Older Age But Not Donor Health Impairs Allogeneic Granulocyte Colony-Stimulating Factor (G-CSF) Peripheral Blood Stem Cell Mobilization

Scoping Review of Factors Associated with Stem Cell Mobilization and Collection in Allogeneic Stem Cell Donors

There is wide interindividual variation in the efficacy of CD34+ cell mobilization and collection in healthy allogenic hematopoietic stem cell donors. Donor characteristics, blood cell counts, and various factors related to mobilization and collection have been associated with blood CD34+ cell count and CD34+ cell yield after granulocyte colony-stimulating factor (G-CSF) mobilization and collection. Given the heterogenous nature of the literature reporting these associations, in this scoping review we clarify the determinants of CD34+ count and yield. Studies published between 2000 and 2023 reporting allogeneic donors undergoing G-CSF mobilization and peripheral blood stem cell (PBSC) collection were evaluated. Eligible studies were those that assessed blood CD34+ cell count or CD34+ cell yield in the first PBSC collection after mobilization with 4 or 5 days of G-CSF treatment. Associations were recorded between these outcomes and donor factors (age, sex, weight, ethnicity), mobilization factors (G-CSF scheduling or dose), collection factors (venous access, processed blood volume [PBV]) or laboratory factors (blood cell counts at baseline or after mobilization). The 52 studies evaluated between 15 and 20,884 donors. Forty-three studies were retrospective, 33 assessed blood CD34+ cell counts, and 39 assessed CD34+ cell yield from PBSCs. Blood CD34+ cell counts consistently predicted CD34+ cell yield. Younger donors usually had higher blood CD34+ cell counts and CD34+ cell yield. Most studies that investigated the effect of donor ancestry found that donors of non-European ancestry had higher blood CD34+ cell counts after mobilization and higher CD34+ cell yields from collection. The poor consensus about the best predictors of blood CD34+ cell count and yield necessitates further prospective studies, particularly of the role of donor ancestry. The current focus on donor sex as a major predictor requires re-evaluation.

Platelet-derived circulating soluble P-selectin is sufficient to induce hematopoietic stem cell mobilization

BACKGROUND

Granulocyte colony-stimulating factor (G-CSF)-mediated mobilization of hematopoietic stem cells (HSCs) is a well-established method to prepare HSCs for transplantation nowadays. A sufficient number of HSCs is critical for successful HSC transplantation. However, approximately 2-6% of healthy stem cell donors are G-CSF-poor mobilizers for unknown reasons; thus increasing the uncertainties of HSC transplantation. The mechanism underlining G-CSF-mediated HSC mobilization remains elusive, so detailed mechanisms and an enhanced HSC mobilization strategy are urgently needed. Evidence suggests that P-selectin and P-selectin glycoprotein ligand-1 (PSGL-1) are one of the cell-cell adhesion ligand-receptor pairs for HSCs to keep contacting bone marrow (BM) stromal cells before being mobilized into circulation. This study hypothesized that blockage of PSGL-1 and P-selectin may disrupt HSC-stromal cell interaction and facilitate HSC mobilization.

METHODS

The plasma levels of soluble P-selectin (sP-sel) before and after G-CSF administration in humans and male C57BL/6J mice were analyzed using enzyme-linked immunosorbent assay. Male mice with P-selectin deficiency (Selp-/-) were further employed to investigate whether P-selectin is essential for G-CSF-induced HSC mobilization and determine which cell lineage is sP-sel derived from. Finally, wild-type mice were injected with either G-CSF or recombinant sP-sel to investigate whether sP-sel alone is sufficient for inducing HSC mobilization and whether it accomplishes this by binding to HSCs and disrupting their interaction with stromal cells in the BM.

RESULTS

A significant increase in plasma sP-sel levels was observed in humans and mice following G-CSF administration. Treatments of G-CSF induced a decrease in the level of HSC mobilization in Selp-/- mice compared with the wild-type (Selp+/+) controls. Additionally, the transfer of platelets derived from wild-type mice can ameliorate the defected HSC mobilization in the Selp-/- recipients. G-CSF induces the release of sP-sel from platelets, which is sufficient to mobilize BM HSCs into the circulation of mice by disrupting the PSGL-1 and P-selectin interaction between HSCs and stromal cells. These results collectively suggested that P-selectin is a critical factor for G-CSF-induced HSC mobilization.

CONCLUSIONS

sP-sel was identified as a novel endogenous HSC-mobilizing agent. sP-sel injections achieved a relatively faster and more convenient regimen to mobilize HSCs in mice than G-CSF. These findings may serve as a reference for developing and optimizing human HSC mobilization in the future.

Should a matched sibling donor still be considered the primary option for allogeneic hematopoietic cell transplantation in patients over 50 years of age with myelodysplastic syndrome?

Human leukocyte antigen (HLA)-matched sibling donors (MSDs) are the preferred choice for allogeneic hematopoietic cell transplantation (HCT). However, as myelodysplastic syndrome (MDS) is most frequently diagnosed in the elderly, MSDs are also likely to be of advanced age. It is unclear whether an MSD should be considered the primary choice for allogeneic HCT in elderly patients with MDS. We retrospectively compared survival and other outcomes in 1787 patients with MDS over 50 years of age and receiving allogeneic HCT between 2014 and 2020, using either MSD (n = 214), 8/8 allele-matched unrelated donor (MUD) (n = 562), 7/8 allele-MUD (n = 334), or unrelated cord blood (UCB) (n = 677) in Japan. In multivariate analysis, compared to MSD transplants, the risk of relapse was significantly lower following 8/8MUD transplants (hazard ratio [HR], 0.74; P = 0.047), whereas non-relapse mortality was significantly higher following UCB transplants (HR, 1.43; P = 0.041). However, donor type did not determine overall survival, disease-free survival, or graft-versus-host disease (GVHD)-free, relapse-free survival, but chronic GVHD-free, relapse-free survival was better after UCB (HR, 0.80; P = 0.025) and 8/8MUD (HR, 0.81; P = 0.032) compared to MSD transplants. Our study demonstrated that MSDs are not superior to alternative HCT methods, such as 8/8MUD, 7/8MUD, or UCB, in this population.

Allogeneic hematopoietic cell transplantation in acute myeloid leukemia

Allogeneic hematopoietic cell transplantation (HCT) is a curative treatment modality for select patients with acute myeloid leukemia (AML), functioning as a restorative agent following intensified chemo- and/or radiotherapy and also engendering the disease-directed immunologic threat of graft-versus-leukemia effect. Advancements in conditioning regimen intensity, donor availability, and supportive care have broadened the eligibility for allogeneic HCT, reduced rates of transplant related mortality, and improved outcomes over time. There are still obstacles to transplant in AML, offering opportunities for ongoing discovery, including poor recipient fitness, insufficient donor availability for certain populations, and limited access to care. Relapse remains the most common cause of treatment failure and a high priority area of investigative efforts. Post-transplant maintenance and novel applications of cellular therapeutics are expected to usher in a new era of promise for successful HCT in AML and will aim to overcome the remaining barriers impeding favorable outcomes for these patients.

Peripheral Blood Allogeneic Stem Cell Mobilization: Can We Predict a Suboptimal Mobilization?

Allogeneic peripheral blood stem cells mobilization is now the basis of most stem cell transplants. In a very limited number of cases, mobilization is suboptimal leading to further collection procedures, to suboptimal cell doses infusion with delayed engraftment time, increased risks of transplant procedure and of related costs. To date we have no recognized and shared criteria for early estimating the probability of poor mobilization in healthy donors. We then analyzed allogeneic peripheral blood stem cell donations performed at the Fondazione Policlinico Universitario A.Gemelli IRCCS Hospital from January 2013 to December 2021 in order to identify premobilization factors associated with successful mobilization. The following data were collected: age, gender, weight, complete blood cell count at baseline, G-CSF dose, number of collection procedures, CD34+ cell count in peripheral blood on the first day of collection, CD34+ cell dose per kg body weight of recipient. Mobilization efficacy was defined according to the number of CD34+ cells in peripheral blood on day +5 of G-CSF administration. We classified donors as sub-optimal mobilizers or good mobilizers according to the achievement of the 50 CD34+ cell/μL threshold. We observed 30 suboptimal mobilizations in 158 allogeneic peripheral blood stem cell donations. Age and baseline white blood cell count were factors significantly associated with negative or positive impact on mobilization, respectively. We did not find significant differences in mobilization based on gender or G-CSF dose. Using cut-off values of 43 years and 5.5×10⁹/L WBC count, we built a suboptimal mobilization score: donors who reach 2, 1 or 0 points have a 46%, 16% or 4% probability of suboptimal mobilization, respectively. Our model explains 26% of the variability of mobilization confirming that most of the mobilization magnitude depends on genetically determined factors; however, suboptimal mobilization score is a simple tool providing an early assessment of mobilization efficacy before G-CSF administration begins in order to support allogeneic stem cells selection, mobilization and collection. Through a systematic review, we looked for confirmation of our findings. According to the published articles, all the variables we included in our model are confirmed to be strongly related to the success of mobilization. We believe that score system approach could be applied in clinical practice to assess the risk of mobilization failure at baseline allowing for a priori intervention.

Factors Associated with Opting Out of Donation among Registered Young Unrelated Hematopoietic Stem Cell Donors

Young adults enrolled in hematopoietic stem cell (HSC) donation registries, including the Be The Match registry in the United States, often opt out of the registry when a potential recipient is identified. This results in a limited supply from the most desirable allogeneic source of HSCs used in transplantation to treat serious health conditions. The differences in demographic, psychosocial, registry-related, and donation-related characteristics between those who continue to donation and those who opt out may elucidate the modifiable risk factors for attrition, but these characteristics have not been extensively studied in young donors up to age 30 years. Our goal was to study demographic, psychosocial, registry-related, and donation-related characteristics in a group of young HSC donor registry members who had recently been contacted about a potential recipient, to determine the key characteristics that differ between those who continued toward donation and those who opted out and to examine the extent of these differences. We conducted a cross-sectional survey in a random sample of young (age 18 to 30 years) current and former registry members, stratified by race/ethnicity and sex. Demographic, psychosocial (eg, life goals, HSC allocation mistrust), registry-related (eg context and motive for joining the registry), and donation-related (eg, ambivalence, religious objections to donation, knowledge about donation) characteristics were assessed. Chi-square and 2-sample t tests were used to examine differences between those who continued (CT-C group) and those who opted out (CT-NI group). Hierarchical logistic regression was used to estimate adjusted covariate effects on the odds of opting out. A total of 935 participants were surveyed. Donation-related knowledge was higher in the CT-C group than in the CT-NI group. HSC allocation mistrust, religious objections, and concerns about donation were higher in the CT-NI group. After adjusting for covariates in a logistic regression model, we found that having more intrinsic life goals, having more ambivalence, and talking with registry staff only once/twice were significantly associated with opting out of the registry. Ambivalence had the strongest association with opting out. In contrast, remembering joining the registry, believing that parents would support donation, and having medical concerns were significantly associated with continuing toward donation. This effect of medical concerns on donation was discovered only after adjusting for the related but distinct ambivalence variable, with the remaining effect of medical concerns relating to engagement with the donation process and information-seeking. The model had strong discriminative ability (area under the receiver operating characteristic curve = .92) and classification accuracy (86.6%). Our data indicate that among young adult members of a national HSC donor registry, ambivalence and limited contact with registry staff were more strongly associated with opting out of donation. Medical concerns were associated with continuing toward donation. Further studies are needed to confirm a causal link between medical concerns and continuing to donation among young donors. Our study suggests that these concerns might not be directly related to attrition, whereas other factors (eg, ambivalence, low donation-related knowledge) are associated with attrition and thus should be targeted for attrition reduction strategies.

Addition of plerixafor in poorly mobilized allogeneic stem cell donors

Background

Peripheral blood stem cells (PBSCs) are the predominant graft source for adult allogeneic hematopoietic stem cell transplantation (HSCT). In poorly mobilized autologous donors, plerixafor improves collection outcomes. We examine plerixafor use in allogeneic donors who mobilize poorly with granulocyte colony‐stimulating factor (G‐CSF) in those who are healthy and those with pre‐existing medical conditions, and determine the optimal threshold to add plerixafor.

Study Design/Methods

We retrospectively examined all allogeneic PBSC collections from January 2013 to October 2020 at our center. Donors received G‐CSF 10 mcg/kg daily for 4 days before undergoing apheresis collection on day 5. Plerixafor was added based on poor CD34+ cell collection yield after the first or second collection day.

Results

Of the 1008 allogeneic donors, 41 (4.1%) received one dose of plerixafor in addition to G‐CSF due to poor collection yield. After starting plerixafor there was a 0.75‐ to 7.74‐fold (median 2.94) increase in CD34+ yield from the previous day. No donors with G‐CSF‐only mobilization who collected <2.0 × 10⁶ CD34+ cells/kg recipient weight on day one achieved the goal of ≥4.0 × 10⁶ CD34+ cells/kg recipient weight total over 2 days but 59.2% of donors who used rescue plerixafor did.

Conclusion

Donors both healthy and those with pre‐existing disease responded well to plerixafor with minimal side effects. If the first‐day collection yield is less than ~63% of the collection goal, addition of plerixafor may be necessary to reach the collection goal and limit the number of collection days in allogeneic donors.

Old is bad? The effect of age on peripheral stem cell mobilization and transplantation outcomes

INTRODUCTION

Allogeneic stem cell transplantation (Allo-SCT) is a well-established treatment option for hematological malignancies. With the introduction of reduced-intensity conditioning regimens (RIC) and better supportive measures the elderly are able to receive Allo-SCT. A considerable number of patients are elderly, and often their HLA matched sibling donor is elderly, moreover. Here, we aim to explore the effect of donors' age on stem cell harvesting, engraftment duration after Allo-SCT, and product quality.

METHOD

Sixty-one healthy allogeneic stem cell donors aged 50 years and older who underwent stem cell mobilization at our center between 2009-2019 were enrolled for the study. All donors received 4-5 days of G-CSF, mostly filgrastim or lenograstim and their biosimilar equivalents were given subcutaneously as a total dose of 10 mcg/kg/day. Groups were separated into three groups as aged 50-54 group A, 55-59 group B, aged 60 and older group C.

RESULTS

Pre-apheresis peripheral blood CD34+ count was similar all groups (p = 0.2). One day apheresis was sufficient for 72.7 % of group A, 27.3 % for group B and 47.1 % for group C (p = 0.02). Total harvested CD34+ cells were comparable among groups (p = 0.5).

CONCLUSION

Adequate stem cell harvest in older donors is feasible. Older donors may require more than one apheresis procedure and generally procedure was well tolerated. When assessing donors, age should represent less significance.

Getting blood out of a stone: Identification and management of patients with poor hematopoietic cell mobilization

Hematopoietic cell transplantation (HCT) has become a primary treatment for many cancers. Nowadays, the primary source of hematopoietic cells is by leukapheresis collection of these cells from peripheral blood, after a forced egress of hematopoietic cells from marrow into blood circulation, a process known as "mobilization". In this process, mobilizing agents disrupt binding interactions between hematopoietic cells and marrow microenvironment to facilitate collection. As the first essential step of HCT, poor mobilization, i.e. failure to obtain a desired or required number of hematopoietic cell, is one of the major factors affecting engraftment or even precluding transplantation. This review summarizes the available mobilization regimens using granulocyte-colony stimulating factor (G-CSF) and plerixafor, as well as the current understanding of the factors that are associated with poor mobilization. Strategies to mobilize patients or healthy donors who failed previous mobilization are discussed. Multiple novel agents are under investigation and some of them have shown the potential to enhance the mobilization response to G-CSF and/or plerixafor. Further investigation of the risk factors including genetic factors will offer an opportunity to better understand the molecular mechanism of mobilization and help develop new therapeutic strategies for successful mobilizations.

Plerixafor on-demand in association with low-dose cyclophosphamide and G-CSF in the mobilization of patients with multiple myeloma: High effectiveness, low toxicity, and affordable cost

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In CD34 mobilization of Multiple Myeloma patients, Cyclophosphamide at the dose of 4 gr/m2 is usually administered. A lower dose of Cyclophosphamide (1.5–2.0 gr/m2) has a lower mobilizing effect and, for this reason, this dose is not widely used in CD34+ cells mobilization.

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The use of Plerixafor on demand, however, could have changed these conclusions. We hypothesized that when used in conjunction with on-demand Plerixafor, low lose CTX is more advantageous than the higher dose.

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The results of this prospective trial support, indeed, the view that low dose Cyclophosphamide in association to on-demand PLX allows the reaching efficacy and low toxicity.

In CD34+ cells mobilization of patients with multiple myeloma (MM), the use of Cyclophosphamide (CTX) at a dose of 2 g/m² has low efficacy although also lower toxicity. The suboptimal mobilizing effect of low-dose CTX, however, may be overcome by plerixafor (PLX) on demand.

We conducted a prospective multicenter study in 138 patients with MM to evaluate CTX 2 g/m² in association with granulocyte-colony stimulating factor (G-CSF) and on-demand PLX. We compared results with a historical group of MM patients (n = 138) mobilized using CTX at a dose of 4 g/m².

CD34+ cells greater than 2 × 10⁶/kg in max three aphereses were harvested in 98.6% of patients in the on-demand PLX study group while in 84.0% in the historical group, (p = 0.0001). In the on-demand-PLX study group, a successful harvest greater than 5 × 10⁶/kg in max three aphereses was observed in 85.5% of patients versus 62.3% of patients in the historical control group, (p=0.0001). In the on-demand-PLX study group, 4.3% (6/138) of patients had febrile complications. Salvage mobilization in the on-demand PLX study group was 1.4%.

In conclusions, on-demand PLX + CTX 2 g/m2 + G-CSF 10 μg/kg has higher efficacy and lower toxicity compared with CTX 4 g/m2 + G-CSF. An analysis of costs is presented.

Plerixafor-based mobilization in pediatric healthy donors with unfavorable donor/recipient body weight ratio resulted in a better CD34+ collection yield: A retrospective analysis

INTRODUCTION

In order to propose risk-adapted mobilization algorithms, several authors have tried to look for predictive factors of the CD34⁺ yield in healthy pediatric donors. Donor recipient body weight ratio (D/R ratio) was identified as one of the main variables related with the success to achieve the target cell dose for transplantation. According to this variable we modified the mobilization schedule.

MATERIAL AND METHODS

We report the results of 46 mobilizations and apheresis procedures performed in our center with unfavorable D/R ratio. Mobilization was attempted by the standard regime of G-CSF (10 mcg/kg/24 hours) in 28 cases (60.9%), with high dose G-CSF (10 mcg/kg/12 hours) in 9 cases (19.6%), and with plerixafor and G-CSF single dose regime in 9 cases (19.6%).

RESULTS

CD34⁺ cell quantification before apheresis is closely related to CD34⁺ yield, being the only factor related to collected CD34⁺ cells (beta .71; P < .0001). The mobilization efficiency was higher in plerixafor group compared to the other two schedules (P < .0001). By using plerixafor for mobilization, we achieved the target CD34⁺ cell dose of ≥2 × 10⁶ /kg per recipient body weight in all cases with unfavorable D/R ratio. It was observed that 17.4% of cases that not reached the established target cell dose were located in the standard or high-dose mobilization regimes. This difference is even greater for optimal collections (≥5 × 10⁶ /kg), since of the 54.3% cases that did not reach this goal none was mobilized by plerixafor.

CONCLUSION

Tailoring the mobilization regime we can reach the target cell dose, even in those cases with the worst D/R ratio.

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.

Prior blood donations do not affect efficacy of G-CSF mobilization nor outcomes of haematopoietic stem cell collection in healthy donors

BACKGROUND AND OBJECTIVES

Many consider volunteer blood donors as ideal candidates for unrelated haematopoietic progenitor cell (HPC) donation. However, frequent blood donations could influence the results of HPC mobilization. To our best knowledge, there are no data on the possible impact of repeated blood donation on efficiency of subsequent HPC mobilization by granulocyte colony-stimulating factor (G-CSF).

MATERIALS AND METHODS

We compared outcomes of HPC mobilization in unrelated donors with and without a history of blood donation. We conducted a prospective study on 287 consecutive donors admitted to the Department of Hematology since January 2016. The final analysis included 153 donors who agreed to take part in the study and had undergone stem cell mobilization with G-CSF.

RESULTS

History of blood donations prior to haematopoietic stem cell mobilization with G-CSF does not have a significant impact on the number of collected CD34+ cells in the first leucocytapheresis (516.2 x 10⁶ (170-1148) in blood donors vs 490.5 x 10⁶ (101-1154) in non-donors) (P = 0.32). In all donors, in this study mobilization of HPC was successful: 87.5% of blood donors and 85.6% of non-donors collected the required cell number in a single apheresis. In blood donors, a higher number of blood donations within 2 and 5 years prior to HPC mobilization correlated significantly with successful donation within one leucocytapheresis (P = 0.014 and P = 0.024, respectively).

CONCLUSION

Multiple blood donations do not significantly influence the outcome of HPC collection in unrelated donors. Blood donors and non-donors have similar results of HPC collection, so there is no reason to favour either group.

Effect of Aging and Predonation Comorbidities on the Related Peripheral Blood Stem Cell Donor Experience: Report from the Related Donor Safety Study

The development of reduced-intensity approaches for allogeneic hematopoietic cell transplantation has resulted in growing numbers of older related donors (RDs) of peripheral blood stem cells (PBSCs). The effects of age on donation efficacy, toxicity, and long-term recovery in RDs are poorly understood. To address this we analyzed hematologic variables, pain, donation-related symptoms, and recovery in 1211 PBSC RDs aged 18 to 79 enrolled in the Related Donor Safety Study. RDs aged > 60 had a lower median CD34+ level before apheresis compared with younger RDs (age > 60, 59 × 106/L; age 41 to 60, 81 × 106/L; age 18 to 40, 121 × 106/L; P < .001). This resulted in older donors undergoing more apheresis procedures (49% versus 30% ≥ 2 collections, P < .001) and higher collection volumes (52% versus 32% > 24 L, P < .001), leading to high percentages of donors aged > 60 with postcollection thrombocytopenia <50 × 109/L (26% and 57% after 2 and 3days of collection, respectively). RDs aged 18 to 40 had a higher risk of grades 2 to 4 pain and symptoms pericollection, but donors over age 40 had more persistent pain at 1, 6, and 12 months (odds ratio [OR], 1.7; P = 0.02) and a higher rate of nonrecovery to predonation levels (OR, 1.7; P = .01). Donors reporting comorbidities increased significantly with age, and those with comorbidities that would have led to deferral by National Marrow Donor Program unrelated donor standards had an increased risk for persistent grades 2 to 4 pain (OR, 2.41; P < .001) and failure to recover to predonation baseline for other symptoms (OR, 2.34; P = .004). This information should be used in counseling RDs regarding risk and can assist in developing practice approaches aimed at improving the RD experience for high-risk individuals.

The impact of donor characteristics on the invariant natural killer T cells of granulocyte-colony-stimulating factor-mobilized marrow grafts and peripheral blood grafts

INTRODUCTION

Invariant natural killer T cells (iNKTs) are a rare but vital subset of immunomodulatory T cells and play an important role in allogeneic hematopoietic stem cell trans-plantation (HSCT). The association of donor characteristics with the number and frequency of the iNKTs subsets in allografts remains poorly understood. In this paper, we prospectively investigate the association of donor characteristics with iNKTs dose and frequency in granulocyte-colony-stimulating factor (G-CSF) mobilized marrow and peripheral blood harvests.

MATERIALS AND METHODS

100 bone marrow (BM) units and 100 peripheral blood (PB) units from 100 healthy donors were examined. Parameters including donor age, sex, weight, height, BMI and blood count [including white blood cells (WBCs), lymphocytes and monocytes] at three time points [donor's steady state before G-CSF administration, the day of G-BM harvesting and the day of G-PB apheresis] were analyzed to explore the impact of donor characteristics on iNKTs composition in BM and PB grafts.

RESULTS

Multivariate analysis showed monocyte counts before G-BM harvest could predict higher frequency of iNKTs in WBC (OR = 2.593, 95%CI: 1.128-5.961, p = 0.025), higher total CD4+ iNKTs dose (OR = 2.250, 95%CI: 1.011-5.008, p = 0.047) and higher total iNKTs dose (OR = 2.662, 95%CI: 1.187-5.970, p = 0.017) in mixture allografts.

DISCUSSION

The results suggested that monocyte counts pre G-BM harvest could predict the yield of total CD4+ iNKTs and total iNKTs in mixture allografts. The male and older donors were associated with a higher dose of total CD4- iNKTs in mixture allografts.

Sixty as the new forty: considerations on older related stem cell donors

The era of reduced-intensity allogeneic stem cell transplantation, with its emphasis on older patients, has created new challenges in the management of what is now an older related stem cell donor population. These donors are now on average no less than 10 years older than in the mid-1990s. Donors over 70 years of age are no longer isolated or exceptional cases. They may still be considered eligible for donation but many of them, based on the older age and their medical history, may no longer fully qualify as 'healthy' or 'normal'. The older the donor, the more likely that hematologic abnormalities, comorbidities and treated malignancies will complicate the picture. Assessing the risk-benefit ratio for both donor and recipient can now be more challenging than ever.

Comparison of transplant outcomes from matched sibling bone marrow or peripheral blood stem cell and unrelated cord blood in patients 50 years or older

Older recipient and donor age were associated with higher incidences of severe graft-versus-host disease (GVHD) and mortality after allogeneic hematopoietic stem cell transplantation from matched sibling donors (MSDs) and matched unrelated donors. Since a lower incidence of severe GVHD is advantageous in unrelated cord blood transplantation (CBT), a higher incidence of GVHD using older MSDs could be overcome using cord blood for older patients. We retrospectively analyzed Japanese registration data of 2,091 patients with acute myeloid leukemia, acute lymphoblastic leukemia (ALL), and myelodysplastic syndrome aged 50 years or older who underwent MSD bone marrow transplantation (BMT) (n = 319), MSD peripheral blood stem cell transplantation (PBSCT) (n = 462), or unrelated CBT (n = 1,310) between 2007 and 2012. Median age of MSD was 56 (range, 38-74) years. Compared with CBT, the risk of developing extensive chronic GVHD was higher after BMT (hazard ratio [HR], 2.00; P = 0.001) or PBSCT (HR, 2.38; P < 0.001), and transplant-related mortality was lower after BMT (HR, 0.61; P < 0.001) or PBSCT (HR, 0.63; P < 0.001). Relapse rates were not significant difference between three groups. Although overall mortality was lower after BMT (HR, 0.67; P < 0.001) or PBSCT (HR, 0.75; P = 0.002) compared with CBT, the rates of a composite endpoint of GVHD-free, relapse-free survival (GRFS) were not significant difference between three groups. These data showed that MSDs remain the best donor source for older patients, but CBT led to similar GRFS to BMT and PBSCT.

Suitability Criteria for Adult Related Donors: A Consensus Statement from the Worldwide Network for Blood and Marrow Transplantation Standing Committee on Donor Issues

The number of allogeneic hematopoietic stem cell (HSC) transplants performed globally each year continues to increase. Advances in HLA typing, better supportive care, and administration of reduced-intensity conditioning regimens allow treatment of older patients with older sibling donors. Pretransplant donor assessment and testing are very important processes affecting the quality and safety of donation. For unrelated HSC donors detailed recommendations for health assessment have been published, allowing donation only if they are unrestrictedly healthy. Eligibility criteria for related donors are less strict and vary significantly between centers. In situations where a family donor does not meet the suitability criteria for unrelated donors, involved physicians often struggle with the decision whether the matched relative is suitable for donation or not. On behalf of the Worldwide Network for Blood and Marrow Transplantation Standing Committee on Donor Issues, we intended to develop a consensus document with recommendations for donor workup and final clearance of family donors who would not be able to serve as unrelated donors because of their age or pre-existing diseases. This article covers different topics intending to support decision-making, with the goal of minimizing medical risk to the donor and protection of the recipient from transmissible diseases.

The impact of donor characteristics on the immune cell composition of mixture allografts of granulocyte-colony-stimulating factor-mobilized marrow harvests and peripheral blood harvests

BACKGROUND

The association of donor characteristics with immune cell composition in allografts remains poorly understood. In this retrospective study, the effects of donor characteristics on immune cell composition in allografts were investigated.

STUDY DESIGN AND METHODS

The correlations of donor characteristics with the immune cell composition in mixture allografts of granulocyte-colony-stimulating factor-mobilized marrow harvests and peripheral blood harvests of 390 healthy donors (male, 240; female, 150; median age, 40 years old) were analyzed.

RESULTS

The median doses of CD3+ T cells, CD4+ T cells, CD8+ T cells, CD3+CD4-CD8- T cells, and monocytes in mixture allografts were 160.57 × 10(6), 89.29 × 10(6), 56.16 × 10(6), 10.87 × 10(6), and 137.94 × 10(6)/kg, respectively. Multivariate analysis showed that younger donor age was associated with a higher dose of CD3+ T cells (p = 0.006), CD3+CD8+ T cells (p < 0.001), CD3+CD4-CD8- T cells (p = 0.004), and monocytes (p = 0.014), as well as a higher ratio of CD3+CD4-CD8- T cells/CD3+ T cells (p < 0.001) in the mixture allografts. A negative association of donor weight with CD3+ T cells (p < 0.001), CD4+ T cells (p = 0.002), CD8+ T cells (p < 0.001), and CD3+CD4-CD8- T cells (p = 0.044) was observed. The count of peripheral blood lymphocyte pre-peripheral blood apheresis was correlated with the yield of CD3+ T cells (p < 0.001) and CD4+ T cells (p = 0.001). The peripheral blood monocyte count before marrow harvest predicted the monocyte dose (p = 0.002).

CONCLUSION

The results suggested that older and overweight donors should not be chosen. The monocyte and lymphocyte counts before harvest could predict the yield of immune cells in allografts.

Chronic wound repair and healing in older adults: current status and future research

Older adults are more likely to have chronic wounds than younger people, and the effect of chronic wounds on quality of life is particularly profound in this population. Wound healing slows with age, but the basic biology underlying chronic wounds and the influence of age-associated changes on wound healing are poorly understood. Most studies have used in vitro approaches and various animal models, but observed changes translate poorly to human healing conditions. The effect of age and accompanying multimorbidity on the effectiveness of existing and emerging treatment approaches for chronic wounds is also unknown, and older adults tend to be excluded from randomized clinical trials. Poorly defined outcomes and variables; lack of standardization in data collection; and variations in the definition, measurement, and treatment of wounds also hamper clinical studies. The Association of Specialty Professors, in conjunction with the National Institute on Aging and the Wound Healing Society, held a workshop, summarized in this article, to explore the current state of knowledge and research challenges, engage investigators across disciplines, and identify research questions to guide future study of age-associated changes in chronic wound healing.

Chronic wound repair and healing in older adults: current status and future research

The incidence of chronic wounds is increased among older adults, and the impact of chronic wounds on quality of life is particularly profound in this population. It is well established that wound healing slows with age. However, the basic biology underlying chronic wounds and the influence of age-associated changes on wound healing are poorly understood. Most studies have used in vitro approaches and various animal models, but observed changes translate poorly to human healing conditions. The impact of age and accompanying multi-morbidity on the effectiveness of existing and emerging treatment approaches for chronic wounds is also unknown, and older adults tend to be excluded from randomized clinical trials. Poorly defined outcomes and variables, lack of standardization in data collection, and variations in the definition, measurement, and treatment of wounds also hamper clinical studies. The Association of Specialty Professors, in conjunction with the National Institute on Aging and the Wound Healing Society, held a workshop, summarized in this paper, to explore the current state of knowledge and research challenges, engage investigators across disciplines, and identify key research questions to guide future study of age-associated changes in chronic wound healing.

Pegfilgrastim vs filgrastim in PBSC mobilization for autologous hematopoietic SCT: a systematic review and meta-analysis

Trial outcomes comparing cytokine agents for PBSC mobilization in autologous hematopoietic transplant patients have been controversial. We performed a systematic review and meta-analysis of evidence available on pegfilgrastim vs filgrastim in chemo-cytokine mobilization. Electronic literature searches of PubMed, EMBASE and CENTRAL identified nine articles eligible for qualitative analysis with one randomized controlled trial. Eight articles involving 719 patients were included in the meta-analysis. Results showed similar CD34+ cell collection yields for pegfilgrastim and filgrastim (SDM -0.08, 95% CI: -0.388 to 0.228). On comparison with filgrastim, pegfilgrastim showed a significantly earlier apheresis onset time (SDM: -0.512, 95% CI: -0.973 to -0.050) and reduction in required apheresis procedures (SDM -0.260, 95% CI: -0.466 to -0.054). Times to leukocyte (⩾1.0 × 10(9)/L) and platelet (⩾20 × 10(9)/L) recovery were similar between groups (SDM: 0.015, 95% CI: -0.41 to 0.44 and SDM: 0.309, 95% CI: -0.11 to 0.72, respectively). Both agents were well tolerated and mild bone pain was the most frequently reported adverse event. Pegfilgrastim may be a convenient alternative to filgrastim in PBSC mobilization for multiple myeloma and lymphoma patients, but further studies are required to clarify effects of cytokine dosage and previous cytotoxic exposure in specific subpopulations.

Race and ethnicity influences collection of granulocyte colony-stimulating factor-mobilized peripheral blood progenitor cells from unrelated donors, a Center for International Blood and Marrow Transplant Research analysis

Little information exists on the effect of race and ethnicity on collection of peripheral blood stem cells (PBSC) for allogeneic transplantation. We studied 10,776 donors from the National Marrow Donor Program who underwent PBSC collection from 2006 to 2012. Self-reported donor race/ethnic information included Caucasian, Hispanic, Black/African American (AA), Asian/Pacific Islander (API), and Native American (NA). All donors were mobilized with subcutaneous filgrastim at an approximate dose of 10 μg/kg/day for 5 days. Overall, AA donors had the highest median yields of mononuclear cells per liter and CD34(+) cells per liter of blood processed (3.1 × 10(9) and 44 × 10(6), respectively), whereas Caucasians had the lowest median yields at 2.8 × 10(9) and 33.7 × 10(6), respectively. Multivariate analysis of CD34(+) per liter mobilization yields using Caucasians as the comparator and controlling for age, gender, body mass index, and year of apheresis revealed increased yields in overweight and obese AA and API donors. In Hispanic donors, only male obese donors had higher CD34(+) per liter mobilization yields compared with Caucasian donors. No differences in CD34(+) per liter yields were seen between Caucasian and NA donors. Characterization of these differences may allow optimization of mobilization regimens to allow enhancement of mobilization yields without compromising donor safety.

Factors determining pbsc mobilization efficiency and nonmobilization following ICE with or without rituximab (R-ICE) salvage therapy for refractory or relapsed lymphoma prior to autologous transplantation

ICE/R-ICE (ifosfamide, carboplatin, and etoposide without or with rituximab) chemotherapy followed by autologous stem cell transplantation is an established regimen in refractory/relapsed lymphoma. Few studies have addressed which factors are important in determining peripheral blood stem cell (PBSC) mobilization efficiency or nonmobilization following ICE/R-ICE. Between 2004 and 2013, 88 patients with refractory/relapsed lymphoma who received ICE/R-ICE salvage-chemotherapy prior to granulocyte colony stimulating factor (G-CSF) stimulated PBSC mobilization at a single center were identified. Mobilization efficiency was assessed by time from ICE/R-ICE to day of harvest, duration of G-CSF use, days to peripheral blood (PB) CD34(+) ≥15/µL, PB CD34(+) number on harvest day, CD34(+) yield and nonmobilization rate. Median PB CD34(+) at harvest were 54/μL (7-524); median days to first apheresis was 15 (11-30); median harvested total CD34(+) were 5.46 × 10(6) /kg (0.96-44.36); 71 patients (80.7%) successfully mobilized; 20 (22.7%) patients were poor mobilizers; 14 (15.9%) patients were considered nonmobilizers with maximal PB CD34(+) <7/µL and did not proceed to apheresis. Six of 20 poor mobilizers were apheresed with PB CD34(+) 7-12/µL, 50% were successfully harvested. No differences were found between ICE and R-ICE regimens. Impaired mobilization efficiency was associated with age, remission status, >1 line of induction chemotherapy, four cycles ICE/R-ICE and grade 4 neutropenia. Prior bone marrow (BM) involvement was associated with nonmobilization. The majority of patients can be successfully mobilized with ICE/R-ICE. Prior BM involvement is associated with high rates of nonmobilization following ICE/R-ICE. Such patients may benefit from novel mobilization agents and/or alternative salvage regimens to ICE/R-ICE.

Older patients/older donors: choosing wisely

Two lingering problems regarding transplantation in older adults have been how to select patients appropriately and whether to use older sibling donors. Allogeneic hematopoietic cell transplantation (HCT) of older patients may result in long-term survival due to GVL, but the data remain observational and mostly restricted to those 50 to 69 years of age. Patients with excellent performance status and low comorbidity have the best long-term survival after HCT. Novel measures of health status such as self-report or performance-based functional measures allow “staging the age” and may inform candidacy for less robust patients. Older matched sibling donors should be preferred over matched unrelated donors (MUDs) because outcomes are equivalent to superior for matched sibling donors compared with MUD. However, MUDs also achieve acceptable outcomes and long-term disease control. An alternative donor can be considered based on institutional protocols and expertise. Very limited information is available in patients or related donors 70 years of age and older. Future efforts to more completely characterize patient health status before transplantation will allow better application of HCT in older adults.

G-CSF in Healthy Allogeneic Stem Cell Donors

Mobilization of peripheral blood stem cells (PBSC) in healthy volunteers with granulocyte colony-stimulating factor (G-CSF) is currently carried out at many institutions worldwide. This report presents the experience of the Dresden center regarding donor evaluation and mobilization schedule. Data regarding efficacy, short- and long-term safety of G-CSF treatment gained from 8290 PBSC collections in healthy donors are outlined. These results are discussed against the background of the available evidence from the literature. Although established as a standard procedure, G-CSF application to allogeneic donors will always be a very delicate procedure and requires the utmost commitment of all staff involved to ensure maximum donor safety.

Risk factors for a poor hematopoietic stem cell mobilization

Poor mobilization is an important problem in autologous stem cell transplantation. We retrospectively reviewed the data of 165 mobilized patients to identify possible risk factors for a poor stem cell mobilization. 27 patients (16.4%) were categorized as poorly mobilized. The poor mobilization ratio differed according to diagnosis (lymphoma: 25.4%, acute leukemia: 15.4%, amyloidosis: 14.3%, and multiple myeloma: 9.6%). Being diagnosed as lymphoma (odds ratio [OR]=6.02, p=0.001), advanced age (OR=1.05, p=0.007) and increased weight (OR=1.03, p=0.03) were found as possible risk factors. Being diagnosed as lymphoma was shown to be the most important risk factor for a poor mobilization. Leukapheresis staff should be aware of the increased risk of a poor mobilization in lymphoma patients and remobilization methods should be considered from the beginning.

Prospective cohort study of the circadian rhythm pattern in allogeneic sibling donors undergoing standard granulocyte colony-stimulating factor mobilization

Introduction

Prior in vivo murine studies suggest circadian oscillations for hematopoietic stem cell release, which are maintained following administration of granulocyte colony-stimulating factor (G-CSF) or plerixafor. Furthermore, retrospective data analysis of healthy donors who underwent G-CSF-induced mobilization demonstrated significantly increased CD34⁺ cell yields when collected in the afternoon compared with the morning.

Methods

A prospective study was conducted to directly examine the number of peripheral blood CD34⁺ and CD34⁺CD38^– progenitor/stem cells at baseline and then every 6 hours for 24 hours on days 4 to 5 of G-CSF (10 μg/kg/day in the morning) mobilization in 11 allogeneic donors. Data were analyzed using mixed-model analysis of repeated measures.

Results

Whereas we observed a significant increase in CD34⁺ cell counts toward the evening, counts were then sustained on the morning of day 5. The correlation between CD34⁺CD38^– cell counts and the less defined CD34⁺ populations was weak.

Conclusions

Our results suggest that the pharmacodynamic activity and timing of G-CSF may alter endogenous progenitor rhythms. Donor age, medical history, and medications may also impact circadian rhythm. Further studies should examine the circadian rhythm at the peak of G-CSF mobilization and should consider potential confounders such as the time of G-CSF administration and the age of the subjects.

Older patients/older donors: choosing wisely

Two lingering problems regarding transplantation in older adults have been how to select patients appropriately and whether to use older sibling donors. Allogeneic hematopoietic cell transplantation (HCT) of older patients may result in long-term survival due to GVL, but the data remain observational and mostly restricted to those 50 to 69 years of age. Patients with excellent performance status and low comorbidity have the best long-term survival after HCT. Novel measures of health status such as self-report or performance-based functional measures allow "staging the age" and may inform candidacy for less robust patients. Older matched sibling donors should be preferred over matched unrelated donors (MUDs) because outcomes are equivalent to superior for matched sibling donors compared with MUD. However, MUDs also achieve acceptable outcomes and long-term disease control. An alternative donor can be considered based on institutional protocols and expertise. Very limited information is available in patients or related donors 70 years of age and older. Future efforts to more completely characterize patient health status before transplantation will allow better application of HCT in older adults.

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.

Use of matched unrelated donors compared with matched related donors is associated with lower relapse and superior progression-free survival after reduced-intensity conditioning hematopoietic stem cell transplantation

As success of reduced-intensity conditioning (RIC) hematopoietic stem cell transplantation (HSCT) relies primarily on graft-versus-leukemia (GVL) activity, increased minor HLA disparity in unrelated compared to related donors could have a significant impact on transplant outcomes. To assess whether use of unrelated donors (URD) engenders more potent GVL in RIC HSCT compared to matched related donors (MRD), we retrospectively studied 433 consecutive T-replete 6/6 HLA matched URD (n = 246) and MRD (n = 187) RIC HSCT for hematologic malignancies at our institution. Diseases included: acute myelogenous leukemia (AML) (127), non-Hodgkin lymphoma (NHL) (71), chronic lymphocytic leukemia (CLL) (68), myelodysplastic syndrome (MDS) (64), Hodgkin disease (HD) (40), chronic myeloid leukemia (CML) (25), multiple myeloma (MM) (23), myeloproliferative disorder (MPD) (12), acute lymphoblastic leukemia (ALL) (7), and other leukemia (1). All received uniform fludarabine and intravenous busulfan conditioning, and GVHD prophylaxis with tacrolimus/mini-methroxate (mini-MTX) or tacrolimus/sirolimus ± mini-MTX. Unrelated donors were younger compared to MRD (median donor age: 33 years versus 52 years, P < .0001), and provided larger CD34(+) products (median CD34(+) cells infused: 8.7 × 10(6)/kg versus 7.5 × 10(6)/kg, P = .002). Distribution of diseases, disease risk, prior transplant, and cytomegalovirus (CMV) status was similar in both cohorts. Cumulative incidence of grade II-IV acute GVHD (at day +180), 2-year chronic GVHD, and 2-year nonrelapse mortality (NRM) were 20% versus 16%, 55% versus 50%, and 8% versus 6% in URD and MRD, respectively (P = NS). Cumulative incidence of relapse at 2 years was lower in URD, 52% versus 65% (P = .005). With median follow-up of 26.5 and 35.8 months, 2-year progression-free survival (PFS) was significantly better in unrelated donor transplants, 39.5% for URD, and 29% for MRD (P = .01). Overall survival (OS) at 2 years were 56% for URD versus 50% for MRD (P = .53). In multivariable analysis, URD was associated with a lower risk of relapse (hazard ratio [HR] 0.67, P = .002) and superior PFS (HR 0.69, P = .002). These results suggest that URD is associated with greater GVL activity than MRD, and could have practice changing impact on future donor selection in RIC HSCT.