246 resultados para Transplantation cornéenne lamellaire postérieure


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BACKGROUND: The burden of enterococcal infections has increased over the last decades with vancomycin-resistant enterococci (VRE) being a major health problem. Solid organ transplantation is considered as a risk factor. However, little is known about the relevance of enterococci in solid organ transplantation recipients in areas with a low VRE prevalence. METHODS: We examined the epidemiology of enterococcal events in patients followed in the Swiss Transplant Cohort Study between May 2008 and September 2011 and analyzed risk factors for infection, aminopenicillin resistance, treatment, and outcome. RESULTS: Of the 1234 patients, 255 (20.7%) suffered from 392 enterococcal events (185 [47.2%] infections, 205 [52.3%] colonizations, and 2 events with missing clinical information). Only 2 isolates were VRE. The highest infection rates were found early after liver transplantation (0.24/person-year) consisting in 58.6% of Enterococcus faecium. The highest colonization rates were documented in lung transplant recipients (0.33/person-year), with 46.5% E. faecium. Age, prophylaxis with a betalactam antibiotic, and liver transplantation were significantly associated with infection. Previous antibiotic treatment, intensive care unit stay, and lung transplantation were associated with aminopenicillin resistance. Only 4/205 (2%) colonization events led to an infection. Adequate treatment did not affect microbiological clearance rates. Overall mortality was 8%; no deaths were attributable to enterococcal events. CONCLUSIONS: Enterococcal colonizations and infections are frequent in transplant recipients. Progression from colonization to infection is rare. Therefore, antibiotic treatment should be used restrictively in colonization. No increased mortality because of enterococcal infection was noted.

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BACKGROUND: In heart transplantation, antibody-mediated rejection (AMR) is diagnosed and graded on the basis of immunopathologic (C4d-CD68) and histopathologic criteria found on endomyocardial biopsies (EMB). Because some pathologic AMR (pAMR) grades may be associated with clinical AMR, and because humoral responses may be affected by the intensity of immunosuppression during the first posttransplantation year, we investigated the incidence and positive predictive values (PPV) of C4d-CD68 and pAMR grades for clinical AMR as a function of time. METHODS: All 564 EMB from 40 adult heart recipients were graded for pAMR during the first posttransplantation year. Clinical AMR was diagnosed by simultaneous occurrence of pAMR on EMB, donor specific antibodies and allograft dysfunction. RESULTS: One patient demonstrated clinical AMR at postoperative day 7 and one at 6 months (1-year incidence 5%). C4d-CD68 was found on 4,7% EMB with a "decrescendo" pattern over time (7% during the first 4 months vs. 1.2% during the last 8 months; P < 0.05). Histopathologic criteria of AMR occurred on 10.3% EMB with no particular time pattern. Only the infrequent (1.4%) pAMR2 grade (simultaneous histopathologic and immunopathologic markers) was predictive for clinical AMR, particularly after the initial postoperative period (first 4 months and last 8 months PPV = 33%-100%; P < 0.05). CONCLUSION: In the first posttransplantation year, AMR immunopathologic and histopathologic markers were relatively frequent, but only their simultaneous occurrence (pAMR2) was predictive of clinical AMR. Furthermore, posttransplantation time may modulate the occurrence of C4d-CD68 on EMB and thus the incidence of pAMR2 and its relevance to the diagnosis of clinical AMR.

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Primary systemic amyloidosis (AL amyloidosis) continues to have a very poor prognosis. Most therapeutic strategies remain unsatisfactory. Conventional chemotherapy is known to offer at best only moderate efficacy. Several studies have yielded higher complete response rates after high-dose chemotherapy and autologous stem cell transplantation (ASCT) in addition to improving outcomes in a subgroup of patients. However, the superiority of an intensive approach in AL amyloidosis has not been confirmed in a randomised trial. The precise role of ASCT remains unclear. We report our experience in 16 patients diagnosed with AL amyloidosis and treated in a multidisciplinary approach with high-dose melphalan and ASCT. Median age was 59 (39-71) years. The kidneys were predominantly affected in 75% of cases; two or more organs were affected in 38%. Median time from diagnosis to transplantation was 2 (1-4) months. Three patients (19%) developed acute renal failure and required transient dialysis. Transplant-related mortality was 6% after 100 days. Haematological complete response (CR) was obtained in nine (56%) and organ response in six (38%) patients. Nine out of 12 patients (75%) with kidney involvement exhibited a sustained clinical benefit at 12 months. Half of all the patients (n = 8) were alive after a median follow-up of 33 months, including two in continuous CR. This suggests that high-dose chemotherapy and ASCT are still valid treatment options in AL amyloidosis and that a significant number of patients with renal involvement might benefit from this approach.

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Fractures due to osteoporosis are one of the major complications after heart transplantation, occurring mostly during the first 6 months after the graft, with an incidence ranging from 18% to 50% for vertebral fractures. Bone mineral density (BMD) decreases dramatically following the graft, at trabecular sites as well as cortical sites. This is explained by the relatively high doses of glucocorticoids used during the months following the graft, and by a long-term increase of bone turnover which is probably due to cyclosporine. There is some evidence for a beneficial effect on BMD of antiresorptive treatments after heart transplantation. The aim of this study was to assess prospectively the effect on BMD of a 3-year treatment of quarterly infusions of 60 mg of pamidronate, combined with 1 g calcium and 1000 U vitamin D per day, in osteoporotic heart transplant recipients, and that of a treatment with calcium and vitamin D in heart transplant recipients with no osteoporosis. BMD of the lumbar spine and the femoral neck was measured by dual-energy X-ray absorptiometry in all patients every 6 months for 2 years and after 3 years. Seventeen patients, (1 woman, 16 men) aged 46+/-4 years (mean +/- SEM) received only calcium and vitamin D. A significant decrease in BMD was observed after 6 months following the graft, at the lumbar spine (- 6.6%) as well as at the femoral neck (-7.8%). After 2 years, BMD tended to recover at the lumbar spine, whereas the loss persisted after 3 years at the femoral neck. Eleven patients (1 woman and 10 men) aged 46+/-4 years (mean +/- SEM) started treatment with pamidronate on average 6 months after the graft, because they had osteoporosis of the lumbar spine and/or femoral neck (BMD T-score below -2.5 SD). Over the whole treatment period, a continuous increase in BMD at the lumbar spine was noticed, reaching 18.3% after 3 years (14.3% compared with the BMD at the time of the graft). BMD at the femoral neck was lowered in the first year by -3.4%, but recovered totally after 3 years of treatment. In conclusion, a 3-year study of treatment with pamidronate given every 3 months to patients with existing osteoporosis led to a significant increase in lumbar spine BMD and prevented loss at the femoral neck. However, since some of these patients were treated up to 14 months after the transplant, they may already have passed through the phase of most rapid bone loss. In patients who were not osteoporotic at baseline, treatment with calcium and vitamin D alone was not able to prevent the rapid bone loss that occurs immediately after transplantation.

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BACKGROUND: Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine produced by many tissues including pancreatic beta-cells. METHODS: This study investigates the impact of MIF on islet transplantation using MIF knock-out (MIFko) mice. RESULTS: Early islet function, assessed with a syngeneic marginal islet mass transplant model, was enhanced when using MIFko islets (P<0.05 compared with wild-type [WT] controls). This result was supported by increased in vitro resistance of MIFko islets to apoptosis (terminal deoxynucleotide tranferase-mediated dUTP nick-end labeling assay), and by improved glucose metabolism (lower blood glucose levels, reduced glucose areas under curve and higher insulin release during intraperitoneal glucose challenges, and in vitro in the absence of MIF, P<0.01). The beneficial impact of MIFko islets was insufficient to delay allogeneic islet rejection. However, the rejection of WT islet allografts was marginally delayed in MIFko recipients by 6 days when compared with WT recipient (P<0.05). This effect is supported by the lower activity of MIF-deficient macrophages, assessed in vitro and in vivo by cotransplantation of islet/macrophages. Leukocyte infiltration of the graft and donor-specific lymphocyte activity (mixed lymphocyte reaction, interferon gamma ELISPOT) were similar in both groups. CONCLUSION: These data indicate that targeting MIF has the potential to improve early function after syngeneic islet transplantation, but has only a marginal impact on allogeneic rejection.

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Background: The pathogenic role of anti-HLA antibodies (AHA) after kidney transplantation is well established. However, its significance after liver transplantation remains unclear. The aim of our study was to determine the prevalence and significance of AHA after liver transplantation. Methods: Between January 2007 and November 2007, all liver transplant recipients who were greater than 6 months posttransplantation and followed regularly at our transplant outpatient clinic (n = 95) were screened for AHA. All clinical and electronic records were reviewed. Serum samples were tested using multiplex technology (Luminex). A liver biopsy had been performed in 55 out of the 95 patients based on clinical grounds but no routine protocol biopsies were performed. Immunosuppression was calcineurin inhibitor-based in 90 patients, sirolimus-based in 4 patients and one patient had no anti-rejection therapy (operationally tolerant recipient). Results: The mean time from transplantation to study was 85 months (range 6-248 months). Overall, AHA were found in 23/95 (24.2%) of patients (5 had anti-class I alone, 13 anti-class II alone, and 4 had both anti-class I and II). However, only 4/95 patients (4.2%) had donor-specific antibodies (DSA) (one anti-class I and 3 anti-class II). Twenty-one out of 95 patients (22.1%) had a history of past or current biopsy-proven or radiological biliary complications (chronic rejection, ischemic cholangitis, ischemic type biliary lesions or biliary anastomosis stricture). Among patients with AHA, 4/23 (17,4%) had biliary complications, while it was 17/72 (23.6%) in patients without AHA (NS). Among patients with DSA, 3/4 (75%) had biliary complications (two with biopsy-proven chronic rejection in association with biliary strictures and one with ischemic cholangitis following hepatic artery thrombosis), versus 1/19 (5.3%) patients with AHA but no DSA (p = 0.009), versus 16/72 (22.2%) patients without AHA (p = 0.046). In patients with DSA, immunosuppression was not different than in patients without DSA. Conclusions: We found a 24% AHA prevalence. The presence of DSA, but not of AHA, was significantly associated with an increased incidence of biliary complications including chronic liver allograft rejection. The exact mechanisms and possible causal relationship linking DSA to biliary complications remain to be studied. Larger prospective trials are thus needed to further define the role of AHA and in particular of DSA after liver transplantation.

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We conducted a 12-year retrospective study to determine the effects that the community respiratory-virus species and the localization of respiratory-tract virus infection have on severe airflow decline, a serious and fatal complication occurring after hematopoietic cell transplantation (HCT). Of 132 HCT recipients with respiratory-tract virus infection during the initial 100 days after HCT, 50 (38%) developed airflow decline < or =1 year after HCT. Lower-respiratory-tract infection with parainfluenza (odds ratio [OR], 17.9 [95% confidence interval {CI}, 2.0-160]; P=.01) and respiratory syncytial virus (OR, 3.6 [95% CI, 1.0-13]; P=.05) independently increased the risk of development of airflow decline < or =1 year after HCT. The airflow decline was immediately detectable after infection and was strongest for lower-respiratory-tract infection with parainfluenza virus; it stabilized during the months after the respiratory-tract virus infection, but, at < or =1 year after HCT, the initial lung function was not restored. Thus, community respiratory virus-associated airflow decline seems to be specific to viral species and infection localization.

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Enjeux La réussite d'une transplantation rénale ou hépatique intègre non seulement le succès de l'acte chirurgical et sa prise en charge médicale post-greffe, mais également pour le patient greffé l'assurance d'une nouvelle qualité de vie dont le retour au travail fait partie. Le retour au travail après greffe est cependant généralement peu étudié dans la littérature et peu discuté semble-t-il au niveau médical que ce soit avant ou après greffe, quand bien même d'un point de vue médico-socio-économique il s'agit d'un sujet important compte tenu des coûts liés à un arrêt de travail prolongé ou à une rente pour incapacité de travail. Contexte Après une greffe réussie, il n'existe théoriquement plus de facteur limitant et peu de contre-indications médicales liées à la greffe pour empêcher une reprise progressive de l'activité professionnelle. Or en réalité le taux de retour au travail après greffe est généralement faible, variant entre 30 et 60% selon la littérature. Ceci a incité l'auteur de cette présente étude à essayer d'en connaître les raisons. Ainsi, l'hypothèse a été que certains facteurs professionnels (« en activité professionnelle ou non avant greffe », « être diplômé ou non»), individuels («âge», «genre», «type d'organe greffé») ou médicaux (« complications médicales aiguës de moins de 6 mois post greffe ») influencent négativement ou positivement le retour au travail des patients greffés. L'étude a porté sur un petit collectif volontaire de patients greffés rénaux et hépatiques opérés entre 1993 et 2003 et suivis depuis lors au centre de transplantation d'organes (CTO) du CHUV. Il leur a été administré en face à face un questionnaire médical spécialement conçu pour l'étude. Conclusion L'étude montre que le taux de retour au travail après greffe rénale ou hépatique s'élève à 39% et qu'il existe effectivement des facteurs pouvant influencer le retour au travail après greffe. Ainsi, être « âgé de moins de 45 ans », être « au bénéfice d'une formation (diplôme) » et « travailler les deux ans précédent la greffe » sont des facteurs significatifs de retour au travail après greffe. Perspective Gage de qualité de vie, le retour au travail après greffe doit être encouragé et favorisé quand il se peut, en s'aidant des facteurs connus qui l'influencent positivement ou négativement. Pour cela, il est indispensable qu'au stade pré greffe déjà s'instaure un dialogue sur le sujet entre patients en attente de greffe et personnel médico-social, afin de mettre en oeuvre le plus précocement possible les mesures socio-professionnelles adéquates comme cela se fait déjà en Allemagne ou aux Etats-Unis par exemple.

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Quality of life has been extensively discussed in acute and chronic illnesses. However a dynamic model grounded in the experience of patients in the course of transplantation has not been to our knowledge developed. In a qualitative longitudinal study, patients awaiting solid organ transplantation participated in semi-structured interviews: Exploring topics pre-selected on previous research literature review. Creative interview was privileged, open to themes patients would like to discuss at the different steps of the transplantation process. A qualitative thematic and reflexive analysis was performed, and a model of the dimensions constitutive of quality of life from the perspective of the patients was elaborated. Quality of life is not a stable construct in a long lasting illness-course, but evolves with illness constraints, treatments and outcomes. Dimensions constitutive of quality of life are defined, each of them containing different sub-categories depending on the organ related illness co-morbidities and the stage of illness-course.

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BACKGROUND: Stem cell labeling with iron oxide (ferumoxide) particles allows labeled cells to be detected by magnetic resonance imaging (MRI) and is commonly used to track stem cell engraftment. However, the validity of MRI for distinguishing surviving ferumoxide-labeled cells from other sources of MRI signal, for example, macrophages containing ferumoxides released from nonsurviving cells, has not been thoroughly investigated. We sought to determine the relationship between the persistence of iron-dependent MRI signals and cell survival 3 weeks after injection of syngeneic or xenogeneic ferumoxides-labeled stem cells (cardiac-derived stem cells) in rats. METHODS AND RESULTS: We studied nonimmunoprivileged human and rat cardiac-derived stem cells and human mesenchymal stem cells doubly labeled with ferumoxides and beta-galactosidase and injected intramyocardially into immunocompetent Wistar-Kyoto rats. Animals were imaged at 2 days and 3 weeks after stem cell injection in a clinical 3-T MRI scanner. At 2 days, injection sites of xenogeneic and syngeneic cells (cardiac-derived stem cells and mesenchymal stem cells) were identified by MRI as large intramyocardial signal voids that persisted at 3 weeks (50% to 90% of initial signal). Histology (at 3 weeks) revealed the presence of iron-containing macrophages at the injection site, identified by CD68 staining, but very few or no beta-galactosidase-positive stem cells in the animals transplanted with syngeneic or xenogeneic cells, respectively. CONCLUSIONS: The persistence of significant iron-dependent MRI signal derived from ferumoxide-containing macrophages despite few or no viable stem cells 3 weeks after transplantation indicates that MRI of ferumoxide-labeled cells does not reliably report long-term stem cell engraftment in the heart.

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This overview summarizes recent data on emerging viruses after hematopoietic cell transplantation (HCT), including adenovirus, BK virus, human metapneumovirus (hMPV), and human herpesvirus (HHV) 6. The increased recognition of these infections is due to improved molecular detection methods, increased surveillance and more profound immunosuppression in the host. Adenovirus can cause serious disease especially in T-cell depleted transplant recipients. Adenovirus viremia is an important risk factor for disease in this setting. BK virus has been associated with hemorrhagic cystitis in HCT recipients. BK viremia is significantly associated with hemorrhagic cystitis. hMPV shows a seasonal distribution and can cause fatal pneumonia in HCT recipients. hMPV may be the etiology of some cases previously categorized as idiopathic pneumonia syndrome. HHV-6 commonly leads to viremia in HCT recipients. HHV-6 has been strongly associated with encephalitis and delayed platelet engraftment. Prospective studies are needed to further examine epidemiology, disease associations, and management strategies for these viruses.

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Background We previously reported the results of a phase II study for patients with newly diagnosed primary central nervous system lymphoma treated with autologous peripheral blood stem-cell transplantation (aPBSCT) and response-adapted whole-brain radiotherapy (WBRT). Now, we update the initial results. Patients and methods From 1999 to 2004, 23 patients received high-dose methotrexate. In case of at least partial remission, high-dose busulfan/thiotepa (HD-BuTT) followed by aPBSCT was carried out. Patients refractory to induction or without complete remission after HD-BuTT received WBRT. Eight patients still alive in 2011 were contacted and Mini-Mental State Examination (MMSE) and the European Organisation for Research and Treatment of Cancer quality-of-life questionnaire (QLQ)-C30 were carried out. Results Of eight patients still alive, median follow-up is 116.9 months. Only one of nine irradiated patients is still alive with a severe neurologic deficit. In seven of eight patients treated with HD-BuTT, health condition and quality of life are excellent. MMSE and QLQ-C30 showed remarkably good results in patients who did not receive WBRT. All of them have a Karnofsky score of 90%-100%. Conclusions Follow-up shows an overall survival of 35%. In six of seven patients where WBRT could be avoided, no long-term neurotoxicity has been observed and all patients have an excellent quality of life.

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Polyclonal intravenous immunoglobulin (IVIg) treatment reduces crossmatch positivity and increases rates of transplantation in highly sensitised patients (HS). We quantified the panel reactive antibody (PRA) by microlymphocytotoxicity (MLCC), and we analysed anti-HLA class I and class II IgG specific antibody repertoire by Luminex before and after IVIg infusion alone in HS patients awaiting kidney transplantation. Five patients received three monthly infusions of 1 g/kg of IVIg. Serum samples collected pre and post IVIg treatment were submitted for PRA analysis by MLCC. Anti-class I and anti-class II antibody specificities were then tested by Luminex. We focused on the anti-HLA class I and class II antibodies directed against HLA expressed by a previous graft. We also analysed the anti-HLA antibody repertoire in three patients who had not received IVIg infusion. The PRA level determined by MLCC decreased significantly in one of the five patients, dropping from 40% to 17%. The Luminex assay showed fluctuations of the anti-HLA antibody levels over time, but no significant longterm modifications of the anti-HLA antibody repertoire were observed, even in the patient with a strong and prolonged reduction of the PRA determined by MLCC. Our results show that IVIg at 1 g/kg is not sufficient to reduce PRA and does not modify the repertoire of specific anti-HLA antibody determined by Luminex.