Use of minors as bone marrow donors: current attitude and management. A survey of 56 pediatric transplantation centers

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.

Family Strategies to Support Siblings of Pediatric Hematopoietic Stem Cell Transplant Patients

OBJECTIVE

To describe the strategies families report using to address the needs and concerns of siblings of children, adolescents, and young adults undergoing hematopoietic stem cell transplant (HSCT).

METHODS

A secondary semantic analysis was conducted of 86 qualitative interviews with family members of children, adolescents, and young adults undergoing HSCT at 4 HSCT centers and supplemented with a primary analysis of 38 additional targeted qualitative interviews (23 family members, 15 health care professionals) conducted at the primary center. Analyses focused on sibling issues and the strategies families use to address these issues.

RESULTS

The sibling issues identified included: (1) feeling negative effects of separation from the patient and caregiver(s); (2) experiencing difficult emotions; (3) being faced with additional responsibilities or burdens; (4) lacking information; and (5) feeling excluded. Families and health care providers reported the following strategies to support siblings: (1) sharing information; (2) using social support and help offered by family or friends; (3) taking siblings to the hospital; (4) communicating virtually; (5) providing special events or gifts or quality time for siblings; (6) offering siblings a defined role to help the family during the transplant process; (7) switching between parents at the hospital; (8) keeping the sibling's life constant; and, (9) arranging sibling meetings with a certified child life specialist or school counselor.

CONCLUSIONS

Understanding the above strategies and sharing them with other families in similar situations can begin to address sibling issues during HSCT and can improve hospital-based, family-centered care efforts.

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.

Children as hematopoietic stem cell donors

In the past half-century, hematopoietic stem cell transplantation has become standard treatment for a variety of diseases in children and adults, including selected hematologic malignancies, immunodeficiencies, hemoglobinopathies, bone marrow failure syndromes, and congenital metabolic disorders. There are 3 sources of allogeneic hematopoietic stem cells: bone marrow, peripheral blood, and umbilical cord blood; each has its own benefits and risks. Children often serve as hematopoietic stem cell donors, most commonly for their siblings. HLA-matched biological siblings are generally preferred as donors because of reduced risks of transplant-related complications as compared with unrelated donors. This statement includes a discussion of the ethical considerations regarding minors serving as stem cell donors, using the traditional benefit/burden calculation from the perspectives of both the donor and the recipient. The statement also includes an examination of the circumstances under which a minor may ethically participate as a hematopoietic stem cell donor, how the risks can be minimized, what the informed-consent process should entail, the role for a donor advocate (or some similar mechanism), and other ethical concerns. The American Academy of Pediatrics holds that minors can ethically serve as stem cell donors when specific criteria are fulfilled.

A review of transfusion practice before, during, and after hematopoietic progenitor cell transplantation

The increased use of hematopoietic progenitor cell (HPC) transplantation has implications and consequences for transfusion services: not only in hospitals where HPC transplantations are performed, but also in hospitals that do not perform HPC transplantations but manage patients before or after transplantation. Candidates for HPC transplantation have specific and specialized transfusion requirements before, during, and after transplantation that are necessary to avert the adverse consequences of alloimmunization to human leukocyte antigens, immunohematologic consequences of ABO-mismatched transplantations, or immunosuppression. Decisions concerning blood transfusions during any of these times may compromise the outcome of an otherwise successful transplantation. Years after an HPC transplantation, and even during clinical remission, recipients may continue to be immunosuppressed and may have critically important, special transfusion requirements. Without a thorough understanding of these special requirements, provision of compatible blood components may be delayed and often urgent transfusion needs prohibit appropriate consultation with the patient's transplantation specialist. To optimize the relevance of issues and communication between clinical hematologists, transplantation physicians, and transfusion medicine physicians, the data and opinions presented in this review are organized by sequence of patient presentation, namely, before, during, and after transplantation.

Multiple BM harvests in pediatric donors for thalassemic siblings: safety, efficacy and ethical issues

Allogeneic BMT represents the only chance of cure for beta-thalassemia. Occasionally, two affected individuals from the same family share a matched healthy sibling. Moreover, a high incidence of transplant rejection is still observed in Pesaro class III patients, requiring a second BMT procedure. In these settings, one option is to perform a second BM harvest from the same donor. Although BM harvest is a safe procedure in children, ethical issues concerning this invasive practice still arise. Here, we describe our series of seven pediatric, healthy donors, who donated BM more than once in favor of their beta-thalassemic HLA-identical siblings between June 2005 and January 2008. Three donors donated BM twice to two affected siblings and four donors donated twice for the same sibling following graft rejection of the first BMT. All donors tolerated the procedures well and no relevant side effects occurred. There was no significant difference between the two harvests concerning cell yield and time to engraftment. Our experience shows that for pediatric donors, a second BM donation is safe and feasible and good cellularity can be obtained. We suggest that a second harvest of a pediatric donor can be performed when a strong indication for BMT exists.

Cord blood stem cell transplantation for haemoglobinopathies

Despite improvements in supportive care, patients with beta-thalassaemia major or sickle cell disease (SCD) may benefit from haematopoietic stem cell transplantation at some point during their lives. Human leucocyte antigen (HLA)-matched sibling bone marrow donors are not always available and alternative sources of stem cells have been sought, including related and unrelated donor cord blood transplants (CBT). The outcome of CBT from related donors for the treatment of both thalassaemia major and SCD is now approaching that for bone marrow transplantation, with around 90% of patients surviving disease-free. The main complication is graft rejection, which may be reduced by increasing pretransplant immune suppression. Transplant-related mortality following HLA-identical matched related donor CBT is extremely low but is significant in the small series of unrelated and/or mis-matched donor CBT. The principal limitation to extending the use of CB stem cells for the cure of haemoglobinopathies is the need to better understand the mechanisms of action and optimal conditioning regimens used to secure long-term engraftment while minimizing morbidity and mortality. Further biological studies and clinical trials are needed to address this aim.

Hematopoietic stem cell transplant research with pediatric donors: when can institutional review boards approve it?

Although pediatric donation of hematopoietic stem cells (HSCs) for allogeneic transplants is common in the clinical setting, the question of when children may donate HSCs in research has received little attention. Our analysis reveals that institutional review boards (IRBs) may approve children's participation as HSC donors in transplant research when it poses no more than minimal risk to them. The risks that IRBs should consider are those that result specifically from the research, as opposed to risks donors would have faced regardless of the research. Transplant protocols that expose pediatric donors to more than minimal risk can be approved by the Secretary of U.S. Department of Health and Human Services in a special category of pediatric research.

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

BACKGROUND

Granulocyte colony stimulating factor (G-CSF) is used for collection of hematopoietic cells in most adult and a smaller but significant percentage of pediatric normal donor harvests. Short and long-term risks of G-CSF administration and leukopheresis are not well understood in the pediatric population.

PROCEDURE

Literature review including observations from the IBMTR, NMDP, EBMT, German Donor Registry, and the authors' work.

RESULTS

G-CSF causes temporary discomfort in a minority of younger donors. Rare serious side effects of G-CSF have yet to be reported in children. To date, an increase in hematological malignancies after short-term G-CSF use has not been detected in adult donors and no cases have been reported in children. Reported complications of leukopheresis in children are rare and minor, but donors <20 kg may be exposed to allogeneic blood products. Pediatric aged donors vary widely in their ability to assent or consent to the risks of a donation procedure. There are key regulations and ethical imperitives, which must be addressed in deciding which donation procedures are appropriate for minors.

CONCLUSIONS

While short term administration of G-CSF and leukopheresis appear to be safe and effective procedures when used to assist in collection of a hematopoietic cell graft from a normal pediatric donor, institutions adding or substituting one or both of these procedures for standard marrow donation must decide whether the donor should be considered a research subject, and if so, whether the new procedures are a minor increase over minimal risk. Because these procedures are being performed on and off study at many pediatric centers, a comprehensive study addressing donor safety could help clarify risks of rare adverse events.

Use of G-CSF in matched sibling donor pediatric allogeneic transplantation: a consensus statement from the Children's Oncology Group (COG) Transplant Discipline Committee and Pediatric Blood and Marrow Transplant Consortium (PBMTC) Executive Committee

Preliminary studies indicate that G-CSF-primed marrow harvesting may result in a graft with increased mononuclear cells collected, increased CD34(+) stem and progenitor cell dose and a potential for more rapid engraftment. Increased cell dose plus other potential positive effects of G-CSF priming have resulted in improved survival in non-randomized preliminary studies. These benefits may be available without the increased risk of chronic graft versus host disease (GVHD) that is experienced with allogeneic peripheral blood stem cell (PBSC) transplant. A phase III Children's Oncology Group (COG)/Pediatric Blood and Marrow Transplant Consortium (PBMTC) trial comparing G-CSF-primed marrow to standard marrow has been proposed. This document reviews background studies of G-CSF-primed marrow and addresses benefits and risks of G-CSF administration to normal pediatric donors. We conclude that the approach is promising and warrants further study. Risks of G-CSF to the donor are minimal and benefits to both donor and recipient may occur.

Evaluation of Hematopoietic Stem Cell Donors

Donation of hematopoietic stem cells, either through bone marrow or peripheral blood collection, is a generally safe procedure for healthy donors. Serious adverse events are uncommon and death is exceedingly rare. Nevertheless, all donors must be carefully evaluated and fully informed prior to donation. This should be done by clinicians having good understanding of the potential physical and psychological complications of donation and the factors that may increase these risks. Additionally, donors and graft products must be evaluated for the potential to transmit infections and other diseases to the recipient and to satisfy an increasing number of national and international regulatory requirements. Donors must be able to provide informed consent without coercion or pressure. Special attention to the clinical, psychological and social needs of pediatric donors is necessary.

Bone marrow donation in childhood: one donor's perspective

Allogeneic bone marrow transplantation is an established treatment modality for leukemia, hematologic disorders and inborn errors of metabolism. while the focus of attention is the transplant recipient, the bone marrow donor (often a sibling) is both physically and emotionally involved in the process. Few reports have been written from the donor's perspective, however. One of the authors of this report (G.P.) was a marrow donor as a child, and he reflects on this experience at the completion of his first year of training in medical school.

Using preimplantation genetic diagnosis to create a stem cell donor: issues, guidelines & limits

Successful preimplantation genetic diagnosis (PGD) to avoid creating a child affected by a genetically-based disorder was reported in 1989. Since then PGD has been used to biopsy and analyze embryos created through in viuo fertilization (IVF) to avoid transferring to the mother’s uterus an embryo affected by a mutation or chromosomal abnormality associated with serious illness. PGD to avoid serious and early-onset illness in the child-to-be is widely accepted. PGD prevents gestation of an affected embryo and reduces the chance that the parents will be faced with a difficult decision of whether to terminate the pregnancy. More controversial have been PGD to select the sex of the child-to-be for “family balancing” (rather than to avoid a sex-linked disorder), PGD for mere susceptibility to disease and for late-onset disorders such as Alzheimer diseas, and most controversially, PGD to create a donor child who is Human Leukocyte Antigen (HLA-matched with a preexisting sibling in need of stem cell transplant.

Using peripheral blood progenitor cells (PBPC) for transplantation in pediatric patients: a state-of-the-art review

This paper presents a state-of-the-art review of using mobilized-peripheral blood progenitor cells (PBPC) for transplantation in children. Our own data and those from Medline searches and meeting reports, are analyzed and presented for the different sections that involve transplantation. Recommendations concerning the choice of mobilization regimens, venous access, priming of separator extracorporeal line, anticoagulation, and number of CD34+ cells to infuse for rapid engraftment are proposed. In the allogeneic setting, we analyze ethical and safety aspects of pediatric donor mobilization and collection. Data from the literature suggest that the use of cytokine-mobilized PBPC for allogeneic transplantation appears to be safe both for pediatric donors and patients leading a rapid hematopoietic engraftment with a similar incidence of acute graft-versus-host disease (GVHD). The high incidence of chronic GVHD and its management emerge as the most concerning aspect in allogeneic PBPC transplantation.

Human neonatal blood: stem cell content, kinetics of CD34+ cell decline and ex vivo expansion capacity

Haemopoietic stem cells are present in fetal blood but their levels decline rapidly in the peripheral circulation of the infant after birth. We previously reported a case of stem cell transplant in a beta-thalassaemia boy using a combination of the cord blood (CB) and neonatal blood (NB) of his sister. This transplant resulted in a successful engraftment. To investigate the possibility of using NB to supplement CB for related transplants, we further characterized stem and progenitor cells and lymphocyte subsets in 20 NB samples, comparing the findings with those in 20 CB samples. Our data showed that NB contained substantial levels of CD34+ cells, CD34+CD38- cells, colony-forming units-granulocyte macrophage (CFU-GM), colony forming units-erythroid (CFU-E), burst forming units-erythroid (BFU-E) and long-term culture initiating cells (LTCIC). NB was similar to CB in the levels of T lymphocytes, but the amounts of B lymphocytes and natural killer cells were higher in CB (P = 0.033, P= 0.001, respectively). The kinetics of CD34+ cells in NB was investigated in serial blood samples obtained from 10 full-term infants at 2, 4, 6, 8, 24 and 48h after birth. CD34+ cells decreased rapidly after birth, declining to only 30% of the 2h level at 48h (P<0012). The rate of decline was greatest in the first 4 h of life. NB from four infants was expanded by culturing the blood samples in the presence of thrombopoietin (Tpo), interleukin 1beta (IL1beta), IL-3, IL-6, flt-3 ligand and stem cell factor (SCF) for 7 d. This resulted in the increase of CD34+ cells, CFU-GM and CFU-MK by 271+/-179, 556+/-385 and 113+/-75 fold respectively. Three of the five samples expanded for 7 d contained LTCIC. These findings suggest that NB might be a supplementary or alternative source of stem cells to CB for transplant. The ethics and practicality of this approach deserve further exploration.