Trends of hematopoietic stem cell transplantation in the third millennium

Internal Guidelines for Reducing Lymph Node Contour Variability in Total Marrow and Lymph Node Irradiation

BACKGROUND

The total marrow and lymph node irradiation (TMLI) target includes the bones, spleen, and lymph node chains, with the latter being the most challenging structures to contour. We evaluated the impact of introducing internal contour guidelines to reduce the inter- and intraobserver lymph node delineation variability in TMLI treatments.

METHODS

A total of 10 patients were randomly selected from our database of 104 TMLI patients so as to evaluate the guidelines' efficacy. The lymph node clinical target volume (CTV_LN) was recontoured according to the guidelines (CTV_LN_GL_RO1) and compared to the historical guidelines (CTV_LN_Old). Both topological (i.e., Dice similarity coefficient (DSC)) and dosimetric (i.e., V95 (the volume receiving 95% of the prescription dose) metrics were calculated for all paired contours.

RESULTS

The mean DSCs were 0.82 ± 0.09, 0.97 ± 0.01, and 0.98 ± 0.02, respectively, for CTV_LN_Old vs. CTV_LN_GL_RO1, and between the inter- and intraobserver contours following the guidelines. Correspondingly, the mean CTV_LN-V95 dose differences were 4.8 ± 4.7%, 0.03 ± 0.5%, and 0.1 ± 0.1%.

CONCLUSIONS

The guidelines reduced the CTV_LN contour variability. The high target coverage agreement revealed that historical CTV-to-planning-target-volume margins were safe, even if a relatively low DSC was observed.

Multimodal Tracking of Hematopoietic Stem Cells from Young and Old Mice Labeled with Magnetic-Fluorescent Nanoparticles and Their Grafting by Bioluminescence in a Bone Marrow Transplant Model

This study proposes an innovative way to evaluate the homing and tracking of hematopoietic stem cells from young and old mice labeled with SPION_NIRF-Rh conjugated with two types of fluorophores (NIRF and Rhodamine), and their grafting by bioluminescence (BLI) in a bone marrow transplant (BMT) model. In an in vitro study, we isolated bone marrow mononuclear cells (BM-MNC) from young and old mice, and analyzed the physical-chemical characteristics of SPION_NIRF-Rh, their internalization, cell viability, and the iron quantification by NIRF, ICP-MS, and MRI. The in vivo study was performed in a BMT model to evaluate the homing, tracking, and grafting of young and old BM-MNC labeled with SPION_NIRF-Rh by NIRF and BLI, as well as the hematological reconstitution for 120 days. 5FU influenced the number of cells isolated mainly in young cells. SPION_NIRF-Rh had adequate characteristics for efficient internalization into BM-MNC. The iron load quantification by NIRF, ICP-MS, and MRI was in the order of 10⁴ SPION_NIRF-Rh/BM-MNC. In the in vivo study, the acute NIRF evaluation showed higher signal intensity in the spinal cord and abdominal region, and the BLI evaluation allowed follow-up (11-120 days), achieving a peak of intensity at 30 days, which remained stable around 10⁸ photons/s until the end. The hematologic evaluation showed similar behavior until 30 days and the histological results confirm that iron is present in almost all tissue evaluated. Our results on BM-MNC homing and tracking in the BMT model did not show a difference in migration or grafting of cells from young or old mice, with the hemogram analysis trending to differentiation towards the myeloid lineage in mice that received cells from old animals. The cell homing by NIRF and long term cell follow-up by BLI highlighted the relevance of the multimodal nanoparticles and combined techniques for evaluation.

Total marrow and total lymphoid irradiation in bone marrow transplantation for acute leukaemia

The use of total body irradiation as part of conditioning regimens for acute leukaemia is progressively declining because of concerns of late toxic effects and the introduction of radiation-free regimens. Total marrow irradiation and total marrow and lymphoid irradiation represent more targeted forms of radiotherapy compared with total body irradiation that have the potential to decrease toxicity and escalate the dose to the bone marrow for high-risk patients. We review the technological basis and the clinical development of total marrow irradiation and total marrow and lymphoid irradiation, highlighting both the possible advantages as well as the current roadblocks for widespread implementation among transplantation units. The exact role of total marrow irradiation or total marrow and lymphoid irradiation in new conditioning regimens seems dependent on its technological implementation, aiming to make the whole procedure less time consuming, more streamlined, and easier to integrate into the clinical workflow. We also foresee a role for computer-assisted planning, as a way to improve planning and delivery and to incorporate total marrow irradiation and total marrow and lymphoid irradiation in multi-centric phase 2-3 trials.

Physical and Psychological Discomfort Experienced by Hematopoietic Stem-Cell Donors

This study investigates the types and degrees of physical and psychological discomfort experienced by hematopoietic stem cell donors before, during, and after the donation process in order to provide helpful information for developing education programs that can help donors to cope with their discomforts. One hundred and thirty-one individuals who donated hematopoietic stem cells from 2017 to 2019 were asked to self-report the types and degrees of physical and psychological discomfort they felt in the process, and the results were analyzed using SPSS. All participants donated peripheral blood stem cells; the most commonly reported physical discomfort was myalgia (72.5%), followed by bone pain (62.6%), fatigue (60.3%), and headache (55.0%). Of the donors, 88.5% responded that they experienced psychological discomforts, including fear (44.3%), anxiety (44.3%), stress (39.7%), depression (31.3%), loneliness (31.3%), regret (29.8%), and ambivalence (23.7%). In particular, female donors experienced more discomfort than males in rash (Z = -2.123, p = 0.034), fear (Z = -2.851, p = 0.004), and anxiety (Z = -1.861, p = 0.044). Therefore, it is necessary for healthcare providers and experts to make efforts to educate and help donors to prepare and mitigate their discomfort throughout the donation process, and to strategically manage donors' well-being by monitoring and evaluating their discomfort levels and providing interventions if necessary.

Increased age-associated mortality risk in HLA-mismatched hematopoietic stem cell transplantation

We investigated a possible interaction between age-associated risk and HLA-mismatch associated risk on prognosis in different age categories of recipients of unrelated hematopoietic stem cell transplants (HSCT) (n=3019). Patients over 55 years of age transplanted with 8/10 donors showed a mortality risk of 2.27 (CI 1.70–3.03, P<0.001) and 3.48 (CI 2.49–4.86, P<0.001) when compared to 10/10 matched patients in the same age group and to 10/10 matched patients aged 18–35 years, respectively. Compared to 10/10 matched transplantations within each age category, the Hazards Ratio for 8/10 matched transplantation was 1.14, 1.40 and 2.27 in patients aged 18–35 years, 36–55 and above 55 years. Modeling age as continuous variable showed different levels of risk attributed to age at the time of transplantation [OS: 10/10: Hazards Ratio 1.015 (per life year); 9/10: Hazards Ratio: 1.019; 8/10: Hazards Ratio 1.026]. The interaction term was significant for 8/10 transplantations (P=0.009). Findings for disease-free survival and transplant-related mortality were similar. Statistical models were stratified for diagnosis and included clinically relevant predictors except cytomegalovirus status and Karnofsky performance status. The risk conferred by age at the time of transplantation varies according to the number of HLA-mismatches and leads to a disproportional increase in risk for elderly patients, particularly with double mismatched donors. Our findings highlight the importance of HLA-matching, especially in patients over 55 years of age, as HLA-mismatches are less well tolerated in these patients. The interaction between age-associated risk and HLA-mismatches should be considered in donor selection and in the risk assessment of elderly HSCT recipients.

[Short-term effects of hemogram in healthy donors after peripheral blood stem cell collection]

目的

探讨连续外周血造血干细胞（PBSC）采集对异基因造血干细胞供者外周血细胞计数的影响以及供者对连续采集的耐受性。

方法

166名于2013至2014年在浙江大学医学院附属第一医院血液科捐献PBSC的亲缘异基因供者，男86名，女80名，中位年龄40.5（15.0~60.0）岁。动员方案为G-CSF 5~10 µg·kg⁻¹·d⁻¹皮下注射至采集结束。于PBSC动员前、采集前、采集1次及2次后检测供者外周血以及采集物中WBC、PLT、HGB。

结果

连续2次PBSC采集后供者外周血HGB中位数由145（94~181）g/L降至138（93~167）g/L（P<0.05），PLT中位数由231（105~490）×10⁹/L降至95（39~210）× 10⁹/L（P<0.05），WBC差异无统计学意义（P>0.05）。采集物中HGB与供者外周血HGB降幅呈低度正相关（r=0.297，P=0.017），采集物中PLT与供者外周血PLT降幅高度相关（r=0.719，P<0.001）。不同年龄组供者在PBSC采集后的HGB降幅两两比较差异无统计学意义（P≥0.05）。PLT差异无统计学意义（P>0.05）。不同体重指数供者在PBSC采集1次及2次后外周血HGB降幅差异均有统计学意义（P=0.003，P<0.001），体重指数<18.5 kg/m²的偏瘦组供者HGB下降最明显（P<0.05）。

结论

健康异基因造血干细胞供者在连续PBSC采集过程中HGB轻度下降，对于偏瘦供者应调整采集参数以保证安全。采集PBSC会使血小板减少的风险增加，减少的程度与年龄及体重指数无关，且均可耐受。

Numerical impairment of nestin(+) bone marrow niches in acute GvHD after allogeneic hematopoietic stem cell transplantation for AML

The nestin(+) perivascular bone marrow (BM) stem cell niche (N(+)SCN) may be involved in GvHD. To investigate whether acute GvHD (aGvHD) reduces the number of N(+)SCN, we examined patients with AML who had undergone allogeneic hematopoietic stem cell transplantation. In the test cohort (n=8), the number of N(+)SCN per mm(2) in BM biopsies was significantly reduced in aGvHD patients at the time of aGvHD compared with patients who did not have aGvHD (1.2±0.78 versus 2.6±0.93, P=0.04). In the validation cohort (n=40), the number of N(+)SCN was reduced (1.9±0.99 versus 2.6±0.90 N(+)SCN/mm(2), P=0.05) in aGvHD patients. Receiver operating curves suggested that the cutoff score that best discriminated between patients with and without aGvHD was 2.29 N(+)SCN/mm(2). Applying this cutoff score, 9/11 patients with clinically relevant aGvHD (⩾grade 2) and 13/20 with any type of GvHD had decreased N(+)SCN numbers compared with only 10/29 patients without clinically relevant aGvHD (P=0.007) and 6/20 patients without any type of GvHD (P=0.028). In patients tracked over time, N(+)SCN density returned to normal after aGvHD resolved or remained stable in patients who did not have aGvHD. Our results show a decrease in the number of N(+)SCN in aGvHD.

Cord blood clinical processing, cryopreservation, and storage

Allogeneic umbilical cord blood (UCB) hematopoietic stem cell transplantation has become a crucial advancement in the treatment for a variety of diseases including hematopoietic and non-hematopoietic malignancies, BM failure syndromes, hemoglobinopathies, and metabolic and immunodeficiency disorders. It has been well documented that the success of UCB engraftment is tied to UCB banking processes, and now there are established guidelines for standardization of collection, banking, processing, and cryopreservation for unrelated UCB units with purpose of achieving consistent production of high quality placental and UCB units for administration. In 2011, Canada's Ministry of Health has announced Canada's first national, publicly funded umbilical cord blood bank, which aims to provide altruistic donations for unrelated allogeneic hematopoietic stem cell transplant. In this chapter, we describe specific protocols for clinical processing, cryopreservation, and storage of UCB used by the Canadian Blood Services National Public Umbilical Cord Blood Bank.

A novel approach for the enumeration of peripheral blood stem cells suitable for transplantation

Stem cells have the capability to proliferate and differentiate into various cells of the body. Few stem cell sources have been approved for transplantation, among them are the hematopoietic progenitor cells which are progenitors of the myeloid and erythroid lineage in the hematopoietic system, that continually provides mature blood cells during the lifespan of the individual. These well-characterized stem cells are clinically relevant in the treatment of diseases such as breast cancer, leukemias, and congenital immunodeficiencies. Peripheral blood stem transplantation is a standard procedure after its first successful transplantation more than 35 years ago. The minimum intended dose of stem cells given to the patient is 2.5 × 10(6) -5 × 10(6) cells. In this study, we are establishing a correlation between the number of stem cells enumerated and the weight of the patient as a determinant for suitable transplantation. We have established a conversion factor to deliver the required dose of approximately 3 × 10(6) stem cells/kg body weight. This will ensure a uniform collection strategy that is sufficient for transplantation irrespective of the weight of the patient. This approach, if incorporated, will lead to a significantly lesser rate of bone marrow transplantation failures as sufficient number of stem cells will ensure engraftment of stem cells.

Mathematical model of stem cell differentiation and tissue regeneration with stochastic noise

Differentiation and self-renewal of stem cells is an essential process for the maintenance of tissue composition. The promise of novel medical therapies combined with the complexity of this process encourage us to employ numerical and mathematical methods. This will allow us to understand better the mechanisms which regulate stem cell behaviour. Perturbations to the cellular environment may have an influence on the death rate, proliferation rate and on the fraction of self-renewal at every stage of differentiation. In this paper, we present mathematical study of the effect of stochastic noise on the process of tissue regeneration. Here, a system of Itô stochastic differential equations with linear diffusion coefficients that is based on a deterministic model of multistage cell lineages is investigated. Numerical simulations of the stochastic model are shown for a different number of stages of differentiation. Interactions between the noise, added to the different stages, are characterised using numerical simulations. The long-time behaviour of the two-dimensional version of the model is fully characterised; asymptotic stability of the related Markov semigroup is proved using the theory of the Markov semigroups and the method of the Khasminskií function.

Intravital imaging of donor allogeneic effector and regulatory T cells with host dendritic cells during GVHD

Graft-versus-host disease (GVHD) is a systemic inflammatory response due to the recognition of major histocompatibility complex disparity between donor and recipient after hematopoietic stem cell transplantation (HSCT). T-cell activation is critical to the induction of GVHD, and data from our group and others have shown that regulatory T cells (Tregs) prevent GVHD when given at the time of HSCT. Using multiphoton laser scanning microscopy, we examined the single cell dynamics of donor T cells and dendritic cells (DCs) with or without Tregs postallogeneic transplantation. We found that donor conventional T cells (Tcons) spent very little time screening host DCs. Tcons formed stable contacts with DCs very early after transplantation and only increased velocity in the lymph node at 20 hours after transplant. We also observed that Tregs reduced the interaction time between Tcons and DCs, which was dependent on the generation of interleukin 10 by Tregs. Imaging using inducible Tregs showed similar disruption of Tcon-DC contact. Additionally, we found that donor Tregs induce host DC death and down-regulate surface proteins required for donor T-cell activation. These data indicate that Tregs use multiple mechanisms that affect host DC numbers and function to mitigate acute GVHD.

High-resolution HLA matching in hematopoietic stem cell transplantation: a retrospective collaborative analysis

HLA mismatches at the allele and antigen level (possibly with the exception of HLA-DQB1) should be treated equally in donor selection. HLA mismatches at >1 locus (including HLA-DQB1) have additive detrimental effects.

Regulatory systems in bone marrow for hematopoietic stem/progenitor cells mobilization and homing

Regulation of hematopoietic stem cell release, migration, and homing from the bone marrow (BM) and of the mobilization pathway involves a complex interaction among adhesion molecules, cytokines, proteolytic enzymes, stromal cells, and hematopoietic cells. The identification of new mechanisms that regulate the trafficking of hematopoietic stem/progenitor cells (HSPCs) cells has important implications, not only for hematopoietic transplantation but also for cell therapies in regenerative medicine for patients with acute myocardial infarction, spinal cord injury, and stroke, among others. This paper reviews the regulation mechanisms underlying the homing and mobilization of BM hematopoietic stem/progenitor cells, investigating the following issues: (a) the role of different factors, such as stromal cell derived factor-1 (SDF-1), granulocyte colony-stimulating factor (G-CSF), and vascular cell adhesion molecule-1 (VCAM-1), among other ligands; (b) the stem cell count in peripheral blood and BM and influential factors; (c) the therapeutic utilization of this phenomenon in lesions in different tissues, examining the agents involved in HSPCs mobilization, such as the different forms of G-CSF, plerixafor, and natalizumab; and (d) the effects of this mobilization on BM-derived stem/progenitor cells in clinical trials of patients with different diseases.

The pediatric sibling donor experience in hematopoietic stem cell transplant: an integrative review of the literature

This integrative review explored and described published research findings focused on the experiences of pediatric sibling hematopoietic stem cell donors. After a comprehensive search, nine studies met the inclusion criteria of the study. There was no evidence of coordinated programs of research to effectively advance and build knowledge about the experiences of pediatric sibling donors. The limited descriptive evidence revealed that differences in the experiences of sibling donors vary by age and developmental stages; however, the use of small or repeated samples and qualitative methods limited the generalizability of study findings. Collaborative research using prospective, longitudinal designs will build and advance the evidence base for the design of developmentally appropriate interventions for pediatric sibling donors and their families.

GVHD after allogeneic haematopoietic SCT for AML: angiogenesis, vascular endothelial growth factor and VEGF receptor expression in the BM

There is increasing evidence suggesting that both angiogenesis and endothelial injury are involved in GVHD. To study the dynamics of angiogenesis, we examined 26 patients with AML who had undergone allogeneic haematopoietic SCT. All were in CR and had either acute GVHD (aGVHD) or chronic GVHD (cGVHD). We performed immunohistochemical studies of BM microvessel density (MVD) using Abs against vascular-endothelial (VE)-cadherin, CD34 and CD105, and expression of vascular endothelial growth factor (VEGF) and its receptors VEGFR-1 and VEGFR-2. At the time of diagnosis, the MVD in AML patients was higher than that in the normal controls, and the MVD decreased after induction chemotherapy. Patients with aGVHD had a significantly higher MVD than patients without aGVHD. Conversely, patients with cGVHD did not have a significantly different MVD. In previous aGVHD, we also found more VEGF+ megakaryocytes. XY FISH in sex-mismatched patients showed that the BM blood vessels consisted mainly of recipient endothelial cells. Taken together, these results suggest that new vessel formation and the VEGF/VEGFR system are involved in aGVHD.

Implementation of JACIE accreditation results in the establishment of new indicators that unevenly monitor processes contributing to the delivery of hematopoietic SCT

More than 145 European hematopoietic SCT programs have received JACIE (Joint Accreditation Committee for ISCT Europe and EBMT) accreditation since 2000, demonstrating compliance with FACT (Foundation for the Accreditation of Cell Therapy)-JACIE international standards. The association of JACIE with improved patient outcome was recently documented. However, conditions in which quality management systems were introduced and the actual benefits remain to be fully evaluated. Our study focuses on one aspect of quality management: introduction and use of indicators. Through a questionnaire sent to JACIE-accredited centers and responses from 32 programs (or 40%), we identified 293 indicators, including 224 (76%) that were introduced during the preparatory phase of JACIE accreditation. Indicators were associated with the following processes: measurement, analysis and improvement (54/293 or 18%); donor collection (49/293 or 16%); processing and storage of cell therapy products (37/293 or 12.5%); and administration of hematopoietic progenitor cells (67/293 or 23%). Mapping revealed an uneven distribution of indicators across the different subprocesses that contribute to this highly specialized medical procedure. Moreover, we found that only 101/293 indicators (34%) complied with the rules for implementation of a quality indicator, as defined by the FDX 50-171 standard. This suggests that risks to donors/recipients are unevenly monitored, leaving critical medical steps with low levels of monitoring.

Polyclonal anti-thymocyte globulins for the prophylaxis of graft-versus-host disease after allogeneic stem cell or bone marrow transplantation in adults

BACKGROUND

Allogeneic haematopoietic stem cell transplantation (HSCT) is an established treatment for many malignant and non-malignant haematological disorders. Graft-versus-host disease (GVHD), a condition frequently occurring after HSCT, is the result of host tissues being attacked by donor immune cells. One strategy for the prevention of GVHD is the administration of anti-thymocyte globulins (ATG), a set of polyclonal antibodies directed against a variety of immune cell epitopes, leading to immunosuppression and immunomodulation.

OBJECTIVES

To assess the effect of ATG used for the prevention of graft-versus-host disease (GVHD) in patients undergoing allogeneic HSCT with regard to overall survival, incidence and severity of acute and chronic GVHD, incidence of relapse, incidence of infectious complications, non-relapse mortality, early mortality within 100 days of transplantation, progression-free survival, quality of life and adverse events.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 3), MEDLINE (January 1950 to February 2012), trials registries and conference proceedings. The search was conducted in October 2010 and was updated in July 2011 and February 2012. We did not apply any language restrictions.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) investigating the impact of ATG on GVHD prophylaxis in adults suffering from haematological diseases and undergoing allogeneic HSCT. Treatment arms had to differ only in the addition of ATG to the standard GVHD prophylaxis regimen.

DATA COLLECTION AND ANALYSIS

Two review authors screened abstracts, extracted data and analysed the data independently. We contacted study authors for additional information.

MAIN RESULTS

We included in the meta-analysis six RCTs which met the pre-defined selection criteria, involving a total of 568 participants. Quality of data reporting was heterogeneous among these studies with a lack of detailed information in the early studies.The primary outcome of overall survival was not significantly changed by the addition of ATG for the prophylaxis of GVHD (harms ratio (HR) 0.88; 95% CI 0.67 to 1.15, P = 0.33).The incidence of treatment-requiring or severe acute GVHD (grade II to IV) was significantly lower in patients who received ATG (risk ratio (RR) 0.68; 95% CI 0.55 to 0.85, P = 0.009; number needed to treat (NNT) 8). Also, the incidence of severe acute GVHD (grade III to IV) was significantly reduced (HR 0.53; 95% CI 0.33 to 0.85, P = 0.0005; NNT 7) but comparable data were available for rabbit ATG only. However, pooled study results regarding the incidence of acute GVHD of all grades (I to IV) showed no significant benefit of ATG treatment (RR 0.89; 95% CI 0.74 to 1.06, P = 0.20).Meta-analysis of data regarding the incidence of overall chronic GVHD (both, limited and extensive) was not possible. Nevertheless, studies reporting on extensive chronic GVHD (only studies evaluating rabbit ATG) suggested a lower incidence of extensive chronic GVHD whereas others that only reported on overall chronic GVHD did not show an advantage for ATG.Pooled results regarding the incidence of relapse were not significantly different (RR 1.13; 95% CI 0.75 to 1.68, P = 0.56), as well as pooled results regarding non-relapse mortality (HR 0.82; 95% CI 0.55 to 1.24, P = 0.35).Due to the lack of comparable data, we could not perform meta-analysis of data regarding the incidence of chronic GVHD, relapse-related mortality, progression-free survival, quality of life, adverse events and engraftment.

AUTHORS' CONCLUSIONS

Our systematic review suggests that the addition of ATG during allogeneic HSCT significantly reduces the incidence of severe grades (II to IV) of acute GvHD, whereas the incidence of overall acute GVHD (grades I to IV) was not significantly lowered. This indicates a reduction of the severity but not the incidence of acute GVHD. However, this effect did not lead to a significant improvement of overall survival, which may be due to the severe potential side effects of the consecutively increased immunosuppression.Furthermore, future research is needed to clarify the effect of ATG on the incidence and severity of chronic GVHD and consequently on all aspects of quality of life.From the currently available data, no recommendation on the general use of ATG in allogeneic HSCT can be supported. Therefore, a careful consideration of the use of ATG based on the patient's condition and the risk factors of the transplantation setting should be made.

Efficacy and safety of peripheral blood stem cell mobilization and collection: a single-center experience in 190 allogeneic donors

BACKGROUND

In the past two decades peripheral blood stem cells (PBSCs) have increasingly replaced marrow as stem cells source for allogeneic transplantation. The PBSC donation initially applied only to related donors; later, due to the safety of the procedure, it was extended to unrelated donors.

STUDY DESIGN AND METHODS

We have retrospectively collected data regarding mobilization, collection, and short- and long-term follow-up of 190 consecutive donors, 174 related and 16 unrelated. All donors followed a standard protocol for mobilization and underwent at least one PBSC collection. Follow-up in related donors was performed every 4 months in the first year and then annually, with no time limits, while unrelated donors were monitored for 10 years.

RESULTS

All 190 donors completed the established mobilization protocol. The mobilizing capacity was significantly greater in males and in donors less than 60 years old. No case of major toxicity by granulocyte-colony-stimulating factor was found, nor thromboembolic events. The total dose of CD34+/recipient (median 5.8×10(6)/kg recipient/body weight) was statistically correlated with age, CD34+ before and after mobilization, and collection efficiency. Compliance to follow-up was 66%, with a significant difference between related and unrelated (63% vs. 100%, p=0.03). During follow-up no significant abnormalities in hematologic variables or hematologic malignancies were reported.

CONCLUSION

Our study allowed us to define the PBSC donation as "a safe procedure for the donors," with short- and long-term effects limited to a small percentage of donors and "effective for the recipient," due to the dose of collected CD34+, adequate for transplantation in almost all recipients.

Pituitary stem cell update and potential implications for treating hypopituitarism

Stem cells have been identified in organs with both low and high cell turnover rates. They are characterized by the expression of key marker genes for undifferentiated cells, the ability to self-renew, and the ability to regenerate tissue after cell loss. Several recent reports present evidence for the presence of pituitary stem cells. Here we offer a critical review of the field and suggest additional studies that could resolve points of debate. Recent reports have relied on different markers, including SOX2, nestin, GFRa2, and SCA1, to identify pituitary stem cells and progenitors. Future studies will be needed to resolve the relationships between cells expressing these markers. Members of the Sox family of transcription factors are likely involved in the earliest steps of pituitary stem cell proliferation and the earliest transitions to differentiation. The transcription factor PROP1 and the NOTCH signaling pathway may regulate the transition to differentiation. Identification of the stem cell niche is an important step in understanding organ development. The niche may be the marginal zone around the lumen of Rathke's pouch, between the anterior and intermediate lobes of mouse pituitary, because cells in this region apparently give birth to all six pituitary hormone cell lineages. Stem cells have been shown to play a role in recurrent malignancies in some tissues, and their role in pituitary hyperplasia, pituitary adenomas, and tumors is an important area for future investigation. From a therapeutic viewpoint, the ability to cultivate and grow stem cells in a pituitary predifferentiation state might also be helpful for the long-term treatment of pituitary deficiencies.

[Reduced intensity allogenic hematopoietic stem cell transplantation in children]

Better understanding of the antitumor effect of allogeneic transplant and the need to reduce the toxicity of the procedure, particularly in elderly patients have spurred the development of reduced-intensity conditioning regimens (RIC). These regimens allow fast engraftment with very low chemotherapy-induced toxicity. They are widely used in adults and there are numerous studies to demonstrate their feasibility and efficiency, but in pediatrics, the place of RIC remains to be determined. They can be proposed in two pediatric populations. First, solid tumors or hematological malignancies remaining unresponsive to the reference strategies according to best practices in pediatrics. Second, in children presenting malignancies for which allografting is the only recognized curative indication but is contraindicated with myeloablative conditioning regimens. More than 100 pediatrics cases have been reported in various pathologies, including blood diseases, acute leukemia, Hodgkin's lymphoma and solid tumors, and promising results published recently underline how RIC warrants further investigation in prospective comparative multicentric trials. The use of new post-graft treatment modalities is expected to pave the way to the development of RIC in pediatric patients.

Thymic T-cell development in allogeneic stem cell transplantation

Cytoreductive conditioning regimens used in the context of allogeneic hematopoietic cell transplantation (HCT) elicit deficits in innate and adaptive immunity, which predispose patients to infections. As such, transplantation outcomes depend vitally on the successful reconstruction of immune competence. Restoration of a normal peripheral T-cell pool after HCT is a slow process that requires the de novo production of naive T cells in a functionally competent thymus. However, there are several challenges to this regenerative process. Most notably, advanced age, the cytotoxic pretransplantation conditioning, and posttransplantation alloreactivity are risk factors for T-cell immune deficiency as they independently interfere with normal thymus function. Here, we discuss preclinical allogeneic HCT models and clinical observations that have contributed to a better understanding of the transplant-related thymic dysfunction. The identification of the cellular and molecular mechanisms that control regular thymopoiesis but are altered in HCT patients is expected to provide the basis for new therapies that improve the regeneration of the adaptive immune system, especially with functionally competent, naive T cells.

Characterization of murine non-adherent bone marrow cells leading to recovery of endogenous hematopoiesis

Non-adherent bone marrow-derived cells (NA-BMCs) are a mixed cell population that can give rise to multiple mesenchymal phenotypes and that facilitates hematopoietic recovery. We characterized NA-BMCs by flow cytometry, fibroblast colony-forming units (CFU-f), real-time PCR, and in in vivo experiments. In comparison to adherent cells, NA-BMCs expressed high levels of CD11b(+) and CD90(+) within the CD45(+) cell fraction. CFU-f were significantly declining over the cultivation period, but NA-BMCs were still able to form CFU-f after 5 days. Gene expression analysis of allogeneic NA-BMCs compared to bone marrow (BM) indicates that NA-BMCs contain stromal, mesenchymal, endothelial cells and monocytes, but less osteoid, lymphoid, and erythroid cells, and hematopoietic stem cells. Histopathological data and analysis of weight showed an excellent recovery and organ repair of lethally irradiated mice after NA-BMC transplantation with a normal composition of the BM.

Safety evaluation of allogeneic umbilical cord blood mononuclear cell therapy for degenerative conditions

Background

The current paradigm for cord blood transplantation is that HLA matching and immune suppression are strictly required to prevent graft versus host disease (GVHD). Immunological arguments and historical examples have been made that the use of cord blood for non-hematopoietic activities such as growth factor production, stimulation of angiogenesis, and immune modulation may not require matching or immune suppression.

Methods

114 patients suffering from non-hematopoietic degenerative conditions were treated with non-matched, allogeneic cord blood. Doses of 1-3 × 10⁷ cord blood mononuclear cells per treatment, with 4-5 treatments both intrathecal and intravenously were performed. Adverse events and hematological, immunological, and biochemical parameters were analyzed for safety evaluation.

Results

No serious adverse effects were reported. Hematological, immunological, and biochemical parameters did not deviate from normal ranges as a result of therapy.

Conclusion

The current hematology-based paradigm of need for matching and immune suppression needs to be revisited when cord blood is used for non-hematopoietic regenerative purposes in immune competent recipients.

[Happy birthday to Joint Accreditation Committee for ISCT Europe and EBMT]

JACIE (Joint accreditation committee for ISCT Europe and EBMT) is a comprehensive quality management system built in under the auspices of two European professional societies. The singularity of JACIE is its coverage of all the main actors - clinical wards as well as collection and processing facilities - that contribute to a hematopoietic stem cell transplantation program. Deployment of JACIE started ten years ago. A recent retrospective analysis of the large-size european registry of autologous and allogenic hematopoietic stem cell transplantations demonstrates that one of the factors affecting the overall survival of recipients of allogenic transplantation is the status of the transplant program regarding JACIE accreditation. This provides one of the first demonstrations that introduction of a quality management system can contribute to the overall survival of patients treated with a highly specific and complex medical procedure.

Plerixafor plus granulocyte CSF can mobilize hematopoietic stem cells from multiple myeloma and lymphoma patients failing previous mobilization attempts: EU compassionate use data

Plerixafor was recently approved by the US Food and Drug Administration (FDA) and the European Medicines Evaluation Agency (EMEA) to enhance stem cell mobilization for autologous transplant in patients with lymphoma and multiple myeloma. In this study, we present the first European compassionate use experience in mobilization failures, patients who are hardest to remobilize but were not included in registration trials. A total of 56 consecutive patients from 15 centers in Spain and the United Kingdom were included: age 60 (33-69) years; 29 men (32 with myeloma and 24 with lymphoma); 2 lines of previous chemotherapy (1-10); 73 previously failed mobilization attempts with G-CSF (28), chemotherapy plus G-CSF (43) or G-CSF plus SCF(2). Overall, 71% of patients reached ≥ 10 CD34+ cells per μL with plerixafor on day 5 after a 7.6-fold expansion from day 4. A total of 42 patients (75%) collected ≥ 2 × 10⁶, average 3.0 ± 1.7 (0.4-10.6) CD34+ cells per kg with plerixafor plus G-CSF. There were no severe drug-related adverse events. In all, 35 patients (63%) underwent transplant, receiving an average of 3.1±1.2 (1.9-7.7) × 10⁶ CD34+ cells per kg. All patients engrafted neutrophils (day 12; 13.4 ± 0.8; 8-30) and platelets (day 15; 18.5 ± 2.4; 8-33). In our experience, plerixafor offers an effective alternative to collect sufficient CD34+ cells for autologous SCT from patients who fail conventional mobilization methods, with good tolerance and a high success rate.