Granulocyte-colony-stimulating factor (G-CSF)-primed allogeneic bone marrow: significantly less graft-versus-host disease and comparable engraftment to G-CSF-mobilized peripheral blood stem cells

Bone Marrow Quality Index: A Predictor of Acute Graft-versus-Host Disease in Hematopoietic Stem Cell Transplantation for Thalassemia

Bone marrow (BM) continues to be the preferred source of stem cells in allogenic transplantation for nonmalignant disorders. Granulocyte colony-stimulating factor (G-CSF)-primed BM is associated with low rates of acute graft-versus-host disease (aGVHD) and allows reduced collection volumes while ensuring speedy engraftment. However, variability in BM harvest quality is a concern. This study evaluated the utility of a novel indicator, the Bone Marrow Quality Index (BMQI), to predict aGVHD. We analyzed 184 consecutive first matched related donor bone marrow transplants for thalassemia using G-CSF-primed bone marrow over 6 years from March 2017 to April 2023 across 2 centers in India. BMQI was defined as the ratio of the G-CSF-primed BM WBC count to the peripheral blood WBC count within 24 hours of harvest. European Society for Blood and Marrow Transplantation criteria were used to grade aGVHD. The log-rank test was used to assess the impact of BMQI on aGVHD. The chi-square test was used to compare categorical data, and the Wilcoxon rank-sum test was used to compare the numerical data. A Cox proportional hazards model was used to investigate the association of BMQI vis-à-vis other factors on aGVHD. Of the 184 patients studied, 19 had a BMQI <.9, 18 had a BMQI between .9 and 1, and the remaining 147 had a BMQI >1. The rate of aGVHD grade II-IV was 37% in patients with a BMQI <.9 , 22% in those with BMQI .9 to 1, and 12% in those with BMQI >1 (P = .018). Patients with BMQI <.9 had a 3.1-fold greater chance (95% confidence interval [CI], .9 to 10.6) and those with BMQI .9 to 1 had a 2-fold greater chance (95% CI, .5 to 6.6) of developing aGVHD grade II-IV. BMQI was the significant predictor associated with aGVHD hazard (P = .014). BMQI appears to be the most relevant and controllable predictor of aGVHD. It is a novel, informative, and very simple indicator that could influence aGVHD prophylaxis decision making. Our indicator is accurately measurable, inexpensive, precise, and timely; furthermore, it does not involve any sophisticated equipment and thus may be widely applicable. Prior knowledge of poor BM quality may help intensify prophylaxis and monitoring for aGVHD, as well as trigger a review of collection procedures.

Allogeneic transplantation of bone marrow versus peripheral blood stem cells from HLA-identical relatives in patients with myelodysplastic syndromes and oligoblastic acute myeloid leukemia: a propensity score analysis of a nationwide database

Bone marrow (BM) and granulocyte colony-stimulating factor-mobilized peripheral blood stem cells (PBSC) are used as grafts from HLA-identical-related donors for adults with myelodysplastic syndrome (MDS). To assess the impact of graft sources on post-transplant outcomes in MDS patients, we conducted a retrospective analysis of a nationwide database. A total of 247 and 280 patients underwent transplantation with BM and PBSC, respectively. The inverse probability of treatment weighting (IPTW) methods revealed that overall survival (OS) was comparable between BM and PBSC (P = .129), but PBSC transplantation was associated with worse graft-versus-host disease (GVHD)-free/relapse-free survival (GRFS) (hazard rate [HR], 1.24; 95% confidence intervals [CIs], 1.00-1.53; P = 0.049) and chronic GVHD-free and relapse-free survival (CRFS) (HR, 1.29; 95% CIs, 1.13-1.73; P = 0.002) than BM transplantation. In the propensity score matched cohort (BM, n = 216; PBSC, n = 216), no significant differences were observed in OS and relapse; 3-year OS rates were 64.7% and 60.0% (P = 0.107), while 3-year relapse rates were 27.1% and 23.5% (P = 0.255) in BM and PBSC, respectively. Three-year GRFS rates (36.6% vs. 29.2%; P = 0.006), CRFS rate (37.7% vs. 32.5%; P = 0.003), and non-relapse mortality rates (13.9% vs. 21.1%; P = 0.020) were better in BM than in PBSC. The present study showed that BM transplantation provides a comparable survival benefit with PBSC transplantation and did not identify an enhanced graft-versus-MDS effect to reduce the incidence of relapse in PBSC transplantation.

Decoding lymphomyeloid divergence and immune hyporesponsiveness in G-CSF-primed human bone marrow by single-cell RNA-seq

Granulocyte colony-stimulating factor (G-CSF) has been widely used to mobilize bone marrow hematopoietic stem/progenitor cells for transplantation in the treatment of hematological malignancies for decades. Additionally, G-CSF is also accepted as an essential mediator in immune regulation, leading to reduced graft-versus-host disease following transplantation. Despite the important clinical roles of G-CSF, a comprehensive, unbiased, and high-resolution survey into the cellular and molecular ecosystem of the human G-CSF-primed bone marrow (G-BM) is lacking so far. Here, we employed single-cell RNA sequencing to profile hematopoietic cells in human bone marrow from two healthy donors before and after 5-day G-CSF administration. Through unbiased bioinformatics analysis, our data systematically showed the alterations in the transcriptional landscape of hematopoietic cells in G-BM, and revealed that G-CSF-induced myeloid-biased differentiation initiated from the stage of lymphoid-primed multipotent progenitors. We also illustrated the cellular and molecular basis of hyporesponsiveness of T cells and natural killer (NK) cells caused by G-CSF stimulation, including the potential direct mechanisms and indirect regulations mediated by ligand–receptor interactions. Taken together, our data extend the understanding of lymphomyeloid divergence and potential mechanisms involved in hyporesponsiveness of T and NK cells in human G-BM, which might provide basis for optimization of stem cell transplantation in hematological malignancy treatment.

Special issues related to the diagnosis and management of acquired aplastic anemia in countries with restricted resources, a report on behalf of the Eastern Mediterranean blood and marrow transplantation (EMBMT) group and severe aplastic anemia working party of the European Society for blood and marrow transplantation (SAAWP of EBMT)

Aplastic anemia is a relatively rare but potentially fatal disorder, with a reported higher incidence in developing countries in comparison to the West. There are significant variations in epidemiological as well as etiological factors of bone marrow failure syndromes in the developing countries in comparison to the developed world. Furthermore, the management of bone marrow failure syndromes in resource constraint settings has significant challenges including delayed diagnosis and referral, limited accessibility to healthcare facilities, treatment modalities as well as limitations related to patients who require allogeneic stem cell transplantation. Here we will provide a review of the available evidence related to specific issues of aplastic anemia in the developing countries and we summarize suggested recommendations from the Eastern Mediterranean blood and bone marrow transplantation (EMBMT) group and the severe aplastic anemia working party of the European Society of blood and marrow transplantation (SAAWP of EBMT) related to the diagnosis and therapeutic options in countries with restricted resources.

G-CSF treatment of healthy pediatric donors affects their hematopoietic microenvironment through changes in bone marrow plasma cytokines and stromal cells

Although G-CSF mobilized peripheral blood stem cell (PBSC) transplantation is commonly used in adults, bone marrow (BM) is still the preferred stem cell source in pediatric stem cell transplantation. Despite the fact that G-CSF is increasingly being used to enhance the hematopoietic stem/progenitor cell (HSPC) yield in BM transplantation (G-BM), the direct effects of G-CSF on the pediatric BM microenvironment have never been investigated. The BM hematopoietic niche provides the physical space where the HSPCs reside. This BM niche regulates HSPC quiescence and proliferation through direct interactions with other niche cells, including Mesenchymal Stromal Cells (MSCs). These cells have been shown to secrete a wide range of hematopoietic cytokines (CKs) and growth factors (GFs) involved in differentiation, retention and homing of hematopoietic cells. Here, we assessed changes in the BM microenvironment by measuring levels of 48 different CKs and GFs in G-BM and control BM (C-BM) plasma from pediatric donors. In addition, the effect of G-CSF on cell numbers and characteristics of HSPCs and MSCs was assessed. IL-16, SCGF-b, MIP-1b (all >1000 pg/mL) and RANTES (>10.000 pg/mL) were highly expressed in healthy donor pediatric BM plasma. Levels of IL-3, IL-18, GROa, MCP-3 (p<0.05) were increased in G-BM, whereas levels of RANTES (p<0.001) decreased after G-CSF treatment. We found a negative correlation with increasing age for IL2-Ra and LIF (p<0.05). In addition, a concomitant increase in the number of both hematopoietic and fibroblast colony forming units was observed, indicating that G-CSF affects both HSPC and MSC numbers. In conclusion, G-CSF treatment of healthy pediatric donors affects the hematopoietic BM microenvironment by expansion of HSPC and MSC numbers and modifying local CK and GF levels.

Decision Analysis of Transplantation for Patients with Myelodysplasia: "Who Should We Transplant Today?"

PURPOSE OF REVIEW

Myelodysplastic syndrome (MDS) is a heterogeneous hematological disorder characterized by a spectrum of clinical presentation, cytogenetic, and somatic gene mutations and the risk of transformation to acute leukemia. Management options include observation, supportive care, blood transfusion, administration of growth factors and/or hypomethylating agents, and hematopoietic cell transplant (HCT) either upfront or after disease progression.

RECENT FINDINGS

Currently, HCT is the only curative therapy available for patients with MDS, with multiple factors such as donor availability, patient, and disease characteristics being involved in making the decision to proceed with transplant. In this article, we summarize (1) overall prognosis and natural history of MDS, (2) currently available non-HCT therapy with a focus on hypomethylating agents (HMA), (3) outcomes after HCT in patients with MDS, (4) factors to be considered to proceed to HCT for treatment of MDS, and (5) more recent/ongoing studies relevant to HCT decision-making processes.

Haploidentical- versus identical-sibling transplant for high-risk pediatric AML: A multi-center study

Background

Human leukocyte antigen‐identical sibling donor (ISD)‐hematopoietic stem cell transplantation (SCT) is a potentially curative treatment for high‐risk pediatric acute myeloid leukemia (AML). A haploidentical donor (HID) is readily available to almost all children. Previous studies have demonstrated that patients with HID‐SCT had similar outcomes compared to ISD‐SCT for pediatric and adult AML. However, the role of HID‐SCT in high‐risk pediatric AML is unclear.

Methods

To compare the overall survival of high‐risk AML children who underwent either HID‐SCT or ISD‐SCT, we analyzed 179 cases of high‐risk AML patients under 18 years of age treated with either ISD‐SCT (n = 23) or HID‐SCT (n = 156). Granulocyte colony‐stimulating factor plus anti‐thymocyte globulin‐based regimens were used for HID‐SCT. We also analyzed the subgroup data of AML patients at first complete remission (CR1) before SCT with known cytogenetic risk.

Results

The numbers of adverse cytogenetic risk recipients were 8 (34.8%) and 13 (18.8%) in the ISD‐SCT group and the HID‐SCT group, and the number of patients with disease status beyond CR1 were 6 (26.1%) and 14 (20.3%) in the two groups. The cumulative rates of grades II‐IV acute graft‐versus‐host disease (GVHD) were 13.0% in the ISD‐SCT group and 34.8% in the HID‐SCT group (P = 0.062), with a three‐year cumulative rates of chronic GVHD at 14.1% and 34.9%, respectively (P = 0.091). The relapse rate in the ISD‐SCT group was significantly higher than that in the HID‐SCT group (39.1% vs. 16.4%, P = 0.027); with non‐relapse mortality at 0.0% and 10.6% (P = 0.113), respectively. The three‐year overall survival rates were 73.0% for the ISD‐SCT group and 74.6% for the HID‐SCT group (P = 0.689). In subgroup analysis, the three‐year relapse rate in the ISD‐SCT group was higher than that in the HID‐SCT group (50.0% vs. 9.2%, P = 0.001) and the three‐year DFS in the ISD‐SCT group (50.0%) was lower than that in the HID‐SCT group (81.2%) (P = 0.021).

Conclusions

Unmanipulated HID‐SCT achieved DFS and OS outcomes comparable to those of ISD‐SCT for high‐risk pediatric AML patients with potentially higher rate but manageable GVHD.

Key Aspects of the Immunobiology of Haploidentical Hematopoietic Cell Transplantation

Hematopoietic stem cell transplantation from a haploidentical donor is increasingly used and has become a standard donor option for patients lacking an appropriately matched sibling or unrelated donor. Historically, prohibitive immunological barriers resulting from the high degree of HLA-mismatch included graft-vs.-host disease (GVHD) and graft failure. These were overcome with increasingly sophisticated strategies to manipulate the sensitive balance between donor and recipient immune cells. Three different approaches are currently in clinical use: (a) ex vivo T-cell depletion resulting in grafts with defined immune cell content (b) extensive immunosuppression with a T-cell replete graft consisting of G-CSF primed bone marrow and PBSC (GIAC) (c) T-cell replete grafts with post-transplant cyclophosphamide (PTCy). Intriguing studies have recently elucidated the immunologic mechanisms by which PTCy prevents GVHD. Each approach uniquely affects post-transplant immune reconstitution which is critical for the control of post-transplant infections and relapse. NK-cells play a key role in haplo-HCT since they do not mediate GVHD but can successfully mediate a graft-vs.-leukemia effect. This effect is in part regulated by KIR receptors that inhibit NK cell cytotoxic function when binding to the appropriate HLA-class I ligands. In the context of an HLA-class I mismatch in haplo-HCT, lack of inhibition can contribute to NK-cell alloreactivity leading to enhanced anti-leukemic effect. Emerging work reveals immune evasion phenomena such as copy-neutral loss of heterozygosity of the incompatible HLA alleles as one of the major mechanisms of relapse. Relapse and infectious complications remain the leading causes impacting overall survival and are central to scientific advances seeking to improve haplo-HCT. Given that haploidentical donors can typically be readily approached to collect additional stem- or immune cells for the recipient, haplo-HCT represents a unique platform for cell- and immune-based therapies aimed at further reducing relapse and infections. The rapid advancements in our understanding of the immunobiology of haplo-HCT are therefore poised to lead to iterative innovations resulting in further improvement of outcomes with this compelling transplant modality.

G-CSF-Mobilized Blood and Bone Marrow Grafts as the Source of Stem Cells for HLA-Identical Sibling Transplantation in Patients with Thalassemia Major

As an inherited anemia, thalassemia major (TM) is currently only curable with allogeneic hematopoietic stem cell transplantation (allo-HSCT). Here we report an allo-HSCT protocol for patients with TM who received a combination of granulocyte colony-stimulating factor-primed bone marrow and peripheral blood stem cells (G-BM & PBSCs) from a matched sibling donor (MSD). The conditioning regimen consisted of i.v. busulfan, cyclophosphamide, fludarabine, and antithymocyte globulin. Chimerism analysis was performed for all patients. Immunosuppressive treatment was terminated if rejection was suspected, and donor lymphocyte infusion was administered once no response was observed. A total of 184 patients with TM were enrolled in the study between July 2007 and July 2018. The cumulative incidence of grade II-IV acute graft-versus-host disease (GVHD) was 13.1%, and that of moderate or severe chronic GVHD was 5.7%. The cumulative incidence of graft rejection was .6%. In the total cohort, the 3-year overall survival, thalassemia-free survival, and GVHD-free, relapse-free survival were 97.8%, 97.3%, and 89.5%, respectively. Collectively, our results indicate that G-BM & PBSCs from an MSD is be a good stem cell source for patients with TM undergoing allo-HSCT.

Comparable Outcome with a Faster Engraftment of Optimized Haploidentical Hematopoietic Stem Cell Transplantation Compared with Transplantations from Other Donor Types in Pediatric Acquired Aplastic Anemia

Haploidentical family donors have been used as an alternative source in hematopoietic cell transplantation for patients with severe aplastic anemia. We evaluated and compared the outcomes of transplantation in pediatric acquired severe aplastic anemia based on donor type. Sixty-seven patients who underwent transplantation between 1998 and 2017 were included. Fourteen patients received grafts from matched sibling donors, 21 from suitable unrelated donors, and 32 from haploidentical family donors. Ex vivo CD3⁺ or αβ⁺ T cell-depleted grafts were used for haploidentical transplantation. Sixty-five patients (97.0%) achieved neutrophil engraftment at a median of 11 days. Haploidentical transplantation resulted in significantly faster neutrophil engraftment at a median of 10 days, compared with 14 days in cases of matched sibling donors and 12 days in cases of unrelated donor recipients. Nine patients experienced graft failure, and 5 of 7 who underwent a second transplantation are alive. There was no difference in the incidence of acute or chronic graft-versus-host disease based on donor type. The 5-year overall survival and failure-free survival rates were 93.8% ± 3.0% and 83.3% ± 4.6%, respectively, and there was no significant survival difference based on donor type. The survival outcomes of haploidentical transplantation in patients were comparable with those of matched sibling or unrelated donor transplantation. Optimized haploidentical transplantation using selective T cell depletion and conditioning regimens including low-dose total body irradiation for enhancing engraftment may be a realistic therapeutic option for pediatric patients with severe aplastic anemia.

Comparable Outcomes of Allogeneic Peripheral Blood versus Bone Marrow Hematopoietic Stem Cell Transplantation in Major Thalassemia: A Multivariate Long-Term Cohort Analysis

Allogeneic hematopoietic stem cell transplantation (HSCT) currently is the only available curative option for transfusion-dependent thalassemia. Peripheral blood is a more convenient source for HSCT in comparison with bone marrow. Information about the relative success of transplantation with these 2 graft sources would help physicians and patients choose between them. The aim of this study was to evaluate the pros and cons of using peripheral blood instead of bone marrow as the graft source in thalassemia transplantation. We analyzed the transplant results of 567 transfusion-dependent thalassemia patients who received a transplant between 1998 and 2015 considering their stem cell source as a comparative variable. In multivariate Cox analysis the survival advantage for bone marrow compared with peripheral blood was not significant after adjusting for sex, age, and hepatic fibrosis presence. Rejection incidence was significantly lower in patients who used peripheral blood as their graft source. Acute and chronic graft-versus-host disease were more frequent in peripheral blood transplants, but the difference was not statistically significant. This study shows that peripheral blood could be an alternative stem cell source in patients undergoing allogeneic HSCT for thalassemia.

Effect of the in vivo application of granulocyte colony-stimulating factor on NK cells in bone marrow and peripheral blood

Granulocyte colony‐stimulating factor (G‐CSF) has been widely used in the field of allogeneic haematopoietic stem cell transplantation (allo‐HSCT) for priming donor stem cells from the bone marrow (BM) to peripheral blood (PB) to collect stem cells more conveniently. Donor‐derived natural killer (NK) cells have important antitumour functions and immune regulatory roles post‐allo‐HSCT. The aim of this study was to evaluate the effect of G‐CSF on donors' NK cells in BM and PB. The percentage of NK cells among nuclear cells and lymphocyte was significantly decreased and led to increased ratio of T and NK cells in BM and PB post‐G‐CSF in vivo application. Relative expansion of CD56^briNK cells led to a decreased ratio of CD56^dim and CD56^briNK subsets in BM and PB post‐G‐CSF in vivo application. The expression of CD62L, CD54, CD94, NKP30 and CXCR4 on NK cells was significantly increased in PB after G‐CSF treatment. G‐CSF treatment decreased the IFN‐γ‐secreting NK population (NK1) dramatically in BM and PB, but increased the IL‐13‐secreting NK (NK2), TGF‐β‐secreting NK (NK3) and IL‐10‐secreting NK (NKr) populations significantly in BM. Clinical data demonstrated that higher doses of NK1 infused into the allograft correlated with an increased incidence of chronic graft‐vs‐host disease post‐transplantation. Taken together, our results show that the in vivo application of G‐CSF can modulate NK subpopulations, leading to an increased ratio of T and NK cells and decreased ratio of CD56^dim and CD56^briNK cells as well as decreased NK1 populations in both PB and BM.

Network geometry of evidence from randomised controlled trials addressing donor selection and source of haematopoietic progenitor cells used in allogeneic transplantation: a systematic scoping review

BACKGROUND AND METHODS

A scoping review of randomised controlled trials (RCTs) addressing source of cells and choice of donor for allogeneic haematopoietic cell transplantation (HCT) was performed to create a network of best evidence that allows us to identify new potential indirect comparisons for the strategic development of future studies that connect to the existing evidence network.

RESULTS

A total of 19 eligible RCTs (2589 total patients) were identified. Nine studies (1566 patients) compared clinical outcomes following the use of peripheral blood progenitor cells (PBPCs) with bone marrow (BM) from matched related donors (eight studies) or matched unrelated donors (one study). The remaining studies compared BM or PBPCs with various methods of BM stimulation or manipulation (six studies), compared different methods of surface molecule-based selection and/or depletion of grafts (two studies) or compared the optimal number of units for paediatric cord blood transplantation (two studies). No published RCTs compared different types of donors. The geometry of the evidence network was analysed to identify opportunities for potential novel indirect comparisons and to identify opportunities to expand the network. Few indirect comparisons are currently feasible due to small sample size and heterogeneity in patient diagnoses and demographics between treatment nodes in the network.

CONCLUSION

More RCTs that enrol greater numbers of similar patients are needed to leverage the current evidence network concerning donor choice and source of cells used in allogeneic HCT.

Two versus three day upfront use of granulocyte-colony stimulating factor in healthy bone marrow donors for pediatric bone marrow transplantation

In order to decrease donors' exposure to granulocyte-colony stimulating factor (G-CSF), we compared the effect of two versus three days of G-CSF priming on CD34+ yield in bone marrow (BM) harvest. Although the number of BM-CD34+ cells was higher in 3day G-CSF priming, we achieved the same number of CD34+ cells per recipient's weight in 2day G-CSF priming group, too. In addition, the number of total nucleated cells (TNC) harvested from BM were similar with two or three day regimen. But mononuclear cells (MNC) of the BM graft was higher in the 3day G-CSF priming group. Similar to CD34+ cell numbers, BM harvest yielded similar TNC, and MNC numbers per kilogram of the recipient. We also found that, young donors (≤10year) had more peripheral blood MNC, bone marrow MNC and CD34+ cell numbers. Another interesting finding of this study was obtaining adequate number of peripheral blood stem cells for leukapheresis with three day G-CSF administration. Since engrafment times were also similar in two groups, we concluded that 2-days G-CSF priming was resulted in sufficient mobilization of BM stem cells.

Differential T cell subsets and cytokine profile between steady-state and G-CSF-primed bone marrow and its association with graft-versus-host disease

Graft-versus-host disease (GVHD) is a major complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT). At our Institution, patients transplanted using G-CSF-primed bone marrow (G-BM), have a lower incidence of GVHD when compared to other sources. The objective of this study was to analyze and compare T cell subsets and cytokines in donor G-BM and steady-state BM (SS-BM). A prospective study was performed in 48 donor samples. Mononuclear cells were isolated by gradient density. T cell subsets and cytokine production in supernatants were analyzed by multiparametric flow cytometry. Six and 16 patients developed acute and chronic GVHD, respectively. Patients who developed GVHD were characterized by a predominant pro-inflammatory response (IL-17A (10.02 vs 0.43pg/mL, p=0.006), TNF-α (54.57 vs 0.81pg/mL, p=0.001)), in contrast to a deficient suppressor profile (IL-10 (7.87 vs 41.37pg/mL, p=0.003)) and Tregs (0.95% vs 1.52%, p=0.004). G-BM showed an enhanced suppressive phenotype (increased Th2 and Tregs) in comparison to SS-BM. GVHD is associated with an imbalance between pro-inflammatory and suppressor immune responses. G-BM showed a more favorable immunologic profile characterized by diminished pro-inflammatory cytokine production, which was associated with a lower frequency of GVHD in our cohort.

Outcomes of Unrelated Donor Stem Cell Transplantion with Post-Transplant Cyclophosphamide for Graft-versus-Host Disease Prophylaxis in Patients with Severe Sickle Cell Disease

Unrelated donor (URD) hematopoietic cell transplantation (HCT) in children with sickle cell disease (SCD) is associated with a high incidence of rejection and graft-versus-host disease (GVHD). We report on the first 4 patients with severe SCD who underwent URD HCT using a novel myeloablative and immunosuppressive regimen composed of busulfan, fludarabine, and antithymocyte globulin with a single dose of post-transplant cyclophosphamide along with tacrolimus and mycophenolate mofetil for GVHD prophylaxis. Three patients engrafted and remain disease-free after a median follow-up period of 2.5 years. One patient had primary graft failure attributed to low stem cell content of the graft. Of interest, none of the engrafted patients developed acute or chronic GVHD. This preparative regimen along with the use of post-transplant cyclophosphamide offers a promising approach for unrelated donor transplants in patients with SCD and needs further corroboration in larger number of patients.

Prospective observational study on the first 51 cases of peripheral blood stem cell transplantation from unrelated donors in Japan

The Japan Marrow Donor Program (JMDP) has facilitated unrelated peripheral blood stem cell transplantation (URPBSCT) since 2010. We conducted a prospective multicenter observational study to evaluate the feasibility of such transplantation. Between 2011 and 2014, 51 patients underwent URPBSCT from 8/8 allele-matched donors for hematological malignancies. The median age of the patients was 50 years; 21 had high-risk disease. Myeloablative conditioning regimens were used in 31 patients, and tacrolimus based graft-versus-host disease (GVHD) prophylaxis was used for all patients. The cumulative rate of engraftment was 96%. With a median follow-up period of 610 days for survivors, 100-day and 1-year overall survival rates were 86 and 59%, respectively. The cumulative incidence of non-relapse mortality and relapse at 1 year were 14 and 35%, respectively. The incidence of grade II to IV acute GVHD at 100 days and extensive type of chronic GVHD at 1 year were 25 and 32%, respectively. The probability of overall survival was comparable with that of bone marrow transplantation from HLA matched-unrelated donors in Japan, although the incidence of chronic GVHD was higher. Further follow-up with more patients is clearly warranted to establish the optimal use of URPBSCT together with the approaches of minimizing chronic GVHD.

Interleukin-6 Inhibition in Inflammatory Diseases: Results Achieved and Tasks to Accomplish

Interleukin-6 (IL-6) is a prototypical cytokine featuring functional pleiotropy and redundancy. Under situations of stress, such as infection or tissue injury, IL-6 is rapidly synthesized and plays a major role in host defense. However, uncontrolled excessive or persistent production of IL-6 has a pathological effect in various diseases. Thus, IL-6 blockade was expected to become a novel therapeutic strategy for IL-6–mediated inflammatory diseases, and the first-in-class IL-6 inhibitor tocilizumab, which blocks IL-6 activity by inhibiting IL-6 binding to its receptor, was developed. Clinical trials of tocilizumab have verified its efficacy and tolerable safety profile in several diseases, and it has been approved for the treatment of patients with rheumatoid arthritis, Castleman's disease, systemic and polyarticular juvenile idiopathic arthritis, and giant cell arteritis. Off-label use and clinical trials strongly indicate that tocilizumab will be applicable for a wide variety of acute and chronic inflammatory diseases.

Superior GVHD-free, relapse-free survival for G-BM to G-PBSC grafts is associated with higher MDSCs content in allografting for patients with acute leukemia

Background

Granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood stem cells (G-PBSC) has largely replaced unstimulated bone marrow (un-BM) for allografting because of accelerated engraftment, but with a higher morbidity and mortality of graft-versus-host-disease (GVHD). Recent studies suggested that G-CSF-primed BM (G-BM) had similar engraftment but lower morbidity and mortality of GVHD comparing to G-PBSC. A prospective, randomized, multicenter study was conducted to compare G-BM with G-PBSC as the grafts in allogeneic hematopoietic stem cell transplantation (allo-HSCT) for acute leukemia in first complete remission (CR1).

Methods

Totally 101 adult leukemia in CR1 undergoing HLA-identical sibling transplants were randomized into G-BM or G-PBSC group. The primary study endpoint was GVHD-free/relapse-free survival (GRFS).

Results

Both the engraftment of neutrophil and platelet were 2 days later in G-BM than in G-PBSC group (P = 0.412, P = 0.39). G-BM group showed significantly lower II–IV acute GVHD (aGVHD) and similar III–IV aGVHD compared with G-PBSC group (12.2% vs 28.8% for II–IV, P = 0.048; 4.1% vs 9.6% for III–IV aGVHD, P = 0.267, respectively). The overall cumulative incidence of chronic GVHD (cGVHD) at 3 years were 22.3% ± 6.3% and 44.8% ± 7.6% (P = 0.026), respectively, and extensive cGHVD were 4.5% ± 3.1% and 15% ± 5.3% (P = 0.08), respectively, in G-BM and G-PBSC groups. Two groups had similar 3-year relapse, transplant-related mortality (TRM), overall survival (OS), and disease-free survival (DFS) (all P > 0.05). G-BM group showed significantly higher probability of GRFS than G-PBSC group (73.5% ± 6.3% vs 55.8% ± 6.9% at 1 year, P = 0.049; 69.0% ± 6.7% vs 49.7% ± 7.0% at 2 and 3 years, P = 0.03, respectively). Graft content analysis revealed statistically higher frequency of myeloid-derived suppressor cells (MDSCs) in the G-BM than in G-PBSC grafts (P < 0.01), and recipients received statistically higher numbers of MDSCs in G-BM than in G-PBSC group (P = 0.045). Numbers of MDSCs infused to patients were negatively correlated with the severity of aGVHD (P = 0.032, r = −0.214). Multivariate analysis showed that MDSC cell dose below the median (HR = 3.49, P < 0.001), recipient age (HR = 2.02, P = 0.039), and high risk of disease (HR = 2.14, P = 0.018) were independent risk factors for GRFS.

Conclusions

G-BM grafts lead a better GRFS and less GVHD associated with a higher MDSCs content compared with G-PBSC grafts.

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.

Higher dose of CD34+ peripheral blood stem cells is associated with better survival after haploidentical stem cell transplantation in pediatric patients

Haploidentical stem cell transplantation (SCT) is increasingly used to treat pediatric patients with malignant or nonmalignant hematological disorders. The CD34+ dose of bone marrow or peripheral blood stem cells (PBSCs) has been shown to be an important determinant of the transplant outcome in adults under various preparative regimens. However, knowledge of the effect of the CD34+ dose in pediatric haploidentical SCT is limited. We analyzed the data of 348 pediatric patients (aged 2-18 years) with acute or chronic leukemia, myelodysplastic syndrome (MDS), and other hematological disorders that received a transplant between 2002 and 2012. The results of multivariate analysis showed that PBSC CD34+ counts greater than 1.01 × 10⁶  kg^-1 improved platelet engraftment, improved overall survival, and reduced nonrelapse mortality. In contrast, a higher PBSC CD34+ dose did not affect the incidence of acute or chronic graft-versus-host disease, including engraftment syndrome. These data suggest that a PBSC CD34+ dose greater than 1.01 × 10⁶  kg^-1 is optimal for pediatric haploidentical SCT.

Matched unrelated donor transplants-State of the art in the 21st century

Hematopoietic stem cell transplantation (HSCT) is the therapy of choice in many hematological malignant and non-malignant diseases by using human leukocyte antigen (HLA)-matched siblings as stem cell source but only one third of the patients will have HLA-matched siblings. Hence, physicians rely on the availability of matched unrelated donors (URD). The possibility of finding a matched URD is now more than 70% due to continuous expansion of URD registries around the world. The use of URD in adult patients is steadily increasing and in the last 8 years has superseded the numbers of matched sibling donor transplants and has become the most commonly used stem cell source. There is also an increasing trend to use peripheral blood (PB) stem cells rather than bone marrow (BM) stem cells. Outcomes following URD transplants depend mainly upon the indication and urgency of transplant, age and comorbidities of recipients, cytomegalovirus (CMV) matching/mismatching between donor and the recipient, and degree of HLA matching. In some studies outcome of unrelated stem cell transplants in terms of treatment-related mortality (TRM), disease-free survival (DFS), and overall survival (OS) is comparable to sibling donors.

Risk Factors and Outcome of Chronic Graft-versus-Host Disease after Allogeneic Stem Cell Transplantation-Results from a Single-Center Observational Study

Chronic graft versus host disease (cGVHD) is the most frequent long-term complication after allogeneic stem cell transplantation (allo-SCT) and results in impaired quality of life and increased long-term morbidity and mortality. We analyzed 243 patients with cGVHD, documented according to the 2005 revised National Institutes of Health consensus criteria, to identify risk factors for the occurrence of cGVHD and outcomes for the patients with cGVHD. Patients without evidence of cGVHD (n = 147) were used as controls. Performing univariate and multivariate Cox regression analyses, we identified prior acute GVHD grades III or IV (hazard ratio [HR], 2.01; P = .005), use of peripheral blood stem cell graft (HR, 2.10; P = .03), and HLA-mismatched allo-SCT from unrelated donor (HR, 1.57; P = .02) as independent risk factors for cGVHD. Performing Kaplan-Meier analyses, progressive compared with de novo and quiescent onset of cGVHD and a platelet count of less than 100/nL compared with more than 100/nL at the time of cGVHD onset were associated with a significantly increased cumulative incidence of transplantation-related mortality (TRM) and significantly decreased overall survival. Furthermore, we found a significantly higher incidence of TRM in patients with severe cGVHD compared with patients without cGVHD (58% versus 11%, P < .0001). However, in subgroup analysis, patients with severe cGVHD and involvement of the lung, liver, or gastrointestinal (GI) tract had a 6.5-fold significantly higher incidence of TRM (72%), whereas patients with severe cGVHD lacking lung, liver, or GI involvement had only a 2.8-fold significantly higher incidence of TRM (31%) compared with patients without cGVHD (11%; P < .0001 and P = .03). Patients without lung, liver, or GI involvement did not have a significantly different TRM compared with patients with moderate cGVHD (31% versus 25%, P = .52). In conclusion, we confirm prior known risk factors for the occurrence of cGVHD and subsequent mortality and we provide evidence that the presence of lung, liver, or GI involvement in patients with severe cGVHD defines a subgroup with high mortality after allo-SCT; however, in the absence of these risk factors, the outcome appears not to be impaired compared with moderate cGVHD.

Haploidentical hematopoietic stem cell transplantation for paediatric high-risk T-cell acute lymphoblastic leukaemia

Paediatric HR T-cell ALL demonstrates dismal prognosis with chemotherapy, and poor outcomes could be improved with allo-SCT. HID-SCT is an almost immediately available choice; however, few studies have focused on the outcomes of HID-SCT for paediatric HR T-ALL. Forty-eight consecutive HR T-ALL children who underwent HID-SCT were included. Survival outcomes and factors predictive of outcomes were retrospectively analysed. Of the 48 patients, 35 were in CR1, 10 in CR2, and three in relapse. The cumulative incidence of grade 3/4 aGVHD was 10.4% and that of extensive cGVHD was 28.4%. The CIR at three yr was 30.8% and that of NRM at three yr was 14.7%. At a median follow-up of 20.0 (range 2.5-124.2) months, the three-yr LFS was 54.4%. Children who received transplants during CR1 had a better LFS (65.7% vs. 26.0%, p = 0.008) and a lower relapse rate (19.8% vs. 56.7%, p = 0.014) compared to those during non-CR1. HID-SCT is feasible for HR T-ALL children, and survival outcomes are better when performed in CR1 compared to non-CR1. Prospective clinical trials would be needed to confirm that.

Haploidentical hematopoietic stem cell transplantation with post-transplant high-dose cyclophosphamide in high-risk children: A single-center study

Recently, haploidentical transplantations have been performed with unmanipulated BM or PBSC. This approach is becoming more widely adopted with the use of PTCY. However, there is limited evidence about this approach in children. We present 15 children who received 16 haploidentical HSCT with unmanipulated BM or PBSC using PTCY for GVHD prophylaxis. Post-transplant CY(50 mg/kg IV) was given on the third and fifth day, and CsA or tacrolimus with MMF or MP was also used for GVHD prophylaxis. All patients engrafted at a median of 16 and 18 days for neutrophil and thrombocyte recovery, respectively. Grades II-III acute GVHD developed in seven patients, and mild chronic GVHD was found in two patients. Two patients died within the first 100 days due to sepsis (TRM 12.5%). Eleven patients are currently alive, with a median follow-up of 12 months (range 6-22 months). The 12-month OS and DFS were 75 ± 10.8% and 68.8 ± 11.6%, respectively. Our results with these high-risk patients are encouraging for haploidentical HSCT in pediatric patients. Future studies should continue to assess haploidentical HSCT, including comparison of other modalities, in a primary pediatric population.

Advances in haploidentical stem cell transplantation for hematologic malignancies

One of the most important advances in allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the use of alternative donors and cell sources, such as haploidentical transplants (haplo-HSCT) from family donors. Several approaches have been developed to overcome the challenging bidirectional alloreactivity. We discuss these approaches, including ex vivo T-cell-depleted grafts with megadose of CD34(+) cells, not requiring immunosuppression after allogeneic transplantation for graft-versus-host disease (GVHD) prophylaxis, and other strategies using unmanipulated T-cell-replete grafts with intensive immunosuppression or post-transplantation cyclophosphamide to minimize the GVHD. We also address the role of other strategies developed in the context of the haplo-HSCT platforms, such as ex vivo selective depletion of alloreactive donor T-cell subpopulations, infusion of antigen-specific T-cells against several pathogens, and infusion of regulatory T-cells, among other experimental approaches. Finally, some considerations about the selection of the most suitable donor, when more than one family member is available, are also addressed.

Reduced intensity conditioning allogeneic hematopoietic cell transplantation for adult acute myeloid leukemia in complete remission - a review from the Acute Leukemia Working Party of the EBMT

Acute myeloid leukemia is the most common indication for an allogeneic hematopoietic cell transplant. The introduction of reduced intensity conditioning has expanded the recipient pool for transplantation, which has importantly made transplant an option for the more commonly affected older age groups. Reduced intensity conditioning allogeneic transplantation is currently the standard of care for patients with intermediate or high-risk acute myeloid leukemia and is now most often employed in older patients and those with medical comorbidities. Despite being curative for a significant proportion of patients, post-transplant relapse remains a challenge in the reduced intensity conditioning setting. Herein we discuss the studies that demonstrate the feasibility of reduced intensity conditioning allogeneic transplants, compare the outcomes of reduced intensity conditioning versus chemotherapy and conventional myeloablative conditioning regimens, describe the optimal donor and stem cell source, and consider the impact of post-remission consolidation, comorbidities, center experience, and more intensive (reduced toxicity conditioning) regimens on outcomes. Additionally, we discuss the need for further prospective studies to optimize transplant outcomes.

Mobilization of hematopoietic stem cells with highest self-renewal by G-CSF precedes clonogenic cell mobilization peak

Harvest of granulocyte colony-stimulating factor (G-CSF)-mobilized hematopoietic stem cells (HSCs) begins at day 5 of G-CSF administration, when most donors have achieved maximal mobilization. This is based on surrogate markers for HSC mobilization, such as CD34(+) cells and colony-forming activity in blood. However, CD34(+) cells or colony-forming units in culture (CFU-C) are heterogeneous cell populations with hugely divergent long-term repopulation potential on transplantation. HSC behavior is influenced by the vascular bed in the vicinity of which they reside. We hypothesized that G-CSF may mobilize sequentially cells proximal and more distal to bone marrow venous sinuses where HSCs enter the blood. We addressed this question with functional serial transplantation assays using blood and bone marrow after specific time points of G-CSF treatment in mice. We found that in mice, blood collected after only 48 hours of G-CSF administration was as enriched in serially reconstituting HSCs as blood collected at 5 days of G-CSF treatment. Similarly, mobilized Lin(-)CD34(+) cells were relatively enriched in more primitive Lin(-)CD34(+)CD38(-) cells at day 2 of G-CSF treatment compared with later points in half of human donors tested (n = 6). This suggests that in both humans and mice, hematopoietic progenitor and stem cells do not mobilize uniformly according to their maturation stage, with most potent HSCs mobilizing as early as day 2 of G-CSF.

The hematopoietic system in the context of regenerative medicine

Hematopoietic stem cells (HSC) represent the prototype stem cell within the body. Since their discovery, HSC have been the focus of intensive research, and have proven invaluable clinically to restore hematopoiesis following inadvertent radiation exposure and following radio/chemotherapy to eliminate hematologic tumors. While they were originally discovered in the bone marrow, HSC can also be isolated from umbilical cord blood and can be "mobilized" peripheral blood, making them readily available in relatively large quantities. While their ability to repopulate the entire hematopoietic system would already guarantee HSC a valuable place in regenerative medicine, the finding that hematopoietic chimerism can induce immunological tolerance to solid organs and correct autoimmune diseases has dramatically broadened their clinical utility. The demonstration that these cells, through a variety of mechanisms, can also promote repair/regeneration of non-hematopoietic tissues as diverse as liver, heart, and brain has further increased their clinical value. The goal of this review is to provide the reader with a brief glimpse into the remarkable potential HSC possess, and to highlight their tremendous value as therapeutics in regenerative medicine.

Granulocyte colony-stimulating factor-primed bone marrow: an excellent stem-cell source for transplantation in acute myelocytic leukemia and chronic myelocytic leukemia

Background:

Steady-state bone marrow (SS-BM) and granulocyte colony-stimulating growth factor-primed BM/peripheral blood stem-cell (G-BM/G-PBSC) are the main stem-cell sources used in allogeneic hematopoietic stem-cell transplantation. Here, we evaluated the treatment effects of SS-BM and G-BM/G-PBSC in human leucocyte antigen (HLA)-identical sibling transplantation.

Methods:

A total of 226 patients (acute myelogenous leukemia-complete remission 1, chronic myelogenous leukemia-chronic phase 1) received SS-BM, G-BM, or G-PBSC from an HLA-identical sibling. Clinical outcomes (graft-versus-host disease [GVHD], overall survival, transplant-related mortality [TRM], and leukemia-free survival [LFS]) were analyzed.

Results:

When compared to SS-BM, G-BM gave faster recovery time to neutrophil or platelet (P < 0.05). Incidence of grade III-IV acute GVHD and extensive chronic GVHD (cGVHD) was lower than seen with SS-BM (P < 0.05) and similar to G-PBSC. Although the incidence of cGVHD in the G-BM group was similar to SS-BM, both were lower than G-PBSC (P < 0.05). G-BM and G-PBSC exhibited similar survival, LFS, and TRM, but were significantly different from SS-BM (P < 0.05). There were no significant differences in leukemia relapse rates among the groups (P > 0.05).

Conclusions:

G-CSF-primed bone marrow shared the advantages of G-PBSC and SS-BM. We conclude that G-BM is an excellent stem-cell source that may be preferable to G-PBSC or SS-BM in patients receiving HLA-identical sibling hematopoietic stem-cell transplantation.

The Effect of Granulocyte Colony-Stimulating Factor on Immune-Modulatory Cytokines in the Bone Marrow Microenvironment and Mesenchymal Stem Cells of Healthy Donors

Granulocyte colony stimulating factor (G-CSF) is sometimes administered to donors before bone marrow (BM) harvest. G-CSF-primed (G-BM) and unprimed BM (U-BM)-derived mesenchymal stem cells (MSC) were obtained from 16 healthy donors and were expanded in vitro. Their proliferative characteristics, morphology, and differentiation capacity were examined. Supernatants of the second passage of MSCs were evaluated for transforming growth factor β1, hepatocyte growth factor, and prostaglandin E2 (PGE2) levels and compared with controls. The analyses of cytokines in the G-BM- and U-BM-derived MSCs supernatants revealed that PGE2 levels were significantly lower in the G-CSF-primed samples. These cytokines were also measured in BM plasma. The level of hepatocyte growth factor in G-BM plasma was significantly increased. The current study is the first to show the effects of G-CSF on the BM microenvironment of healthy human donors. The preliminary data suggest that G-BM- and U-BM-derived MSCs have similar morphologic/phenotypic properties and differentiation capacity but differ in their secretory capacity. Significant changes in cytokine levels of BM plasma in G-CSF-primed donors were also demonstrated. These findings suggest that BM MSCs and changes in the BM microenvironment may contribute to the effects of G-CSF on inflammation and immunomodulation.

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.

Higher frequency of regulatory T cells in granulocyte colony-stimulating factor (G-CSF)-primed bone marrow grafts compared with G-CSF-primed peripheral blood grafts

BACKGROUND

Regulatory T cells (Treg) in allografts are important for the prevention of graft-versus-host disease (GVHD) post-transplantation. The aim of this study was to compare the contents of Tregs and effector T cells in granulocyte colony-stimulating factor (G-CSF)-primed bone marrow grafts (G-BM) and peripheral blood grafts (G-PB).

METHOD

G-BM and G-PB were obtained from 20 allogeneic donors. T-cell subgroups, including conventional T cells and different types of Treg cells, as well as the percentage of Ki67 expression on CD4(+)CD25(high)Foxp3(+) Treg cells, were analyzed using flow cytometry. The levels of interferon-γ (IFN-γ) and interleukin-17 (IL-17) secreted by T cells stimulated with PMA and ionomycin were also determined by flow cytometry.

RESULTS

The percentage of CD4(+)CD25(high)CD127(-/dim)CD62L(+) Treg cells was significantly higher in the G-BM group, with higher proportions of CD45RA(+) naïve Treg cells and higher expression of CD69 on Treg cells in G-BM (P < 0.05). The percentage of Ki67 expression in CD4(+)CD25(high)Foxp3(+) Treg cells in G-BM was significantly higher than that on G-PB. The suppressive functions of Treg cells in inhibiting T-cell activation were comparable between G-BM and G-PB. The proportions of CD4(+)CD25(-)CD69(+) Treg subsets as well as Th1 cells in G-BM were also significantly higher than those in G-PB (P < 0.001). The proportions of conventional T cells and Th17 effector cells were comparable in G-BM compared with those in G-PB. Thus, the ratio of conventional T cells and CD4(+)CD25(high)CD127(-/dim) regulatory T cells were lower in G-BM than that in G-PB (P = 0.014).

CONCLUSION

In addition to the much higher T-cell counts in G-PB grafts that may contribute to more severe GVHD, the higher frequency of Treg cells and lower ratio of conventional T cells to Treg cells in G-BM compared with G-PB grafts might reduce GVHD post-transplantation in G-BM compared with G-PB transplantation.

G-CSF-primed bone marrow as a source of stem cells for allografting: revisiting the concept

The source of hematopoietic stem cells (HSCs) for allogeneic transplantation has evolved over the last decades, from the sole use of unstimulated bone marrow (BM) to the use of G-CSF (filgrastim)-mobilized peripheral blood, G-CSF-primed BM (G-BM) and cord blood. G-CSF-mobilized PBSC has replaced BM as the most commonly used source of allogeneic stem cells. G-BM is a source of HSCs, with studies demonstrating the safety and feasibility of this strategy with the potential for reducing GvHD, while retaining the speed of engraftment. Although the G-BM had lost its use as the optimal source of stem cells, after the widespread use of haploidentical transplantation, their use has resurfaced in 2010. This source can still be used in today's world of transplantation in aplastic anemia and other benign diseases, as well as in children donors. This study intends to review the evidence for this approach and whether this approach still has merit in the ever-evolving field of allogenic HSC transplantation. The merit of G-BM is its ability to offer speed of engraftment with reduced GvHD.

Clinical outcomes and graft characteristics in pediatric hematopoietic stem cell transplantation: Effect of granulocyte-colony stimulating factor priming

In this study, we aimed to determine the effect(s) of G-CSF priming on graft and transplantation parameters and compare these findings with those obtained without priming. A total of 64 pediatric patients transplanted from HLA-matched family donors were enrolled in the study. Twenty-nine patients received G-CSF primed marrow (G-BM group) and 35 patients received steady state bone marrow (S-BM group). Number of total nucleated cells (TNC) and CD34(+) cells, CFU-GM colony number, neutrophil and platelet engraftment times, total length of stay in hospital, overall and disease free survival, and occasions of acute and chronic GvHD has been compared between these two groups. Granulocyte colony stimulating factor primed bone marrow (G-BM) yielded higher numbers of CD34(+) cells, TNCs, and CFU-GM colony numbers compared to those obtained in S-BM. The neutrophil engraftment time, platelet engraftment time, length of stay in hospital, overall survival and disease free survival were not different between G-BM and S-BM groups. Also the cumulative incidence of grades II-IV acute and chronic GvHD were similar. It was observed that the use of G-CSF did not increase the risk of acute or chronic GvHD. We concluded that use of G-CSF for stem cell mobilization is an effective and safe method in children.