic for an alloreactive T-cell receptor. In protocols inducing tolerance through macrochimerism, the preexisting mature T-cell repertoire is controlled by either globally destroying all T cells before the hematopoietic cell transplantation or, in more recent models, by tolerizing it through co-stimulation blockade. The peripheral mechanisms induced by hematopoietic stem-cell transplantation and co-stimulation blockade include both extrathymic clonal deletion and the nondeletional mechanisms anergy, suppression, or both. In addition to these immunologic hurdles, a physiologic engraftment barrier has to be surmounted for the successful induction of mixed chimerism. This can be achieved by cytoreductive host treatment or by the infusion of high numbers of donor hematopoietic cells. A detailed delineation of the mechanisms responsible for tolerance induction after hematopoietic stem-cell transplantation is expected to help in the translation of these experimental protocols to clinical organ transplantation.
Asunto(s)
Donantes de Tejidos , Tolerancia al Trasplante/fisiología , Animales , Trasplante de Células Madre Hematopoyéticas , Humanos , Quimera por Trasplante/fisiología , Inmunología del Trasplante/fisiologíaRESUMEN
This is the first multicenter, randomized, open-label study to compare the efficacy and safety of cyclosporine A microemulsion (CsA-ME) (Neoral, Novartis, Basel, Switzerland ) with C2 monitoring versus tacrolimus in de novo liver transplant recipients. Patients were stratified according to hepatitis C virus status and randomized to receive CsA-ME (n= 250) or tacrolimus (n= 245) with steroids, with or without azathioprine. The primary endpoint was the incidence of biopsy-proven acute rejection (BPAR) at 3 months. Secondary endpoints included death or graft loss and safety evaluations at 6 months. The incidence of BPAR at 3 months was 26% in the CsA-ME group and 24% in the tacrolimus group (not significant). At 6 months, 89% of patients receiving CsA-ME and 88% of patients receiving tacrolimus were alive with a functioning graft. Among the hepatitis C virus-positive patients, there was no difference in BPAR, but death or graft loss was more frequent in those receiving tacrolimus (15% vs. 6%, P <0.05). Diabetes mellitus (14% vs. 7%, P <0.02) and diarrhea (29% vs. 14%, P <0.001) were significantly more often reported in patients receiving tacrolimus. The incidence of hypertension was similar in both groups. At 6 months, the median total cholesterol was 4.7 mmol/L (2.9-7.4 mmol/L) in the CsA-ME arm versus 4.3 mmol/L (2.5-6.4 mmol/L) in the tacrolimus arm; the median serum creatinine was 106 micromol/L (52-238 micromol/L) in the CsA-ME arm versus 103 micromol/L (44-477 micromol/L) in the tacrolimus arm. Efficacy is equivalent with CsA-ME using C2 monitoring or tacrolimus in liver transplant recipients. The incidence of adverse events is comparable except for a significantly higher incidence of diabetes mellitus and diarrhea in the tacrolimus group. Both agents are effective primary immunosuppressants in liver transplant recipients.
Asunto(s)
Ciclosporina/sangre , Ciclosporina/uso terapéutico , Inmunosupresores/sangre , Inmunosupresores/uso terapéutico , Trasplante de Hígado , Monitoreo Fisiológico , Tacrolimus/uso terapéutico , Adulto , Anciano , Biopsia , Ciclosporina/efectos adversos , Diabetes Mellitus/etiología , Emulsiones , Rechazo de Injerto/epidemiología , Hepacivirus/aislamiento & purificación , Humanos , Inmunosupresores/efectos adversos , Incidencia , Hígado/patología , Hepatopatías/cirugía , Hepatopatías/virología , Persona de Mediana Edad , Tacrolimus/efectos adversos , Factores de Tiempo , Resultado del TratamientoRESUMEN
The routine induction of tolerance in organ transplant recipients remains an unattained goal. The creation of a state of mixed chimerism through allogeneic bone marrow transplantation leads to robust donor-specific tolerance in several experimental models and this approach has several features making it attractive for clinical development. One of its major drawbacks, however, has been the toxicity of the required host conditioning. The use of costimulation blocking reagents (anti-CD 154 monoclonal antibodies and the fusion protein CTLA4Ig) has led to much less toxic models of mixed chimerism in which global T cell depletion of the host is no longer necessary and which has even allowed the elimination of all cytoreductive treatment when combined with the injection of very high doses of bone marrow cells. In this overview we will briefly discuss general features of tolerance induction through bone marrow transplantation, will then describe recent models using costimulation blockade to induce mixed chimerism and will review the mechanisms of tolerance found with these regimens. Finally we will attempt to identify issues related to the clinical introduction of bone marrow transplantation with costimulation blockade which remain unresolved.
Asunto(s)
Anticuerpos Monoclonales/uso terapéutico , Trasplante de Médula Ósea , Ligando de CD40/inmunología , Inmunoconjugados/uso terapéutico , Terapia de Inmunosupresión/métodos , Quimera por Trasplante/inmunología , Abatacept , Animales , Humanos , Linfocitos T/inmunologíaRESUMEN
Careful staging of hepatic tumors forms the basis of appropriate selection of, and is a precondition for, customized treatment. Advances in radiodiagnostic technology have increased the sensitivity of noninvasive liver staging by means of magnetic resonance imaging (MRI), computed tomography (CT), and helical CT (HCT). Nevertheless, surgical exploration and intraoperative ultrasonography (IOUS) are considered the "gold standard." The value of HCT and IOUS was investigated in patients who underwent orthotopic liver transplantation (OLT) (group A; n=23) or hepatic resection for hepatocellular carcinoma (HCC) (group B; n=52). In group A, the results of liver imaging (HCT performed immediately before OLT, IOUS) were compared with histopathological results after 3-mm slicing of the explanted liver. In group B, patients were evaluated by CT (n=8), HCT (n=43), MRI (n=18), or both, as indicated by the respective surgeon. The results were compared with those of surgical exploration and IOUS (n=52), as well as with the pathological examination of the resected liver specimen. In group A, 52 malignant lesions were detected by histopathology. By each of the preoperative examinations (IOUS, HCT), 54 lesions were suspected of being malignant. Thirteen HCCs were missed by HCT (for IOUS: n=4) and 15 lesions were false-positive (for IOUS: n=6). Thirty-nine of 52 lesions were verified to be true-positive by HCT in contrast to 48/52 by IOUS, which resulted in sensitivities of 75% (HCT) and 92% (IOUS, P=0.017), respectively. In group B, the sensitivity of CT was 77%, HCT 90%, MR 93%, and IOUS 99% (P<0.01). In 10%, the strategy of surgical treatment was changed because of IOUS findings. IOUS offered relevant additional information in 6%. Even after sufficient preoperative evaluation, IOUS can provide additional information that frequently has a remarkable impact on surgical decision-making. Identification of HCC is commonly hampered by coexistent cirrhosis. Identification of lesions and orientation of borders to non-tumorous tissue are assessed reliably by IOUS. Thus, IOUS remains a mandatory tool in patients treated by locoregional surgical modalities such as resection, cryotherapy, and intraoperative ethanol instillation for HCC even after refinement of radiological technologies.
Asunto(s)
Carcinoma Hepatocelular/diagnóstico por imagen , Carcinoma Hepatocelular/cirugía , Neoplasias Hepáticas/diagnóstico por imagen , Neoplasias Hepáticas/cirugía , Trasplante de Hígado , Ultrasonografía Intervencional , Humanos , Periodo Intraoperatorio , Imagen por Resonancia Magnética , Sensibilidad y Especificidad , Tomografía Computarizada EspiralRESUMEN
Allergy represents a hypersensitivity disease that affects >25% of the population in industrialized countries. The underlying type I allergic immune reaction occurs in predisposed atopic individuals in response to otherwise harmless Ags (i.e., allergens) and is characterized by the production of allergen-specific IgE, an allergen-specific T cell response, and the release of biologically active mediators such as histamine from mast cells and basophils. Regimens permanently tolerizing an allergic immune response still need to be developed. We therefore retrovirally transduced murine hematopoietic stem cells to express the major grass pollen allergen Phl p 5 on their cell membrane. Transplantation of these genetically modified hematopoietic stem cells led to durable multilineage molecular chimerism and permanent immunological tolerance toward the introduced allergen at the B cell, T cell, and effector cell levels. Notably, Phl p 5-specific serum IgE and IgG remained undetectable, and T cell nonresponsiveness persisted throughout follow-up (40 wk). Besides, mediator release was specifically absent in in vitro and in vivo assays. B cell, T cell, and effector cell responses to an unrelated control allergen (Bet v 1) were unperturbed, demonstrating specificity of this tolerance protocol. We thus describe a novel cell-based strategy for the prevention of allergy.
Asunto(s)
Alérgenos/administración & dosificación , Alérgenos/genética , Trasplante de Células Madre Hematopoyéticas , Hipersensibilidad/genética , Hipersensibilidad/inmunología , Tolerancia Inmunológica/genética , Alérgenos/inmunología , Animales , Antígenos de Plantas , Betula/genética , Betula/inmunología , Trasplante de Médula Ósea/inmunología , Trasplante de Médula Ósea/métodos , Femenino , Trasplante de Células Madre Hematopoyéticas/métodos , Hipersensibilidad/clasificación , Pruebas Intradérmicas , Ratones , Ratones Endogámicos BALB C , Phleum/genética , Phleum/inmunología , Proteínas de Plantas/administración & dosificación , Proteínas de Plantas/genética , Proteínas de Plantas/inmunología , Polen/genética , Polen/inmunología , Proteínas Recombinantes de Fusión/administración & dosificación , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/inmunología , Retroviridae/genética , Transducción Genética , Acondicionamiento PretrasplanteRESUMEN
Clinical translation of the mixed-chimerism approach for inducing transplantation tolerance would be facilitated if mobilized peripheral blood stem cells (mPBSCs) could be used instead of bone marrow cells (BMCs). Because the use of mPBSCs for this purpose has not been investigated in nonmyeloablative murine protocols, we explored the engraftment potential of mPBSCs in a CD45-congenic model as a first step. After 2, 1.5, or 1 Gy of total body irradiation, CD45.1 B6 hosts received unseparated granulocyte colony-stimulating factor-mobilized CD45.2 B6 PBSCs or unseparated CD45.2 B6 BMCs. The same total cell numbers, or aliquots of mPBSCs and BMCs containing similar numbers of c-kit+ cells, were transplanted both with and without a short course of rapamycin-based immunosuppression (IS). Transplantation of mPBSCs induced long-term multilineage macrochimerism, but chimerism levels were significantly lower than among recipients of the same number of BMCs. Transplanting aliquots containing similar numbers of c-kit+ cells reduced the difference between mPBSCs and BMCs, but lower levels of chimerism were nonetheless observed in mPBSC recipients. Chimerism levels correlated more closely with the number of transplanted progenitor cells as determined by colony-forming unit assays. IS did not affect chimerism levels, indicating that the donor CD45 isoform or other minor disparities do not pose a major barrier to engraftment. Our findings indicate that under nonmyeloablative conditions, progenitor cells contained in mPBSCs have an engraftment capacity similar to progenitor cells from BMCs, allowing induction of lasting mixed chimerism with moderate cell numbers. On a cell-per-cell basis, unseparated BMCs have some advantages that may be minimized if the number of progenitor cells is equalized. These results are expected to facilitate the development of mPBSC-based allogeneic tolerance protocols.
Asunto(s)
Movilización de Célula Madre Hematopoyética , Antígenos Comunes de Leucocito , Trasplante de Células Madre de Sangre Periférica , Quimera por Trasplante , Acondicionamiento Pretrasplante , Animales , Femenino , Movilización de Célula Madre Hematopoyética/métodos , Ratones , Trasplante de Células Madre de Sangre Periférica/métodos , Acondicionamiento Pretrasplante/métodos , Trasplante Homólogo , Irradiación Corporal Total/métodosRESUMEN
Model for end-stage liver disease (MELD) score has emerged as a useful tool in predicting mortality in patients awaiting liver transplantation. There is still, however, discussion as to whether further parameters could improve the sensitivity and specificity of the MELD score. From 1997 to 2003, 621 adult patients with end-stage liver disease were listed for orthotopic liver transplantation (OLT). Patients suffering from hepatoma were excluded from analysis (113 patients). The MELD score was investigated at the time of listing (MELD ON) and of coming off the list (MELD OFF). Patients who died while on the waiting list showed a significant increase in their MELD score during the waiting time (MELD ON: 21 +/- 7 vs. MELD OFF: 28 +/- 9) as well as a significantly higher MELD ON compared with patients who were transplanted (MELD ON: 16 +/- 5 vs. MELD OFF: 17 +/- 7) or removed from the waiting list (MELD ON: 16 +/- 6 vs. MELD OFF: 12 +/- 3). Multivariate analysis identified MELD ON, ascites and recurrent infection as independent risk factors for death on the waiting list (P < 0.01). MELD score was not identified as a predictor for the post-transplant survival rate. MELD score is a strong predictor for death on the waiting list, but refractory ascites and recurrent infection are independent risk factors, too.
Asunto(s)
Fallo Hepático/mortalidad , Fallo Hepático/cirugía , Trasplante de Hígado/mortalidad , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Modelos Biológicos , Asignación de Recursos , Factores de Riesgo , Tasa de Supervivencia , Obtención de Tejidos y Órganos , Listas de EsperaRESUMEN
Peripheral and central clonal deletion are important tolerance mechanisms in models using bone marrow transplantation (BMT) with costimulation blockade (CB). However, since tolerance can be found before peripheral deletion is complete and since elimination of recipient CD4(+) cells at the time of BMT prevents tolerance induction, we investigated the potential roles of regulation and anergy in such a murine model. We found that transient elimination of CD25(+) cells or neutralization of IL2 immediately after BMT and CB prevented the induction of skin graft tolerance. Cotransfer into SCID mice of CD4(+) cells taken from chimeras early after BMT, together with naive recipient-type CD4(+) cells significantly prolonged donor skin graft survival. In contrast, cotransfer of CD4(+) cells harvested from chimeras late after BMT did not prolong donor skin graft survival. Besides, depletion of CD25(+) cells in established chimeras several months post-BMT did not break tolerance. In vivo administration of recombinant IL2 inhibited chimerism and tolerance neither early nor late post-BMT, arguing against a decisive role for classical anergy. Thus, CD4 cell-mediated regulation contributes significantly to tolerance induction early after BMT, but appears to have no critical role in the maintenance of tolerance.
Asunto(s)
Trasplante de Médula Ósea/inmunología , Ligando de CD40/fisiología , Supresión Clonal/inmunología , Supervivencia de Injerto/inmunología , Tolerancia Inmunológica/fisiología , Interleucina-2/antagonistas & inhibidores , Quimera por Trasplante/inmunología , Animales , Anticuerpos Monoclonales/administración & dosificación , Linfocitos T CD4-Positivos/inmunología , Ligando de CD40/inmunología , Femenino , Rechazo de Injerto/inmunología , Humanos , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C3H , Ratones Endogámicos C57BL , Ratones SCID , Trasplante de Piel/inmunologíaRESUMEN
Despite extensive efforts in the fields of donor selection and management, standardisation of organ retrieval procedures, storage solutions, and novel immunosuppressive protocols, the rates of delayed graft function (DGF) after renal transplantation have been stagnating between 30% and 50%. As DGF exerts negative influences on acute rejection episodes and long-term organ function, the early phase of transplantation immediately following reperfusion deserves special interest. Several studies on machine-controlled reperfusion showed promising results in various organs, in experimental and clinical settings. Moreover, the flushing of organs with Carolina rinse solution (CR) immediately prior to reperfusion has been proven beneficial and is being clinically applied in human liver transplantation in recognised departments. In our study, we set up an autogenic porcine kidney transplantation model and assessed the normal values (control group) for creatinine clearance (ClCr) and urine output per hour (U/h) after "standard" reperfusion similar to clinical transplantation. Subsequently, kidneys of the experimental group 1 were reperfused at a blood pressure (RR) under the systemic level by means of a roller pump. Group 2 kidneys were rinsed with CR before controlled reperfusion, analogous to group 1. Both groups were compared with each other and with the assessed normal values. Our findings for Group 1 are that pressure-reduced reperfusion negatively affected immediate graft function. ClCr was reduced from 9.9 (control group) to 3.4 ml/min, U/h from 233 to 132 ml ( P<0.05). Group 2 showed that rinsing the kidneys with CR before reperfusion improved functional parameters highly significantly, compared with group 1 (ClCr: 13.5 vs 3.4 ml/min, U/h: 384 vs 132 ml; P<0.05) and even showed a positive trend compared with the control group (ClCr: 13.5 vs 9.9 ml/min, U/h: 384 vs 233 ml; P=0.0546). We can conclude that in a model of porcine renal autotransplantation, pressure-reduced reperfusion via a roller pump is detrimental to early kidney graft function. The flushing of organs with CR prior to controlled reperfusion significantly improves ClCr as well as urine output.
Asunto(s)
Trasplante de Riñón/fisiología , Daño por Reperfusión/prevención & control , Soluciones , Conservación de Tejido/métodos , Trasplante Autólogo/fisiología , Animales , Creatinina/metabolismo , Trasplante de Riñón/métodos , Reperfusión/métodos , Daño por Reperfusión/fisiopatología , Porcinos , Factores de Tiempo , Trasplante Autólogo/métodosRESUMEN
The goal of this study was to analyze the influence of multiple anastomosis on outcome in orthotopic liver transplantation (OLT) and its implications for split-liver and living related liver transplantation programs. In a retrospective study, 683 first OLTs in adults were analyzed. Complex hepatic artery reconstruction was defined as revascularization of the graft requiring additional anastomosis between donor hepatic arteries. OLT was performed in a standard manner. All patients had daily ultrasound examination. In this series we found 72 grafts (10.5%) with anatomic arterial variations that required complex hepatic artery reconstruction. There was no difference in primary organ function and demographic data compared with patients with simple arterial reconstruction. However, hepatic artery thrombosis (HAT) occurred in 9.7% of patients (7 of 72) with complex reconstruction in contrast to 2.0% in the control group (12 of 638; P <.001). Statistical analysis identified multiple anastomoses (P <.002) and primary nonfunction (P <.02) as significant risk factors for HAT. Three patients underwent successful thrombectomy for HAT, all others had to undergo retransplantation. Although in the group with complex arterial reconstruction increased graft loss caused by HAT was found early postoperatively, the overall 5-year patient and graft survival was not different for both groups. Although complex reconstruction is a risk factor for HAT, early diagnosis of HAT by daily ultrasound and early repeat OLT can provide similar 5-year survival as for patients with simple reconstruction. We conclude that complex hepatic artery reconstruction challenges conventional OLT as well as split-liver and living related liver transplantation, but does not necessarily affect its long-term outcome.
Asunto(s)
Arteria Hepática/cirugía , Fallo Hepático/cirugía , Trasplante de Hígado/métodos , Adolescente , Adulto , Anciano , Femenino , Supervivencia de Injerto , Humanos , Fallo Hepático/mortalidad , Trasplante de Hígado/mortalidad , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias/mortalidad , Modelos de Riesgos Proporcionales , Procedimientos de Cirugía Plástica , Estudios Retrospectivos , Factores de Riesgo , Trombosis/mortalidadRESUMEN
Sufficient assessment of potential candidates for orthotopic liver transplantation (OLT) is the most important factor for a low alcohol relapse rate after transplantation in patients suffering from alcoholic cirrhosis. In the current study the efficiency of pretransplant screening with carbohydrate-deficient transferrin (CDT) was analysed in patients on the waiting list for OLT. A prospective study was performed in 44 patients who had undergone OLT for alcoholic cirrhosis. All patients had had pretransplant assessment by a specialist psychologist and were found to have no problems with alcohol. Pre- and post-transplant CDT monitoring was performed. Overall, 790 CDT values were measured in the study population. The median observation period was 2.1 months before and 41.2 months after transplantation, respectively. In 35 patients (80%) pretransplant CDT values were found to be above the reference value, but only one patient suffered an alcohol relapse after transplantation. Of the nine patients (20%) who demonstrated normal CDT before transplantation, two suffered an alcohol relapse after transplantation. CDT is a very useful marker for the monitoring of an alcohol relapse in patients following OLT for alcoholic cirrhosis, as has been previously indicated. However, CDT does not appear to be useful as a pretransplant screening marker for selection of potential transplant candidates suffering from alcoholic cirrhosis.