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Die Lebertransplantation ist ein etabliertes Therapieverfahren bei akuten sowie chronischen Leberversagen. Aufgrund des stetig steigenden Bedarfs an Transplantationsorganen stellt die Verteilung der Spenderorgane eine immense Herausforderung dar. Im Jahr 2006 wurde ein neues Allokationssystem eingeführt, welches objektiv anhand vorliegender Labordaten die Dringlichkeit einer Organtransplantation einschätzt. Die hier vorliegende Dissertation zeigt die Auswirkungen des neuen Allokationssystems auf die Ergebnisse nach einer Lebertransplantation am Universitätsklinikum Leipzig. Die Einführung des neuen Allokationssystems führte zu einer Verkürzung der Wartezeit auf der Transplantationsliste und zu einer niedrigeren Wartelistenmortalität. Dem gegenüber stehen erhöhte postoperative Komplikationsraten sowie Kosten. Um die limitiert verfügbaren Spenderorgane mit größtmöglicher Erfolgsaussicht transplantieren zu können, sind prädiktive Modelle zur Abschätzung des outcomes nach Lebertransplantation etabliert worden. In dem betrachteten Patientenkollektiv am Universitätsklinikum Leipzig konnten sowohl der SALT-Wert als auch die präoperative intensivmedizinische Trias als Prognosefaktoren für das Überleben nach Lebertransplantation beschrieben werden. In Zukunft wird die Anwendung eines Prognosefaktors bereits im Organallokationsprozess eine immer größere Rolle einnehmen um im ethischen Problemfeld aus Organknappheit und erhöhtem Organbedarf den gesellschaftlichen Ansprüchen gerecht zu werden.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

Transplantation is the best therapeutic solution for patients with chronic renal failure. Due to the great advances in immunosuppressive therapy in the last decades, graft and patient survival have improved significantly. On the other hand, immunosuppressive therapy has serious side effects - too strong immunosuppression may lead to infection or malignancies, conversely insufficient immunosuppression may lead to graft rejection. Due to the grave consequences of acute rejection, the main goal of cooperation of clinicians and transplant immunologists is to stratify patients into groups with low, moderate and high risk of rejection based on the evaluation of various immunologic risk factors. There are reports in the literature that the numbers (frequencies) of interferon gamma (IFNγ) producing cells before transplantation may be helpful to identify patients with high risk of acute cellular rejection and to predict long-term survival of the graft. In this retrospective study we determined the pre-transplant frequencies of activated donor specific T lymphocytes producing IFNγ after short stimulation (24 hrs) by ELISpot (Enzyme-linked immunosorbent spot assay). The results were correlated with the incidence of acute cellular (ACR) and antibody-mediated (AMR) rejection and with other risk factors. In our...

Current immunogenetic tests before organ transplantation include HLA typing and detection of HLA-specific antibodies. However, these tests do not provide information about the B cells participating in the humoral response against the transplanted organ. BAFF (B activating factor) plays an important role in the proliferation, maturation and differentiation of B cells. A soluble form of the cytokine arises after splicing the membrane form of BAFF. The soluble cytokine binds to three types of receptors - TACI, BCMA and BCMA. Some recent studies suggest that BAFF could serve as a marker or predictor of antibody-mediated (humoral) rejection in kidney transplant recipients. Our study consists of two parts. The first part is focused on the detection of soluble BAFF levels in patients after renal transplantation. The aim of our study was therefore to correlate levels of soluble BAFF cytokine in patients before and after transplantation with the clinical course and incidence of rejection after transplantation. The study included 92 kidney recipients. Humoral rejection was diagnosed on the basis of a positive finding of C4d deposits in peritubular capillaries (imunoflorescenční detection), and the presence of donor- specific antibodies. BAFF levels were determined using Xmap methodology by the Luminex method...

Etablierung und Untersuchung Diabetischer Schweine Transplantation isolierter Langerhansinseln Optimierung der Isolierungsergbnisse

A thesis submitted to the Faculty of Humanities, University of the Witwatersrand, Johannesburg in fulfillment of the requirements for the degree of Doctor of Philosophy December 2015 / Introduction South Africa is characterised by numerous dichotomies and diversities, within which its two-tier healthcare system operates. An under-resourced state sector serves a majority of the population and a resource-intensive private sector serves a small minority. Within the constitutional framework of human rights and distributive justice there are nevertheless expectations of fair and equal access to healthcare services. There is furthermore an expectation of quality care across the health system, in spite of a number of systemic challenges related to staff and equipment shortages, unrealistic working hours and poor working conditions. Organ transplant is available to different degrees within the South African healthcare sector. Whilst transplant programmes are burgeoning internationally, cadaver transplant numbers in South Africa have decreased over recent years as donor organs have become increasingly scarce. Current research suggests that these challenges to transplant in South Africa arise from aspects of personal and cultural beliefs, illegal transplant practices and resource constraints - which all serve to compromise the ethical implementation of transplant services in the two-tier healthcare system. The impact of interprofessional communication and transplant professional–patient communication has not been previously researched in South Africa. However, research into other healthcare issues has shown that communication is vital to the ethical provision of healthcare services, especially those which involve patient-centeredness and multidisciplinary interaction. Transplant involves a significant amount of communication within a particularly large network of recipients and their families, cadaver donor families, living donors and a range of transplant professionals. This communication seems a vital part of the transplant process, disseminating information which role-players need in order to promote favourable outcomes. Given the extensive networks involved in the transplant process, communication would seem to be a fertile area for research. This study aimed to explore communication in organ transplant in Gauteng province, South Africa. It considered both interprofessional communication and communication with patients as this took place within the hierarchical healthcare system and throughout the transplant process. An ethics of care framework was utilised in order to account for the expectations of care which South Africans confer upon their health system. Methods The study took place in the Gauteng province of South Africa across six healthcare institutions. Both the state and the private sector were equally represented. Altogether, thirty in-depth interviews with transplant professionals, two focus groups with transplant coordinators, two interviews with cadaver donor families, and one focus group with living kidney donors, were conducted. Thematic analysis and triangulation of the data utilising Braun and Clarke’s (2006) principles revealed three main themes relating to context, communication with patients, and interprofessional communication Findings The South African transplant context is complex and multifaceted, shaped by both the patients’ expectations of care and the transplant professionals’ perceptions of care. These expectations and perceptions are influenced by personal beliefs, suspicions of biomedicine, the media, and resource inequalities which pose challenges to accessing transplant services. The transplant context is characterised by ethical dilemmas relating to distributive justice, as questions about resource distribution and allocation of donor organs are raised. Transplant communication is influenced by context and varies depending upon role-players in transplant and the different phases of transplant. Demands for care by those hoping to receive an organ had a noticeable influence on transplant professional-potential recipient communication in the pre-transplant phase, a period when emotions of desperation and uncertainty were prominent. By the time recipients had received their organ and entered the more stable post-transplant phase, a relationship of trust developed in which communication was regular and caring roles seemed fulfilled. The opposite trend was evident in communication between transplant professionals and donor families. This was characterised by notions of care in the pre-transplant phase, contrasting with a perception amongst donor families that care was sometimes overlooked in the post-transplant phase - a time often imbued with chronic uncertainty. Even in the pre-transplant phase numerous ethical issues surrounding autonomy, decision-making and informed consent proved to complicate and challenge transplant communication. Interprofessional communication was shaped by hierarchical institutional organisation, a lack of continuity of care, and resource constraints, all of which challenged transplant professionals seeking to provide care, and sometimes resulted in aggressive interchanges. The pressure to procure an organ timeously – which could result in patient care and professional respect being somewhat disregarded – could so compromise interprofessional communications that moral distress was created. Furthermore, as a result of miscommunications, an ethical vacuum where the best interests of patients in the transplant process were not, apparently, a foremost consideration, was identified. Conclusion Transplant is a highly complex process requiring a number of different communication styles and skills and accompanied by intricate ethical challenges. Although transplant professionals seemed cognisant of the need for careful communication, inequalities, resource scarcity and conflict intervened to create a space for moral distress and uncertainty in which communication was affected, and the provision of care was the casualty. Appraising results within an ethics of care framework suggests that transplant in Gauteng cannot be considered to be a process fully informed by the imperative of care. The ethics of care proved to be a helpful framework for understanding transplant communication in Gauteng because of the way it accounts for interpersonal relationships - fundamental to the transplant process - whilst also emphasising the importance of resources necessary to provide good care. It was concluded that in the current environment, where there is little legal direction or political buy-in, transplant in Gauteng will be unable to reach its full potential. / MT2016

INTRODUCTION Cardiovascular diseases (CVD) are more common in kidney transplant recipients (KTRs) than in the general population. The high incidence of CVD in the KTRs can be attributed to traditional risk factors, additional risk factors associated with graft dysfunction and those specifically related to transplantation. Carotid intima-media thickness (cIMT) is a proven surrogate of atherosclerosis; it correlates with vessel pathology and is precisely imaged using ultrasound technology. This study was aimed at determining the prevalence and predictors of cardiovascular risk among KTRs at the Charlotte Maxeke Johannesburg Academic Hospital (CMJAH) and to examine the relationship between cardiovascular risk factors and carotid intima media thickness. METHODS Patients aged 18 years and above who received a kidney transplant at the CMJAH between January 2005 and December 2009 were recruited. A questionnaire that captured cardiovascular risk factors was administered. Patients records were assessed for information on their post transplant follow up. All patients had echocardiography and carotid doppler done for measurement of intima-media thickness. The Framingham Risk Score was used to categorize patients into low, moderate, high risk and very high risk groups. Results were analyzed using statistical package for social sciences (SPSS) version 17, p value of 0.05 was considered significant. RESULTS One hundred (KTRs) 63 male (63%) and 37 female (37%) were recruited ranging in age from 19 to 70 years, with a mean age of 42.2 ± 12.42. Thirty six patients (36%) were found to have high cardiovascular risk. Multiple regression showed proteinuria (p = 0.022), higher cumulative steroid dosage (p = 0.028), elevated serum triglycerides (p = 0.04) and the presence of plaques in the carotid artery (p = 0.012) as predictors of higher cardiovascular risk.Carotid intima-media thickness correlates with higher CVD risk. Fourteen patients (14%) had a carotid artery plaque. Twenty five patients (25%) had cIMT of >0.7 mm. CONCLUSION Kidney transplant recipients in CMJAH were found to have high cardiovascular risk (36%) and carotid intima-media thickness correlates with this high CVD risk. Routine follow up of KTRs should include measurement of cIMT as it provides a simple non-invasive assessment of subclinical atherosclerosis.

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Introduction : l’infection par le cytomégalovirus (CMV) humain est la plus fréquente des infections après greffe d'organe. Des effets indirects à long terme sont fortement suspectés mais restent encore largement incompris. Notre travail de thèse s’est intéressé à mieux comprendre les conséquences de l’infection du donneur par le CMV sur la réponse immunitaire du receveur et sur le devenir de son greffon. Résultat : nous avons initialement rapporté que l'infection du donneur (D+) par le CMV est un facteur de risque indépendant de perte de fonction du greffon rénal particulièrement si le receveur est également séropositif avant la greffe (D+R+ comparé aux D+R-). Le risque est fortement majoré en cas de mésappariement complet en HLA de classe I entre le receveur et son donneur. Puis nous avons analysé le rôle du greffon infecté dans le développement de la réponse lymphocytaire anti-CMV. Nous avons rapporté pour la première fois que la superinfection CMV entraine une augmentation du nombre de LT CD8 répondeurs spécifiques du CMV à distance de la transplantation, à condition que le donneur et le receveur partagent des identités HLA-I. De plus nous avons montré chez le sujet D+R- que l'expansion des lymphocytes T CD8 anti CMV restreints par le HLA-A2 nécessite l'expression de ce HLA par le donneur. Ces résultats ensemble indiquent le rôle des cellules du donneur dans l’inflation des LT CD8 anti-CMV à distance de la greffe. Dans un troisième travail, nous avons montré qu’un polymorphisme du gène de Programmed Cell Death 1 (PD-1.3) influe sur la survie des greffons rénaux et pulmonaires D+, les patients porteurs de l’allèle variant A ayant un meilleur pronostic que les patients homozygotes GG. Nos données indiquent aussi que les patients homozygotes AA ont un plus grand nombre de lymphocytes anti-CMV producteurs d'IFN-ɣ, suggérant que ce polymorphisme pourrait être associé à une dysfonction de la réponse immunitaire spécifique anti-CMV. Conclusion : ensemble ces données suggèrent pour la première fois que la qualité de la réponse lymphocytaire cytotoxique anti-CMV pourrait être importante pour contrôler la réplication virale dans le greffon et les lésions induites par cette dernière. Ainsi nous proposons deux mécanismes à l’origine du développement des lésions liées à l'infection à CMV dans le rein: défaut de reconnaissance des cellules allogéniques infectées en cas de mésappariement complet en HLA de classe I et une dysfonction LT CD8 anti-CMV. / Background: cytomegalovirus (CMV) is the leading cause of viral infection after solid organ transplantation. Despite a large body of literature, the effects of chronic cytomegalovirus (CMV) infection on graft outcome remain controversial.Results: we first reported that donor CMV infection (D+) was an independent risk factor of kidney graft loss, especially in pretransplant infected recipients (R+). In addition, we observed that full HLA-I mismatching was an important determinant of this risk. In a second study, we focused on effect of donor CMV infection on anti-CMV specific immune response. We reported that CMV superinfection greatly increased the number of anti-CMV IFN-ɣ-producing T cells, provided that donor and recipient shared at least one HLA-I identity. Then in D+R- HLA-A2-expressing recipients, we compared the number of anti-CMVpp65 CD8+T cells restricted by HLA-A2 depending on whether the donor expressed or not HLA-A2. Patients who received non-HLA-A2 kidneys developed very few anti-CMVpp65 T-cells restricted by HLA-A2 as compared to those who received an HLA-A2-expressing kidney. This result indicated that presentation of CMV peptides by donor cells was crucial to stimulate the expansion of pp65-specific memory CD8 T cells. Finally, we established that a SNP in the Programmed Cell Death 1 gene (PD-1.3) influenced D+ kidney and lung transplants survival, while it was also associated with the level of anti-CMV specific T-cell response. Conclusion: taken together, these data suggest that anti-CMV specific immune response is pivotal to control infection within the graft and prevent subsequent organ damages. We propose two mechanisms to explain effect of donor CMV infection on graft outcome: (1) inability of anti-CMV CD8 T cells to recognize donor-infected cells in case of full HLA-I mismatching, (2) dysfunction of anti-CMV CD8 T cells after transplantation in some patients, highlighted by our genetic study.