Treosulfan-Based Conditioning Regimen in Sibling and Alternative Donor Hematopoietic Stem Cell Transplantation for Children with Sickle Cell Disease.

BACKGROUND AND OBJECTIVES: Lack of suitable donors and regimen related toxicity are major barriers for hematopoietic stem cell transplantation (HSCT) in patients with sickle cell disease (SCD). The aim of the study is the assessment of efficacy and toxicity of Treosulfan-based conditioning regimen for SCD also when alternative donors such as mismatched unrelated donor and haploidentical donor are employed. METHODS: We report our single-center experience: 11 patients with SCD received HSCT with a Treosulfan/Thiotepa/Fludarabine/Anti-thymoglobulin conditioning regimen between 2010 and 2015. The donor was a matched sibling donor (n= 7), a haploidentical parent (n= 2), a matched unrelated donor (n= 1) or a mismatched unrelated donor (n=1). The haploidentical and mismatched unrelated donor grafts were manipulated by removing TCRαß and CD19 positive cells. RESULTS: All patients survived the procedure and achieved stable engraftment. Stable mixed chimerism was observed in 5/11 patients. Grade III-IV regimen related toxicity was limited to mucositis and no grade III-IV graft-versus-host disease (GvHD) occurred. No SCD manifestation was observed post transplant and cerebral vasculopathy improved in 3/5 evaluable patients. Organ function evaluation showed no pulmonary, cardiac or renal toxicity but gonadal failure occurred in 1/4 evaluable patients. CONCLUSION: Our data suggest that Treosulfan is associated with low toxicity and may be employed also for unrelated and haploidentical donor HSCT.

Treatment of Acute Graft-versus-Host Disease in Childhood with Extracorporeal Photochemotherapy/Photopheresis: The Padova Experience.

Acute graft-versus-host disease (aGVHD) is the major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation. Systemic steroid treatment represents the first-line therapy for aGVHD and is associated with a response rate of 30% to 60%. Steroid-resistant patients have a poor prognosis with high transplantation-related mortality (TRM). Several second-line therapies have been proposed for the management of unresponsive aGVHD, without proven beneficial effects on patients' outcome or overall long-term survival. For these reasons, extracorporeal photochemotherapy/photopheresis (ECP), a cell-based approach to control GVHD that spares generalized immunosuppression, seems to be promising. In this study, we report the outcome of 72 consecutive pediatric patients treated with ECP between 1997 and 2013 for aGVHD. Among them, 21 patients had steroid-resistant aGVHD, 42 had steroid-dependent aGVHD, and 9 did not receive steroid as first-line therapy because of clinical contraindications. A complete response was obtained in 72% of patients, a partial response was observed in 11%, and there was no response in 17% of patients. At day +180, TRM was 4% in the whole cohort; TRM was 3% and 20% among responders and nonresponders to ECP, respectively (P < .0001). The 5-year overall survival was 71%, showing a difference between responders and nonresponders of 78% and 30%, respectively (P = .0004). The 5-year time to progression of primary disease was 81%, without any significant difference between the 2 groups. Moreover, the 5-year progression-free survival of primary disease was 72%, with a significant difference (P = .0007) between responders (79%) and nonresponders (30%) to ECP. In conclusion, this study demonstrates that ECP is highly effective in aGVHD without a negative impact on primary disease.

Mesenchymal stromal cells can be derived from bone marrow CD133+ cells: implications for therapy.

It is known that the bone marrow (BM) CD133(+) cells play an important role in the hematopoietic compartment, but this is not their only role. The cells indeed can take part in vascular reconstitution when they become endothelial cells (EC), in skeletal muscle fiber regeneration when there is a switch in muscle precursors, and to cardiomyocyte phenotypic conversion when differentiating in cardiomyocytes-like cells. While the role in hematopoiesis and vasculogenesis of the selected cells is well established, their ability to differentiate along multiple non-EC lineages has not yet been fully elucidated. The goal of this study is to assert whether human CD133(+)BM-derived cells are able to differentiate in vitro, besides to blood cells, cell lineages pertinent to the mesoderm germ layers. To this end, we isolated CD133(+) cells using a clinically approved methodology and compared their differentiation potential to that of hematopoietic progenitor cells (HPCs) and mesenchymal stem cells (MSCs) obtained from the same BM samples. In our culture conditions, CD133 expression was consistently decreased after passage 2, as well as the expression of the stemness markers c-kit and OCT4, whereas expression of Stage Specific Embryonic Antigen 4 (SSEA4) remained consistent in all different conditions. Expanded CD133 were also positive for HLA-ABC, but negative for HLA-DR, in accordance with what has been previously reported for MSCs. Moreover, CD133(+) cells from human BM demonstrated a wide range of differentiation potential, encompassing not only mesodermal but also ectodermal (neurogenic) cell lineages. CD133 antigen could be potentially used to select a cell population with similar characteristics as MSCs for therapeutic applications.

Interleukin-8 and CXCR1 receptor functional polymorphisms and susceptibility to acute pyelonephritis.

PURPOSE: We performed a case-control study in children diagnosed by the first episode of upper urinary tract infection with or without vesicoureteral reflux to evaluate the association of functional polymorphism of interleukin-8 (-251A>T and +2767A>G), and its receptor CXCR1 (+2607G>C). MATERIALS AND METHODS: Genomic DNA was obtained from 265 children with a clinical and laboratory diagnosis of urinary tract infection who were recruited in northeast Italy. The children were subdivided as 173 who were dimercapto-succinic acid scan positive with positive static renal scintigraphy in acute conditions, consistent with the diagnosis of acute pyelonephritis, and 92 who were dimercapto-succinic acid scan negative. Genetic analysis for the same polymorphisms was also extended to a control population of 106 umbilical cord DNA samples. RESULTS: Statistical analysis of genotype data showed that 1) the tested populations were in Hardy-Weinberg equilibrium, 2) there were significant differences between the dimercapto-succinic acid scan positive and negative groups (p=0.049), and the dimercapto-succinic acid scan positive group vs controls (p=0.032) in terms of interleukin-8 -251A>T polymorphism frequency, 3) there was also a significant difference in the distribution of IL-8 -251A>T and +2767A>G polymorphisms between dimercapto-succinic acid scan positive and negative children in the subgroup without vesicoureteral reflux (p=0.03 and 0.02, respectively) and 4) no significant differences were found in the frequency of the distribution of CXCR1 +2607G>C polymorphism in all groups. CONCLUSIONS: These data suggest that the gene for the proinflammatory chemokine interleukin-8 is involved in susceptibility to acute pyelonephritis during upper urinary tract infection in children with or without vesicoureteral reflux.

Isolation of mesenchymal stem cells from human vermiform appendix.

BACKGROUND: Recent findings have shown that pluripotent stem cells exist in areas outside the bone marrow (BM). Moreover, it has been demonstrated that the appendix is important for the development of mucosal gut immunity, and hematopoietic progenitors have been isolated from animal and human appendices. MATERIALS AND METHODS: Non-inflamed appendices removed during laparotomy were processed and cultured until the appearance of adherent cells. Differentiations (performed under osteogenic, adipogenic, and myogenic conditions) were confirmed by immunohistochemistry and cytochemistry. Polymerase chain reaction and cytofluorimetric analyses were performed to evidence the presence of genes and protein specific lineages in appendix-derived mesenchymal stem cells (ADMCs). RESULTS: ADMCs were present in non-inflamed appendices. ADMCs under osteogenic conditions differentiated in osteoblasts and showed increased alkaline phosphatase expression; at the gene level, we observed the expression of Core binding factor alpha 1 (Cbfa1) and osteocalcin in osteogenic induced ADMCs. Under adipogenic conditions, lipidic drops in the cytoplasm, expression of lipoprotein lipase (LpL), and peroxisome proliferator-activated receptor gamma were observed; under myogenic conditions, myotubes expressing muscle specific proteins like desmin were formed. Myogenic regulatory factor 4 and MyoD were selectively induced in the ADMCs under myogenic conditions. CONCLUSIONS: This study shows for the first time that mesenchymal stem cells can be isolated from normal appendices obtained from a pediatric and adult age group (0-18 years of age). This finding not only may further knowledge of the maturation of the intestinal immunesystem but also could indicate a new physiological role of the human vermiform appendix.

A prospective survey on incidence, risk factors and therapy of hepatic veno-occlusive disease in children after hematopoietic stem cell transplantation.

BACKGROUND AND OBJECTIVES: Veno-occlusive disease (VOD) is one of the most frequent complications after stem cell transplantation. We conducted a prospective survey of 244 hematopoietic stem cell transplants in children to determine the incidence of VOD, its main risk factors, treatment and effect on the transplant. DESIGN AND METHODS: Two hundred and forty-four hematopoietic stem cell transplants (HSCT) performed in 220 pediatric patients from 1993 to 2003 were evaluated. The series included 127 males and 93 females with a median age of 6.7 years at the time of transplantation. RESULTS: VOD was diagnosed following 26 of the 244 transplants (cumulative incidence 11%), but a higher incidence was found in patients with at least one known risk factor for VOD (cumulative incidence 20%). In multivariate analysis, risk factors for VOD were age < 6.7 years; type of VOD prophylaxis, and busulphan-containing conditioning regimens. Routine treatment of VOD was based on supportive care and, starting from 1999, defibrotide was used. All patients were monitored with daily Doppler ultrasound-(US) for early diagnosis of inversion of portal blood flow. Twelve patients developed inversion of portal flow (9 had severe VOD; 3 had moderate VOD) and were promptly started on fibrinolytic and anticoagulant therapy with heparin and recombinant tissue plasminogen activator (rt-PA). Hepatic flow reverted to normal in all 12 patients; only 4 patients ultimately developed multiorgan failure and died. The transplant-related-mortality (TRM) rate in patients with or without inversion of portal flow was 33% vs 7%, (p=0.1). The TRM in patients with or without VOD was 19% vs 8% (p=0.001). INTERPRETATION AND CONCLUSIONS: This study showed that younger age, type of VOD prophylaxis, and busulphan-based conditioning regimens are independent risk factors for VOD. Inversion of portal flow was found in 9 of 10 patients with severe VOD. Doppler US monitoring may be helpful in early identification of the patients with VOD-induced inversion of portal flow who might benefit from therapy with heparin and rt-PA.

Successful engraftment and stable full donor chimerism after myeloablation with thiotepa, fludarabine, and melphalan and CD34-selected peripheral allogeneic stem cell transplantation in hemophagocytic lymphohistiocytosis.

Allogeneic hematopoietic stem cell transplantation (HSCT) represents the only curative option for primary hemophagocytic lymphohistiocytosis (HLH), a rare disease of infants and young children, characterized by recurrent fever, hepatosplenomegaly, and cytopenia. We report a case of successful engraftment and stable full-donor chimerism in a patient with HLH who underwent peripheral allogeneic CD34-selected HSCT. The donor was his 1-antigen-HLA-mismatched grandmother. After a conditioning regimen based on the combination of thiotepa, fludarabine, melphalan, and rabbit antilymphocyte serum, the patient received a megadose of 26.3 x 10(6)/kg of CD34(+) peripheral blood cells. Neutrophil (>0.5 x 10(9)/L) and platelet (>50 x 10(9)/L) engraftment was observed on days +16 and +12, respectively, and the patient was discharged home on day +24. No acute or chronic GVHD was observed. Infectious complications were the main causes of re-hospitalization in the first year after transplantation, but no significant morbidity was observed thereafter. Thirty-two months after HSCT, the patient is alive and well, still in complete clinical remission of his underlying disease with a durable engraftment, normal NK activity and full donor chimerism. This case suggests that a fludarabine-based conditioning regimen and CD34-selected peripheral allogeneic HSCT may be a feasible option in case of unavailability of a fully HLA-matched related or unrelated donor.

The use of cytokine-stimulated healthy donors in allogeneic stem cell transplantation.

Treatment of healthy donors with recombinant human granulocyte colony-stimulating factor (rhG-CSF) allows the mobilization and peripheralization into circulating blood of an adequate number of CD34+ cells that can then be collected by leukapheresis (PBSC). This procedure avoids the invasiveness of bone marrow harvest and the risks related to general anesthesia. The main adverse effects of rhG-CSF are: bone pain, 84%, headache, 54%, fatigue, 31%, and nausea, 13%, which are usually scored by the donors as moderate to severe, resolving within 2-3 days after discontinuation of the cytokine. Analgesics, mainly acetaminophen, are sufficient to control the pain. Less than 5% of the donors experience non-cardiac chest pain, a local reaction at the injection site, insomnia, dizziness or a low-grade fever. Discontinuation of the PBSC procedure because of adverse effects of rhG-CSF or leukapheresis is rarely necessary (0.5%) but this good tolerability can be hampered by the need, in 5-20% of cases, for an adequate venous access that requires insertion of a central or venous catheter. There are no absolute contraindications to the stimulation of healthy donors with rhG-CSF but the description of cases of non-traumatic splenic rupture, iritis, cardiac ischemia, and gouty arthritis suggests that further precautionary restrictions are advisable when deciding eligibility for PBSC collection. The main advantages for patients receiving an allogeneic PBSC transplant are the faster hematologic and immunologic recovery and the potential for a greater efficacy in advanced disease by lowering the transplant-related mortality. One of the major concerns regarding the use of rhG-CSF in unrelated healthy donors is the uncertainty about its possible role in triggering malignancy, in particular myelodysplastic syndrome and acute myeloid leukemia. There are no studies with an adequate sample size and follow-up that can answer this question but two recent retrospective studies reported that in the medium term rhG-CSF is not associated with an excess of lymphoproliferative disorders. Currently, caution on the long-term safety of the use of rhG-CSF in healthy donor is still warranted but the data so far accumulated on allogeneic PBSC transplants are encouraging both as far as concerns the good short-medium tolerability profile of G-CSF-stimulation of the donor and the potential major efficacy in leukemia patients.