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BACKGROUND Current treatment strategies in pediatric oncology are intensive and lead to high survival rates but also to treatment-related complications. Therefore, supportive care plays an increasingly important role. This study was designed to evaluate variations in supportive care practice in children with cancer in the Netherlands and adherence to selected existing international guidelines through an in-depth review of local guidelines and protocols at all 6 Dutch pediatric cancer centers. METHODS Based on shared expert opinion, a questionnaire regarding current supportive care practice was compiled. For each center, the required information was extracted from local supportive care guidelines, and the list was sent to a pediatric oncologist of that center to verify its correspondence with local daily practice. Subsequently, it was determined whether clinical practice was concordant (same in ≥ 5 of 6 centers), partly concordant (highly overlapping in ≥ 5 of 6 centers), or discordant (same in

Currently, very few guidelines for supportive care for children with cancer exist. In the Netherlands, nationwide guidelines are over 10 years old and mostly based on expert opinion. Consequently, there is growing support and need for clinical practice guidelines (CPGs), which ought to be developed with a well-defined methodology and include a systematic search of literature, evidence summaries, and a transparent description of the decision process for the final recommendations. Development of CPGs is time consuming; therefore, it is important to prioritize topics for which there is the greatest clinical demand.This study aims to prioritize childhood cancer supportive care topics for development of CPGs.A Delphi survey consisting of two rounds was conducted to prioritize relevant childhood cancer supportive care topics for the development of CPGs. A group of experts comprising 15 pediatric oncologists, 15 pediatric oncology nurses, and 15 general pediatricians involved in care for childhood cancer patients were invited to participate. All relevant supportive care topics in childhood cancer were rated.In both rounds, 36 panellists (82 %) responded. Agreement between panellists was very good, with an intraclass correlation coefficient of 0.918 (95 % confidence interval (CI) = 0.849-0.966, p We successfully used a Delphi survey to prioritize childhood cancer supportive care topics for the development of CPGs. This is a first step towards uniform and evidence-based Dutch guidelines in supportive care in childhood cancer. Even though performed nationally, we believe that this study can also be regarded as an example starting point for international development of CPGs in the field of supportive care in cancer or any other field for that matter.

Background Ovarian insufficiency (OI) and infertility are common and devastating late effects of cancer treatment and hematopoietic stem cell transplantation (HSCT). In children, gonadal insufficiency may subsequently lead to abnormal pubertal development. The aim of this study was to assess the cumulative incidence of OI and the need for hormonal induction of pubertal development after HSCT in childhood. We additionally assessed HSCT-related risk factors for OI. Procedures A single center cohort study was undertaken of female patients transplanted during childhood, surviving at least 2 years post-HSCT and who were at least 10 years old at initiation of the study. Of 141 eligible patients, 109 were included and hormone levels and clinical data of these patients during follow-up were collected. Risk factors for OI were analyzed by multivariate Cox regression analysis. Results Cumulative incidence of OI was 56% at a median follow-up of 7.2 years. Eight patients, initially diagnosed with OI, showed recovery of ovarian function over time. Hormonal induction of puberty was necessary in 44% of females who were pre-pubertal or pubertal at HSCT. In multivariate analysis, more advanced pubertal stage at HSCT was associated with OI. We found a trend for an association of busulfan with OI in patients conditioned with chemotherapy only. Conclusions The incidence of OI after HSCT was high and associated with more advanced pubertal stage at HSCT. Almost half of the females who were pre-pubertal or pubertal at HSCT required hormonal induction of pubertal development. Pediatr Blood Cancer 2014;61:2048–2053. © 2014 Wiley Periodicals, Inc.

Summary Background Graft-versus-host disease (GVHD) is the major limitation of allogeneic haemopoietic stem-cell transplantation (HSCT), for which no approved treatments are available. Use of mesenchymal stromal cells (MSCs) has become standard practice in some European countries, but controversy exists for their benefit. The aim of this meta-analysis was to analyse available evidence for the benefit of MSC treatments in steroid-resistant acute GVHD. Methods We did a systematic review and meta-analysis to assess response to and survival after MSC treatment in patients with steroid-refractory acute GVHD. We searched MEDLINE, Embase, Ovid, and Cochrane Central databases for published studies, and we used ClinicalTrials.gov and other websites to find unpublished studies and conference abstracts. We included prospective and retrospective studies in which MSCs were administered to patients with steroid-refractory acute GVHD. Data were extracted independently by two investigators based on strict selection criteria. A random-effects model was used to pool outcomes across studies because of anticipated heterogeneity. Our primary outcome was survival at 6 months from the first infusion of MSCs. Findings We identified 628 citations with our search, of which 610 were excluded after review and a further five did not contain pertinent data. Thus, our meta-analysis included 13 non-randomised studies at moderate risk of bias, comprising a total of 336 patients. Six studies provided data for the primary outcome analysis (119 patients). Survival at 6 months after MSC treatment was 63% (95% CI 50–74; I 2 =41%). Survival did not differ with respect to age, MSC culture medium, or dose of MSCs delivered. Interpretation Available evidence suggests that infusion of MSCs could be an acceptable treatment for patients with steroid-refractory acute GVHD. Randomised clinical trials are needed urgently to assess different treatment modalities for steroid-refractory acute GVHD. Funding None.

Background: In this national multicentre study, we examined the safety of reducing antibiotics in selected paediatric cancer patients with febrile neutropenia.Methods: Patients with signs of a bacterial infection and/or abnormal vital signs indicating sepsis were considered high risk and received antibiotic therapy. Remaining patients were allocated to low-or medium risk, depending on their interleukin-8 level. Low-risk patients did not receive any antibiotics and were discharged from the hospital after having been afebrile for 12 h. Medium-risk patients were re-evaluated after 72 h of antibiotic treatment and, in selected patients, antibiotics were stopped.Results: Two hundred thirty-three febrile neutropenic episodes in 141 paediatric cancer patients were included in the study. Sixty-four episodes were classified high risk (28%), 122 medium risk (52%), and 47 (20%) low risk. In the medium-risk group, antibiotics were stopped after 72 h in 50 in 122 episodes (41%). Median duration of antibiotic treatment and hospital admission was significantly lower in low-and medium-risk episodes with early discharge. No failures were observed in the medium-risk group with early discharge. In the low-risk group, six failures were observed (12.8%), due to coagulase-negative staphylococci-positive blood cultures and recurrent fever.Conclusion: We showed that it is safe to shorten antibiotic treatment to 72 h in selected medium-risk patients with febrile neutropenia, regardless of the neutrophil count. The safety of withholding antibiotics in selected low-risk paediatric cancer patients with febrile neutropenia requires further investigation, using more suitable definitions for safety. Reduction in hospital admissions allows children with cancer more time at home and consequently improves their quality of life. (C) 2015 Elsevier Ltd. All rights reserved.

Allogeneic hematopoietic stem cell transplantation (HSCT) is a curative treatment for many children with life-threatening diseases. One of the most significant long-term complications of transplantation is chronic graft-versus-host disease (cGVHD). Although the rates of cGVHD after HSCT are lower in the pediatric population than in adults, cGVHD remains a significant cause of morbidity and mortality. Medicines used to prevent and treat cGVHD remain unsatisfactory, with protracted use of immune suppression necessary and high rates of first-line treatment failure. Efforts to improve salvage treatment are urgently required. Nonpharmacologic strategies attempt to modulate the cellular inflammation response and possibly allow reduction or cessation of immunosuppressive drugs. Mesenchymal stromal cells (MSC) have been shown in vitro to mediate a wide variety of immune responses. MSC have been used in the prophylaxis of acute GVHD (aGVHD) and for the treatment of established steroid refractory aGVHD and, more recently, in the management of cGVHD. Extracorporeal photochemotherapy (ECP) has shown promising efficacy in graft-versus-host disease, and may allow a significant reduction in the use of systemic steroids and other immunosuppressants, reducing long-term morbidity and mortality. The accumulated experience shows ECP to be well tolerated, with no clinically significant side effects.

Hematopoietic stem cell transplantation is an effective therapy for life-threatening hematological diseases. Parents may be asked to donate hematopoietic stem cells for their child when no compatible related or unrelated donor is available. Objective: Parents donating G-CSF mobilized peripheral blood stem cells simultaneously and uniquely fulfill the dual role of donor and caregiver for their ill child. The experiences of both sibling and unrelated stem cell donors have been extensively reported but not those of parental donors. Methods: We therefore undertook a study specifically to investigate the experiences and coping strategies of parental stem cell donors. In-depth qualitative interviews were conducted with 13 parental donors, which were subsequently transcribed and subjected to thematic analysis. In addition, parental coping was assessed utilizing the Utrecht Coping List. Results: Qualitative analyses revealed four main thematic categories describing the way parental stem cell donation was experienced, namely ‘Hope and Fear’, ‘Need for Information’, ‘Do Anything for your Child’ and ‘Transplant Outcome’ In addition parents noted similar difficulties which were unrelated to their specific role as a donor, for example they felt socially isolated. Conclusions: Individual information for the parents needs to address not only the transplantation procedure but particularly those aspects related to the donation process. We feel there is a need for a protocol specifically designed to support and coach parental donors. Copyright © 2010 John Wiley & Sons, Ltd.

A nine-yr-old boy with EPP suffered from severe skin burns and liver failure caused by progressive cholestasis and fibrosis. OLT was performed without major complications. Four months following liver transplantation he underwent parental haploidentical HSCT. The myeloablative conditioning regimen was relatively well tolerated and hematological engraftment was rapid (on day 10). Protoporphyrin concentrations returned to normal following HSCT. However, immune recovery was significantly delayed. Varicella zoster virus reactivation resulted in impaired vision, prolonged hospitalization and eventually in multiorgan failure and death. Sequential liver and haploidentical HSCT proved feasible though a high risk procedure in this EPP patient. The management of post-IST after these combined transplantations remains a challenge and needs to be further established.

Immunotherapy in the context of hematopoietic stem cell transplantation has been dominated for many years by T-cell- and dendritic-cell-based treatment modalities. During the last decade, insight into the biology of natural killer (NK) cells and mesenchymal stromal cells (MSC) has rapidly increased and resulted in NK- and MSC-based therapeutic strategies in clinical practice. This article reviews current knowledge of the biology and clinical aspects of NK cells and MSC.

Background: Severe graft-versus-host disease (GVHD) is a life-threatening complication after allogeneic transplantation with haemopoietic stem cells. Mesenchymal stem cells modulate immune responses in vitro and in vivo. We aimed to assess whether mesenchymal stem cells could ameliorate GVHD after haemopoietic-stem-cell transplantation. Methods: Patients with steroid-resistant, severe, acute GVHD were treated with mesenchymal stem cells, derived with the European Group for Blood and Marrow Transplantation ex-vivo expansion procedure, in a multicentre, phase II experimental study. We recorded response, transplantation-related deaths, and other adverse events for up to 60 months' follow-up from infusion of the cells. Findings: Between October, 2001, and January, 2007, 55 patients were treated. The median dose of bone-marrow derived mesenchymal stem cells was 1·4×106 (min-max range 0·4-9×106) cells per kg bodyweight. 27 patients received one dose, 22 received two doses, and six three to five doses of cells obtained from HLA-identical sibling donors (n=5), haploidentical donors (n=18), and third-party HLA-mismatched donors (n=69). 30 patients had a complete response and nine showed improvement. No patients had side-effects during or immediately after infusions of mesenchymal stem cells. Response rate was not related to donor HLA-match. Three patients had recurrent malignant disease and one developed de-novo acute myeloid leukaemia of recipient origin. Complete responders had lower transplantation-related mortality 1 year after infusion than did patients with partial or no response (11 [37%] of 30 vs 18 [72%] of 25; p=0·002) and higher overall survival 2 years after haemopoietic-stem-cell transplantation (16 [53%] of 30 vs four [16%] of 25; p=0·018). Interpretation: Infusion of mesenchymal stem cells expanded in vitro, irrespective of the donor, might be an effective therapy for patients with steroid-resistant, acute GVHD. Funding: Swedish Cancer Society, Children's Cancer Foundation, Swedish Research Council, Cancer Society in Stockholm, Cancer and Allergy Foundation, Karolinska Institutet, Istituto Superiore di Sanità, European Union, Regione Lombardia, Fondazione CARIPLO, Associazione Italiana Ricerca contro il Cancro, Compagnia di San Paolo Torino, Progetto CARIGE Cellule Staminali, European Commission, Ministero dell'Università e della Ricerca Scientifica e Tecnologica, Ricerca Finalizzata Regione Liguria 2005 Assistenza Domiciliare, Dutch Programme for Tissue Engineering. © 2008 Elsevier Ltd. All rights reserved.

Objectives We present an overview of the literature between 1997 and 2007 on parental stress reactions following the diagnosis of childhood cancer and we evaluate methodological strengths and weaknesses of the studies. Methods PubMed, PsychInfo, and Cinahl databases were used. Sixty-seven were included in the review. Results The conceptualization of parental stress and timing of assessment varies considerably between the studies, which makes comparison difficult. Most emotional stress reactions are seen around the time of diagnosis, with mothers reporting more symptoms than fathers. As a group, parents seem relatively resilient, although a subset of parents reports continuing stress even up to 5 years or more postdiagnosis. Conclusions The authors recommend clear definitions of parental stress, fixed points in time to assess parental stress, and an approach that highlights both parental strengths and weaknesses.Improved assessment can contribute to tailoring psychological care to those parents most in need.

BACKGROUND: Granulocyte transfusion has been proposed as a bridging therapy for patients with prolonged periods of chemotherapy-induced neutropenia, who suffer from severe fungal and bacterial infections. To recover, adequate numbers of granulocytes are required when the patients are refractory to standard treatment. The aim of this study was to assess the functional characteristics and efficacy of granulocyte colony-stimulating factor/dexamethasone-mobilized granulocytes used for transfusions. DESIGN AND METHODS: Granulocytes from the leukapheresis products were tested for the expression of cell-surface antigens, interactions with endothelial cells, motility, killing of microbes and survival. The granulocytes were used in vivo for transfusion in 16 severely ill children, who were--apart from a patient with a granulocyte dysfunction--all suffering from prolonged neutropenia. RESULTS: Mobilization of granulocytes with granulocyte colony-stimulating factor and dexamethasone caused phenotypic changes (decreased CD62L expression and increased levels of CD66b and CD177). The ability of the granulocytes to interact with endothelial cells (rolling, adhesion, transmigration) and to kill various types of pathogens was not affected by the mobilization, leukapheresis and irradiation procedures. The granulocytes were functionally indistinguishable from those isolated from untreated donors, even after 24 hours of storage. Granulocyte transfusion seemed to benefit 70% of patients, as 11 out of the 16 children showed clinical recovery within 1-2 weeks after beginning the transfusions. CONCLUSIONS: Although CD62L expression is downregulated on granulocytes used for granulocyte transfusions, concomitant CD177 upregulation may explain the intact interactions with endothelial cells. All other granulocyte functions tested were intact, including the ability to kill fungi. Granulocyte concentrates can be stored without loss of in vitro viability and functionality for at least 24 hours. As demonstrated in vivo, granulocyte transfusions may be an effective therapy for neutropenic pediatric patients suffering from life-threatening infections

Summary Background Severe bacterial and fungal infection remains a persistent cause of morbidity and mortality in severely neutropenic patients undergoing intensive chemotherapy and/or haematopoietic stem cell transplantation Aim To analyze granulocyte source, collection and storage as well as clinical efficacy and toxicity of modern granulocyte transfusions for treatment of severe bacterial and fungal infections in neutropenic patients undergoing intensive chemotherapy and/or haematopoietic stem cell transplantation. Materials/Methods A review of PubMed references based on evidence-based recommendations and own experience. Results A single dose regimen of subcutaneous G-CSF plus oral dexamethasone administered 12 hours prior to leukapheresis appears to be a cost-effective regimen for mobilizing granulocytes from normal donors. Modern continuous flow centrifugation is used to collect granulocytes, whilst a sedimenting agent such as hydroxyethyl starch removes erythrocytes. If required storage at 10°C rather than 22°C better preserves function of collected granulocytes for up to 24 hours. Peters et al. (1999) treated 30 children for documented infection, with just over half receiving G-CSF stimulated donor granulocytes. In this series 82% of bacterial and 54% of fungal infections responded. In the Netherlands 18 children have been treated with granulocyte transfusions. In children with established infection 75% responded. Transfusion reactions associated with mobilized granulocyte transfusions are similar to other blood components, and are generally mild. Conclusions Modern granulocyte transfusions are a relatively safe albeit controversial modality of treatment. Reasonable indications are resistant severe bacterial infection with no response to antibiotics and localized fungal infections in neutropenic patients as well as neutropenic typhilitis. The efficacy in treating or preventing sepsis remains to be established in prospective controlled trials. Within the paediatric setting, literature other than in neonates is relatively sparse and deserves further clinical studies.

Summary Aim To review literature data concerning treatment of procedure-related complications in the intensive care unit in children undergoing allogeneic haematopoietic stem cell transplantation with a focus on clinical results, limitations of studies, recent improvements and remaining problems. Materials/Methods A review of PubMed references based on evidence-based recommendations and own experience. Results Modern ICU care both for adults and children undergoing HSCT has improved in the last decade. However, multi-organ system failure and those requiring mechanical ventilation have the worst outcome. Within the paediatric setting the majority of children are transferred for respiratory support and pulmonary complications. Septic shock and its consequences are associated with far fewer admissions to the ICU. The role of the ICU requires constant revision as protocols and treatments change both in the HSCT unit as well as in intensive care. Conclusions An adequate scoring system such as an adapted O-PRISM should be developed and would lead to the possibility of multi-centre comparative data acquisition and develop future studies in this critically ill group of patients.

Background Although delayed red cell engraftment and/or hemolysis have been thoroughly documented in association with ABO incompatibility between donor and recipient in patients undergoing hematopoietic stem cell transplantation (HSCT), there are no studies defining the general, long term clinical outcome in a large group of pediatric patients. Methods We undertook a retrospective single center analysis of children undergoing pediatric allogeneic stem cell transplantation to determine the influence of ABO donor/recipient incompatibility. Outcome was analyzed according to donor type and included survival, graft versus host disease (GvHD), relapse, days of infection, antibiotic use, transfusion requirement and duration of hospital stay. Results Two hundred and sixteen children (136 males; 80 females, aged 0–19) transplanted between January 1992 and December 2003 were included in the study. Indications for transplantation were hematological malignancies (n = 179) and aplastic conditions (n = 37). ABO compatibility was documented in 121 donor/recipient pairs. ABO incompatibility was documented in 95 donor/recipient pairs with 40 major, 40 minor and 15 bi-directional incompatible pairs. ABO incompatibility did not influence survival rate (P = 0.3762), the incidence of GvHD (P = 0.253) or rate of relapse (P = 0.930). Recovery of leucocytes was influenced by ABO incompatibility (P = 0.0493), but the rate of infection, transfusion requirements and duration of hospital stay are not. Conclusion In the pediatric setting, ABO major and/or minor mismatch between donor and recipient did not significantly influence the outcome of HSCT. The choice of donor should be determined by the degree of HLA match and CMV status in preference to ABO blood group compatibility. Pediatr Blood Cancer 2007;49:313–317. © 2006 Wiley-Liss, Inc.

An aberrant interaction between hematopoietic stem cells and mesenchymal stromal cells has been linked to disease and shown to contribute to the pathophysiology of hematologic malignancies in murine models. Juvenile myelomonocytic leukemia is an aggressive malignant disease affecting young infants. Here we investigated the impact of juvenile myelomonocytic leukemia on mesenchymal stromal cells. Mesenchymal stromal cells were expanded from bone marrow samples of patients at diagnosis (n=9) and after hematopoietic stem cell transplantation (n=7; from 5 patients) and from healthy children (n=10). Cells were characterized by phenotyping, differentiation, gene expression analysis (of controls and samples obtained at diagnosis) and in vitro functional studies assessing immunomodulation and hematopoietic support. Mesenchymal stromal cells from patients did not differ from controls in differentiation capacity nor did they differ in their capacity to support in vitro hematopoiesis. Deep-SAGE sequencing revealed differential mRNA expression in patient-derived samples, including genes encoding proteins involved in immunomodulation and cell-cell interaction. Selected gene expression normalized during remission after successful hematopoietic stem cell transplantation. Whereas natural killer cell activation and peripheral blood mononuclear cell proliferation were not differentially affected, the suppressive effect on monocyte to dendritic cell differentiation was increased by mesenchymal stromal cells obtained at diagnosis, but not at time of remission. This study shows that active juvenile myelomonocytic leukemia affects the immune response-related gene expression and function of mesenchymal stromal cells. In contrast, the differential gene expression of hematopoiesis-related genes could not be supported by functional data. Decreased immune surveillance might contribute to the therapy resistance and progression in juvenile myelomonocytic leukemia.

Current treatment strategies in pediatric oncology are intensive and lead to high survival rates but also to treatment-related complications. Therefore, supportive care plays an increasingly important role. This study was designed to evaluate variations in supportive care practice in children with cancer in the Netherlands and adherence to selected existing international guidelines through an in-depth review of local guidelines and protocols at all 6 Dutch pediatric cancer centers.Based on shared expert opinion, a questionnaire regarding current supportive care practice was compiled. For each center, the required information was extracted from local supportive care guidelines, and the list was sent to a pediatric oncologist of that center to verify its correspondence with local daily practice. Subsequently, it was determined whether clinical practice was concordant (same in ≥ 5 of 6 centers), partly concordant (highly overlapping in ≥ 5 of 6 centers), or discordant (same in 5 of 6 centers). Local practices were compared with strong recommendations from high-quality, evidence-based guidelines.The questionnaire comprised 67 questions regarding supportive care practice. Concordance was observed for 11 of 67 practice items (16%), partial concordance was observed for 6 of 67 practice items (9%), and discordance was observed for 50 of 67 practice items (75%). Adherence to strong recommendations of 4 high-quality, evidence-based guidelines varied but was generally low.Large variations exist in pediatric oncology supportive care practice, and this could negatively influence care. Adherence to existing evidence-based guidelines and the development and implementation of new clinical practice guidelines have the potential of standardizing supportive care practice and thereby improving outcomes for children with cancer.

Children with advanced stages (relapsed/refractory and stage IV) of rhabdomyosarcoma (RMS) have a poor prognosis despite intensive chemotherapy and autologous stem cell rescue, with 5-year survival rates ranging from 5 to 35 %. Development of new, additional treatment modalities is necessary to improve the survival rate. In this preclinical study, we investigated the potential of resting and cytokine-activated natural killer (NK) cells to lyse RMS cell lines, as well as the pathways involved, to explore the eventual clinical application of (activated) NK cell immunotherapy. RMS cell lines (n = 3 derived from embryonal RMS and n = 2 derived from alveolar RMS) were susceptible to cytolysis mediated by resting NK cells, and this susceptibility was significantly increased using IL-15-activated NK cells. Flow cytometry and cytolytic assays were used to define the activating and inhibitory pathways of NK cells involved in recognizing and lysing RMS cells. NKG2D and DNAM-1 receptor-ligand interactions were essential in cytolysis by resting NK cells, as simultaneous blocking of both pathways resulted in almost complete abrogation of the cytotoxicity. In contrast, combined blocking of DNAM-1 and NKG2D only led to partial reduction of the lytic activity of IL-15-activated NK cells. In this respect, residual lysis was, at least partly, mediated by pathways involving the natural cytotoxicity receptors NKp30 and NKp46. These findings support further exploration of NK cell-based immunotherapy as adjuvant modality in current treatment strategies of RMS. Electronic supplementary material The online version of this article (doi:10.1007/s00262-015-1657-9) contains supplementary material, which is available to authorized users.

Cidofovir is frequently used to treat life-threatening human adenovirus (HAdV) infections in immunocompromised children after hematopoietic stem cell transplantation (HSCT). However, the antiviral effect irrespective of T cell reconstitution remains unresolved. Plasma HAdV DNA levels were monitored by real-time quantitative PCR during 42 cidofovir treatment episodes for HAdV viremia in 36 pediatric allogeneic HSCT recipients. HAdV load dynamics were related to T and natural killer (NK) cell reconstitution measured by flow cytometry. To evaluate the in vivo antiadenoviral effect of cidofovir, we focused on 20 cidofovir treatment episodes lacking concurrent T cell reconstitution. During 2 to 10 weeks of follow-up in the absence of T cells, HAdV load reduction (n = 7) or stabilization (n = 8) was observed in 15 of 20 treatments. Although HAdV load reduction was always accompanied by NK cell expansion, HAdV load stabilization was measured in 2 children lacking both T and NK cell reconstitution. In cases with T cell reconstitution, rapid HAdV load reduction (n = 14) or stabilization (n = 6) was observed in 20 of 22 treatments. In the absence of T cells, cidofovir treatment was associated with HAdV viremia control in the majority of cases. Although the contribution of NK cells cannot be excluded, cidofovir has the potential to mediate HAdV load stabilization in the time pending T cell reconstitution.

Key Clinical Message Hemolytic anemia due to GPI deficiency can be severe and life threatening during fetal life. When parents decline invasive testing, ultrasound monitoring of fetuses at risk is feasible. Intrauterine transfusion can be effective for the treatment of severe fetal anemia due to GPI deficiency.

For many children with life-threatening hematological diseases, hematopoietic stem cell transplantation (HSCT) is the only curative option. In children lacking a matched related or unrelated donor and with the certainty that, left untreated, death will ensue alternative donors must be sought. Haplo-identical peripheral blood stem cell transplantation (PBSCT) from a healthy parent is a feasible alternative. To reduce the risk of fatal graft-versus-host disease (GvHD) as a complication of transplant across major histocompatibility antigens, intense T-cell depletion is required. Large numbers of purified, cytokine mobilized peripheral stem cells (the so-called mega-dose concept) are required to compensate for the significantly increased risk of either graft failure or early rejection. In our unit, despite this approach, graft dysfunction has, in a significant group of children, proved problematic and, despite salvage attempts at re-transplantation, usually fatal. In children with hematological malignant disease, our overall relapse-free survival is 41%. However, successful transplant outcome has been associated with considerable delays in immune reconstitution that can be implicated in subsequent viral reactivation. We are investigating new strategies to improve the outcome of haplo-identical PBSCT, which may allow us to offer this form of treatment to more children requiring urgent HSCT.

We studied the pharmacokinetics of intravenous busulfan (Bu) in children in order to further optimize intravenous Bu dosing in relation to toxicity and survival. A total of 31 children undergoing Bu-based conditioning for allogeneic SCT were enrolled in a study. The starting dose was 1.0 mg/kg (age4 years) and 0.8 mg/kg (ageor =4 years), four doses per day during 4 days. Dose adjustment was allowed up to a maximum dose of 1.0 mg/kg per dose if the target area under the serum concentration-time curve (AUC) was not reached. Pharmacokinetic studies were performed after the first dose. Donor engraftment was established in 28 out of 31 patients. The average AUC after the first dose was the same in children4 years as in childrenor =4 years. Mean clearance was higher in children4 years than in childrenor =4 years. In 35% of all patients, total AUC was within the target AUC. The other children's AUCs were below the target range. No relationships were found between systemic exposure to Bu and toxicity or clinical outcome. We concluded that, in accordance with previous data, within the observed AUCs no clear relationship was observed between Bu AUC and outcome with respect to toxicity, engraftment and relapse.

We reviewed the results of the Dutch paediatric bone marrow transplant (BMT) program for children receiving HLA-identical BMT for beta-thalassaemia major over an 18-year period. In all, 19 patients underwent a total of 21 transplants in our treatment centre between July 1984 and February 2002. Eight females (age 0.3-12 years; median 5 years) and 11 males (age 0.8-18 years; median 6 years) were included. Information, prospectively collected, included molecular defects, donor genotype, beta/alpha-globin expression rates, serum ferritin levels, hepato-splenomegaly, chelation history, virology screening, liver pathology together with post-transplant outcome inclusive of leucocyte chimerism. In total, 11 patients received standard busulphan/cyclophosphamide (Bu/Cy) conditioning, with or without ATG. Stable engraftment was seen in 5/11 with late rejection occurring in six patients. Of these, two children underwent a second successful SCT. For this group, overall event-free survival (EFS) and disease-free survival (DFS) were 90 (10/11) and 64% (7/11), respectively. The probability of rejection was 55%. Subsequent addition of melphalan to the conditioning regimen resulted in long-term stable engraftment in all patients with an EFS/DFS for this group of 90% (9/10). Treatment-related mortality, irrespective of conditioning, was low at 5% (1/19 patients). Veno-occlusive disease (VOD) occurred in 19% (4/21 transplants) and acute GvHD in 19% (4/21 transplants). Post-BMT beta/alpha synthetic ratio measurement monitored donor erythroid engraftment and predicted rejection with a return to transfusion dependency. Maintained full donor chimerism is indicative of stable engraftment both for leucocyte and erythroid lineages, whereas mixed donor chimerism is not. Our results emphasise the importance of the conditioning regimen and post-transplant chimerism surveillance predictive of rejection or long-term stable engraftment.

Aims Intravenous formulations of busulfan have recently become available. Although busulfan is used frequently in children as part of a myeloablative regimen prior to bone marrow transplantation, pharmacokinetic data on intravenous busulfan in children are scarce. The aim was to investigate intravenous busulfan pharmacokinetics in children and to suggest a limited sampling strategy in order to determine busulfan systemic exposure with the minimum of inconvenience and risk for the patient. Methods Plasma pharmacokinetics after the first administration was investigated in six children using nonlinear mixed effect modelling. Results Pharmacokinetics showed little variability and were described adequately with a one-compartment model (population estimates CL,av=0.29 l h−1 kg−1; V,av=0.84 l kg−1; t1/2=1.7–2.8 h). Combined with limited sampling and a Bayesian fitting procedure, the model can adequately estimate the systemic exposure to intravenous busulfan, which in children appears to be at the lower end of the adult range. Conclusions Busulfan systemic exposure in children during intravenous administration can be estimated adequately with limited sampling and a Bayesian fitting procedure from a one-compartment model. Intravenous busulfan pharmacokinetics in children should be the subject of more research.

Beneficial effects of mesenchymal stromal cells (MSCs) in patients with severe steroid-refractory acute graft-versus-host disease (aGvHD) have been reported. However, controversy exists about the effect of MSCs on virus-specific T cells. We evaluated 56 patients with grade II-IV aGvHD who responded to steroids (n = 21) or were steroid refractory receiving either MSCs (n = 22) or other second-line therapy (n = 13). Although the overall incidence of cytomegalovirus (CMV), Epstein-Barr virus, and human adenovirus (HAdV) infections was not significantly increased, HAdV infection was associated with decreased survival in children treated with MSCs. Thus, we investigated in vitro the effects of MSCs on virus-specific T cells. Both CMV-specific and, to a lesser extent, HAdV-specific T-cell activation and proliferation were negatively affected by MSCs either after induction of a response in peripheral blood mononuclear cells (PBMCs) or after restimulation of virus-specific T-cell lines. In patient-derived PBMCs, CMV-specific proliferative responses were greatly decreased on first-line treatment of aGvHD with systemic steroids and slowly recovered after MSC administration and tapering of steroids. HAdV-specific T-cell proliferation could not be detected. In contrast, the proportion of CMV- and HAdV-specific effector T cells, measured as interferon-γ-secreting cells, remained stable or increased after treatment with MSCs. In conclusion, although in vitro experimental conditions indicated a negative impact of MSCs on CMV- and HAdV-specific T-cell responses, no solid evidence was obtained to support such an effect of MSCs on T-cell responses in vivo. Still, the susceptibility of steroid-refractory severe aGvHD patients to viral reactivation warrants critical viral monitoring during randomized controlled trials on second-line treatment including MSCs.

Background and aims Varicella zoster virus (VZV) reactivation following hematopoietic stem cell transplantation (HSCT) may cause significant morbidity and mortality. We undertook a retrospective study to determine the frequency and risk factors associated with VZV reactivation, including underlying disease, the use of fludarabine in high-risk leukemia chemotherapy protocols, and immune status before HSCT. Patients and methods We studied 163 children who underwent a first HSCT between 2002 and 2008, before introduction of routine VZV prophylaxis on our unit. VZV diagnosis was based on clinical features and supported by polymerase chain reaction on plasma and/or vesical fluid. Patient data and possible risk factors pre- and post HSCT were recorded and compared using a multivariate regression analysis. Results Within this cohort, 41 (25%) patients developed VZV reactivation during the first year after transplantation at a median of 60 days post HSCT. VZV reactivation occurred more often within the subgroup of patients with acute leukemia compared with the remainder of patients (38% vs. 15%, P

Ovarian insufficiency (OI) and infertility are common and devastating late effects of cancer treatment and hematopoietic stem cell transplantation (HSCT). In children, gonadal insufficiency may subsequently lead to abnormal pubertal development. The aim of this study was to assess the cumulative incidence of OI and the need for hormonal induction of pubertal development after HSCT in childhood. We additionally assessed HSCT-related risk factors for OI.A single center cohort study was undertaken of female patients transplanted during childhood, surviving at least 2 years post-HSCT and who were at least 10 years old at initiation of the study. Of 141 eligible patients, 109 were included and hormone levels and clinical data of these patients during follow-up were collected. Risk factors for OI were analyzed by multivariate Cox regression analysis.Cumulative incidence of OI was 56% at a median follow-up of 7.2 years. Eight patients, initially diagnosed with OI, showed recovery of ovarian function over time. Hormonal induction of puberty was necessary in 44% of females who were pre-pubertal or pubertal at HSCT. In multivariate analysis, more advanced pubertal stage at HSCT was associated with OI. We found a trend for an association of busulfan with OI in patients conditioned with chemotherapy only.The incidence of OI after HSCT was high and associated with more advanced pubertal stage at HSCT. Almost half of the females who were pre-pubertal or pubertal at HSCT required hormonal induction of pubertal development.

Two adolescents, on immunosuppressive therapy for graft-versus-host disease, developed hemophagocytic lymphohistiocytosis (HLH) after varicella zoster virus (VZV) reactivation. In the absence of dermatome restricted characteristic skin lesions, VZV reactivation was not immediately recognized and treatment with acyclovir was delayed. The first patient developed optical neuritis and died 2 months after the VZV episode due to massive intracranial hemorrhage. The second patient presented with severe abdominal pain and pancreatitis, followed by atypical skin eruptions, which prompted a faster diagnosis. Both patients recovered from their HLH, the first patient being successfully treated with immunosuppressive agents and the second with VZV treatment only. These two cases demonstrate the difficulties in recognizing VZV reactivation, and in order to start adequate and timely treatment, the need to consider VZV as a possible cause of HLH in severely immunocompromised patients.

Steroid-nonresponsive acute graft-versus-host disease (aGVHD) after hematopoietic stem cell transplantation carries a poor prognosis. Various groups have reported beneficial effects of mesenchymal stromal cell (MSC) infusion as salvage treatment. Response to treatment is typically evaluated using the diagnostic clinical criteria for aGVHD. In this study, we evaluated the usefulness of additional gastrointestinal biopsy specimens paired with serum biomarkers. In a cohort of 22 pediatric patients, persistent or recurrent diarrhea was seen in 18 children treated with MSC infusion for steroid-refractory aGVHD. To exclude other causes of gastrointestinal pathology, patients were biopsied for histological analysis. Eight of 12 patients exhibited residual tissue damage and villous atrophy, but no active aGVHD. Serum biomarkers have been identified as an alternative tool for monitoring the response to aGVHD treatment. The value of biomarkers for inflammation, tissue, and endothelial cell damage was evaluated in our cohort. Although predictive of response to treatment and survival, these markers lack the necessary specificity and sensitivity to predict response to MSC therapy. Objective endpoints for clinical trials on the treatment of steroid-refractory aGVHD remain to be defined. Thus, we recommend including biopsies and biomarkers to discriminate between ongoing aGVHD and postinflammatory malabsorption.

Mesenchymal stromal cell (MSC) infusions have been reported to be effective in patients with steroid-refractory, acute graft-versus-host disease (aGvHD) but comprehensive data on paediatric patients are limited. We retrospectively analysed a cohort of 37 children (aged 3months-17years) treated with MSCs for steroid-refractory grade III-IV aGvHD. All patients but three received multiple MSC infusions. Complete response (CR) was observed in 24 children (65%), while 13 children had either partial (n=8) or no response (n=5). Cumulative incidence of transplantation-related mortality (TRM) in patients who did or did not achieve CR was 17% and 69%, respectively (P=0·001). After a median follow-up of 2·9years, overall survival (OS) was 37%; it was 65% vs. 0% in patients who did or did not achieve CR, respectively (P=0·001). The median time from starting steroids for GvHD treatment to first MSC infusion was 13d (range 5-85). Children treated between 5 and 12d after steroid initiation showed a trend for better OS (56%) and lower TRM (17%) as compared with patients receiving MSCs 13-85d after steroids (25% and 53%, respectively; P=0·22 and 0·06, respectively). Multiple MSC infusions are safe and effective for children with steroid-refractory aGvHD, especially when employed early in the disease course. © 2013 John Wiley & Sons Ltd.

Since 1968, when Leiden undertook the first successful European pediatric BM transplantation with a 7-year-old sibling donor, more than 300 young children have donated BM in our unit. We first retrospectively studied a cohort of 210 donors, younger than 13 years at donation, to survey procedures of donor eligibility and study immediate effects of BM donation. We then performed a long-term follow-up (FU) and health-related quality of life (HRQoL) study. Despite documentation of previous medical conditions, no child was declared unfit to donate. We found that iron deficiency anemia or low-iron stores in BM did not result in treatment or extended FU. Harvest volumes exceeded 15 mL/kg in 65% of donors, with more than half requiring allogeneic blood transfusions. Donors had no structured FU after their first post-donation control. In this study, 25% of donors reported at least one somatic complaint at long-term FU. Finally long-term HRQoL revealed high scores in most subdomains (representing a higher QoL), compared to norm groups. These results indicate the need for development of (inter)national guidelines for pediatric stem cell donor care management.

Mesenchymal stromal cells (MSCs) are multipotent cells that can be isolated from several human tissues and expanded ex vivo for clinical use. They comprise a heterogeneous population of cells, which, through production of growth factors, cell-to-cell interactions and secretion of matrix proteins, play a key role in the regulation of haematopoiesis. In recent years, several experimental studies have shown that MSCs are endowed with potent immunomodulatory properties directed in vitro at all cells involved in immune responses. Due to their immunomodulatory and engraftment-promoting properties, MSCs have been tested in the clinical setting both to facilitate haematopoietic engraftment and to treat steroid-resistant acute graft-versus-host disease (GvHD). More recently, experimental findings and clinical trials have focused on the ability of MSCs to home to injured tissues and to produce paracrine factors with anti-inflammatory properties, resulting in functional recovery of damaged tissues. The mechanisms through which MSCs exert this pleomorphic therapeutic potential rely on some key properties of these cells: the capacity to home to sites of injury, the ability to blunt exaggerated immune responses and the ability to secrete soluble factors capable of stimulating both the survival and recovery of injured cells. This chapter focuses on recent advances in MSC biology and summarises the clinical studies on their immunomodulatory and anti-inflammatory properties, particularly in the setting of allo- and autoimmune disorders.

Hematopoietic stem cell transplantation (HSCT) is an accepted treatment for some children with certain life-threatening conditions such as malignant diseases, immune deficiency, inborn errors of metabolism, bone marrow failure syndromes, and hemoglobinopathies. The introduction of alternative donor population such as cord blood and haploidentical transplantations has resulted in this treatment becoming more readily available. Inherent risks with alternative donor sources are mainly immune-mediated complications, with graft rejection or graft failure and graft-versus-host disease (GVHD) as main obstacles. Mesenchymal stromal cells (MSCs) through cell-to-cell interactions, production of growth factors, and secretion of matrix proteins play a vital role in the regulation of hematopoiesis and exhibit a wide range of immunomodulatory and anti-inflammatory properties in vitro and in vivo. Use of MSCs in phase I/II clinical studies with HSCT in children indicates that their infusion is safe and effective in preventing graft failure after T-cell-depleted allogeneic HSCT from an HLA-disparate relative as well as in rescuing patients with severe, steroid-refractory GVHD.

Infusion of mesenchymal stromal cells (MSCs) has been reported to be an effective treatment modality for acute graft-versus-host disease, and MSCs have been considered for use in the treatment of patients with autoimmune diseases. Before contemplating clinical studies with MSCs in patients with systemic juvenile idiopathic arthritis (sJIA), the immunomodulatory capacity of MSCs in this setting needs to be explored. A comparative analysis of bone marrow-derived MSCs from children with sJIA and healthy pediatric controls was performed.MSCs were successfully expanded from 11 patients with sJIA and 10 controls. The phenotype, differentiation and immunomodulatory capacity of these MSCs were compared. The effect of immunosuppressive drugs on MSC function was also investigated.MSCs from patients with sJIA and controls showed no differences in their suppressive effect using control peripheral blood mononuclear cells. Furthermore, the suppression of the response of peripheral blood mononuclear cells from patients with sJIA by autologous sJIA MSCs and allogeneic control MSCs was comparable. The immunosuppressive effect of both groups of MSCs was diminished in the presence of indomethacin (P 0.05). MSCs from patients with sJIA and controls suppressed interleukin-2-induced natural killer cell activation to a similar extent. In addition, MSCs of patients with sJIA and controls inhibited the differentiation of monocytes to dendritic cells.This is the first explorative study in a significant cohort of patients with sJIA to evaluate the effect of MSCs on adaptive and innate immune responses. The comparable immunosuppressive characteristics of MSCs derived from patients with sJIA to age-matched controls support the potential use of patient-derived MSCs in the treatment of sJIA.

When compared with BMT, umbilical cord blood transplantation (UCBT) is associated with a lower rate of engraftment and delayed hematological/immunological recovery. This leads to increased risk of TRM in the early post transplantation period due to infection. Acute GVHD, although occurring less frequently in UCBT compared with BMT, is also significantly associated with increased rate of early TRM. BM MSCs are known to support normal in vivo hematopoiesis, and co-transplantation of MSCs has been shown to enhance engraftment of human cord blood hematopoietic cells in nonobese diabetic/SCID mice. In 13 children with hematological disorders (median age 2 years) undergoing UCBT, we co-transplanted paternal, HLA-disparate MSCs with the aim of improving hematological recovery and reducing rejection. We observed no differences in hematological recovery or rejection rates compared with 39 matched historical controls, most of whom received G-CSF after UCBT. However, the rate of grade III and IV acute GVHD was significantly decreased in the study cohort when compared with controls (P = 0.05), thus resulting in reduced early TRM. Although these data do not support the use of MSCs in UCBT to support hematopoietic engraftment, they suggest that MSCs, possibly because of their immunosuppressive effect, may abrogate life-threatening acute GVHD and reduce early TRM. Bone Marrow Transplantation (2011) 46, 200-207; doi: 10.1038/bmt.2010.87; published online 19 April 2010

The aim of our study was to assess the cumulative incidence and severity ('burden') of late effects in a single-centre cohort of childhood haematopoietic stem cell transplantation (HSCT) survivors, at least 2 years after transplantation. The presence and severity of late effects in each survivor was documented according to the Common Terminology Criteria for Adverse Events (version 3.0). The burden of late effects was graded from mild to disabling/life-threatening. Risk factors for a high burden of late effects were assessed by univariate and multivariate logistic regression analyses. Among 162 survivors of HSCT seen in our late effects outpatient clinic, cumulative incidence of late effects was 93.2% after a median follow-up time of 7.2 years (range 2.0-21.0 years) after HSCT. The burden of late effects was mild, moderate, severe and disabling in 28, 41, 24 and 1% of survivors respectively. Risk factors for a severe or disabling burden of late effects were older age at HSCT (P for trend

Background: Mesenchymal stromal cells are employed in various different clinical settings in order to modulate immune response. However, relatively little is known about the mechanisms responsible for their immunomodulatory effects, which could be influenced by both the cell source and culture conditions. Design and Methods: We tested the ability of a 5% platelet lysate-supplemented medium to support isolation and ex vivo expansion of mesenchymal stromal cells from full-term umbilical-cord blood. We also investigated the biological/functional properties of umbilical cord blood mesenchymal stromal cells, in comparison with platelet lysate-expanded bone marrow mesenchymal stromal cells. Results: The success rate of isolation of mesenchymal stromal cells from umbilical cord blood was in the order of 20%. These cells exhibited typical morphology, immunophenotype and differentiation capacity. Although they have a low clonogenic efficiency, umbilical cord blood mesenchymal stromal cells may possess high proliferative potential. The genetic stability of these cells from umbilical cord blood was demonstrated by a normal molecular karyotype; in addition, these cells do not express hTERT and telomerase activity, do express p16ink4a protein and do not show anchorage-independent cell growth. Concerning alloantigen-specific immune responses, umbilical cord blood mesenchymal stromal cells were able to: (i) suppress T- and NK-lymphocyte proliferation, (ii) decrease cytotoxic activity and (iii) only slightly increase interleukin-10, while decreasing interferon-g secretion, in mixed lymphocyte culture supernatants. While an indoleamine 2,3-dioxygenase-specific inhibitor did not reverse mesenchymal stromal cell-induced suppressive effects, a prostaglandin E2-specific inhibitor hampered the suppressive effect of both umbilical cord blood- and bone marrowmesenchymal stromal cells on alloantigen-induced cytotoxic activity. Mesenchymal stromal cells from both sources expressed HLA-G. Conclusions: Umbilical cord blood- and bone marrow-mesenchymal stromal cells may differ in terms of clonogenic efficiency, proliferative capacity and immunomodulatory properties; these differences may be relevant for clinical applications. ©2009 Ferrata Storti Foundation.

A nine-yr-old boy with EPP suffered from severe skin burns and liver failure caused by progressive cholestasis and fibrosis. OLT was performed without major complications. Four months following liver transplantation he underwent parental haploidentical HSCT. The myeloablative conditioning regimen was relatively well tolerated and hematological engraftment was rapid (on day 10). Protoporphyrin concentrations returned to normal following HSCT. However, immune recovery was significantly delayed. Varicella zoster virus reactivation resulted in impaired vision, prolonged hospitalization and eventually in multiorgan failure and death. Sequential liver and haploidentical HSCT proved feasible though a high risk procedure in this EPP patient. The management of post-IST after these combined transplantations remains a challenge and needs to be further established.

Two adolescents, on immunosuppressive therapy for graft-versus-host disease, developed hemophagocytic lymphohistiocytosis (HLH) after varicella zoster virus (VZV) reactivation. In the absence of dermatome restricted characteristic skin lesions, VZV reactivation was not immediately recognized and treatment with acyclovir was delayed. The first patient developed optical neuritis and died 2 months after the VZV episode due to massive intracranial hemorrhage. The second patient presented with severe abdominal pain and pancreatitis, followed by atypical skin eruptions, which prompted a faster diagnosis. Both patients recovered from their HLH, the first patient being successfully treated with immunosuppressive agents and the second with VZV treatment only. These two cases demonstrate the difficulties in recognizing VZV reactivation, and in order to start adequate and timely treatment, the need to consider VZV as a possible cause of HLH in severely immunocompromised patients.

Allogeneic hematopoietic SCT (HSCT) is an established treatment for some children with life-threatening hematological disease, immune deficiencies and inborn errors of metabolism. Despite advances in prevention and post transplant immuno-suppressive strategies, acute GvHD (aGvHD) remains a major cause of morbidity and mortality in children undergoing SCT. Although reported incidence rates differ, it has been estimated that, depending upon the patient and donor cohort studied, 20-50% of all transplanted patients will experience grade 2 or more aGvHD despite immuno-suppressive prophylaxis. aGvHD occurs when transplanted donor T lymphocytes recognize antigenic disparities between the host and recipient. Pathways other than direct T-cell-mediated cytotoxicity have been shown to be important in the pathogenesis. Inflammatory cytokine release has been implicated as the primary mediator of aGvHD and activation of T cells is one step in the complex process. Deregulated cytokine release by cells other than T cells leads to tissue damage associated with aGvHD. GvHD is a factor that compromises the overall success rate of allogeneic HSCT and remains a challenge, which, in turn, requires an understanding of the pathophysiology, clinical presentation and management of this complication. The authors concentrate on the most recent knowledge of the pathogenesis as well as the classification of aGvHD.

Mesenchymal stem cells (MSCs) suppress alloantigen-induced T-cell functions in vitro and infusion of third-party MSCs seems to be a promising therapy for graft-versus-host disease (GVHD). Little is known about the specificity of immunosuppression by MSCs, in particular the effect on immunity to pathogens. We have studied how MSCs affect T-cell responses specific to Epstein-Barr virus (EBV) and cytomegalovirus (CMV). We found that EBV- and CMV-induced proliferation and interferon-γ (IFN-γ) production from peripheral blood mononuclear cells (PBMCs) was less affected by third-party MSCs than the response to alloantigen and that MSCs had no effect on expansion of EBV and CMV pentamer-specific T cells. Established EBV-specific cytotoxic T cells (CTL) or CMV-CTL cultured with MSCs retained the ability to proliferate and produce IFN-γ in response to their cognate antigen and to kill virally infected targets. Finally, PBMCs from 2 patients who received MSCs for acute GVHD showed persistence of CMV-specific T cells and retained IFN-γ response to CMV after MSC infusion. In summary, MSCs have little effect on T-cell responses to EBV and CMV, which contrasts to their strong immunosuppressive effects on alloreactive T cells. These data have major implications for immunotherapy of GVHD with MSCs and suggest that the effector functions of virus-specific T cells may be retained after MSC infusion.

Mesenchymal stromal cells (MSCs) can be isolated from several human tissues and expanded for clinical use. MSCs are identified by phenotypic and functional characteristics, and are poor Ag-presenting cells not expressing MHC class II or co-stimulatory molecules. MSCs have potent immune-modulatory effects and in vitro induce a more anti-inflammatory or tolerant phenotype. Clinical studies have exploited both the immune-modulatory properties of MSCs as well as their hematopoietic supportive role. MSCs have been safely administered for the treatment of severe steroid refractory GVHD. A phase I/II multicenter study included 25 children in whom 80% responded to either one or two infusions of MSCs derived mainly from third party donors. Twenty children have undergone co-transplantation of haploidentical MSCs with PBSC in a phase I/II study, which has overcome the problems of graft failure in HLA-disparate grafts. Similarly, co-transplantation of MSCs and cord blood stem cells is under investigation. MSCs may have important future potential for the treatment of pediatric autoimmune disease as well as inborn errors such as osteogenesis imperfecta. Currently, much needed randomized studies under the auspices of the EBMT are ongoing to determine the optimal use of these exciting new modalities of treatment.

Haploidentical hematopoietic stem-cell transplantation (HSCT) is associated with an increased risk of graft failure. Adult bone marrow-derived mesenchymal stromal cells (MSCs) have been shown to support in vivo normal hematopoiesis and to display potent immune suppressive effects. We cotransplanted donor MSCs in 14 children undergoing transplantation of HLA-disparate CD34+ cells from a relative. While we observed a graft failure rate of 15% in 47 historic controls, all patients given MSCs showed sustained hematopoietic engraftment without any adverse reaction. In particular, children given MSCs did not experience more infections compared with controls. These data suggest that MSCs, possibly thanks to their potent immunosuppressive effect on alloreactive host T lymphocytes escaping the preparative regimen, reduce the risk of graft failure in haploidentical HSC transplant recipients. © 2007 by The American Society of Hematology.

Human Adenovirus (HAdV) reactivation is a frequent and potentially fatal complication in pediatric allogeneic stem cell transplantation (HSCT) recipients, especially after in vivo T-cell depletion. Patients with HAdV reactivations are generally treated with the antiviral agent Cidofovir (CDV), a monophosphate nucleotide analogue. Studies reporting effectiveness of CDV therapy are mostly incomplete due to lack of data on the immune status of the patients. Here, we report the relationship between the effectiveness of CDV therapy and lymphocyte reconstitution as well as the acute and chronic nephrotoxicity of CDV in the setting of pediatric .infections after pediatric HSCT. Between 2003 and 2012, 321 children received 363 allogeneic transplantations in our pediatric HSCT center. HAdV reactivations were monitored by weekly plasma HAdV DNA RQ-PCR. Disseminated infections, defined as two consecutive PCR values above 103 (3 log ) copies / mL occurred in 40 patients (12 %). 30 patients were treated with CDV for infections with an HAdV load ≥ 3 log at start of therapy. In 27 patients, sufficient data were available to evaluate the effectiveness of CDV. Cidofovir was administered IV 3x / week at 1 mg / kg. Prehydration and Probenecid were used to reduce the risk of nephrotoxicity. Patient were median 4.5 (0.5 - 18) years of age and 26 of 27 patients received in vivo T-cell depletion. CDV therapy was initiated median 28 (1 - 121) days after HSCT while the median treatment duration was 15 (1 - 99) days. At start of CDV treatment, the HAdV load was median 4.2 log (range 3.1 log - 6.5 log) copies / mL. Response was evaluated after 14 days of CDV therapy. A ≥ 10x (1 log) reduction of HAdV load was measured in 10 of 27 evaluable patients (37%) while 13 patients (48%) showed a stabilization of HAdV load. CDV treatment failed in 4 patients (15 %), as define by a 1 log increase of HAdV load despite uninterrupted CDV therapy. In 23 patients with a reduction or stabilization of the HAdV load, lymphocyte numbers increased strongly in the two weeks after initiation of CDV treatment (median 130 to 608 lymphocytes / µL, p < 0.0001, Wilcoxon signed-rank test). This increase was caused by reconstitution of NK cells (n = 5), T-cells (n = 4) or both (n = 12). In only 2 patients with a stabilization of HAdV load, no concomitant reconstitution of NK or T-cells was observed. Ultimately, 17 patients (63 %) cleared the virus 5 - 89 (median 33) days after the initiation of CDV therapy. The moment of HAdV clearance was strongly correlated to the first day the T-lymphocytes reached 50 cells/ µl (R2 = 0.79, p < 0.0001, linear regression analysis). 7 patients died of progressive HAdV viremia with multi-organ failure (MOF) at 20 - 154 (median 51) days after initiation of CDV therapy. Three patients were not evaluable as they died of another cause (n=2) or were lost to follow up (n=1) without clearance of the virus. For the analysis of CDV nephrotoxicity, 3 patients with HAdV related MOF during CDV therapy were excluded, leaving 24 patients. In 4 patients (17%), CDV therapy had to be discontinued because of acute glomerular failure, which invariably occurred within the first 2 weeks of treatment. Tubular kidney failure, defined by the need for suppletion of phosphate, magnesium or bicarbonate, was observed in 17 of 24 patients (71%). Kidney failure was transient in the majority of patients. After 1 year, 1 of 12 survivors (8 %) had chronic glomerular and tubular kidney failure that could not be explained by nephrotoxic co-medication. In 9 additional HSCT recipients who received > 7 days of CDV therapy for non-disseminated HAdV infections, 1 of 8 surviving patients (13 %) had chronic kidney failure that was unlikely to be caused by other nephrotoxic medication. In conclusion, a reduction of HAdV load in the first 2 weeks of therapy was always accompanied by lymphocyte recovery while Cidofovir could not prevent further dissemination in 4 of 27 patients. In most patients with a stabilization of the viremia, this could be attributed to both CDV as well as T- or NK-cell reconstitution whereas in only 2 patients (7%), the HAdV load stabilized in the absence of lymphocyte recovery. These data suggest that CDV possibly plays a role in the stabilization of HAdV viremia in the time pending T-cell recovery. In view of the considerable toxicity profile, a multicenter randomized clinical trial is warranted to establish efficacy of CDV treatment for disseminated HAdV infections after pediatric HSCT. Disclosures: Off Label Use: The antiviral agent Cidofovir (CDV), a monophosphate nucleotide analogue, is widely used off-label for the treatment of disseminated Human Adenovirus infections after Pediatric Hematopoietic Stem Cell Tansplantation.

Cell proliferation rates of diagnostic marrow aspirate cells of 21 children with Acute Lymphoblastic Leukaemia and 16 controls were compared using immunocytochemical labelling of PCNA and Ki-67 antigen as assessed by Confocal Laser Scanning Microscopy. The results showed an unexpected, highly significant degree of dissociation between PCNA and Ki-67 expression in ALL blasts. The PCNA labelling indices of ALL patients were significantly increased (mean 44, range 24-77) compared with normal reactive marrow cells (mean 13.8, range 4-26) (p0.000001, Mann Whitney U two tailed test), suggesting an abnormal commitment to proliferation. Ki-67 expression was raised to a lesser extent in ALL cells (mean 14.8, range 1.2-35) when compared to non-malignant proliferations (mean 6.6, range 1.7-25) (p0.02). PCNA/Ki-67 LI ratios in ALL (mean 7, range 1.1-35) were higher than in controls (mean 2.7, range 1.04-6.5, p0.09). As cell proliferation rates actually achieved in the bone marrow do not differ as strongly as suggested by the extreme difference in PCNA labelling, a pathological dissociation of PCNA/Ki-67 expression exists, suggesting immortalisation.