Treosulfan-Based Conditioning Regimen In Pediatric Hematopoietic Stem Cell Transplantation: A Retrospective Analysis on Behalf of the Spanish Group for Hematopoietic Transplantation and Cellular Therapy (GETH-TC).

Increasing data on treosulfan-based conditioning regimens before hematopoietic stem cell transplantation (HSCT) demonstrate the consistent benefits of this approach, particularly regarding acute toxicity. This study aimed to describe the results of treosulfan-based conditioning regimens in children, focusing on toxicity and outcomes when used to treat both malignant and nonmalignant diseases. This retrospective observational study of pediatric patients treated in Spain with treosulfan-based conditioning regimens before HSCT was based on data collection from electronic clinical records. We studied a total of 160 treosulfan-based conditioning HSCTs to treat nonmalignant diseases (n = 117) or malignant diseases (n = 43) in 158 children and adolescents. The median patient age at HSCT was 5.1 years (interquartile range, 2 to 10 years). The most frequent diagnoses were primary immunodeficiency (n = 42; 36%) and sickle cell disease (n = 42; 36%) in the nonmalignant disease cohort and acute lymphoblastic leukemia (n = 15; 35%) in the malignant disease cohort. Engraftment occurred in 97% of the patients. The median times to neutrophil engraftment (17 days versus 14 days; P = .008) and platelet engraftment (20 days versus 15 days; P = .002) were linger in the nonmalignant cohort. The 1-year cumulative incidence of veno-occlusive disease was 7.98% (95% confidence interval [CI], 4.6% to 13.6%), with no significant differences between cohorts. The 1-year cumulative incidence of grade III-IV acute graft-versus-host disease (GVHD) was higher in the malignant disease cohort (18% versus 3.2%; P = .011). Overall, the malignant cohort had both a higher total incidence (9% versus 3%; P < .001) and a higher 2-year cumulative incidence (16% versus 1.9%; P < .001) of total chronic GVHD. The 2-year cumulative transplantation-related mortality was 15%, with no difference between the 2 cohorts. The 5-year overall survival was 80% (95% CI, 72% to 86%) and was higher in the nonmalignant cohort (87% versus 61%; P = .01). The 2-year cumulative incidence of relapse was 25% in the malignant cohort. The 5-year cumulative GVHD-free, relapse-free survival rate was 60% (95% CI, 51% to 70%) and was higher in the nonmalignant cohort (72% versus 22%; P < .001). A treosulfan-based radiation-free conditioning regimen is feasible, achieving a high engraftment rate and 5-year overall survival, and is an emerging option for the first HSCT in nonmalignant diseases.

Haploidentical vs. HLA-matched donor hematopoietic stem-cell transplantation for pediatric patients with acute lymphoblastic leukemia in second remission: A collaborative retrospective study of the Spanish Group for Bone Marrow Transplantation in Children (GETMON/GETH) and the Spanish Childhood Relapsed ALL Board (ReALLNet).

Introduction: Studies addressing the role of haploidentical as alternative to HLA-matched donors for stem cell transplantation (SCT) often include patients with diverse hematological malignancies in different remission statuses. Methods: We compared outcomes of children with acute lymphoblastic leukemia (ALL) undergoing SCT in second complete remission (CR2) from haploidentical (n = 25) versus HLA-matched donor (n = 51). Results: Patients were equally distributed across both groups according to age, immunophenotype, time to and site of relapse, relapse risk-group allocation, and minimal residual disease (MRD) before SCT. Incidence of graft failure, acute graft versus host disease (GVHD), and other early complications did not differ between both groups. We found no differences in overall survival (58.7% versus 59.5%; p = .8), leukemia free survival (LFS) (48% versus 36.4%; p = .5), event free survival (40% versus 34.4%; p = .69), cumulative incidence (CI) of subsequent relapse (28% versus 40.9%; p = .69), treatment related mortality (24% versus 23.6%; p = .83), CI of cGVHD (4.5% versus 18.7%; p = .2), and chronic GVHD-free and leukemia-free survival (44% versus 26.3%; p = .3) after haploidentical donor SCT. Chronic GVHD (HR = 0.09; p=.02) had protective impact, and MRD ≥ 0.01% before SCT (HR = 2.59; p=.01) had unfavorable impact on LFS. Discussion: These results support the role of haploidentical donor SCT in children with ALL in CR2.

Haploidentical hematopoietic stem cell transplantation in pediatric and adolescent patients: A study of the Spanish hematopoietic stem cell transplantation group (GETH)

Introduction: The main advantages of haploidentical hematopoietic stem cell transplantation (haplo-HSCT) are the immediate availability of donors, the possibility of developing cell therapy approaches with different novel transplant platforms, and the procedure's cost savings.MethodologyWe retrospectively analyzed the pediatric haplo-HSCT activity of the Spanish hematopoietic stem-cell transplantation group (GETH) between 1999 and 2016, aiming to study clinical characteristics and outcomes by describing patient groups with non-malignant disease (NMD) or malignant disease (MD) and the impact of 2 different periods (1999–2009 and 2010–2016) on long-term outcomes.ResultsTwelve centers performed 232 haplo-HSCTs in 227 children, representing 10% of all pediatric allogeneic HSCT activity in Spain from 1999 to 2016, with a notable increase since 2013. Most haplo-HSCTs (86.7%) were performed in patients with MD; 95% received peripheral blood stem cells from donors, and 78.9% received ex vivo T-cell depleted grafts. Non-manipulated grafts using post-transplantation cyclophosphamide have been incorporated since 2012. We observed a higher percentage of graft failure in NMD versus MD (32% vs. 15.6%; p=0.029). Relapse and transplant-related mortality were the procedure's main limitations in MD and NMD, respectively. Five-year overall survival was 48.5% (SE 3.9), with no statistically significant difference when comparing the MD and NMD cohorts. Patients who received previously a HSCT the overall survival was significantly decreased. We observed no survival improvement over time.ConclusionsAlthough haplo-HSCT is an increasingly employed treatment option, our patients’ results need improvement. We need to develop reference centers, especially for NMD whose rarity makes it difficult to gain experience. (AU)

Introducción: Las principales ventajas del trasplante de progenitores hematopoyéticos de donante haploidéntico (haplo-TPH) son la disponibilidad inmediata de donantes, la posibilidad de desarrollar terapia celular postrasplante y el ahorro de costes al obviar el proceso de búsqueda de donante.MetodologíaAnalizamos retrospectivamente la actividad haplo-TPH en población pediátrica del grupo español de trasplante hematopoyético (GETH) entre 1999 y 2016, con el objetivo de estudiar las características clínicas y los resultados mediante la descripción de grupos de pacientes con enfermedad no malignas (ENM) o enfermedad maligna (EM) y el impacto de dos períodos diferentes (1999-2009 y 2010-2016) en los resultados a largo plazo.ResultadosDoce centros realizaron 232 haplo-TPH en 227 niños, lo que representa el 10% de toda la actividad de TPH alogénicos pediátricos en España entre 1999-2016, con un aumento notable desde 2013. La mayoría de los haplo-TPH (86,7%) se realizaron en pacientes con EM; el 95% recibió progenitores hematopoyéticos de sangre periférica y el 78,9% recibió injertos con purgado de células T ex vivo. Los injertos no manipulados con ciclofosfamida postrasplante se realizaron a partir de 2012. Observamos un mayor porcentaje de fallos del injerto en la ENM que en la EM (32% frente a 15,6%; p=0,029). La recaída y la mortalidad relacionada con el trasplante fueron las principales limitaciones del procedimiento en la EM y la ENM, respectivamente. La supervivencia global a cinco años fue del 48,5% (EE 3,9), sin diferencias estadísticamente significativas al comparar las cohortes con EM y ENM. En los pacientes que recibieron previamente un TPH, la supervivencia global se redujo significativamente. No observamos mejoría en la supervivencia a lo largo del tiempo. (AU)

Mesenchymal Stromal Cells for Treating Steroid-Resistant Acute and Chronic Graft Versus Host Disease: A Multicenter Compassionate Use Experience.

Graft versus host disease (GVHD) is a severe complication after allogenic hematopoietic cell transplantation (HSCT). Several clinical trials have reported the use of mesenchymal stromal cells (MSCs) for the treatment of GVHD. In March 2008, the Andalusian Health Care System launched a compassionate use program to treat steroid-resistant GVHD with MSC. Clinical-grade MSC were obtained under GMP conditions. MSC therapy was administered intravenously in four separate doses of 1 × 106 cells/kg. Sixty-two patients, 45 males (7 children) and 17 females (2 children), received the treatment. Patients had a median age of 39 years (range: 7-66) at the time of the allogenic HSCT. The overall response was achieved in 58.7% of patients with acute (a)GVHD. Two years' survival for aGVHD responders was 51.85%. The overall response for patients with chronic (c)GVHD was 65.50% and the 2-year survival rate for responders was 70%. Age at the time of HSCT was the only predictor found to be inversely correlated with survival in aGVHD. Regarding safety, four adverse events were reported, all recovered without sequelae. Thus, analysis of this compassionate use experience shows MSC to be an effective and safe therapeutic option for treating refractory GVHD, resulting in a significant proportion of patients responding to the therapy.

Haploidentical hematopoietic stem cell transplantation in pediatric and adolescent patients: A study of the Spanish hematopoietic stem cell transplantation group (GETH).

INTRODUCTION: The main advantages of haploidentical hematopoietic stem cell transplantation (haplo-HSCT) are the immediate availability of donors, the possibility of developing cell therapy approaches with different novel transplant platforms, and the procedure's cost savings. METHODOLOGY: We retrospectively analyzed the pediatric haplo-HSCT activity of the Spanish hematopoietic stem-cell transplantation group (GETH) between 1999 and 2016, aiming to study clinical characteristics and outcomes by describing patient groups with non-malignant disease (NMD) or malignant disease (MD) and the impact of 2 different periods (1999-2009 and 2010-2016) on long-term outcomes. RESULTS: Twelve centers performed 232 haplo-HSCTs in 227 children, representing 10% of all pediatric allogeneic HSCT activity in Spain from 1999 to 2016, with a notable increase since 2013. Most haplo-HSCTs (86.7%) were performed in patients with MD; 95% received peripheral blood stem cells from donors, and 78.9% received ex vivo T-cell depleted grafts. Non-manipulated grafts using post-transplantation cyclophosphamide have been incorporated since 2012. We observed a higher percentage of graft failure in NMD versus MD (32% vs. 15.6%; p=0.029). Relapse and transplant-related mortality were the procedure's main limitations in MD and NMD, respectively. Five-year overall survival was 48.5% (SE 3.9), with no statistically significant difference when comparing the MD and NMD cohorts. Patients who received previously a HSCT the overall survival was significantly decreased. We observed no survival improvement over time. CONCLUSIONS: Although haplo-HSCT is an increasingly employed treatment option, our patients' results need improvement. We need to develop reference centers, especially for NMD whose rarity makes it difficult to gain experience.

Haploidentical transplantation in pediatric non-malignant diseases: A retrospective analysis on behalf of the Spanish Group for Hematopoietic Transplantation (GETH).

OBJECTIVE: Describe the GETH haploidentical stem cell transplantation (haplo-HSCT) activity in non-malignant disease (NMDs). METHODS: We retrospectively analyzed data from children with NMDs who underwent haplo-HSCT. RESULTS: From January 2001 to December 2016, 26 pediatric patients underwent 31 haplo-HSCT through ex vivo T cell-depleted (TCD) graft platforms or post-transplantation cyclophosphamide (PT-Cy) at 7 Spanish centers. Five cases employed unmanipulated PT-Cy haplo-HSCT, 16 employed highly purified CD34+ cells, and 10 employed ex vivo TCD grafts manipulated either with CD3+ CD19+ depletion, TCRαß+ CD19+ selection or naive CD45RA+ T-cell depletion. Peripheral blood stem cells were the sole source for patients following TCD haplo-HSCT, and bone marrow was the source for one PT-Cy haplo-HSCT. The most common indications for transplantation were primary immunodeficiency disorders (PIDs), severe aplastic anemia, osteopetrosis, and thalassemia. The 1-year cumulative incidence of graft failure was 27.4%. The 1-year III-IV acute graft-versus-host disease (GvHD) and 1-year chronic GvHD rates were 34.6% and 16.7%, respectively. The 2-year overall survival was 44.9% for PIDs, and the 2-year graft-versus-host disease-free and relapse-free survival rate was 37.6% for the other NMDs. The transplantation-related mortality at day 100 was 30.8%. CONCLUSION: Although these results are discouraging, improvements will come if procedures are centralized in centers of expertise.

Haploidentical transplantation in high-risk pediatric leukemia: A retrospective comparative analysis on behalf of the Spanish working Group for bone marrow transplantation in children (GETMON) and the Spanish Grupo for hematopoietic transplantation (GETH).

A total of 192 pediatric patients, median age 8.6 years, with high-risk hematological malignancies, underwent haploidentical stem cell transplantation (haplo-HSCT) using post-transplantation cyclophosphamide (PT-Cy), or ex vivo T cell-depleted (TCD) graft platforms, from January 1999 to December 2016 in 10 centers in Spain. Some 41 patients received an unmanipulated graft followed by PT-Cy for graft-vs-host disease (GvHD) prophylaxis. A total of 151 patients were transplanted with CD3-depleted peripheral blood stem cells (PBSCs) by either CD34+ selection, CD3+ CD19+ depletion, TCRαß+ CD19+ depletion or CD45RA+ depletion, added to CD34+ selection for GvHD prophylaxis. The PBSCs were the only source in patients following ex vivo TCD haplo-HSCT; bone marrow was the source in 9 of 41 patients following PT-CY haplo-HSCT. Engraftment was achieved in 91.3% of cases. A donor younger than 30 years, and the development of chronic GvHD were positive factors influencing survival, whereas positive minimal residual disease (MRD) before transplant and lymphoid disease were negative factors. The probability of relapse increased with lymphoid malignancies, a donor killer-cell immunoglobulin-like receptor (KIR) haplotype A and positive MRD pretransplant. No difference was found in overall survival, disease-free survival or relapse incidence between the two platforms. Relapse is still of concern in both platforms, and it should be the focus of future efforts. In conclusion, both platforms for haplo-HSCT were effective and could be utilized depending on the comfort level of the center.

Measurable Residual Disease Assessed by Flow-Cytometry Is a Stable Prognostic Factor for Pediatric T-Cell Acute Lymphoblastic Leukemia in Consecutive SEHOP Protocols Whereas the Impact of Oncogenetics Depends on Treatment.

Robust and applicable risk-stratifying genetic factors at diagnosis in pediatric T-cell acute lymphoblastic leukemia (T-ALL) are still lacking, and most protocols rely on measurable residual disease (MRD) assessment. In our study, we aimed to analyze the impact of NOTCH1, FBXW7, PTEN, and RAS mutations, the measurable residual disease (MRD) levels assessed by flow cytometry (FCM-MRD) and other reported risk factors in a Spanish cohort of pediatric T-ALL patients. We included 199 patients treated with SEHOP and PETHEMA consecutive protocols from 1998 to 2019. We observed a better outcome of patients included in the newest SEHOP-PETHEMA-2013 protocol compared to the previous SHOP-2005 cohort. FCM-MRD significantly predicted outcome in both protocols, but the impact at early and late time points differed between protocols. The impact of FCM-MRD at late time points was more evident in SEHOP-PETHEMA 2013, whereas in SHOP-2005 FCM-MRD was predictive of outcome at early time points. Genetics impact was different in SHOP-2005 and SEHOP-PETHEMA-2013 cohorts: NOTCH1 mutations impacted on overall survival only in the SEHOP-PETHEMA-2013 cohort, whereas homozygous deletions of CDKN2A/B had a significantly higher CIR in SHOP-2005 patients. We applied the clinical classification combining oncogenetics, WBC count and MRD levels at the end of induction as previously reported by the FRALLE group. Using this score, we identified different subgroups of patients with statistically different outcome in both Spanish cohorts. In SHOP-2005, the FRALLE classifier identified a subgroup of high-risk patients with poorer survival. In the newest protocol SEHOP-PETHEMA-2013, a very low-risk group of patients with excellent outcome and no relapses was detected, with borderline significance. Overall, FCM-MRD, WBC count and oncogenetics may refine the risk-stratification, helping to design tailored approaches for pediatric T-ALL patients.

Cribado oportunista de arteriopatía periférica en pacientes hipertensos de mediana edad que acuden al centro de salud / Opportunistic screening for peripheral arterial disease in middle-aged hypertensive patients attended in a primary health center

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Trasplante de progenitores hematopoyéticos con intensidad reducida en enfermedades genéticas. Experiencia del grupo GETMON (Grupo Español de Trasplante de Médula Ósea en Niños) / Reduced-intensity conditioning haematopoietic stem cell transplantation in genetic diseases: Experience of the Spanish Working Group for Bone Marrow Transplantation in Children

INTRODUCCIÓN: El trasplante de progenitores hematopoyéticos (TPH) consiste en implantar elementos celulares capaces de generar un sistema hematopoyético nuevo y sano. El régimen de intensidad reducida (RIR) consiste en un tratamiento predominantemente inmunosupresor, para facilitar un implante progresivo con menor morbilidad. Este tipo de acondicionamiento puede también provocar mielosupresión, aunque potencialmente reversible en el tiempo. El acondicionamiento RIR permite aplicar TPH a pacientes con enfermedad genética en los que no es deseable añadir comorbilidad por las altas dosis de quimioterapia que conlleva el régimen mieloablativo convencional. PACIENTES Y MÉTODOS: Se analiza la evolución de 68 pacientes pediátricos con enfermedades genéticas que entre los años 2005-2013 se han sometido a un TPH con RIR en las Unidades pediátricas de Trasplante Hematopoyético de los hospitales españoles integrantes del Grupo Español para Trasplante de Médula Ósea en niños. Se trata de un estudio multicéntrico que incluye a 68 pacientes, de los cuales 43 presentan inmunodeficiencia primaria, 21 presentan hemopatía congénita y 4 están afectados de metabolopatía. RESULTADOS: Cincuenta de los 68 pacientes se encuentran vivos (73,5%). La supervivencia global (SG) a 9 años es de 0,74. Veintitrés (33,8%) han presentado en el transcurso del TPH algún evento. Supervivencia libre de evento de 0,66. La SG en los pacientes con hemopatía es de 0,81; en las inmunodeficiencias primarias es de 0,70 y en las metabolopatías es de 0,4. No se observa diferencia significativa entre los 3 grupos de enfermedades. Respecto a la fuente de progenitores hematopoyéticos, la SG en los pacientes trasplantados con sangre periférica es de 0,74; con médula ósea es de 0,70 y con la sangre de cordón umbilical es de 0,70. No se observa tampoco diferencia estadística significativa. CONCLUSIONES: En nuestro trabajo, de ámbito nacional, hemos evidenciado unos resultados favorables en TPH con régimen de intensidad reducida en las enfermedades genéticas. Cabe destacar que las metabolopatías requieren una consideración individualizada para sopesar en cada paciente los riesgos y beneficios que comporta el RIR

INTRODUCTION: Haematopoietic stem cell transplantation (HSCT) involves implanting cellular elements capable of generating a new and healthy haematopoietic system. Reduced intensity conditioning (RIC) consists of an immunosuppressive treatment to facilitate a progressive implant with lower morbidity. This type of conditioning can also lead to myelosuppression, which is potentially reversible over time. Reduced intensity conditioning enables HSCT to be performed on patients with genetic diseases for whom added comorbidity is undesirable due to the high doses of chemotherapy that accompanies conventional myeloablative regimens. PATIENTS AND METHODS: An analysis was performed on the outcomes of 68 paediatric patients with genetic diseases who underwent HSCT with RIC between 2005 and 2013 in the of Paediatric Haematopoietic Stem Cell Transplantation Units that are part of the Spanish Working Group for Bone Marrow Transplantation in Children. A multicentre study was conducted including 68 patients, of whom 43 had Primary Immunodeficiency, 21 with congenital haematological diseases, and 4 with metabolic diseases. RESULTS: Fifty (73.5%) of the 68 patients were still alive. The Overall Survival (OS) at nine years was 0.74. Twenty-three (33.8%) had some event during the course of the HSCT, with an event-free survival rate of 0.66. The OS in patients with haematological diseases was 0.81, being 0.7 in primary immunodeficiencies, and 0.4 in metabolic diseases. No significant difference was observed between the 3 groups of diseases. As regards the source of haematopoietic progenitors, there was an OS rate of 0.74 in patients transplanted with peripheral blood, 0.70 with bone marrow, and 0.70 and with cord blood, with no statistically significant differences. CONCLUSIONS: Favourable results have been obtained in HSCT with reduced intensity conditioning in genetic diseases. It should be noted that the risks and benefits of the RIC in patients with metabolic diseases need to be assessed on an individual basis

Autoimmune hemolytic anemia (AIHA) following allogeneic hematopoietic stem cell transplantation (HSCT): A retrospective analysis and a proposal of treatment on behalf of the Grupo Español De Trasplante de Medula Osea en Niños (GETMON) and the Grupo Español de Trasplante Hematopoyetico (GETH).

Autoimmune hemolytic anemia (AIHA) is a complication of allogeneic hematopoietic stem cell transplantation (HSCT) associated with poor outcome. However, an optimal therapeutic approach is lacking. Between 2000 and 2015, 4099 allogeneic HSCT were performed in eight pediatric centers of the Grupo Español De Trasplante de Medula Osea en Niños (GETMON) and six adult centers of the Grupo Español de Trasplante Hematopoyetico (GETH). Sixty cases of AIHA were registered with a cumulative incidence of 1.5% occurring at a median of 6 months after HSCT. Patients aged less than 15 years (P=.005), and patients using cord blood (P=.005) or an HLA mismatch donor (P=.005) were more likely to develop AIHA. Most patients were lymphopenic at the time of diagnosis of AIHA, including a low number of regulatory T lymphocytes (median 3/µL). Median lines of treatment received for AIHA was 3 (range, 1-7). Almost all patients received corticosteroids (88%) and more than half received immunoglobulins or rituximab (63% and 67%, respectively). Complete resolution of AIHA was achieved in 33 of 60 cases (55%). Cumulative incidence of AIHA-related mortality was 17±6%. We found a correlation of AIHA outcome with age (better outcome in younger than 15 years, RR=1.87, P=.01) and rituximab response (higher rate of complete remission in patients responding to rituximab, RR=1.72, P=.025). We analyzed the factors involved in the response to rituximab and found a better response when there was ABO donor/receptor disparity (P=.014) and in those patients with B lymphocytes count above the median (38/µL) (P=.05).Thirty-six of 60 patients survived yielding a disease free survival of 52±8% at 40 months. In Cox analysis, age (children vs adults, HR: 8.19, CI 95%: 2.39-28.12, P=.001) and AIHA outcome (complete remission vs partial remission/non-response, HR: 4.18, CI 95%: 1.55-11.22, P=.005) were associated with a better survival. Our data suggest that patients who developed AIHA after HSCT are severely lymphopenic and have a high risk of mortality. Outcome is better in children and in patients treated with rituximab. We also propose an algorithm for treatment of AIHA after HSCT.

[Reduced-intensity conditioning haematopoietic stem cell transplantation in genetic diseases: Experience of the Spanish Working Group for Bone Marrow Transplantation in Children]. / Trasplante de progenitores hematopoyéticos con intensidad reducida en enfermedades genéticas. Experiencia del grupo GETMON (Grupo Español de Trasplante de Médula Ósea en Niños).

INTRODUCTION: Haematopoietic stem cell transplantation (HSCT) involves implanting cellular elements capable of generating a new and healthy haematopoietic system. Reduced intensity conditioning (RIC) consists of an immunosuppressive treatment to facilitate a progressive implant with lower morbidity. This type of conditioning can also lead to myelosuppression, which is potentially reversible over time. Reduced intensity conditioning enables HSCT to be performed on patients with genetic diseases for whom added comorbidity is undesirable due to the high doses of chemotherapy that accompanies conventional myeloablative regimens. PATIENTS AND METHODS: An analysis was performed on the outcomes of 68 paediatric patients with genetic diseases who underwent HSCT with RIC between 2005 and 2013 in the of Paediatric Haematopoietic Stem Cell Transplantation Units that are part of the Spanish Working Group for Bone Marrow Transplantation in Children. A multicentre study was conducted including 68 patients, of whom 43 had Primary Immunodeficiency, 21 with congenital haematological diseases, and 4 with metabolic diseases. RESULTS: Fifty (73.5%) of the 68 patients were still alive. The Overall Survival (OS) at nine years was 0.74. Twenty-three (33.8%) had some event during the course of the HSCT, with an event-free survival rate of 0.66. The OS in patients with haematological diseases was 0.81, being 0.7 in primary immunodeficiencies, and 0.4 in metabolic diseases. No significant difference was observed between the 3 groups of diseases. As regards the source of haematopoietic progenitors, there was an OS rate of 0.74 in patients transplanted with peripheral blood, 0.70 with bone marrow, and 0.70 and with cord blood, with no statistically significant differences. CONCLUSIONS: Favourable results have been obtained in HSCT with reduced intensity conditioning in genetic diseases. It should be noted that the risks and benefits of the RIC in patients with metabolic diseases need to be assessed on an individual basis.

Pattern of expression of CXCR4 and adhesion molecules by human CD34+ cells from different sources: role in homing efficiency in NOD/SCID mice.

BACKGROUND AND OBJECTIVES: The role of adhesion molecules (AM) and CXCR4 in the homing of CD34+ cells to NOD/SCID marrow and spleen is not completely elucidated. In this work, we study the differences in the expression of CXCR4 and AM by human CD34+ cells from different sources and their impact on homing ability in NOD/SCID mice. DESIGN AND METHODS: We used flow cytometry to analyze the expression of CXCR4 and AM ( CD49d, CD49e, CD11a, CD58, CD54, CD31, CD62L, CD43 and CD44) on fresh CD34+ cells from bone marrow (BM), mobilized peripheral blood (MPB), positively selected CD34+ cells (PS) and after expansion cultures with two cytokine combinations. Secondly, we studied the homing efficiency of CD34+ cells from each source in 75 irradiated NOD/SCID mice, and finally the pattern of expression of CXCR4 and AMs by retrieved human CD34+ cells that had efficiently homed. RESULTS: The homing efficiency of PS CD34+ cells was significantly lower than that of BM and MPB CD34+ cells. Our results reveal that changes in the expression of CXCR4 and AM are induced by mobilization, PS and in vitro expansion. However none of these changes has definitive impact on the homing efficiency. Human CD34+ cells found in the marrow and spleen of NOD/SCID mice have the same adhesive profile as the injected cells: CXCR4, CD62L and CD11a mainly negative, and CD49d+, indicating that homing is not restricted to positive cells. INTERPRETATION AND CONCLUSIONS: We conclude that changes induced in CXCR4 and AM expression after mobilization, selection and expansion of human CD34+ cells do not cause significant differences in the homing efficiency of these cells. The lower homing efficiency of PS CD34 cells could be explained by the absence of accessory cells.

Diseño y aplicación de una hoja de intercomunicación entre farmacéuticos y médicos en el medio comunitario

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