Researches on Hematopoietic Stem Cell (HSC) have been expanding that leads to an increase in our understanding of HSC normal behaviors and abnormal alterations. One of the most important issues in the research on HSCs is to understand the mechanism of the homing process of these cells to settle in their niche in the bone marrow and establish the production of various blood cell types after bone marrow transplantation. The cells first must come in contact with the endothelial cells. This contact is known as adhesion and occurs through a multi-step paradigm ending with transmigration to the bone marrow niche. The initial step of the homing, tethering and rolling of HSC, is mediated by P- and E-Selectins present on endothelial cell surface through their interactions with the ligands expressed on the surface of HSC. Thus, understanding the adhesion process and its contribution for efficient HSCs homing will have great impact on HSC therapy. The selectin – ligands interaction has been intensively studied using in vivo and in vitro approaches. However, the molecular mechanism involved by HSCs at single molecule level is poorly understood. Here in this study, a novel experimental method to unravel the molecular mechanisms of the Selectin-ligands interactions in vitro at the single molecule level is developed by combining microfluidics, epi-fluorescence microscopy and live cells. In this work, the new single-molecule imaging technique enabled us to directly visualize the nanoscale spatiotemporal dynamics of the membrane protein-ligand interactions under conditions of shear stress acting on the cells at the molecular level in real time. Using this method, we revealed that selectin ligands on membrane-tethers and slings show unique spatiotemporal dynamics that is distinct from those on the cell body. We demonstrated that the membrane tethers are formed from single microvilli on the cells, which provides a mechanism to spatially localize selectin ligands, PSGL-1 and CD44 on the tethers and slings. We also demonstrated that the selectin ligands show fast diffusional motion along the tethers and slings compared with that on the cell body due to the detachment of cell membranes from actin cytoskeleton during the formation of the tethers. Our results suggest that the spatial confinement of the selectin ligands together with the fast scanning of a large area by the selectin ligands increase the efficiency of selectin-ligands interaction during the rolling, resulting in slow and stable rolling of the cell on selectin. Our findings contribute significantly to molecular level understanding of the initial step of HSCs. This single-molecule imaging technique that we developed in this study will find wide applications in the molecular-level studies on cell-cell interactions including cancer cell metastasis.

Introdução: A diarréia por Clostridium difficile é uma das principais causas de diarréia infecciosa associada à assistência à saúde. Objetivo: Descrever os casos e a incidência de diarréia por C. difficile em pacientes hematológicos e TCTH internados na enfermaria da Hematologia e do Transplante de Medula óssea do Hospital das Clinicas da Faculdade de Medicina da Universidade de São Paulo (HC-FMUSP). Métodos: Foi utilizada uma ficha para coleta de dados de todos os pacientes na unidade de hematologia e TCTH do HC-FMUSP que tinham resultado positivo para toxina A/B do C. difficile durante o período de janeiro 2007 a junho de 2011 e criado um banco de dados no programa Epiinfo. Os desfechos avaliados foram forma grave de doença e óbito até 14 dias da diarréia. Qui-quadrado para tendência foi usado para avaliar a incidência de diarréia por C. difficile durante o período do estudo. Resultados: Um total de 69 episódios foi identificado em 64 pacientes em 439 pacientes suspeitos. Na distribuição temporal o qui-quadrado para tendência evidenciou que o número de casos suspeitos de diarréia por C. difficile permaneceu estável (p=0,418), em contraste com o aumento do número de casos confirmados (p=0,0006). A incidência de diarréia por C. difficile por 1.000 pacientes variou de 0,65 a 5,45 durante o período do estudo. O qui-quadrado para tendência evidenciou aumento do número de casos confirmados de C. difficile nas unidades de TMO (p=0,00004) e Hematologia (p=0,006). Já, a incidência de diarréia por C. difficile por 1.000 neutropênicos dia variou de 0,78 a 5,45 durante o período do estudo. A maioria 68% dos pacientes era do gênero masculino, a média de idade foi 38 anos. A doença de base mais comum foi Leucemia mielóide aguda (44%), destes 46% estavam neutopênicos, 45% TCTH alogênicos, 88% dos pacientes usaram antibióticos prévios. A maioria dos pacientes 88% recebeu tratamento com metronidazol via oral, 37% tiveram resposta parcial nos primeiros sete dias de tratamento, 57% terminaram o tratamento e três pacientes tiveram recidiva, 24% evoluíram para óbito. A análise bivariada dos fatores de risco associados com a forma grave de diarréia por C. difficile, identificou o tipo de transplante alogênico como o único fator de risco significantivo, já a análise multivariada não identificou nenhum fator de risco independente. A análise bivariada de fatores de risco associados com óbito até 14 dias do diagnóstico de diarréia por C. difficile, identificou o tipo de transplante alogênico, forma grave de doença, internação em UTI e uso de linezolida como fatores de risco para óbito e Linfoma como protetor. Os fatores de risco independentes associados com óbito foram forma grave de doença, internação em UTi e uso de linezolida. Conclusão: A incidência de infecção por C. difficile durante o período do estudo aumentou, entretanto, a manifestação da forma grave da doença se manteve estável. Os fatores de risco independentes associados com óbito foram forma grave de doença, internação em UTI e uso de linezolida / Introduction: Diarrhea caused by Clostridium difficile is one of the main causes of infectious diarrhea associated with healthcare. Objective: To describe cases and the incidence of diarrhea by C.difficile in hematological and HSCT inpatients of the infirmary of Hematology and Bone Marrow Transplant of the Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (HC-FMUSP). Methods: A form was used to collect data from all patients in the hematology and HSCT unit of the HCFMUSP who showed positive results for toxin A/B of the C. difficile during the period from January 2007 to June 2011, and to create a databank in the Epiinfo program. The outcomes evaluated were the severe form of the disease and death within 14 days of the [onset of] diarrhea. The Chi-squared test for tendency was used to evaluate the incidence of diarrhea by C. difficile during the study period. Results: A total of 69 episodes were identified in 64 patients in 439 suspect patients. In the temporal distribution, the chi-squared test for tendency evidenced that the number of cases of suspected diarrhea due to C. difficile remained stable (p=0.418), in contrast with the increase in number of confirmed cases (p=0.0006). The incidence of diarrhea by C. difficile per 1,000 patients varied from 0.65 to 5.45 during the study period. The chi-squared test for tendency demonstrated an increase in number of cases confirmed of C. difficile in the BMT TMO (p=0.00004) and Hematology (p=0.006) units. On the other hand, the incidence of diarrhea by C. difficile per 1,000 neutropenic individualsday varied from 0.78 to 5.45 during the study period. Most of the 68% of patients were of the male gender; the average age was 38 years. The most common underlying disease was acute myeloid leukemia (44%); of these, 46% were neutropenic, 45% HSCT allogeneic, and 88% of the patients had previously used antibiotics. Most of the patients (88%) received treatment with oral metronidazole, 37% had a response in the first seven days of treatment, 57% finished the treatment, three patients experienced relapse, and 24% died. The bivariate analysis of the risk factors associated with the severe form of diarrhea by C. difficile, identified the type of allogeneic transplant as the only significant risk factor, whereas the multivariate analysis did not identify any independent risk factor. Bivariate analysis of risk factors associated with death within 14 days of the diagnosis of diarrhea due to C. difficile, identified the type of allogeneic transplant, severe form of the disease, stay in the ICU, and use of linezolide as risk factors for death, and Lymphoma as a protector. Independent risk factors associated with death were the severe form of the disease, stay in the ICU, and use of linezolide. Conclusion: The incidence of infection by C. difficile during the study period increased; nevertheless, the manifestation of the severe form of the disease remained stable. The independent risk factors associated with death were the severe form of the disease, stay in the ICU, and use of linezolide

Este trabalho aborda o uso da realidade virtual aplicada à simulação de procedimentos invasivos em oncologia pediátrica. Para tanto, apresenta uma revisão dos conceitos relacionados à concepção de simuladores baseados em realidade virtual, descrevendo requisitos específicos como estereoscopia e interação háptica. Particularmente, é apresentado um estudo de caso em coleta de medula óssea para transplante, para o qual um simulador foi desenvolvido. Este é o primeiro trabalho em simulação cirúrgica para oncologia pediátrica baseado em realidade virtual e apresenta detalhes relacionados à implementação do simulador e aspectos relacionados à calibragem de propriedades físicas em modelos tridimensionais. O trabalho também analisa e demonstra vantagens no uso de sistemas dessa natureza voltados para o treinamento médico, apontando necessidades e novos problemas a serem tratados por simuladores futuros. / This work approaches the use of the Virtual Reality applied to the simulation of invasive procedures in pediatric oncology. It presents a revision of the concepts related to the conception of simulators based on virtual reality, describing requirements as stereoscopy and haptic interaction. As specific problem, it was made a case study in bone marrow harvest for transplant, for which a simulator was developed. This is the first work in surgical simulation for pediatrics based on Virtual Reality and it presents details related to the implementation of the simulator and aspects related to physical properties in three-dimensional models. The work also analyzes and demonstrates advantages in the use of this kind of system for medical training besides to point needs and new problems to be addressed in future work.

Introdução: A diarréia por Clostridium difficile é uma das principais causas de diarréia infecciosa associada à assistência à saúde. Objetivo: Descrever os casos e a incidência de diarréia por C. difficile em pacientes hematológicos e TCTH internados na enfermaria da Hematologia e do Transplante de Medula óssea do Hospital das Clinicas da Faculdade de Medicina da Universidade de São Paulo (HC-FMUSP). Métodos: Foi utilizada uma ficha para coleta de dados de todos os pacientes na unidade de hematologia e TCTH do HC-FMUSP que tinham resultado positivo para toxina A/B do C. difficile durante o período de janeiro 2007 a junho de 2011 e criado um banco de dados no programa Epiinfo. Os desfechos avaliados foram forma grave de doença e óbito até 14 dias da diarréia. Qui-quadrado para tendência foi usado para avaliar a incidência de diarréia por C. difficile durante o período do estudo. Resultados: Um total de 69 episódios foi identificado em 64 pacientes em 439 pacientes suspeitos. Na distribuição temporal o qui-quadrado para tendência evidenciou que o número de casos suspeitos de diarréia por C. difficile permaneceu estável (p=0,418), em contraste com o aumento do número de casos confirmados (p=0,0006). A incidência de diarréia por C. difficile por 1.000 pacientes variou de 0,65 a 5,45 durante o período do estudo. O qui-quadrado para tendência evidenciou aumento do número de casos confirmados de C. difficile nas unidades de TMO (p=0,00004) e Hematologia (p=0,006). Já, a incidência de diarréia por C. difficile por 1.000 neutropênicos dia variou de 0,78 a 5,45 durante o período do estudo. A maioria 68% dos pacientes era do gênero masculino, a média de idade foi 38 anos. A doença de base mais comum foi Leucemia mielóide aguda (44%), destes 46% estavam neutopênicos, 45% TCTH alogênicos, 88% dos pacientes usaram antibióticos prévios. A maioria dos pacientes 88% recebeu tratamento com metronidazol via oral, 37% tiveram resposta parcial nos primeiros sete dias de tratamento, 57% terminaram o tratamento e três pacientes tiveram recidiva, 24% evoluíram para óbito. A análise bivariada dos fatores de risco associados com a forma grave de diarréia por C. difficile, identificou o tipo de transplante alogênico como o único fator de risco significantivo, já a análise multivariada não identificou nenhum fator de risco independente. A análise bivariada de fatores de risco associados com óbito até 14 dias do diagnóstico de diarréia por C. difficile, identificou o tipo de transplante alogênico, forma grave de doença, internação em UTI e uso de linezolida como fatores de risco para óbito e Linfoma como protetor. Os fatores de risco independentes associados com óbito foram forma grave de doença, internação em UTi e uso de linezolida. Conclusão: A incidência de infecção por C. difficile durante o período do estudo aumentou, entretanto, a manifestação da forma grave da doença se manteve estável. Os fatores de risco independentes associados com óbito foram forma grave de doença, internação em UTI e uso de linezolida / Introduction: Diarrhea caused by Clostridium difficile is one of the main causes of infectious diarrhea associated with healthcare. Objective: To describe cases and the incidence of diarrhea by C.difficile in hematological and HSCT inpatients of the infirmary of Hematology and Bone Marrow Transplant of the Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (HC-FMUSP). Methods: A form was used to collect data from all patients in the hematology and HSCT unit of the HCFMUSP who showed positive results for toxin A/B of the C. difficile during the period from January 2007 to June 2011, and to create a databank in the Epiinfo program. The outcomes evaluated were the severe form of the disease and death within 14 days of the [onset of] diarrhea. The Chi-squared test for tendency was used to evaluate the incidence of diarrhea by C. difficile during the study period. Results: A total of 69 episodes were identified in 64 patients in 439 suspect patients. In the temporal distribution, the chi-squared test for tendency evidenced that the number of cases of suspected diarrhea due to C. difficile remained stable (p=0.418), in contrast with the increase in number of confirmed cases (p=0.0006). The incidence of diarrhea by C. difficile per 1,000 patients varied from 0.65 to 5.45 during the study period. The chi-squared test for tendency demonstrated an increase in number of cases confirmed of C. difficile in the BMT TMO (p=0.00004) and Hematology (p=0.006) units. On the other hand, the incidence of diarrhea by C. difficile per 1,000 neutropenic individualsday varied from 0.78 to 5.45 during the study period. Most of the 68% of patients were of the male gender; the average age was 38 years. The most common underlying disease was acute myeloid leukemia (44%); of these, 46% were neutropenic, 45% HSCT allogeneic, and 88% of the patients had previously used antibiotics. Most of the patients (88%) received treatment with oral metronidazole, 37% had a response in the first seven days of treatment, 57% finished the treatment, three patients experienced relapse, and 24% died. The bivariate analysis of the risk factors associated with the severe form of diarrhea by C. difficile, identified the type of allogeneic transplant as the only significant risk factor, whereas the multivariate analysis did not identify any independent risk factor. Bivariate analysis of risk factors associated with death within 14 days of the diagnosis of diarrhea due to C. difficile, identified the type of allogeneic transplant, severe form of the disease, stay in the ICU, and use of linezolide as risk factors for death, and Lymphoma as a protector. Independent risk factors associated with death were the severe form of the disease, stay in the ICU, and use of linezolide. Conclusion: The incidence of infection by C. difficile during the study period increased; nevertheless, the manifestation of the severe form of the disease remained stable. The independent risk factors associated with death were the severe form of the disease, stay in the ICU, and use of linezolide

Este trabalho aborda o uso da realidade virtual aplicada à simulação de procedimentos invasivos em oncologia pediátrica. Para tanto, apresenta uma revisão dos conceitos relacionados à concepção de simuladores baseados em realidade virtual, descrevendo requisitos específicos como estereoscopia e interação háptica. Particularmente, é apresentado um estudo de caso em coleta de medula óssea para transplante, para o qual um simulador foi desenvolvido. Este é o primeiro trabalho em simulação cirúrgica para oncologia pediátrica baseado em realidade virtual e apresenta detalhes relacionados à implementação do simulador e aspectos relacionados à calibragem de propriedades físicas em modelos tridimensionais. O trabalho também analisa e demonstra vantagens no uso de sistemas dessa natureza voltados para o treinamento médico, apontando necessidades e novos problemas a serem tratados por simuladores futuros. / This work approaches the use of the Virtual Reality applied to the simulation of invasive procedures in pediatric oncology. It presents a revision of the concepts related to the conception of simulators based on virtual reality, describing requirements as stereoscopy and haptic interaction. As specific problem, it was made a case study in bone marrow harvest for transplant, for which a simulator was developed. This is the first work in surgical simulation for pediatrics based on Virtual Reality and it presents details related to the implementation of the simulator and aspects related to physical properties in three-dimensional models. The work also analyzes and demonstrates advantages in the use of this kind of system for medical training besides to point needs and new problems to be addressed in future work.

La drépanocytose est une maladie chronique et génétique de l’hémoglobine. Elle se caractérise par la survenue très précoce de crises de douleurs extrêmement intenses et le plus souvent imprévisibles. Le seul traitement qui permet, à l’heure actuelle, d’obtenir la guérison du malade est la transplantation de cellules souches hématopoïétiques à partir d’un donneur compatible et apparenté. Or, si la greffe est curative, elle est aussi un processus dangereux et incertain qui conduit à une prise de risque importante. En outre, la guérison n’offre pas le retour à un état de santé d’avant la maladie, mais l’accès à un état inédit et jusque-là inconnu, elle conduit donc le sujet à opérer d’importants remaniements, notamment identitaires.Dans une première partie, nous décrirons la drépanocytose dans ses dimensions somatiques, anthropologiques et psychiques afin de déployer les différents aspects qui contribuent à sa puissance identificatoire. Puis, nous nous intéresserons aux effets de la greffe et aux remaniements qu’elle provoque, depuis son annonce et jusqu’à 20 ans après la transplantation. Notre objectif est d’interroger la notion de guérison telle qu’elle est annoncée par le monde médical et de soutenir qu’elle ne peut se réduire aux seuls effets somatiques. Nous souhaitons, ainsi, plaider pour l’organisation systématique d’un accompagnement des effets psychiques induits par ce processus complexe, radical et profondément bouleversant, à toutes ses étapes, tant chez l’adulte que chez l’enfant. / Sickle cell disease is a chronic and genetic disease of hemoglobin. It is characterized by the very early onset of extremely intense and often unpredictable pain attacks. The only treatment that currently enables the patient to be cured is the transplantation of hematopoietic stem cells from a compatible and related donor. However, if the graft is curative, it is also a dangerous and uncertain process that leads to significant risk taking. In addition, healing does not offer a return to a state of health before the disease, but access to a new and unknown state, it leads the subject to make major changes, notably identitary.In a first part, we will describe sickle cell disease in its somatic, anthropological and psychic dimensions in order to deploy the various aspects that contribute to its identificatory power. Then, we will focus on the effects of the transplant and the changes it causes, since its announcement and until 20 years after transplantation. Our goal is to question the notion of healing as it is announced by the medical world and to argue that it can not be reduced only to somatic effects. We thus wish to advocate for the systematic organization of an accompaniment of the psychic effects induced by this complex radical and deeply upsetting process, at all its stages, for the adult as well as for the child.

Despite Human Leukocyte Antigen (HLA) matching and use of immunosuppressive drugs, graft-versus-host disease (GVHD) following hematopoietic stem cell transplant (HSCT) is prevalent and often fatal. Additionally, older HSCT recipients experience increased morbidity and mortality. Prophylactic treatment with age-matched syngeneic (recipient strain-derived) cultured regulatory DC (DCreg) has been shown to decrease GVHD-associated mortality in young bone marrow transplanted (BMT) mice. The purpose of this study was to investigate: 1) the potential to generate DCreg from older mice and their subsequent ability to ameliorate GVHD in older BMT mice, 2) the mechanism(s) by which DCreg mitigate GVHD in vivo, 3) the ability of DCreg-treated BMT mice to respond to infectious pathogens, and 4) whether DCreg can be generated under clinically relevant conditions from healthy donor and HSCT recipient PBMCs. To evaluate the efficacy of DCreg treatment in older mice, complete MHC-mismatched BMT mice were treated with DCreg (hereafter referred to as DCreg-treated BMT mice). Although DCreg treatment ameliorated GVHD in older BMT mice, these mice had increased morbidity and decreased survival compared to their young counterparts. Following transfer into BMT mice, older DCreg failed to increase inhibitory molecule (PD-L1 and PIR B) expression while significantly upregulating co-stimulatory molecule (CD40 and CD80) expression, conversely young DCreg upregulated inhibitory molecules as well as co-stimulatory molecules. These phenotypic differences between young and older DCreg in vivo provide a potential mechanism for modestly increased morbidity and mortality in older DCreg-treated BMT mice relative to their young counterparts. Indeed, BMT mice treated with DCreg deficient in PD-L1 or PIR B had significantly reduced overall survival, thus both molecules are required for optimal GVHD mitigation. A murine H1N1 influenza (IAV) infection model was used to assess the donor immune system's capacity to respond to relevant antigens other than those responsible for GVHD. Surprisingly, sub-lethally IAV-infected DCreg-treated BMT mice began to die after d. +21 and all were deceased by d. +25. Virus-specific CD8+ T cell and antibody (Ab) responses were undetectable following primary infection. Interestingly, following a prime-boost infection strategy, DCreg-treated BMT mice survived lethal IAV challenge with no signs of morbidity and had demonstrable IAV-specific Ab and CD8+ T cell responses. Thus a prime-boost IAV infection strategy establishes a protective immune response in the DCreg-treated BMT mice and underscores the potential role vaccination may play in establishing immune competence in DCreg-treated BMT mice. We investigated whether human DCreg can be generated under clinically relevant conditions: 1) following peripheral blood mononuclear cell (PBMC) cryopreservation, 2) in bovine serum-free media, and 3) from older individuals and HSCT recipients. DCreg were generated from healthy donor and HSCT patient PBMCs isolated from young (old) and older (> 50 years old) individuals by culturing cells in X-vivo serum-free. Human DCreg generated from both young and older healthy donor PBMCs had comparable numbers, surface molecule phenotype, cytokine production, and able to induce Treg. Cryopreserved and fresh PBMCs generated DCreg with similar phenotypes and cytokine production. DCreg generated from HSCT recipients maintained low co-stimulatory molecule and high inhibitory molecule expression as well as immunosuppressive cytokine production. These studies confirm DCreg can be generated under clinically relevant conditions.

No description available.

Thesis (Ph.D.)--Indiana University, 2010. / Title from screen (viewed on April 8, 2010). School of Nursing, Indiana University-Purdue University Indianapolis (IUPUI). Advisor(s): Betsy L. Fife, Joan K. Austin, Patrick O. Monahan, Silvia M. Bigatti, Linda G. Bell. Includes vitae. Includes bibliographical references (leaves 233-248).

The Mucopolysaccharide (MPS) diseases are a group of lysosomal storage disorders, caused by a lack of the enzymes required for catabolism of glycosaminoglycans (GAGs), leading to severe neurological decline, skeletal deformities, organomegaly, cardiac and respiratory compromise, and premature death. The severe form of MPS I, Hurler syndrome, can be successfully treated using haematopoietic stem cell transplantation (HSCT), but the risks associated with myeloablation and immune suppression limit the broader application of HSCT to attenuated diseases. Successful engraftment in MPS I has been difficult to achieve, and requires fully myeloablative conditioning, whilst reduced intensity conditioning is a risk factor for graft rejection. Non-myeloablative conditioning generating reliable graft acceptance and high donor chimerism could increase safety and applicability of HSCT in genetic disease, therefore the aim of this research was to identify such a regimen in a clinically relevant mouse model of HSCT.Conditioning regimens developed in existing mouse models of HSCT have had limited clinical success, and often require clinically unachievable high cell doses or less stringent strain combinations to overcome allogeneic transplant rejection. To improve clinical relevance we used CBA donors and C57BL/6 recipients, which require full myeloablation with busulfan and immune suppression using non-depleting anti-CD4 and anti-CD8 monoclonal antibodies for engraftment of low cell doses across a major histocompatibility complex barrier. In syngeneic transplant donor chimerism was improved by generating a greater ratio of donor:recipient haematopoietic cells in the bone marrow initially, therefore we tested granulocyte colony stimulating factor (G-CSF), high cell dose and stem cell niche disruption and compared this to anti-CD40L costimulatory blockade in allogeneic transplant performed with a reduced dose of busulfan that was insufficient for graft acceptance. Despite improvements in initial engraftment with some of these treatments, only combined signal 1 and 2 T cell blockade were effective in reducing the dose of busulfan required for long-term graft acceptance. Early detection of MPS is important in treatment success; good disease biomarkers are vital, and biomarkers suitable for monitoring treatment outcome in MPS are lacking. We evaluated serum heparin cofactor II-thrombin (HCII-T) complex for MPS. We determined optimal sample collection and storage conditions, assay limitations and developed measurement in dried blood spots. Dermatan sulphate has a greater effect on in vivo HCII-T complex formation than heparan sulphate, thus in the MPS mouse models HCII-T is a reliable biomarker for MPS I, but not MPS IIIA or IIIB. HCII-T is greatly elevated in MPS I, II and VI patients, who all store dermatan sulphate, but it is also elevated by a small but significant amount in MPS III patients, who store heparan sulphate. HCII-T was also measured longitudinally in MPS I, II and VI patients, compared to an existing clinical biomarker, and validated against clinical outcomes to show that it is a good biomarker of short-term treatment outcomes and responds rapidly to perturbations in treatment. Finally, we determined whether an engraftment defect was observed in the MPS I mouse model, and show that this is present following both syngeneic and allogeneic HSCT. The effect of enzyme replacement therapy (ERT) and anti-inflammatory treatment prior to allogeneic HSCT was investigated, and initial results suggest that ERT, but not ibuprofen, may improve HSCT outcome. Overall, a clinically relevant mouse model of allogeneic HSCT has been developed and used to determine a non-myeloablative conditioning regimen that generates high levels of donor chimerism with a minimal dose of busulfan and blockade of both signal 1 and 2 of T cell activation. The conditions required to observe an engraftment defect in MPS I mice have also been defined, and preliminary studies have suggested that ERT, but not anti-inflammatory treatment, may overcome the engraftment defect in MPS I. Alongside this work, the HCII-T biomarker has been evaluated in MPS mouse models and patients, determining that it correlates well with short-term treatment outcomes. The techniques and models developed here will provide an excellent basis for further work in developing non-myeloablative conditioning for bone marrow transplant in MPS I.