Weighing the risks of G-CSF administration, leukopheresis, and standard marrow harvest: ethical and safety considerations for normal pediatric hematopoietic cell donors

[Haematopoietic stem cell donation from minor donor: Respecting laws, assessing fitness, delivering information and good care (SFGM-TC)]

Haematopoietic stem cell collection from paediatric donors is a common and life-saving practice, as evidenced by the fact that there is a growing annual number of cases of transplants from minor donors among SFGM-TC centers over the last decade. Still, medical use of human tissue from a healthy and underage donor requires proper regulations and medical management. The guidelines below aim at underlining the importance of pondering the legal, medical and ethical aspects of using stem cells from healthy paediatric donors and stress out the importance of obtaining informed consent at the time of assessing HLA compatibility. Combined medical and psychological assessments are required before the donation, as well as one month later and one year later to ensure of the child's physical and mental wellbeing. Bone marrow harvest under general anaesthetics remains the preferred method of collection for children. Peripheral blood stem cell collection should only be considered for children who will not require a central venous access for collection. We aim at offering guidelines centered on the healthy child donating stem cells and his/her wellbeing, and these should be regularly reviewed as medical practices evolve.

The Philosophical Underpinning of the Family for Pediatric Decision-Making

Although traditional medical ethics focuses on the dyadic doctor-patient relationship, when the patient is a child, the relationship is triadic, meaning it involves the patient, the parent(s), and the clinician. A brief examination of the family, the rights and responsibilities of parents, the rights of children, and the moral basis of the parent-child relationship provide a philosophic underpinning for understanding the family in pediatric decision-making. Although biological parents have presumptive authority to make health-care decisions for their children, and are given wide discretion, parental autonomy is not absolute.

Genotoxicity of cytokines at chemotherapy-induced 'storm' concentrations in a model of the human bone marrow

Donor cell leukaemia (DCL) is a complication of haematopoietic stem cell transplantation where donated cells become malignant within the patient's bone marrow. As DCL predominates as acute myeloid leukaemia, we hypothesized that the cytokine storm following chemotherapy played a role in promoting and supporting leukaemogenesis. Cytokines have also been implicated in genotoxicity; thus, we explored a cell line model of the human bone marrow (BM) to secrete myeloid cytokines following drug treatment and their potential to induce micronuclei. HS-5 human stromal cells were exposed to mitoxantrone (MTX) and chlorambucil (CHL) and, for the first time, were profiled for 80 cytokines using an array. Fifty-four cytokines were detected in untreated cells, of which 24 were upregulated and 10 were downregulated by both drugs. FGF-7 was the lowest cytokine to be detected in both untreated and treated cells. Eleven cytokines not detected at baseline were detected following drug exposure. TNFα, IL6, GM-CSF, G-CSF, and TGFβ1 were selected for micronuclei induction. TK6 cells were exposed to these cytokines in isolation and in paired combinations. Only TNFα and TGFβ1 induced micronuclei at healthy concentrations, but all five cytokines induced micronuclei at storm levels, which was further increased when combined in pairs. Of particular concern was that some combinations induced micronuclei at levels above the mitomycin C positive control; however, most combinations were less than the sum of micronuclei induced following exposure to each cytokine in isolation. These data infer a possible role for cytokines through chemotherapy-induced cytokine storm, in the instigation and support of leukaemogenesis in the BM, and implicate the need to evaluate individuals for variability in cytokine secretion as a potential risk factor for complications such as DCL.

Reduced-toxicity myeloablative conditioning regimen using fludarabine and full doses of intravenous busulfan in pediatric patients not eligible for standard myeloablative conditioning regimens: Results of a multicenter prospective phase 2 trial

Data regarding the safety and efficacy of reduced-toxicity conditioning regimen (RTC) prior to allogeneic stem cell transplantation (allo-SCT) to treat hematological malignancies in pediatric patients are limited. This prospective multicenter, phase 2 trial investigated a RTC regimen based on the combination of intravenous busulfan (3.2 mg/kg/d x 4 days), fludarabine (30 mg/m²/d x 5 days) and antithymocyte globulin (Thymoglobulin®, Genzyme; 5 mg/kg total dose) with the aim of delivering high dose myeloablation that would allow optimal disease control while minimizing toxicity, in a subgroup of children at very high risk of non-relapse mortality (NRM). The primary endpoint was NRM at 1 year after allo-SCT. A total of 48 high risk patients were included (median age, 13 years; range, 3-24). At 1 year, the cumulative incidence of recurrence/disease progression and NRM were 33% and 8%, respectively. With a median follow-up of 23 months, the Kaplan-Meier estimates of overall survival (OS) and disease-free survival (DFS) at 1 year were 69% and 58%, respectively. We conclude that the RTC regimen used in this prospective trial is safe, with a < 10% NRM rate noted among high-risk children and adolescents, paving the way for larger phase 3 trials incorporating novel agents pre- and post-allo-SCT.(ClinicalTrials.gov Identifier: NCT01572181).

Suitability of haematopoietic cell donors: updated consensus recommendations from the WBMT standing committee on donor issues

The contribution of related donors to the globally rising number of allogeneic haematopoietic stem cell transplantations (HSCT) remains increasingly important, particularly because of the growing use of haploidentical HSCT. Compared with the strict recommendations on the suitability for unrelated donors, criteria for related donors allow for more discretion and vary between centres. In 2015, the donor outcome committee of the Worldwide Network for Blood and Marrow Transplantation (WBMT) proposed consensus recommendations of suitability criteria for paediatric and adult related donors. This Review provides updates and additions to these recommendations from a panel of experts with global representation, including the WBMT, the European Society for Blood and Marrow Transplantation donor outcome committee, the Center for International Blood and Marrow Transplant Research donor health and safety committee, the US National Marrow Donor Program, and the World Marrow Donor Association, after review of the current literature and guidelines. Sections on the suitability of related donors who would not qualify as unrelated donors have been updated. Sections on communicable diseases, clonal haematopoiesis of indeterminate potential, paediatric aspects including psychological issues, and reporting on serious adverse events have been added. The intention of this Review is to support decision making, with the goal of minimising the medical risk to the donor and protecting the recipient from transmissible diseases.

Variceal Bleed and Portal Hypertensive Gastropathy in a Noncirrhotic Patient with Isolated Splenomegaly

Portal hypertension caused by cirrhosis is the most common etiology of esophageal varices. However, abnormalities of the splenoportal axis in the absence of liver disease may also cause portal hypertension resulting in varices. We report a rare case of esophageal variceal bleed in a noncirrhotic patient with isolated splenomegaly secondary to chronic granulocyte colony stimulating factor (G-CSF) therapy. The patient is a 26-year-old male with Cohen syndrome who required long-term G-CSF treatment for chronic neutropenia. He presented with large volume hematemesis and pancytopenia in the setting of known splenomegaly with no evidence of cirrhosis. An urgent EGD revealed active variceal bleeding and portal hypertensive gastropathy. The patient was appropriately resuscitated and underwent a successful transjugular intrahepatic portosystemic shunt and CT-guided coil placement for the bleeding varices. We are the first to report variceal bleed as a complication of long-term G-CSF use, a life-threatening consequence that requires urgent intervention.

Donor Evaluation for Hematopoietic Stem and Progenitor Cell Collection

With the increasing incidence of hematopoietic allogeneic cell transplantation (allo-HCT), the importance of securing a cellular product, safely from a donor, and ensuring that the product is without additional risk to the recipient, continues to be of paramount importance. The evaluation of the donor’s medical eligibility and suitability is designed to identify and limit the risk of transmitting infectious, genetic, or neoplastic diseases to the recipient through the product. It also aims to ensure a maximum level of safety for the donor and informs them of the risks of donation. Several regulatory agencies, national and international registries, and accreditation bodies have facilitated the availability and safe provision of human cells, tissues, and cellular- and tissue-based products not only at local institutions but also through international exchange.

The MarrowMiner: A Novel Minimally Invasive and Effective Device for the Harvest of Bone Marrow

Bone marrow (BM) is a rich source of hematopoietic stem cells (HSCs), mesenchymal stem cells (MSCs), and other important stem/progenitor cells. It is the traditional source of cells used in hematopoietic cell transplantation, which is a proven curative treatment for many blood and immune diseases. BM-derived cells have also been shown to have other diverse clinical uses and are increasingly being used in orthopedic medicine, regenerative medicine, and gene therapy applications. Traditional methods for harvesting BM are crude, tedious, time-consuming, and expensive, requiring multiple bone punctures under general anesthesia with serial small-volume aspirates often diluted with peripheral blood. The MarrowMiner (MM) is a novel device designed for rapid and minimally invasive BM harvest. Here we show the safety and efficacy of the MM in both preclinical and clinical settings. In a large-animal porcine model, the MM enabled effective BM collection with similar total nucleated cell collection and increased colony formation compared with standard methods. The MM was subsequently evaluated in a clinical study showing effective and complication-free anterior and posterior BM collection of 20 patients under only local anesthesia or light sedation. Increased total nucleated and mononucleated cell collection was achieved with the MM compared with standard methods in the same patients. Importantly, stem cell content was high with trends toward increased HSC, MSC, and endothelial progenitor cells with similar T cell content. Given the MM is a novel device approved by the US Food and Drug Administration, enabling safe, effective, and minimally invasive harvest of BM, we anticipate rapid adoption for various applications.

Higher Risks of Toxicity and Incomplete Recovery in 13- to 17-Year-Old Females after Marrow Donation: RDSafe Peds Results

Although donation of bone marrow (BM) or peripheral blood stem cells (PBSCs) from children to family members undergoing allogeneic transplantation are well-established procedures, studies detailing levels of pain, symptoms, and long-term recovery are lacking. To address this lack, we prospectively enrolled 294 donors age <18 years at 25 pediatric transplantation centers in North America, assessing them predonation, peridonation, and at 1 month, 6 months, and 1 year postdonation. We noted that 71% of children reported pain and 59% reported other symptoms peridonation, with resolution to 14% and 12% at 1 month postdonation. Both older age (age 13 to 17 years versus younger) and female sex were associated with higher levels of pain peridonation, with the highest rates in older females (57% with grade 2-4 pain and 17% with grade 3-4 pain). Multivariate analyses showed a 4-fold increase in risk for older females compared with males age <13 years (P <.001). At 1 year, 11% of 13- to 17-year-old females reported grade 2-4 pain, compared with 3% of males age 13 to 17 years, 0% of females age <13 years, and 1% of males age <13 years (P = .01). Males and females age 13 to 17 years failed to return to predonation pain levels at 1 year 22% and 23% of the time, respectively, compared with 3% and 10% in males and females age <13 years (P = .002). Our data show that females age 13 to 17 years are at increased risk of grade 2-4 pain at 1 year and >20% of females and males age 13 to 17 years do not return to baseline pain levels by 1 year after BM donation. Studies aimed at decreasing symptoms and improving recovery in older children are warranted.

Ethical considerations of using a single minor donor for three bone marrow harvests for three HLA-matched siblings with primary immunodeficiency

Allogeneic hematopoietic stem cell transplantation is curative for primary immunodeficiencies. Bone marrow from an unaffected human leukocyte antigen (HLA)-identical sibling donor is the ideal graft source. For minor donors, meaningful consent or assent may not be feasible, and permission from parents or legal guardians is considered acceptable. Adverse events, albeit extremely small, can be associated with bone marrow harvest in pediatric donors. Donor safety concerns potentially increase with multiple bone marrow harvests. Very little is known about multiple bone marrow harvests from pediatric donors. We describe the ethical considerations and clinical decision-making in an unusual clinical situation where three patients with the same primary immunodeficiency were HLA identical to one another and their younger sibling, who underwent bone marrow harvests three times between 1.3 and 4 years of age, resulting in successful transplantation for all three patients. We hope that this experience will provide guidance to providers and families in a similar situation.

Collection of hematopoietic stem cells and immune effector cells in small children

Apheresis procedures are standard of care for a wide range of indications in children, collection of hematopoietic stem cells being the most frequent one. With increasing numbers of hematopoietic stem cell transplants, advances in graft manipulation techniques and the development of innovative therapies using immune effector cells and gene therapy, apheresis within the pediatric population is growing in demand. While young children have higher circulating white blood cell counts and robustly mobilize hematopoietic stem cells, apheresis machines were designed for use within the adult population and apheresis procedures in children, particularly small children, can be more challenging as vascular access, collection techniques and impact of extracorporeal volumes increase the rate of adverse events. In this article we review topics of particular relevance to hematopoietic stem cell and immune effector cell collections in small children.

Donor Selection for Allogenic Hemopoietic Stem Cell Transplantation: Clinical and Ethical Considerations

Allogenic hematopoietic progenitor cell transplantation (allo-HSCT) is an established treatment for many diseases. Stem cells may be obtained from different sources: mobilized peripheral blood stem cells, bone marrow, and umbilical cord blood. The progress in transplantation procedures, the establishment of experienced transplant centres, and the creation of unrelated adult donor registries and cord blood banks gave those without an human leucocyte antigen- (HLA-) identical sibling donor the opportunity to find a donor and cord blood units worldwide. HSCT imposes operative cautions so that the entire donation/transplantation procedure is safe for both donors and recipients; it carries with it significant clinical, moral, and ethical concerns, mostly when donors are minors. The following points have been stressed: the donation should be excluded when excessive risks for the donor are reasonable, donors must receive an accurate information regarding eventual adverse events and health burden for the donors themselves, a valid consent is required, and the recipient's risks must be outweighed by the expected benefits. The issue of conflict of interest, when the same physician has the responsibility for both donor selection and recipient care, is highlighted as well as the need of an adequate insurance protection for all the parties involved.

Factors associated with bone marrow stem cell yield for pediatric allogeneic stem cell transplantation: The impact of donor characteristics

The aim of this study was to investigate the effects of donor characteristics on CD34⁺ cell yield in BM harvest. Between April 2010 and November 2013, consecutive donors who underwent BM harvesting in our BM transplantation unit were retrospectively investigated. Donors were classified into two groups: those who donated BM without mobilization (steady-state BM donors) and those who received G-CSF for stem cell mobilization (G-CSF-primed BM donors). Donor characteristics (age, gender, race, body weight, BMI, and laboratory factors including donor's leukocyte, platelet, and monocyte) and their relationship with total nuclear cell and CD34⁺ cell numbers has been evaluated. A total of 64 healthy related donors (29 males/35 females, median age 11.2 years; 49 [76.6%] younger than 18 and 36 [56.3%] younger than 12 years) were included in the study. The median CD34⁺ cell yield in the harvest was 0.12×10⁶ /L (0.02-0.21) in SS-BM donors and 0.18×10⁶ /L (0.09-0.67) in GP-BM donors (P=.03). Median of CD34⁺ cell count given to recipients was 2.6×10⁶ /recipient body weight (1.3-19.3) in SS-BM yields and 3.8×10⁶ /recipient body weight (1.1-10.2) in GP-BM yields, respectively. Multiple regression analysis showed that donor height and pre-G-CSF platelet were the most important parameters to obtain a sufficient BM harvest. Our data suggest that the shorter donors and the donors with higher thrombocyte counts may offer more hematopoietic stem cell. The height and thrombocyte count of the donors should be taken into consideration before planning the targeted CD34⁺ cell count especially for pediatric donors.

Health-Related Quality of Life among Pediatric Hematopoietic Stem Cell Donors

OBJECTIVES

To examine health-related quality of life (HRQoL) among sibling pediatric hematopoietic stem cell donors from predonation through 1 year postdonation, to compare donor-reported HRQoL scores with proxy-reports by parents/guardians and those of healthy norms, and to identify predonation factors (including donor age) potentially associated with postdonation HRQoL, to better understand the physical and psychosocial effects of pediatric hematopoietic stem cell donation.

STUDY DESIGN

A random sample of 105 pediatric donors from US centers and a parent/guardian were interviewed by telephone predonation and 4 weeks and 1 year postdonation. The interview included sociodemographic, psychosocial, and HRQoL items. A sample of healthy controls matched to donors by age, gender, and race/ethnicity was generated.

RESULTS

Key findings included (1) approximately 20% of donors at each time point had very poor HRQoL; (2) child self-reported HRQoL was significantly lower than parent proxy-reported HRQoL at all 3 time points and significantly lower than that of norms at predonation and 4 weeks postdonation; and (3) younger children were at particular risk of poor HRQoL.

CONCLUSIONS

Additional research to identify the specific sources of poorer HRQoL among at-risk donors (eg, the donation experience vs having a chronically ill sibling) and the reasons that parents may be overestimating HRQoL in their donor children is critical and should lead to interventions and policy changes that ensure positive experiences for these minor donors.

Research involving pediatric stem cell donors: A way forward

The most suitable donor for younger patients who undergo hematopoietic stem cell transplantation in the research setting is frequently a minor sibling. These cases raise the question of whether minors who serve as stem cell donors for research subjects should be regarded as research subjects themselves. Regarding pediatric donors as research subjects ensures that an Institutional Review Boards reviews their involvement and determines whether it is appropriate. Yet, Institutional Review Boards must follow the US regulations for pediatric research, which were designed for patients and healthy volunteers, not for healthy donors. As a result, regarding pediatric donors as research subjects also can pose unnecessary obstacles to appropriate and potentially life-saving research. This article considers a new way to address this dilemma. The federal research regulations allow for waiver of some or all of the included requirements when they are unnecessary for a study or a class of studies. We argue that this option offers a way to ensure that the involvement of pediatric donors receives sufficient review and approval without inadvertently undermining valuable and potentially life-saving research.

Mononuclear cells from the cord blood and granulocytecolony stimulating factor-mobilized peripheral blood: is there a potential for treatment of cerebral palsy?

To investigate a possible therapeutic mechanism of cell therapy in the field of cerebral palsy using granulocyte-colony stimulating factor (G-CSF)-mobilized peripheral blood mononuclear cells (mPBMCs), we compared the expression of inflammatory cytokines and neurotrophic factors in PBMCs and mPBMCs from children with cerebral palsy to those from healthy adult donors and to cord blood mononuclear cells donated from healthy newborns. No significant differences in expression of neurotrophic factors were found between PBMCs and mPBMCs. However, in cerebral palsy children, the expression of interleukin-6 was significantly increased in mPBMCs as compared to PBMCs, and the expression of interleukin-3 was significantly decreased in mPBMCs as compared to PBMCs. In healthy adults, the expression levels of both interleukin-1β and interleukin-6 were significantly increased in mPBMCs as compared to PBMCs. The expression of brain-derived neurotrophic factors in mPBMC from cerebral palsy children was significantly higher than that in the cord blood or mPBMCs from healthy adults. The expression of G-CSF in mPBMCs from cerebral palsy children was comparable to that in the cord blood but significantly higher than that in mPBMCs from healthy adults. Lower expression of pro-inflammatory cytokines (interleukin-1β, interleukin-3, and -6) and higher expression of anti-inflammatory cytokines (interleukin-8 and interleukin-9) were observed from the cord blood and mPBMCs from cerebral palsy children rather than from healthy adults. These findings indicate that mPBMCs from cerebral palsy and cord blood mononuclear cells from healthy newborns have the potential to become seed cells for treatment of cerebral palsy.

Stem cell mobilization and collection from pediatric patients and healthy children

Today, hematopoietic stem cell transplantation (HSCT) is a standard treatment for a variety of conditions in children, including certain malignancies, hemoglobinopathies, bone marrow failure syndromes, immunodeficiency and inborn metabolic disease. Two fundamentally different types of HSCT are categorized by the source of the stem cells. The first, autologous HSCT represents infusion of patient's own hematopoietic stem cells (HSCs) obtained from the patient; the second, allogeneic HSCT refers to the infusion of HSCs obtained from a donor via bone marrow harvest or apheresis. Bone marrow has been the typical source for HSCs for pediatric donors. Bone marrow harvest is a safe procedure mainly related to mild and transient side effects. Recently, a dramatically increased use of mobilized peripheral blood stem cells (PBSCs) in the autologous as well as allogeneic setting has been seen worldwide. There are limited data comparing mobilization regimens; also mobilization practices vary widely in children. The most commonly used approach includes granulocyte colony stimulating factor (G-CSF) at 10 mg/kg/day as a single daily dose for 4 days before the day of leukapheresis. G-CSF induced pain was less reported in children compared to adult donors. For the collection, there are several technical problems, derived from the size of the patient or donor, which must be considered before and during the apheresis. Vascular access, extracorporeal circuit volume, blood flow rates are the main limiting factors for PBSC collection in small children. Most children younger than 12 years require central vascular access for apheresis; line placement may require either general anesthesia or conscious sedation and many of the complications arise from the central venous catheter. In this review, we discuss that the ethical considerations and some principals regarding children serving as stem cell donors and the commonest sources of HSCs are presented in children, together with a discussion of how to collect and process these cells.

Related hematopoietic cell donor care: is there a role for unrelated donor registries?

In almost half of allogeneic hematopoietic progenitor cell (HPC) transplants, a related donor (RD) is used, yet a lack of standardized guidelines means that their care is heterogeneous. Changes to regulatory standards aim to improve uniformity, but adherence to these regulations can prove logistically difficult for the transplant centers (TCs) managing RDs. Discussion has ensued around possible alternative models of related donor care and a session at the European Society for Blood and Marrow Transplantation (EBMT) annual meeting in 2013 debated the question of whether a role exists for unrelated donor registries in the management of 'related' donors. In this overview, we discuss the issues raised at this debate and the pros and cons of donor registry involvement in various aspects of RD management. By examining existing models of related donor care that have been adopted by members of the World Marrow Donor Association (WMDA), we look for ways to enhance and homogenize RD care, while also enabling transplant centers to meet standards required for mandatory accreditation.

Children as hematopoietic cell donors in research: when is it approvable?

With increasing frequency, allogeneic hematopoietic cell transplantation involving children is being performed in the research setting. Allogeneic hematopoietic cell transplantation, however, cannot be performed without a hematopoietic stem cell (HSC) donor. This donor is often a sibling of the recipient and may also be a child. In such circumstances, it is unclear whether or how the federal regulations for pediatric research apply to the minor donors. This introductory paper reviews the issues to be considered while evaluating studies that use HSCs obtained from minor donors and identifies areas where further research is needed. In the era of increasing applicability for donor-derived cellular therapies, we provide a suggested framework for determining when minor donors qualify as human research subjects and when their participation can be approved under the federal regulations.

Hematopoetic stem cell transplantation in children

Bone marrow transplantation is called hematopoetic stem cell transplantation (HSCT), since peripheral blood and umbilical cord blood can also be used as sources of stem cell currently. In children, bone marrow transplantation is used as a definite treatment method in many diseases including hemoglobinopaties, immune deficiencies, bone marrow failure and congenital metabolic diseases in addition to hematological malignancies. In addition to the underlying disease, the most important factors which have an impact on prognosis include infections which develop during the process of transplantation and graft-versus-host disease. In this article, it was aimed to give brief information on stem cell sources, preparation therapies, HSCT indications and post-transplantation complications in children.

Feasibility of marrow harvesting from pediatric sibling donors without hematopoietic growth factors and allotransfusion

We retrospectively studied 108 marrow harvests from 105 pediatric sibling donors. The median age of donors was 8 years (range: 1-15) and the median body weight was 27 kg (range: 10-100). The volumes of aspirated marrow were 5.0-23.8 mL/kg donor body weight, and harvested bone marrow volume exceeded 15 mL/kg in 42% of the donors. A total of 100 autologous blood donations were performed, and eight donors had red cells salvaged from their harvests reinfused. The median Hb levels before and after harvests were 12.3 g/dL (range: 10.0-14.7) and 11.0 g/dL (range: 8.9-13.8), respectively. None of the donors received allogeneic blood transfusions or hematopoietic growth factors such as EPO and G-CSF before or after collection. Transplanted dose was 1.4-10.8 × 10(8) cells/kg recipient body weight without differences due to donor age. Higher concentrations of nucleated and CD34(+) cells were obtained from younger donors. All donors tolerated the procedures well, with no serious complications. Thus, children may safely donate marrow for allogeneic transplantation, and the yields of nucleated cells for engraftment are substantial.

Granulocyte-colony stimulating factor for hematopoietic stem cell donation from healthy female donors during pregnancy and lactation: what do we know?

BACKGROUND Hematopoietic growth factors (HGFs) are mostly used as supportive measures to reduce infectious complications associated with neutropenia. Over the past decade, the use of HGFs became a common method for mobilizing human CD34+ stem cells, either for autologous or allogeneic transplantation. However, since their introduction the long-term safety of the procedure has become a major focus of discussion and research. Most information refers to healthy normal donors and data concerning pregnant and lactating women are scarce. The clinical question, which is the core of this review, is whether stem cell donation, preceded by administration of granulocyte-colony stimulating factor (G-CSF) for mobilization, is a safe procedure for pregnant donors. METHODS Literature searches were performed in Pubmed for English language articles published before the end of May 2012, focusing on G-CSF administration during pregnancy, lactation and hematopoietic stem cell donation. Searches included animal and human studies. RESULTS Data from animals (n = 15 studies) and women (n = 46 studies) indicate that G-CSF crosses the placenta, stimulates fetal granulopoiesis, improves neonatal survival mostly for very immature infants, promotes trophoblast growth and placental metabolism and has an anti-abortive role. Granulocyte macrophage-CSF is a key cytokine in the maternal immune tolerance towards the implanted embryo and exerts protective long-term programming effects to preimplantation embryos. The available data suggest that probably CSFs should not be administered during the time of most active organogenesis (first trimester), except perhaps for the first week during which implantation takes place. Provided CSF is administered during the second and third trimesters, it appears to be safe, and pregnant women receiving the CSF treatment can become hematopoietic stem cell donors. There are also risks related to the anesthesia, which is required for the bone marrow aspiration. During lactation, there should be a period of at least 3 days to allow for clearance of CSF from milk before resuming breast feeding. With regard to teratogenicity or leukaemogenity, in non-pregnant or non-lactating women reports show that CSF administration is associated with a risk for leukemia; however, this risk is not higher compared with the control population. CONCLUSIONS The information available to date indicates that administration of CSF in general, and G-CSF in particular, is safe and healthy pregnant women can serve as donors of either bone marrow or peripheral blood stem cells. However, the clinical experience is rather limited and therefore until more data become available, G-CSF should not be used during pregnancy and lactation when other therapeutic options, instead of stem cell transplantation, are available.

Acute toxicities of unrelated bone marrow versus peripheral blood stem cell donation: results of a prospective trial from the National Marrow Donor Program

Although peripheral blood stem cells (PBSCs) have replaced bone marrow (BM) as the most common unrelated donor progenitor cell product collected, a direct comparison of concurrent PBSC versus BM donation experiences has not been performed. We report a prospective study of 2726 BM and 6768 PBSC donors who underwent collection from 2004 to 2009. Pain and toxicities were assessed at baseline, during G-CSF administration, on the day of collection, within 48 hours of donation, and weekly until full recovery. Peak levels of pain and toxicities did not differ between the 2 donation processes for most donors. Among obese donors, PBSC donors were at increased risk of grade 2 to 4 pain as well as grade 2 to 4 toxicities during the pericollection period. In contrast, BM donors were more likely to experience grade 2 to 4 toxicities at 1 week and pain at 1 week and 1 month after the procedure. BM donors experienced slower recovery, with 3% still not fully recovered at 24 weeks, whereas 100% of PBSC donors had recovered. Other factors associated with toxicity included obesity, increasing age, and female sex. In summary, this study provides extensive detail regarding individualized risk patterns of PBSC versus BM donation toxicity, suggesting donor profiles that can be targeted with interventions to minimize toxicity.

Ethical issues in neonatal and pediatric clinical trials

Children have been identified as uniquely vulnerable clinical research subjects since the early 1970s. This article reviews the historical underpinnings of this designation, the current regulatory framework for pediatric and neonatal research, and common problems in pediatric research oversight. It also presents 3 areas of pediatric and neonatal research (genomic screening, healthy children donating stem cells, and therapeutic hypothermia for neonates with hypoxic-ischemic encephalopathy) that highlight contemporary challenges in pediatric research ethics, including balancing risk and benefit, informed consent and assent, and clinical equipoise.

The management of the sibling hematopoietic stem cell donor

Hematopoietic stem cell transplants are procedures with curative potential for patients with diseased, damaged, or absent stem cells. Because a sibling has the best chance of immunocompatibility with one in need of a transplant, siblings are the most suitable donors of stem cells. However, when siblings are stem cell donors, various ethical issues arise concerning the risks and benefits to the pediatric donor. Because of the critical and potential rapid deterioration of the recipient's condition, the needs of the sibling donor may be overlooked. This potential lack of advocacy for the pediatric sibling donor creates a role for the primary care provider to assess the child's physical and psychological ability to undergo the donation procedure, examine the ethical issues in choosing to use the pediatric sibling as the stem cell donor, prepare the child for the procedure, and follow-up with the sibling donor once the procedure is completed.

Risk of complications during hematopoietic stem cell collection in pediatric sibling donors: a prospective European Group for Blood and Marrow Transplantation Pediatric Diseases Working Party study

We investigated prospectively factors influencing the safety of hematopoietic stem cell (HSC) collection in 453 pediatric donors. The children in the study donated either BM or peripheral blood stem cells (PBSCs) according to center policy. A large variability in approach to donor issues was observed between the participating centers. Significant differences were observed between BM and PBSC donors regarding pain, blood allotransfusion, duration of hospital stay, and iron supplementation; however, differences between the groups undergoing BM vs PBSC donation preclude direct risk comparisons between the 2 procedures. The most common adverse event was pain, reported mainly by older children after BM harvest, but also observed after central venous catheter (CVC) placement for PBSC collection. With regard to severe adverse events, one patient (0.7%) developed a pneumothorax with hydrothorax after CVC placement for PBSC collection. The risk of allotransfusion after BM harvest was associated with a donor age of < 4 years and a BM harvest volume of > 20 mL/kg. Children < 4 years were at higher risk than older children for allotransfusion after BM harvest and there was a higher risk of complications from CVC placement before apheresis. We conclude that PBSC and BM collection are safe procedures in children.

Ethical issues in bone marrow transplantation in children

In the 50 years since the first successful human bone marrow transplant (BMT) was performed in 1959, BMT has become the optimal therapy for a wide variety of life-threatening paediatric haematological, immunological and genetic disorders. Unfortunately, while BMT generally provides the only possibility of cure for such afflicted children, few (25%) have a matched sibling available, and suitably matched unrelated donors are often not identified for many children in need of BMT. And even where BMT is possible, treatment is complex and arduous and associated with significant mortality and morbidity. The issues raised when either or both the donor and recipient are children and lack the capacity to make informed and rational decisions relating to BMT pose great challenges for all involved. This paper examines some of the ethical dilemmas that confront patients, families and medical practitioners when considering bone marrow transplantation in a child.

Effects of granulocyte-colony stimulating factor on chromosome aneuploidy and replication asynchrony in healthy peripheral blood stem cell donors

As peripheral blood has surpassed bone marrow as a predominant source of stem cells for transplantation, use of the cytokine granulocyte colony-stimulating factor (G-CSF) to mobilize peripheral blood stem cells (PBSCs) is increasing. Issues regarding potential genotoxic effects of even short-term, low-dose G-CSF treatment for the healthy donors have been raised. To address the question of chromosomal instability, we used FISH to evaluate the peripheral blood lymphocytes of 22 PBSC donors and 22 matched controls at 5 time points over a 12-month period. The specimens obtained were a pre-G-CSF, followed by collections at the time of PBSC harvest (days 5-7) and at 2, 6, and 12 months after donation. Eight additional PBSC donors provided a single sample at 12 months. Nine loci (mapped to chromosomes 7, 8, 9, 17, 21, and 22) were evaluated for aneuploidy, including 3 mapped to chromosome 7 because of the specific relevance of monosomy 7. Replication timing was evaluated for chromosome 15 and 17 loci. No evidence was found of G-CSF-induced chromosomal instability. This work supports the epidemiologic data that have demonstrated no increased risk for hematologic malignancies in G-CSF-primed PBSC donors.

Bone marrow as a source of hematopoietic stem cells for human gene therapy of β-thalassemia

β-Thalassemia is a severe inherited anemia caused by insufficient production of β-globin chains. Allogeneic hematopoietic stem cell (HSC) transplantation is currently the only cure, and is limited by donor availability and regimen-related toxicity and mortality. Gene therapy is a promising therapeutic tool for all thalassemic patients lacking a compatible donor and potentially provides transfusion independence in the absence of transplant-related complications, such as graft rejection and graft-versus-host disease. The issue of HSC procurement is critical in this setting because of the specific features of thalassemic syndromes, which include bone marrow (BM) expansion, ineffective erythropoiesis, and splenomegaly. Little is known about the efficiency of CD34(+) cell yield from steady-state BM harvests from thalassemic patients. We have collected data on safety and cell yield from 20 pediatric patients with β-thalassemia who underwent autologous BM harvest before allogeneic HSC transplantation, and from 49 age-matched sibling donors who also underwent BM harvest. The procedure was safe, as no significant adverse events occurred. In terms of cell yield, no difference was found between patients and normal donors in the number of CD34(+) cells and total nucleated cells harvested. Most importantly, no difference was found in the proportion of myeloid and erythroid progenitors, suggesting a similar repopulating capacity. On the basis of these results, we conclude that steady-state BM can be used as a safe and efficient source of HSC for gene therapy of β-thalassemia.

Reduced intensity transplantation for primary immunodeficiency disorders

Many advances have been made since the first successful hematopoietic cell transplants (HCT) in children with primary immunodeficiency disorders (PID) were reported 40 years ago, and many children with PID can now be cured from their otherwise lethal disorders through well-matched HCT procedures. Preexisting morbidity and infection remain the principal adverse factors for poor outcomes with HCT. To improve current results, earlier diagnosis, well-tolerated pretransplant conditioning regimens, and promotion of immune reconstitution need to be considered. This article addresses modifications in the conditioning regimen that might lead to further improvement in HCT outcomes.

The aberrant asynchronous replication - characterizing lymphocytes of cancer patients - is erased following stem cell transplantation

BACKGROUND

Aberrations of allelic replication timing are epigenetic markers observed in peripheral blood cells of cancer patients. The aberrant markers are non-cancer-type-specific and are accompanied by increased levels of sporadic aneuploidy. The study aimed at following the epigenetic markers and aneuploidy levels in cells of patients with haematological malignancies from diagnosis to full remission, as achieved by allogeneic stem cell transplantation (alloSCT).

METHODS

TP53 (a tumor suppressor gene assigned to chromosome 17), AML1 (a gene assigned to chromosome 21 and involved in the leukaemia-abundant 8;21 translocation) and the pericentomeric satellite sequence of chromosome 17 (CEN17) were used for replication timing assessments. Aneuploidy was monitored by enumerating the copy numbers of chromosomes 17 and 21. Replication timing and aneuploidy were detected cytogenetically using fluorescence in situ hybridization (FISH) technology applied to phytohemagglutinin (PHA)-stimulated lymphocytes.

RESULTS

We show that aberrant epigenetic markers are detected in patients with hematological malignancies from the time of diagnosis through to when they are scheduled to undergo alloSCT. These aberrations are unaffected by the clinical status of the disease and are displayed both during accelerated stages as well as in remission. Yet, these markers are eradicated completely following stem cell transplantation. In contrast, the increased levels of aneuploidy (irreversible genetic alterations) displayed in blood lymphocytes at various stages of disease are not eliminated following transplantation. However, they do not elevate and remain unchanged (stable state). A demethylating anti-cancer drug, 5-azacytidine, applied in vitro to lymphocytes of patients prior to transplantation mimics the effect of transplantation: the epigenetic aberrations disappear while aneuploidy stays unchanged.

CONCLUSIONS

The reversible nature of the replication aberrations may serve as potential epigenetic blood markers for evaluating the success of transplant or other treatments and for long-term follow up of the patients who have overcome a hematological malignancy.