Background: Our innate immunesystem protects us from infections but, since its methods is not all specific for microorganisms, may also induce collateral damage. Severe physical injury often proved deadly throughout evolution. Such injuries may induce massive collateral damage. Nowadays we can initiate advanced critical care for affected patients and save them from imminent trauma-related death. We are therefore faced with the fact that the collateral damage from the immune system may pose a major threat to the patient, the pathophysiology of which is not amenable to direct medical treatment and which leaves us with only passive supportive measures. In this thesis we investigated the role of leucocytes under such circumstances. Our main aim was to understand better the role of leucocytes in the development of increased vascular permeability after burns and trauma. More specifically we investigated the impact of an injury on the function of leucocytes such as the dynamic change of certain cell-surface receptors on the leucocytes and in their numbers and immature forms. We wanted to find out if the increased pulmonary vascular permeability after a burn could be mediated through heparin binding protein (HBP) released from granuloctes, and whether HBP could be used as a biomarker for respiratory failure after trauma. We also wanted to confirm the possible role of histamine as a mediator of the systemic increase in vascular permeability after burns. Methods: The dynamic change of cell-surface receptors was measured by flow-acquired cytometer scanning (FACS) on blood samples taken after burns. The concentrations of HBP after a burn and mechanical trauma were analysed in plasma. Pulmonary vascular permeability after a burn was assessed using transpulmonary thermodilution. The histamine turnover after a burn was assessed with high performance liquid chromatography (HPLC) for concentrations of histamine and methylhistamine in urine. Results: We confirmed earlier investigations showing altered expression of receptors on leucocytes after a burn, receptors intimately associated with leucocyte functions (study I). In a pilot study of 10 patients we measured plasma concentrations of HBP and found them to be increased soon after a burn (study II). This finding was not confirmed in a larger, more extensive and specific study of 20 patients. We did, however, find an association between alterations in the number of leucocytes soon after a burn and pulmonary vascular permeability, indicating that they had a role in this process (study III). In another study of trauma (non burn) we found an association between the concentration of HBP in early plasma-samples after injury and the development of ARDS, indicating that granulocytes and HBP have a role in its aetiology (study IV). We found a small increase in urinary histamine and normal urinary methylhistamine concentrations but had anticipated a distinct increase followed by a decrease after reading the current papers on the subject. This indicates that the role of histamine as a mediator of increased vascular permeability after burns may have been exaggerated (study V). Conclusions: We conclude that leucocytes are affected by burns and trauma, and it is likely that they contribute to the development of respiratory failure and acute respiratory distress syndrome (ARDS). HBP is a candidate biomarker for the early detection of ARDS after trauma, and the white blood count (WBC) is a useful biomarker for the detection of decreased oxygenation soon after a burn.

No description available.

L’injection de cellules immunologiquement compétentes à un hôte histo-incompatible amène une réaction qui peut se traduire par la maladie du greffon-contre-l’hôte (GVHD). La GVHD demeure une barrière importante à une utilisation plus répandue de la greffe allogénique de cellules hématopoïétiques (AHCT), pourtant un traitement efficace pour traiter de nombreuses maladies. Une meilleure compréhension des mécanismes qui sous-tendent cette pathologie pourrait en faciliter le traitement et la prévention. L’Interféron-gamma (IFN-γ) et le Transforming Growth Factor-béta (TGF-β) sont deux cytokines maîtresses de l’immunité impliquées dans la fonction et l’homéostasie des cellules greffées. Nous démontrons chez la souris que l’IFN-γ limite la reconstitution lympho-hématopoïétique de façon dose-dépendante en mobilisant des mécanismes d’apoptose et en inhibant la prolifération cellulaire. Le TGF-β est quant à lui généralement connu comme un immunosuppresseur qui contrôle l’immunité en utilisant plusieurs voies de signalisation. Le rôle relatif de ces voies en AHCT est inconnu. Nous avons étudié une de ces voies en greffant des cellules provenant de donneurs déficients pour le gène SMAD3 (SMAD3-KO), un médiateur central de la voie canonique du TGF-β, à des souris histo-incompatibles. Bien que l’absence de SMAD3 ne cause aucune maladie chez nos souris donneuses, l’injection de cellules SMAD3-KO amène une GVHD du colon sévère chez le receveur. Cette atteinte est caractérisée par une différenciation Th1 et une infiltration massive de granulocytes témoignant d’un rôle central de SMAD3 dans la physiologie des lymphocytes T CD4 et des cellules myéloïdes. Nous avons focalisé ensuite nos efforts sur le rôle de SMAD3 chez les lymphocytes T CD4 en sachant que SMAD3 était actif chez les lymphocytes T CD4 tolérants. Nous avons découvert que SMAD3 était rapidement inactivé après une activation des cellules T, suggérant que l’inactivation de SMAD3 était fonctionnellement importante pour briser l’état de tolérance. Des études de micro-puces d’ADNc nous ont montré que SMAD3 contrôlait en effet l’expression de nombreux transcrits de gènes connus comme étant reliés à la tolérance et/ou à des processus biologiques dont les rôles dans le maintien de la tolérance sont plausibles. / The injection of immuno-competent cells into a histo-incompatible host can result in the development of Graft-versus-Host disease (GVHD). GVHD is the most significant barrier to a more widespread use of allogeneic hematopoietic cell transplantation (AHCT), a potent treatment for several diseases. A better understanding of the pathophysiological underpinnings of GVHD would facilitate the design of rational approaches to treat and prevent this complication of AHCT. Gamma-interferon (IFN-γ) and Transforming Growth Factor-beta (TGF-β) are master cytokines of immunity and have a role in the function and homeostasis of transplanted cells. Using a murine model, we show that IFN-γ curtails lympho-hamatopoitic reconstitution in a dose-dependent fashion by increasing apoptosis and by limiting donor cell proliferation. TGF-β is an immunosuppressive cytokine that controls immune cells through multiple signaling pathways. The relative contribution of these pathways in AHCT is unknown. We specifically studied the role of one of these pathways by transplanting SMAD3 deficient cells (SMAD3-KO) in histo-incompatible hosts. SMAD3 is a key mediator of the so-called canonical TGF-β signaling pathway. Although SMAD3-KO donor mice are healthy, the injection of SMAD3-KO cells leads to severe GVHD in the hosts, characterized by intestinal involvement associated with Th1 skewing and massive granulocyte infiltration. These findings hint at a crucial role for SMAD3 in CD4 T-cell and myeloid cell biology. We then focalized on the role of SMAD3 in CD4 T cells knowing that SMAD3 is active in tolerant, resting CD4 T cells. We found that SMAD3 was rapidly inactivated upon T cell activation, suggesting that SMAD3 inactivation was functionally important to break the state of tolerance. Our cDNA microarray experiments show that indeed, SMAD3 regulates the transcript levels of multiple genes known to be involved in T cell tolerance and in biological processes plausibly related to immune tolerance.

<p>Diss. (sammanfattning) Umeå : Umeå universitet, 1994, härtill 5 uppsatser.</p> / digitalisering@umu

The granulocyte-colony stimulating factor (G-CSF) is a hematopoietic cytokine that stimulates and regulates the proliferation and differentiation of neutrophil precursor cells of the bone marrow. The recombinant hormone (rhG-CSF) non-glycosylated, filgrastim, is used to treat the neutropenia induced by chemotherapy and bone marrow transplantion. The identification and characterization was carried out by electrophoresis and western blotting, showing the typical band in the region of 18.8 kDa. The neutropenia mouse bioassay was standardized with the BALB/c strain, previously treated with ifosfamide and used for the potency assessment of pharmaceutical products. A gradient reversed-phase liquid chromatography (RP-LC) was validated for the analysis of rhG-CSF in pharmaceutical formulations. The LC method was carried out on a Jupiter C4 column 300 Å (250 mm x 4.6 mm i.d.), maintained at ambient temperature. The mobile phase A consisted of water:acetonitrila (90:10, v/v) with 0.1% trifluoroacetic acid and the mobile phase B was water:acetonitrile (20:80, v/v) with 0.1% trifluoroacetic acid, run at a flow rate of 0.5 mL/min with detection at 280 nm. The chromatographic separation was obtained with the retention time of 31.9 minutes and the method was linear in the range of 10 300 μg/mL. Validation parameters such as sensitivity, precision, accuracy, detection limit, quantitation limit and robustness were evaluated giving results in the acceptable range. The specificity was evaluated by the peak purity of the rhG-CSF biological reference preparation subjected to oxidative conditions. The proposed method was applied for the analysis of filgrastim pharmaceutical products, evaluating the sulphoxides and deamidates forms as well. Moreover, the size-exclusion chromatography (SE-LC) was performed for the potency evaluation of 7 filgrastim, dimers and high-molecular-mass forms. Samples of pharmaceutical formulations were subjected to aggregation, degradation and than each one evaluated by the neutropenia mouse bioassay giving biological activities of 14.60%, 13.47% and 15.63%, for the dimers, high-molecular-mass substances and the sulphoxides/deamidates, respectively. The pharmaceutical samples were analysed by the chromatographyc methods and compared to the bioassay showing mean difference between the estimated potencies of 2.04% lower for the RP-LC, and 4.03% lower for the SE-LC, with significant correlation (p>0.05). Due to the reduced bioactivity of the rhG-CSF-related proteins, the SE-LC is proposed in combination with the RP-LC as an alternative to the bioassay for the potency assessment of filgrastim in pharmaceutical dosage forms. The alternative established represents a contribution towards the replacement of the animals improving the quality control and assuring the safety and efficacy of the biological product. / O fator estimulador da colônia de granulócitos humanos é uma citocina hematopoiética que estimula e regula a proliferação e diferenciação de células precursoras de neutrófilos da medula óssea. O hormônio recombinante (rhG-CSF) sob a forma nãoglicosilada, filgrastima, é usado para o tratamento de neutropenias. Realizou-se a identificação de filgrastima em produtos farmacêuticos por eletroforese, transferência e detecção com anticorpos específicos, demonstrando-se banda única na região de peso molecular de, aproximadamente, 18,8 kDa. Avaliou-se a atividade pelo ensaio biológico da neutropenia em camundongos da linhagem BALB/c, pré-tratados com ifosfamida. Desenvolveu-se e validou-se o método por cromatografia líquida em fase reversa (CL-FR), utilizando coluna Júpiter C4 300 Å (250 mm x 4,6 mm, i.d.), mantida a temperatura ambiente. A fase móvel A foi constituída de água/acetonitrila (90:10, V/V)/ 0,1% ácido trifluoroacético e a fase móvel B de água/acetonitrila (20:80, V/V)/ 0,1% ácido trifluoroacético, eluída em gradiente na vazão de 0,5 mL/min com detecção no ultravioleta a 280 nm. A análise cromatográfica viabilizou a separação da filgrastima no tempo de retenção de 31,9 min, sendo linear na faixa de concentração de 10 300 μg/mL. Avaliaram-se os parâmetros de precisão, exatidão, limite de detecção, limite de quantificação e robustez. Estudou-se também a especificidade, através da determinação da pureza do pico da Substância biológica de referência de rhG-CSF, submetida à degradação sob condições oxidativas. O método proposto foi utilizado para análise de filgrastima em produtos farmacêuticos, determinando-se as formas de sulfóxidos e desamidados. Paralelamente, efetuaram-se avaliações de potência por cromatografia líquida por exclusão molecular (CL-EM), determinando as formas diméricas e de alta massa molecular. Amostras de produtos farmacêuticos foram submetidas a condições de agregação e degradação e, então, avaliadas pelo bioensaio da neutropenia em 5 camundongos, obtendo-se atividades biológicas de 14,60%, 13,47% e 15,63%, para os dímeros, substâncias de alta massa molecular e sulfóxidos/desamidados, respectivamente. Estudou-se a correlação entre métodos e demonstrou-se que as análises dos produtos farmacêuticos forneceram diferenças médias 2,04% menor por CL-FR, e significativa de 4,03% menor por CL-EM, em relação ao ensaio biológico. Devido à reduzida bioatividade das formas alteradas, conclui-se sugerindo a adoção do método por CL-EM para a avaliação de potência de filgrastima, em combinação com CL-FR. Desse modo, estabeleceu-se alternativa no contexto da substituição do uso de animais, contribuindo para aprimorar o controle da qualidade, garantindo a segurança e eficácia terapêutica do produto biológico.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The granulocyte-macrophage colony stimulating factor (GM-CSF) is a cytokine that regulates the proliferation and differentiation of hematopoietic progenitor cells and activates mature granulocytes and macrophages. Clinically is used in enhancing hematopoietic recovery after cancer chemotherapy and bone marrow transplantation. A reversed-phase liquid chromatography (RP-LC) method was validated for the determination of the non-glycosylated recombinant rhGM-CSF (Molgramostim) in biopharmaceutical formulations. The RP-LC method was carried out on a Jupiter C4 column (250 mm x 4.6 mm i.d.), maintained at 45 ºC. The mobile phase A consisted of 0.1% TFA and the mobile phase B consisted of 0.1% TFA in acetonitrile, run at a gradient from: 0.01 34 min, 37% 50% of B; 34 35 min linear back to 37% of B and 35 40 min, 37% of B. The flow rate was 1 mL/min, and using photodiode array (PDA) detection at 214 nm. The chromatographic separation was obtained with the retention time of 29.2 min, and was linear over the concentration range of 2-300 μg/mL (r2 = 0.9992). The procedure was validated evaluating parameters such as the specificity, linearity, precision, accuracy, robustness, limit of detection and limit of quantitation. The specificity was proven through degradation studies, showing that also there was no interference of the excipients. Moreover, the in vitro cytotoxicity test of the degraded products showed significant differences (p<0.05). The proposed method was applied for the analysis of molgramostim and their related proteins, and the results were correlated to the bioassay, showing mean differences of the potency 1.02% higher for the RP-LC method, contributing to establish alternatives to characterize and monitoring its instability, improving the quality control and assuring the therapeutic efficacy. / O fator estimulador da colônia de granulócitos e macrófagos (GM-CSF) é uma citocina que regula a proliferação e diferenciação de células progenitoras hematopoiéticas e ativa granulócitos e macrófagos maduros. É clinicamente indicado após quimioterapia para o câncer e após transplante de medula óssea. No presente trabalho foi validado método por cromatografia líquida em fase reversa (CL-FR) para a avaliação da molgramostima, forma recombinante não-glicosilada do GM-CSF, em formulação biofarmacêutica. Utilizou-se coluna Júpiter C4 (250 mm x 4,6 mm d.i.), mantida a 45 °C. A fase móvel A foi composta de ácido trifluoracético 0,1% e a fase móvel B de ácido trifluoracético 0,1% em acetonitrila, eluídas no gradiente: 0,01 34 min, 37 50% de B; 34 35 min, 50 37% de B, mantendo-se nesta proporção até 40 min. Utilizou-se vazão de 1 mL/min, usando detector de arranjo de diodos (DAD) a 214 nm. A separação cromatográfica foi obtida no tempo de 29,2 min, sendo linear na faixa de concentração de 2 300 μg/mL (r2 = 0,9992). O procedimento foi validado, avaliando-se os parâmetros de especificidade, linearidade, precisão, exatidão, robustez, limite de detecção e quantificação. A especificidade foi comprovada através de estudos de degradação, demonstrando também que não houve interferência dos excipientes. Além disso, realizou-se o teste de citotoxicidade in vitro dos produtos degradados que apresentaram diferença significativa (p<0,05). O método foi aplicado para avaliação de potência de molgramostima e de proteínas relacionadas, e os resultados foram correlacionados com o bioensaio, observando-se diferenças médias de potência 1,02% superiores por CL-FR. Contribuiu-se assim para o estabelecimento de alternativas que aprimoram o controle da qualidade, garantindo a segurança e eficácia terapêutica.

Introdução: Várias são as propostas descritas para tratar farmacologicamente a lesão traumática da medula espinal. A metilprednisolona já foi padronizada para uso clínico. O fator estimulador de colônia de granulócitos (G-CSF) tem sido promissor em estudos experimentais e clínicos. Não há pesquisas quanto ao efeito da associação dos dois fármacos. Objetivo: Avaliar o efeito do tratamento com o fator estimulador de colônia de granulócitos associado a metilprednisolona na lesão medular aguda experimental em ratos. Material e métodos: Foram avaliados 40 ratos Wistar submetidos a lesão medular moderada com o NYU-Impactor. Os animais foram divididos em quatro grupos de 10 ratos. O Grupo Controle não recebeu tratamento; o Grupo G-CSF, foi tratado com G-CSF no momento da lesão e diariamente ao longo dos cinco dias subsequentes; o Grupo Metilprednisolona, com metilprednisolona durante 24 horas; e o Grupo G-CSF/Metilprednisolona, com metilprednisolona durante 24 horas e G-CSF no momento da lesão e ao longo de cinco dias. Os animais foram mantidos vivos durante 42 dias; a avaliação funcional foi realizada com a aplicação da escala funcional de Basso, Beattie e Bresnahan (BBB) nos dias 2, 7, 14, 21, 28, 35 e 42 subsequentes à lesão. A avaliação dos potenciais evocados motores foi realizada no dia 42 e a avaliação histológica da lesão da região da medula espinal lesada, realizada logo após a eutanásia ocorrida no dia 42. Resultados e conclusões: A associação de metilprednisolona e G-CSF no tratamento do traumatismo medular contuso experimental em ratos promoveu melhora neurológica avaliada pela escala BBB superior à melhora promovida pela metilprednisolona e G-CSF quando utilizadas isoladamente. A associação teve também efeito sinérgico que resultou em melhora nos parâmetros histológicos no local da lesão. Não houve diferença entre os grupos quanto à avaliação neurofisiológica / Introduction: There are several proposals to pharmacologically treat traumatic spinal cord injury. Methylprednisolone has already been standardized for clinical use. Granulocyte colony stimulating factor (G-CSF) has been promising in experimental and clinical studies. There is no research on the effect of the association of the two drugs. Objective: to evaluate the effect of combined treatment of the granulocyte colony-stimulating factor (G-CSF) associated with methylprednisolone in experimental acute spinal cord injury in rats. Material and methods: Forty male Wistar rats were submitted to a moderate spinal cord injury with the NYU-Impactor. The animals were divided into four groups of ten rats each. The Control Group was not treated; the G-CSF Group was treated with G-CSF at the time of injury and daily over the next five days; the Methylprednisolone Group was treated with methylprednisolone for 24 hours; the G-CSF/methylprednisolone Group, was treated with methylprednisolone for 24 hours and G-CSF at the time of injury and daily over the next five days. The animals were kept alive for 42 days; Functional evaluation was performed using the Basso, Beattie and Bresnahan (BBB) score on days 2, 7, 14, 21, 28, 35 and 42 following the spinal cord injury. Evaluation of motor evoked potentials was held and histological examination of the lesion of the spinal cord was done immediately after euthanasia on day 42. Results and conclusions: The combination of methylprednisolone and G-CSF in the treatment of experimental spinal cord injury in rats promoted neurological improvement as assessed by BBB scale with greater improvement than with methylprednisolone or G-CSF when used alone. The combination of treatment had also a synergistic effect resulting in improvement in histological parameters at the injury site. There was no difference between groups regarding neurophysiological evaluation

Orientadores: Alessandro dos Santos Farias, Leonilda Maria Barbosa dos Santos / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-23T01:58:27Z (GMT). No. of bitstreams: 1 Pradella_Fernando_M.pdf: 4468527 bytes, checksum: 63d6760bd0ea06c5fcab94d1421da291 (MD5) Previous issue date: 2013 / Resumo: O resumo poderá ser visualizado no texto completo da tese digital / Abstract: The abstract is available with the full electronic document / Mestrado / Imunologia / Mestre em Genética e Biologia Molecular

Les nanomatériaux combinant des fonctions de ciblage, d'imagerie, de thérapie et de détection font l'objet de nombreuses recherches dans le domaine de la santé. Les travaux présentés dans cette thèse concernent la multi‐fonctionnalisation de nanoparticules (NPs) par un procédé de synthèse supportée. Le support solide développé dans cette étude est constitué d'un matériau poreux en verre sur lequel sont greffées de manière temporaire des nanoparticules de silice. La fonctionnalisation de la surface des nanoparticules a été réalisée de façon automatisée par une chimie de synthèse dite aux phosphoramidites. Dans un premier temps, cette technique a permis d'obtenir des densités de greffage de l'ordre de 5000 à 7000 oligonucléotides par nanoparticule, ce qui représente une fonctionnalisation 10 à 20 fois supérieure à celles obtenues par des méthodes de greffage en solution. Les brins d'ADN synthétisés sur les NPs ont montré une bonne accessibilité pour l'hybridation avec un brin d'ADN complémentaire, ouvrant la voie à des applications thérapeutiques ou à l'intégration de ces objets dans des systèmes de détection. La deuxième partie de ces travaux est consacrée à la vectorisation d'une protéine thérapeutique, le G‐CSF (facteur de croissance de colonies de granulocytes), par des nanoparticules présentant également des propriétés d'imagerie. Ces nanovecteurs thérapeutiques ont montré des propriétés de stimulation cellulaire in vitro et de ciblage de la rate, organe réservoir de neutrophiles, in vivo. Enfin il a été démontré que la modification de NPs sur support ouvre des perspectives intéressantes pour la préparation d'assemblages complexes de nanoparticules (dimères et NPs dissymétriques) / Nanomaterials combining targeting, imaging, therapy and sensing properties are of growing interest for biomedical applications. The work reported in this thesis concerns nanoparticle (NP) multifunctionalization by solid phase synthesis. The solid support developed in this study is composed of a porous glass material on which silica NPs are temporarily grafted. Nanoparticle surface functionalization was performed by automated synthesis using phosphoramidite chemistry. Firstly, high surface loadings from 5000 to 7000 oligonucleotides per NP were achieved, representing a functionalization 10 to 20‐fold greater than those obtained by coupling methods in solution. DNA strands synthesized on NPs showed a good accessibility for hybridization with a complementary DNA strand, paving the way for therapeutic applications or integration of these objects in detection systems. The second part of this work was devoted to the vectorization of a therapeutic protein, GCSF (Granulocyte‐Colony Stimulating Factor) by nanoparticles that also exhibited imaging properties. These therapeutic nanocarriers showed cell stimulating properties in vitro and spleen targeting, which is a reservoir of neutrophils, in vivo. Finally, it was demonstrated that the solid phase modification of NPs opens interesting perspectives for the production of complex nanoparticle assemblies (dimers and asymmetric NPs)

Orientador: Simone dos Santos Aguiar / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-27T08:24:49Z (GMT). No. of bitstreams: 1 Eid_KatiaAparecidadeBrito_D.pdf: 1187431 bytes, checksum: e62e4911ad1d92b3213551ba2a1b41a7 (MD5) Previous issue date: 2015 / Resumo: Introdução: As células progenitoras periféricas hematopoiéticas (CPHP) é uma das alternativas de enxerto para a realização de transplante autólogo em crianças, adolescente e adulto jovem portadores de tumores sólidos e linfomas. Na mobilização, a dose clássica de G-CSF é 10µg/kg/peso do paciente SC em dose única. Acredita-se que doses maiores de G-CSF aplicadas duas vezes ao dia aumentariam o número de CD34+ coletadas com o menor número de leucaféreses. A tecnologia atual permite que seja realizado leucaférese em crianças com baixo peso (<10 kg). Objetivo: o mote do estudo foi avaliar se o G-CSF na dose de 15µg/kg peso do paciente ao dia e fracionado em duas doses, 10µg/kg e 5µg/kg, diminuiria o número de leucaférese realizada para atingir o mínimo de 3x106/kg/peso do paciente de CD34+ quando comparada com G-CSF na dose convencional, 10µg/kg/peso do paciente em dose única. Métodos: Os pacientes foram divididos em dois grupos. Grupo 10 formado por pacientes que receberam G-CSF 10µg/kg/peso SC ao dia em dose única às 6h e grupo 15 formado por pacientes que receberam G-CSF 15µg/kg/peso SC ao dia dividido em duas vezes, 10µg/kg SC às 6h e 5µg/kg SC às 18h. As leucaféreses foram realizadas em um separador celular automático de fluxo contínuo com anticoagulante ACD-A, foram processados 4 volemias em cada leucaférese. Pacientes com < 20 kg receberam priming de concentrado de hemácias filtradas e irradiadas (CHFI) durante as leucaféreses. A realização do transplante autólogo ocorreu com o número mínimo de 3x106/kg/peso de CD34+. Resultados: Sessenta e cincos pacientes portadores de tumores sólidos e linfomas foram avaliados, 39 pacientes receberam 10µg/kg/peso SC ao dia em dose única às 6h de G-CSF e 26 pacientes receberam 10µg/kg SC às 6h e 5µg/kg SC às 18h de G-CSF. Foram realizadas 146 leucaféreses, 110 (75,3%) no grupo 10 e 36 (24,7%) leucaféreses no grupo 15. No grupo 10 foi obtido uma mediana de 3 (1-7) leucaféreses e coletado uma média de 8,89x106/kg (± 9,59) de CD34+, o grupo 15 realizou uma mediana de 1 (1-3) leucaféreses e coletado uma média de 5,29x106/kg (± 4,95) de CD34+. Uma diferença estatística importante foi o número de leucaféreses (p<0,0001). Nenhum paciente apresentou intercorrências durante as leucaféreses. Os pacientes que receberam CHFI (<20 kg) não apresentaram hipovolemia nas leucaféreses realizadas. Conclusão: Para coletar o mínimo de 3x106/kg/peso de CD34+, a aplicação de G-CSF 15µg/kg/peso fracionada diminuiu significativamente o número de leucaférese realizada / Abstract: Introduction: The peripheral hematopoietic progenitor cells are a graft choice for performing autologous transplantation. In the mobilization, the classical dose of G-CSF is 10?g/kg of the patient in a single dose. There is a theory that higher doses of G-CSF applied twice daily could increase the number of collected CD34+ cells with a smallest number of leukapheresis. Objective: The aim of this study is to evaluate if a fractionated-dose of G-CSF at 15?g/kg of patient may reduce the number of leukapheresis for achieving the minimum target of 3 x 106/kg of CD34+ cells as compared to conventional dose of G-CSF. Methods: Patients were divided into two groups. Group 10: patients who received a single dose daily of G-CSF 10?g/kg and Group 15: patients who received twice dose daily of G-CSF 15?g/kg. The leukapheresis were processed in an automated cell separator. The autologous transplantation happened when the minimum number of 3x106/kg CD34+ was reached. Results: Group 10 enrolled 39 patients who received 10?g/kg of G-CSF and group 15 had 26 patients who received 15?g/kg fractionated of G-CSF. There were a total of 146 aphaeresis; 110 (75.3%) in group 10 and 36 (24.7%) group 15. Group 10 collected a median of 3 (1-7) leukapheresis and a mean of 8.89 x106/kg (± 9.59) CD34+, whereas group 15 had a median of 1 (1-3) leukapheresis and collected a mean of 5.29 x106/kg (± 4.95). The relevant difference statistic was the number of aphaeresis (p<0.0001). Conclusion: To collect a minimum target of 3x106/kg of CD34 +, the application of fractionated-dose of 15?g/kg G-CSF decreased significantly the number of leukapheresis performed / Doutorado / Saude da Criança e do Adolescente / Doutora em Ciências