Long-Term Safety of Short-Term Administration of Filgrastim (rhG-CSF) and Leukophresis Procedure in Healthy Children: Application of Peripheral Blood Stem Cell Collection in Pediatric Donors

Long-term follow-up of cancer and catastrophic diseases in hematopoietic stem cell donors: a comprehensive matched cohort study

Hematopoietic stem cell (HSC) transplantation, using either bone marrow (BM) or peripheral blood stem cells (PBSC), is a well-established therapy for various hematologic and non-hematologic diseases. However, the long-term health outcomes after HSC donation remain a major concern for several potential donors. Thus, we aimed to conduct a matched cohort study of 5003 unrelated donors (1099 BM and 3904 PBSC) and randomly selected 50,030 matched controls based on age, sex, and resident area from the donor registry between 1998 and 2018. The medical insurance claims of all the participants were retrieved from the Taiwan National Health and Welfare Data Science Center after de-identification. Our findings revealed no differences in the incidence of cancer, death, and catastrophic diseases between HSC donors and matched healthy participants during long-term follow-up. Kaplan-Meier curves depicting the cumulative incidence of cancer and overall mortality throughout the follow-up period also demonstrated similar outcomes between donors and non-donors. In conclusion, our results indicate that HSC donation, whether through BM or PBSC, is safe and not associated with an increased risk of cancer, death, or catastrophic diseases. These findings provide valuable information for counseling potential HSC donors and for long-term management of HSC donor health.

The Reconstitution of T-cells after Allogeneic Hematopoietic Stem Cell Transplant in a Pediatric Patient with Congenital Amegakaryocytic Thrombocytopenia (CAMT)

BACKGROUND

Congenital amegakaryocytic thrombocytopenia (CAMT) is a bone marrow failure syndrome with autosomal recessive inheritance characterized by the lack of megakaryocytes and thrombocytopenia. The cause of the disease is a mutation in the c-Mpl gene, which encodes the thrombopoietin (TPO) receptor. The main treatment for this genetic disorder is an allogeneic hematopoietic stem cell transplant (allo-HSCT). However, transplant-related mortality, development of acute and chronic graft-versushost disease (GvHD), and susceptibility to opportunistic infections are major barriers to transplantation. Delay in the reconstitution of T cells and imbalance in the regeneration of distinct functional CD4 and CD8 T-cell subsets mainly affect post-transplant complications. We report a case of CAMT, who developed acute GvHD but had no signs and symptoms of chronic GvHD following allo-HSCT.

CASE PRESENTATION

At the age of four, she presented with petechiae and purpura. In laboratory investigations, pancytopenia without organomegaly, and cellularity less than 5% in bone marrow biopsy, were observed. A primary diagnosis of idiopathic aplastic anemia was made, and she was treated with prednisolone, cyclosporine, and anti-thymocyte globulin (ATG), which did not respond. Genetic analysis revealed the mutation c.1481T>G (p. L494W) in exon 10 of the c-Mpl gene, and the diagnosis of CAMT was confirmed. The patient underwent allo-HSCT from a healthy sibling donor. Alloimmunization reactions and immune disorders were present due to long-term treatment with immunosuppressive medications and repeated blood and platelet transfusions. Hence, the regeneration of T-lymphocytes after allo-HSCT was evaluated.

CONCLUSION

Successful treatment of acute GvHD prevented advancing the condition to chronic GvHD, and this was accompanied by delayed T-cell reconstitution through an increase in Treg:Tcons ratio.

Disturbance in the reconstitution of distinct T-cell subsets and the incidence of GvHD following allo-HSCT in pediatric patients with non-malignant hematological disorders

BACKGROUND

The reconstitution of different T-cell subsets following allogeneic hematopoietic stem cell transplantation (allo-HSCT) is critical for efficient pathogen protection and the prevention of graft-versus-host disease (GvHD). In particular, studies have highlighted the importance of balanced ratios of regulatory T-cells (Tregs) and distinct functionally T-cells in preventing acute and chronic GvHD.

METHODS

We evaluated the regeneration of CD4 and CD8 T-cell subpopulations in nine pediatric patients with non-malignant disorders following allo-HSCT from a fully HLA-identical donor.

RESULTS

CD4 and CD8 T-cells were higher 12 months after the transplant but still lower than in healthy controls and pre-transplant. However, we found after allo-HSCT, central memory and effector memory cell subsets were the predominant phenotypes in the CD4 and CD8 T-cell populations, respectively. In patients who had developed acute GvHD, there was an increase in the frequency of TEMRA (effector memory T cells that re-express CD45RA) cells within the CD4 T-cell population. Meanwhile, in patients with chronic GvHD, we observed a decrease in Th1 cells in CD4 T-cells and effector memory cells within the CD8 T-cell population. In addition, we found decreased TEMRA cell subsets in CD4 and CD8 T-cell populations in chronic GvHD.

CONCLUSION

Our findings suggest a possible relationship between the influence of acute GvHD and its prevention on delayed CD4 T-cell reconstitution and, reciprocally, unbalanced regeneration of CD4 and CD8 T-cell subsets in the development of chronic GvHD.

T helper 17 and regulatory T-cell profile and graft-versus-host disease after allogeneic hematopoietic stem cell transplantation in pediatric patients with beta-thalassemia

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an effective treatment option for hereditary hemoglobin disorders, such as beta-thalassemia; However, this procedure is not without constraints, mainly engendering complications such as acute graft-versus-host disease (aGvHD), chronic GvHD (cGvHD), and susceptibility to infections. The clinical outcomes of allo-HSCT are highly dependant on the quality and quantity of T-cell subsets reconstitution. Following the allo-HSCT of six pediatric patients afflicted with beta-thalassemia, their mononuclear cells were isolated, and then cultured with a combination of phorbol myristate acetate (PMA)/ionomycin and Brefeldin A. The content of CD4 T-cell subsets, including T helper 17 (Th17) cells and regulatory T cells (Tregs), were determined by specific conjugated-monoclonal antibodies three and six months post-HSCT. An increased frequency of total CD4 T-cells, Tregs and Th17 cells was observed at day 90 and 180 after allo-HSCT, albeit the numbers were still lower than that of our healthy controls. In patients who developed cGvHD, a lower Th17/Treg ratio was observed, owing it to a decreased proportion of Th17 cells. In conclusion, creating balance between Th17 and Treg subsets may prevent acute and chronic GvHD in patients after allo-HSCT.

Basic characteristics and safety of donation in related and unrelated haematopoietic progenitor cell donors - first 10 years of prospective donor follow-up of Swiss donors

Since July 2007 prospective life-long follow-up (FU) for unrelated (URD) and related donors (RD) is mandatory in Switzerland and data on every allogeneic haematopoietic progenitor cell (HPC) donation are collected prospectively. We report the real-world experience of HPC donation during a 10-year study period (01.07.2007-30.06.2017) with basic characteristics and FU data. 1105 donors underwent 1155 HPC donation procedures. Eighty percent of first donations performed by 802 (73%) RDs and 303 (27%) URDs were peripheral blood stem cells (PBSC), 20% bone marrow (BM). Male donors were over-represented as URD (60% male vs 40% female). Main differences between RDs and URDs concerned age and pre-existing health disorders. RDs were significantly older at first donation (median age 48 years) compared to URD (34 years, p < 0.0001) and had more pre-existing health problems: 25% vs 9% in URD (p < 0.0001). No fatal complications occurred, collection related severe adverse events (SAE) after first donation were not significantly different between groups (RD 1.2%, URD 0.99%), incidence rates for neoplastic and autoimmune diseases did not exceed the rates of the general population. RDs are a more heterogeneous and potentially more vulnerable group, but if donor evaluation is performed appropriately, HPC donation is still safe.

Quantification and Qualification of Stem Cells From Blood After Mobilization With Filgrastim, and Concentration Using a Platelet-Rich Plasma System

PURPOSE

To determine the cellular composition of a product created with peripheral blood harvested after systemic mobilization with filgrastim and processed with one point-of-care blood concentrating system, i.e., a platelet-rich plasma (PRP) system. The second purpose was to compare mobilized platelet-rich plasma (M-PRP) with a concentrated bone marrow aspirate (cBMA) and a PRP created from the same subjects with the same PRP system.

METHODS

Ten healthy volunteer subjects were recruited for collection and analysis of 3 tissue sources: non-treated peripheral blood, bone marrow aspirate, and filgrastim-mobilized peripheral blood, involving 4 doses of weight-based filgrastim. One point-of-care blood and bone marrow concentrating system was used to create 3 products: PRP, cBMA, and M-PRP. Automated hematologic analysis was performed on all products to quantify total red blood cells, white blood cells (WBCs), monocyte, platelet, and hematopoietic progenitor cell (HPC) concentrations. Flow cytometry was used to determine hematopoietic and mesenchymal progenitor cell populations. Lastly, concentrates were cultured and fibroblast colony-forming units (CFU-F) and morphology of adherent cells were evaluated.

RESULTS

M-PRP contained a greater concentration of WBC (mean difference = 53.2 k/μL; P < .0001), monocytes (mean difference = 8.3 k/μL; P = .002), and a trend toward a greater concentration of HPC (mean difference = 200.5 /μL; P = .060) when compared with PRP. M-PRP contained a greater concentration of monocytes (mean difference = 5.5 k/μL; P = .017) and a trend toward a greater concentration of platelets (mean difference = 348 k/μL; P = .051) and HPC (mean difference = 193.4 /μL; P = .068) when compared with cBMA. M-PRP had a similar concentration of platelets to PRP (mean difference = 110 k/μL; P = .051) and PRP had a greater concentration than cBMA (mean difference = 458 k/μL; P = .003). cBMA remained the only product capable of producing CFU-Fs (446 ± 247 /mL) as neither the M-PRP nor PRP produced CFU-Fs. M-PRP produced colonies consistent with WBC.

CONCLUSIONS

M-PRP, produced with filgrastim mobilized blood and a proprietary PRP system, contained more total WBCs, monocytes, platelets, and HPCs than cBMA and more WBCs, monocytes, and HPCs than PRP.

CLINICAL RELEVANCE

Filgrastim mobilized PRP may be an alternative to cBMA for use as a point-of-care product for orthopaedic treatments.

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-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.

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

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