The changing role of stem cell transplantation in childhood

Human leukocyte antigen evolutionary divergence influences outcomes of paediatric patients and young adults affected by malignant disorders given allogeneic haematopoietic stem cell transplantation from unrelated donors

High genetic heterogeneity in the human leukocyte antigen (HLA) increases the likelihood of efficient immune response to pathogens and tumours. As measure of HLA diversity, HLA evolutionary divergence (HED) has been shown to predict the response of tumours to immunotherapy and haematopoietic stem cell transplantation (HSCT) in adults. We retrospectively investigated the association of HED with outcomes of 153 paediatric/young adults patients, treated for malignant disorders with HSCT from 9-10/10 HLA-matched unrelated donors. HED was calculated as pairwise genetic distance between alleles in patient HLA-A, -B, -C, -DRB1, -DQB1 and -DPB1, using the locus median to stratify patients with 'high' or 'low' HED. Patients with high HED-B and -DRB1 showed significantly improved disease-free survival (DFS), especially when combined (70.8% vs 53.7% p = 0.008). High HED-B + -DRB1 was also associated with improved overall survival (OS) (82.1 vs 66.4% p = 0.014), and concomitant reduction of non-relapse-mortality (5.1% vs 21.1% p = 0.006). The impact on OS and DFS of combined HED-B + -DRB1 was confirmed in multivariate analysis [hazard ratio (HR) 0.39, p = 0.009; and HR 0.45, p = 0.007 respectively]. Only high HED scores for HLA-DPB1 were associated, in univariate analysis, with reduced incidence of relapse (15.9% vs 31.1%, p = 0.03). These results support HED as prognostic marker in allogeneic HSCT and, if confirmed in larger cohorts, would allow its use to inform clinical risk and potentially influence clinical practice.

Immune Modulation Properties of Zoledronic Acid on TcRγδ T-Lymphocytes After TcRαβ/CD19-Depleted Haploidentical Stem Cell Transplantation: An analysis on 46 Pediatric Patients Affected by Acute Leukemia

TcRαβ/CD19-cell depleted HLA-haploidentical hematopoietic stem cell transplantation (haplo-HSCT) represents a promising new platform for children affected by acute leukemia in need of an allograft and lacking a matched donor, disease recurrence being the main cause of treatment failure. The use of zoledronic acid to enhance TcRγδ+ lymphocyte function after TcRαβ/CD19-cell depleted haplo-HSCT was tested in an open-label, feasibility, proof-of-principle study. Forty-six children affected by high-risk acute leukemia underwent haplo-HSCT after removal of TcRαβ+ and CD19+ B lymphocytes. No post-transplant pharmacological graft-versus-host disease (GvHD) prophylaxis was given. Zoledronic acid was administered monthly at a dose of 0.05 mg/kg/dose (maximum dose 4 mg), starting from day +20 after transplantation. A total of 139 infusions were administered, with a mean of 3 infusions per patient. No severe adverse event was observed. Common side effects were represented by asymptomatic hypocalcemia and acute phase reactions (including fever, chills, malaise, and/or arthralgia) within 24–48 h from zoledronic acid infusion. The cumulative incidence of acute and chronic GvHD was 17.3% (all grade I-II) and 4.8% (all limited), respectively. Patients given 3 or more infusions of zoledronic acid had a lower incidence of both acute GvHD (8.8 vs. 41.6%, p = 0.015) and chronic GvHD (0 vs. 22.2%, p = 0.006). Transplant-related mortality (TRM) and relapse incidence at 3 years were 4.3 and 30.4%, respectively. Patients receiving repeated infusions of zoledronic acid had a lower TRM as compared to those receiving 1 or 2 administration of the drug (0 vs. 16.7%, p = 0.01). Five-year overall survival (OS) and disease-free survival (DFS) for the whole cohort were 67.2 and 65.2%, respectively, with a trend toward a better OS for patients receiving 3 or more infusions (73.1 vs. 50.0%, p = 0.05). The probability of GvHD/relapse-free survival was significantly worse in patients receiving 1–2 infusions of zoledonic acid than in those given ≥3 infusions (33.3 vs. 70.6%, respectively, p = 0.006). Multivariable analysis showed an independent positive effect on outcome given by repeated infusions of zoledronic acid (HR 0.27, p = 0.03). These data indicate that the use of zoledronic acid after TcRαβ/CD19-cell depleted haploHSCT is safe and may result in a lower incidence of acute GvHD, chronic GvHD, and TRM.

Hematopoietic Stem Cell Transplantation: A Bioethical Lens

Hematopoietic stem cell transplantation (HSCT) is one of a range of therapeutic options available to patients suffering from various diseases. HSCT procedure involves important ethical and legal aspects that can occur at every phase of the procedure: the clinical choice of whether to perform the procedure, pretransplantation preparation regimens, donor selection, stem cell harvest procedure, transplantation phase, and short-term and long-term follow-up care. In this discussion paper, we outline the ethical issue-facing physicians involved in HSCT. Currently, HSCT is a widely accepted treatment for many life-threatening diseases. It thus represents a real therapeutic hope for many patients. It does, however, carry a burden of possible morbidity and mortality. Consequently, there are substantial information and communication issues involved in the consent process for HSCT. In the final decision, the judgements of different parties, such as patients, family members, and healthcare professionals, intersect and overlap and this is particularly true when the patient is a minor. Finally, HSCT is a very expensive procedure. The social and economic concerns of HSCT are discussed within the actual contextual framework of the dramatic increase in healthcare costs and inequalities in healthcare in relation to socioeconomic status, educational status, and ethnicity.

Immune reconstitution in patients with Fanconi anemia after allogeneic bone marrow transplantation

BACKGROUND AIMS

Fanconi anemia is an autosomal recessive or X-linked genetic disorder characterized by bone marrow (BM) failure/aplasia. Failure of hematopoiesis results in depletion of the BM stem cell reservoir, which leads to severe anemia, neutropenia and thrombocytopenia, frequently requiring therapeutic interventions, including hematopoietic stem cell transplantation (HSCT). Successful BM transplantation (BMT) requires reconstitution of normal immunity.

METHODS

In the present study, we performed a detailed analysis of the distribution of peripheral blood subsets of T, B and natural killer (NK) lymphocytes in 23 patients with Fanconi anemia before and after BMT on days +30, +60, +100, +180, +270 and +360. In parallel, we evaluated the effect of related versus unrelated donor marrow as well as the presence of graft-versus-host disease (GVHD).

RESULTS

After transplantation, we found different kinetics of recovery for the distinct major subsets of lymphocytes. NK cells were the first to recover, followed by cytotoxic CD8(+) T cells and B cells, and finally CD4(+) helper T cells. Early lymphocyte recovery was at the expense of memory cells, potentially derived from the graft, whereas recent thymic emigrant (CD31(+) CD45RA(+)) and naive CD4(+) or CD8(+) T cells rose only at 6 months after HSCT, in the presence of immunosuppressive GVHD prophylactic agents. Only slight differences were observed in the early recovery of cytotoxic CD8(+) T cells among those cases receiving a graft from a related donor versus an unrelated donor. Patients with GVHD displayed a markedly delayed recovery of NK cells and B cells as well as of regulatory T cells and both early thymic emigrant and total CD4(+) T cells.

CONCLUSIONS

Our results support the utility of post-transplant monitoring of a peripheral blood lymphocyte subset for improved follow-up of patients with Fanconi anemia undergoing BMT.

Conditioned mesenchymal stem cells attenuate progression of chronic kidney disease through inhibition of epithelial-to-mesenchymal transition and immune modulation

Mesenchymal stem cells (MSCs) have been shown to improve the outcome of acute renal injury models; but whether MSCs can delay renal failure in chronic kidney disease (CKD) remains unclear. In the present study, the were cultured in media containing various concentrations of basic fibroblast growth factor, epidermal growth factor and ascorbic acid 2-phosphate to investigate whether hepatocyte growth factor (HGF) secretion could be increased by the stimulation of these growth factors. Then, TGF-β1-treated renal interstitial fibroblast (NRK-49F), renal proximal tubular cells (NRK-52E) and podocytes were co-cultured with conditioned MSCs in the absence or presence of ascorbic acid 2-phosphate to quantify the protective effects of conditioned MSCs on renal cells. Moreover, male Sprague-Dawley rats were treated with 1 × 10⁶ conditioned MSCs immediately after 5/6 nephrectomy and every other week through the tail vein for 14 weeks. It was found that basic fibroblast growth factor, epidermal growth factor and ascorbic acid 2-phosphate promoted HGF secretion in MSCs. Besides, conditioned MSCs were found to be protective against TGF-β1 induced epithelial-to-mesenchymal transition of NRK-52E and activation of NRK-49F cells. Furthermore, conditioned MSCs protected podocytes from TGF-β1-induced loss of synaptopodin, fibronectin induction, cell death and apoptosis. Rats transplanted with conditioned human MSCs had a significantly increase in creatinine clearance rate, decrease in glomerulosclerosis, interstitial fibrosis and increase in CD4⁺CD25⁺Foxp3⁺ regulatory T cells counts in splenocytes. Together, our studies indicated that conditioned MSCs preserve renal function by their anti-fibrotic and anti-inflammatory effects. Transplantation of conditioned MSCs may be useful in treating CKD.

Human umbilical mesenchymal stem cells attenuate the progression of focal segmental glomerulosclerosis

Previous studies have suggested the potential of mesenchymal stem cells (MSCs) to repair damaged kidney diseases. However, the effect of human umbilical cord MSCs (HuMSCs) on the progression of focal segmental glomerulosclerosis (FSGS) remains poorly understood. Adriamycin-induced nephropathy is a rodent model of chronic kidney disease that has been studied extensively and has enabled a greater understanding of the processes underlying the progression of FSGS. This study aimed to investigate the role of HuMSCs on the progression of kidney disease using a model of adriamycin-induced nephropathy. Human MSCs were labeled with 5-bromo-2'-deoxyuridine to track their localization to the kidneys after infusion. Clinical parameters and histology suggested amelioration of FSGS in MSC-treated animals at 12 weeks, especially in those that received repeated doses. These results were associated with reduced serum interleukin (IL)-6 and tumor necrosis factor-α, transforming growth factor-β levels, connective tissue growth factor messenger RNA expression and upregulated serum IL-10 levels. In short, this experiment found that HuMSCs improved kidney fibrosis and modulated the inflammatory response, suggesting that xenogenic transplantation of HuMSCs is a novel approach for improving the progression of FSGS and may be a promising therapeutic intervention in the future.

Autologous hematopoietic stem cell transplantation following high-dose chemotherapy for non-rhabdomyosarcoma soft tissue sarcomas

BACKGROUND

Soft tissue sarcomas (STS) are a highly heterogeneous group of rare malignant solid tumors. Non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) comprise all STS except rhabdomyosarcoma. In patients with advanced local or metastatic disease, autologous hematopoietic stem cell transplantation (HSCT) applied after high-dose chemotherapy (HDCT) is a planned rescue therapy for HDCT-related severe hematologic toxicity.

OBJECTIVES

To assess the effectiveness and safety of HDCT followed by autologous HSCT for all stages of soft tissue sarcomas in children and adults.

SEARCH STRATEGY

We searched the electronic databases CENTRAL (The Cochrane Library 2010, Issue 2), MEDLINE and EMBASE (February 2010). Online trial registers, congress abstracts and reference lists of reviews were searched and expert panels and authors were contacted.

SELECTION CRITERIA

Terms representing STS and autologous HSCT were required in the title, abstract or keywords. In studies with aggregated data, participants with NRSTS and autologous HSCT had to constitute at least 80% of the data. Comparative non-randomized studies were included because randomized controlled trials (RCTs) were not expected. Case series and case reports were considered for an additional descriptive analysis.

DATA COLLECTION AND ANALYSIS

Study data were recorded by two review authors independently. For studies with no comparator group, we synthesised results for studies reporting aggregate data and conducted a pooled analysis of individual participant data using the Kaplan-Meyer method. The primary outcomes were overall survival (OS) and treatment-related mortality (TRM).

MAIN RESULTS

We included 54 studies, from 467 full texts articles screened (11.5%), reporting on 177 participants that received HSCT and 69 participants that received standard care. Only one study reported comparative data. In the one comparative study, OS at two years after HSCT was estimated as statistically significantly higher (62.3%) compared with participants that received standard care (23.2%). In a single-arm study, the OS two years after HSCT was reported as 20%. In a pooled analysis of the individual data of 54 participants, OS at two years was estimated as 49% (95% CI 34% to 64%). Data on TRM, secondary neoplasia and severe toxicity grade 3 to 4 after transplantation were sparse. All 54 studies had a high risk of bias.

AUTHORS' CONCLUSIONS

Due to a lack of comparative studies, it is unclear whether participants with NRSTS have improved survival from autologous HSCT following HDCT. Owing to this current gap in knowledge, at present HDCT and autologous HSCT for NRSTS should only be used within controlled trials.

Amniotic fluid-derived mesenchymal stem cells lead to bone differentiation when cocultured with dental pulp stem cells

Mesenchymal stem cells are present in many tissues of the human body, including amniotic fluid (AF) and dental pulp (DP). Stem cells of both AF and DP give rise to a variety of differentiated cells. In our experience, DP stem cells (DPSCs) display a high capacity to produce bone. Therefore, our aim was to investigate if AF-derived stem cells (AFSCs) were able to undergo bone differentiation in the presence of DPSCs. AFSCs were seeded under three different conditions: (i) cocultured with DPSCs previously differentiated into osteoblasts; (ii) cultured in the conditioned medium of osteoblast-differentiated DPSCs; (iii) cultured in the osteogenic medium supplemented with vascular endothelial growth factor and bone morphogenetic protein-2 (BMP-2). Results showed that AFSCs were positive for mesenchymal markers, and expressed high levels of Tra1-60, Tra1-80, BMPR1, BMPR2, and BMP-2. In contrast, AFSCs were negative for epithelial and hematopoietic/endothelial markers. When AFSCs were cocultured with DPSCs-derived osteoblasts, they differentiated into osteoblasts. A similar effect was observed when AFSCs were cultured in the presence of a conditioned medium originated from DPSCs. We found that osteoblasts derived from DPSCs released large amounts of BMP-2 and vascular endothelial growth factor into the culture medium and that those morphogens significantly upregulate RUNX-2 gene, stimulating osteogenesis. This study highlights the mechanisms of osteogenesis and strongly suggests that the combination of AFSCs with DPSCs may provide a rich source of soluble proteins useful for bone engineering purposes.

Therapeutic effects of umbilical cord blood-derived mesenchymal stem cell transplantation in experimental lupus nephritis

Mesenchymal stem cells (MSCs) have been shown to possess immunomodulatory properties. Systemic lupus erythematosus is an autoimmune disease that results in nephritis and subsequent destruction of renal microstructure. We investigated whether transplantation of human umbilical cord blood-derived MSCs (uMSCs) is useful in alleviating lupus nephritis in a murine model. It was found that uMSCs transplantation significantly delayed the development of proteinuria, decreased anti-dsDNA, alleviated renal injury, and prolonged the life span. There was a trend of decreasing T-helper (Th) 1 cytokines (IFN-γ, IL-2) and proinflammatory cytokines (TNF-α, IL-6, IL-12) and increasing Th2 cytokines (IL-4, IL-10). The in vitro coculture experiments showed that uMSCs only inhibited lymphocytes and splenocytes proliferation but not mesangial cells. Long-term engraftment of uMSCs in the kidney was not observed either. Together, these findings indicated that uMSCs were effective in decreasing renal inflammation and alleviating experimental lupus nephritis by inhibiting lymphocytes, inducing polarization of Th2 cytokines, and inhibition of proinflammatory cytokines production rather than direct engraftment and differentiating into renal tissue. Therapeutic effects demonstrated in this preclinical study support further exploration of the possibility to use uMSCs from mismatched donors in lupus nephritis treatment.

Life-sparing effect of human cord blood-mesenchymal stem cells in experimental acute kidney injury

In search for new sources of mesenchymal stem cells (MSCs) for renal repair in acute kidney injury (AKI), we investigated the potential of human cord blood (CB)-MSCs to cure mice with AKI. Infusion of CB-MSCs in immunodeficient mice with cisplatin-induced AKI ameliorated both renal function and tubular cell injury, and prolonged survival. Transplanted CB-MSCs localized in peritubular areas, limited capillary alterations and neutrophil infiltration. Apoptosis reduced and tubular cell proliferation increased by virtue of stem cell capacity to produce growth factors. The reno-protective effect of CB-MSCs was further confirmed by their ability to inhibit oxidative damage and to induce the prosurvival factor Akt in tubular cells. The evidence that CB-MSCs in vitro increased the production of growth factors and inhibited IL-1 beta and TNFalpha synthesis when cocultured with damaged proximal tubular cells indicates a regenerative and anti-inflammatory action of stem cell treatment. Altogether these results highlight the potential of human CB-MSCs as future cell therapy for testing in human AKI.

Adequacy of Nutritional Support in Pediatric Blood and Marrow Transplantation

The use of nutrition support has become standard practice in blood and marrow transplantation, but what remains unclear is whether patients receive adequate nutrition supplementation during this time. This study is a retrospective audit of the nutritional supplementation of 34 pediatric patients admitted to a pediatric oncology unit for a blood and marrow transplantation. All patients received parenteral nutrition (PN) as their standard nutritional therapy with an average of 79 ± 10.6% of their estimated requirements given over the transplant period. The glucose/amino acid infusion was inadequate on 40% of PN days mainly because of fluid overload causing a reduction in infusion rates. The lipid infusion was inadequate on 60% of PN days mainly because of stoppages when drugs and/or blood were infused. The mean percentage weight change on discharge was +0.3 ± 4.7%. This had a large range of between −9.9% and +7.9% of body weight and did not seem to be related to adequacy of nutrition during transplant. This study showed that although frequent rate reductions in nutrition infusions did occur, most patients still received the majority of their nutritional requirements.