Control of Immune Response to Allogeneic Embryonic Stem Cells by CD3 Antibody-Mediated Operational Tolerance Induction.

Implantation of embryonic stem cells (ESCs) and their differentiated derivatives into allogeneic hosts triggers an immune response that represents a hurdle to clinical application. We established in autoimmunity and in transplantation that CD3 antibody therapy induces a state of immune tolerance. Promising results have been obtained with CD3 antibodies in the clinic. In this study, we tested whether this strategy can prolong the survival of undifferentiated ESCs and their differentiated derivatives in histoincompatible hosts. Recipients of either mouse ESC-derived embryoid bodies (EBs) or cardiac progenitors received a single short tolerogenic regimen of CD3 antibody. In immunocompetent mice, allogeneic EBs and cardiac progenitors were rejected within 20-25 days. Recipients treated with CD3 antibody showed long-term survival of implanted cardiac progenitors or EBs. In due course, EBs became teratomas, the growth of which was self-limited. Regulatory CD4(+)FoxP3(+) T cells and signaling through the PD1/PDL1 pathway played key roles in the CD3 antibody therapeutic effect. Gene profiling emphasized the importance of TGF-ß and the inhibitory T cell coreceptor Tim3 to the observed effect. These results demonstrate that CD3 antibody administered alone promotes prolonged survival of allogeneic ESC derivatives and thus could prove useful for enhancing cell engraftment in the absence of chronic immunosuppression.

Intragraft mechanisms associated with the immunosuppressive versus the tolerogenic effect of CD3 antibodies in a mouse model of islet allografts.

We previously demonstrated the ability of CD3-specific antibodies (Abs) to induce tolerance of fully mismatched pancreatic islets when administered at the time of effector T-cell priming (day +7). When administered on day -1, CD3 Abs only displayed an immunosuppressive effect with no permanent acceptance. Here we show that rejection correlates with progressive migration of CD4(+) and CD8(+) T cells into the graft. In contrast, the day +7 CD3 Ab tolerogenic effect is associated with absence of de novo accumulation of CD8(+) T cells within the allograft while CD4(+) T-cell migration is not altered. Furthermore, the increased proportion in T-regulatory cells, observed both in the draining lymph nodes and in the transplanted islets, was more pronounced after the delayed (day +7) than the early (day -1) CD3 Ab course. Last, tolerance-promoting (day +7), but not immunosuppressive (day -1) CD3 Ab treatment was associated with an elevated in situ Foxp3/α-1,2-mannosidase gene expression ratio, identified as a biomarker predicting tolerance in renal transplant patients. In conclusion, intragraft-enhanced regulation over effector function after the delayed but not the early CD3 antibody therapy discriminates between the tolerance-promoting and immunosuppressive effect of CD3 Ab treatment and further highlights the importance of the therapeutic window.

Induction of allograft tolerance by monoclonal CD3 antibodies: a matter of timing.

Despite remarkable progress in organ transplantation through the development of a wealth of immunosuppressive drugs highly effective at controlling acute rejection, two major problems still remain, the loss of transplants due to chronic rejection and the growing number of sensitized recipients due to previous transplants, transfusions or pregnancies. Induction of immune tolerance appears to be the only way to curb this complex situation. Here we describe that a therapy, already successfully used to restore immune tolerance to self-antigens in overt autoimmunity, is effective at promoting transplant tolerance. We demonstrate that a short low-dose course with CD3 antibodies started after transplantation, at the time of effector T cell priming to alloantigens, induces permanent acceptance of fully mismatched islet allografts. Mechanistic studies revealed that antigen-specific regulatory and effector T cells are differentially affected by the treatment. CD3 antibody treatment preferentially induces apoptosis of activated alloreactive T cells which is mandatory for tolerance induction. In contrast, regulatory T cells are relatively spared from CD3 antibody-induced depletion and can transfer antigen-specific tolerance thus arguing for their prominent role in sustaining long-term graft survival.

Comparison of positron emission tomography and lymphangiography in the diagnosis of infradiaphragmatic Hodgkin's disease.

PURPOSE: To evaluate the respective roles of positron emission tomography using 18F-fluorodeoxyglucose (FDG-PET) and lymphangiography (LAG) in staging Hodgkin's disease (HD) patients with negative contrast-enhanced infradiaphragmatic computed tomography (CT). MATERIAL AND METHODS: 28 patients underwent FDG-PET and LAG at initial staging. Concordant positive findings on both tests were regarded as actual HD locations and concordant negative findings as true negative. In case of discrepancy, the reference was biopsy or magnetic resonance imaging (MRI). RESULTS: Concordant results were obtained in 26 patients (24 negative, two positive). In two of the 24 negative patients, PET showed additional lesions in the spleen and one celiac lymph node (one patient), and in the right kidney and the right iliac crest (one patient). Discordant results were obtained in two patients. Both methods indicated infradiaphragmatic involvement in different locations in one patient. In the other, PET was falsely positive (PET done within 24 hours after a negative LAG), which was confirmed by biopsy (benign inflammatory, probably due to LAG medium). CONCLUSION: FDG-PET and LAG gave comparable results, making invasive LAG unnecessary. Furthermore, LAG, when performed before PET, can be responsible for false-positive PET results.

Design of a climate-dependent water reuse project.

Reclaimed water storage is imperative in water reuse management. Climate is a primary factor controlling reclaimed water storage design by its significant influence on irrigation water needs as well as on stored water quality. This study presents a modelling approach that has been applied to assist the design of a climate-dependent water reuse project on an Atlantic island. Models for predicting irrigation water needs and water quality in tertiary lagoons were coupled with a technical-economic model to design reclaimed water storage facilities. Three scenarios corresponding to different augmentation of current reclaimed water reuse were investigated. According to the modelling, the storage sizes to meet the water quantity required for irrigation increased with water deficit--the difference between evapotranspiration and precipitation. The size of tertiary lagoons to meet required water quality was found to be larger than the size to meet required water quantity. To meet both quantitative irrigation needs and <1,000 FC/100 ml irrigation and disposal regulation, extending the tertiary lagoon system would be more cost-effective than storage calculated to meet only quantitative irrigation needs supplemented with UV disinfection. The reliability of reclaimed water storage design was estimated with 40 years historic climatic records.

Technical-economic modelling of integrated water management: wastewater reuse in a French island.

An integrated technical-economic model is used to address water management issues in the French island of Noirmoutier. The model simulates potable water production and supply, potable and non potable water demand and consumption, wastewater collection, treatment and disposal, water storage, transportation and reuse. A variety of water management scenarios is assessed through technical, economic and environmental evaluation. The scenarios include wastewater reclamation and reuse for agricultural and landscape irrigation as well as domestic non potable application, desalination of seawater and brackish groundwater for potable water supply. The study shows that, in Noirmoutier, wastewater reclamation and reuse for crop irrigation is the most cost-effective solution to the lack of water resources and the protection of sensitive environment. Some water management projects which are regarded as having less economic benefit in the short-term may become competitive in the future, as a result of tightened environmental policy, changed public attitudes and advanced water treatment technologies. The model provides an appropriate tool for water resources planning and management.

Fluconazole versus oral polyenes in the prophylaxis of immunocompromised patients: a cost-minimization analysis.

This study compares 100 mg daily fluconazole with oral polyenes four times daily in the prophylaxis of fungal infections in immunocompromised patients, to determine a cost-minimization strategy. Data was gathered through a literature survey and clinical interviews conducted in nine different UK hospitals. This was used to construct a decision tree, modelling the drug choices available to a clinician at various stages of a patient's treatment, and assigning probabilities to the different corresponding outcomes. UK cost data were fed into this model to determine the expected cost per patient of the different prophylaxis strategies. Two different patient groups were considered: chemotherapy-only patients, and bone-marrow-transplant (BMT) patients who have higher risks of fungal infection. Probabilities derived from the literature suggest that a cost-minimization strategy to manage both chemotherapy patients and BMT patients is to administer oral fluconazole, both as prophylaxis and as first line treatment, against superficial fungal infection. Probabilities gathered from clinical interviews yield similar results, suggesting that the cost-minimization strategy with chemotherapy-only patients is to administer oral polyenes as prophylaxis, and oral fluconazole in case of superficial fungal infection, while for BMT patients it is a combination of fluconazole and oral polyenes as prophylaxis, with oral fluconazole for the treatment of superficial fungal infections. Using the probabilities from the literature, the lowest cost strategies produce an expected cost of pounds 567.20 for chemotherapy-only patients, and an expected cost of pounds 804.87 for BMT patients for a course of treatment lasting from seven to 28 days. The clinical interview probabilities produce expected costs of pounds 826.48 and pounds 1529.43, respectively. Sensitivity analysis was then conducted, and it was found that in the majority of cases, using the literature probabilities, the cost-minimizing strategy remained prophylaxis with oral fluconazole. The sensitivity analysis for chemotherapy-only patients using the interview probabilities tended to favour oral polyenes as the cost-minimization strategy, whereas for BMT patients the sensitivity analysis favoured a combination of fluconazole and oral polyenes in the majority of cases. The key economic advantage of prophylaxis with fluconazole or a combination of fluconazole with oral polyenes in the prophylaxis of fungal infection in immunocompromised patients, results from the reduction of the expected cost of subsequent fungal infection among those who are most at risk.