Diagnosis and severity criteria for sinusoidal obstruction syndrome/veno-occlusive disease in pediatric patients: a new classification from the European society for blood and marrow transplantation.

The advances in hematopoietic cell transplantation (HCT) over the last decade have led to a transplant-related mortality below 15%. Hepatic sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD) is a life-threatening complication of HCT that belongs to a group of diseases increasingly identified as transplant-related, systemic endothelial diseases. In most cases, SOS/VOD resolves within weeks; however, severe SOS/VOD results in multi-organ dysfunction/failure with a mortality rate >80%. A timely diagnosis of SOS/VOD is of critical importance, given the availability of therapeutic options with favorable tolerability. Current diagnostic criteria are used for adults and children. However, over the last decade it has become clear that SOS/VOD is significantly different between the age groups in terms of incidence, genetic predisposition, clinical presentation, prevention, treatment and outcome. Improved understanding of SOS/VOD and the availability of effective treatment questions the use of the Baltimore and Seattle criteria for diagnosing SOS/VOD in children. The aim of this position paper is to propose new diagnostic and severity criteria for SOS/VOD in children on behalf of the European Society for Blood and Marrow Transplantation.

Fertility preservation issues in pediatric hematopoietic stem cell transplantation: practical approaches from the consensus of the Pediatric Diseases Working Party of the EBMT and the International BFM Study Group.

Fertility preservation is an urgent challenge in the transplant setting. A panel of transplanters and fertility specialists within the Pediatric Diseases Working Party of the European Society for Blood and Marrow Transplantation (EBMT) and the International BFM Study Group provides specific guidelines. Patients and families should be informed of possible gender- and age-specific cryopreservation strategies that should be tailored according to the underlying disease, clinical condition and previous exposure to chemotherapy. Semen collection should be routinely offered to all postpubertal boys at the diagnosis of any disease requiring therapy that could potentially impair fertility. Testicular tissue collection might be offered to postpubertal boys; nevertheless, its use has been unsuccessful to date. Oocyte collection after hormonal hyperstimulation should be offered to postpubertal girls facing gonadotoxic therapies that could be delayed for the 2 weeks required for the procedure. Ovarian tissue collection could be offered to pre-/post-pubertal girls. Pregnancies have been reported after postpubertal ovarian tissue reimplantation; however, to date, no pregnancy has been reported after the reimplantation of prepubertal ovarian tissue or in vitro maturation of pre-/post-pubertal ovarian tissue. Possible future advances in reproductive medicine could change this scenario. Health authorities should prioritize fertility preservation projects in pediatric transplantation to improve patient care and quality of life.

State-of-the-art fertility preservation in children and adolescents undergoing haematopoietic stem cell transplantation: a report on the expert meeting of the Paediatric Diseases Working Party (PDWP) of the European Society for Blood and Marrow Transplantation (EBMT) in Baden, Austria, 29-30 September 2015.

Nowadays, allogeneic haematopoietic stem cell transplantation (allo-HSCT) is a well-established treatment procedure and often the only cure for many patients with malignant and non-malignant diseases. Decrease in short-term complications has substantially contributed to increased survival. Therefore long-term sequelae are reaching the focus of patient care. One of the most important risks of stem cell transplant survivors is infertility. As well as in the field of allo-HSCT also the field of reproductive medicine has achieved substantial advances to offer potential options for fertility preservation in both boys and girls. Access to these procedures as well as their financing differs significantly throughout Europe. As all European children and adolescents should have the same possibility, the Paediatric Diseases Working Party of the European Society for Blood and Marrow Transplantation organised an expert meeting in September 2015. This manuscript describes the recommendations for the diagnosis and pre-emptive procedures that should be offered to all children and adolescents in Europe who have to undergo an allo-HSCT.

Homozygous deletion of RAG1, RAG2 and 5' region TRAF6 causes severe immune suppression and atypical osteopetrosis.

Mutations of several genes have been implicated in autosomal recessive osteopetrosis (OP), a disease caused by impaired function and differentiation of osteoclasts. Severe combined immune deficiencies (SCID) can likewise result from different genetic mutations. We report two siblings with SCID and an atypical phenotype of OP. A biallelic microdeletion encompassing the 5' region of TRAF6, RAG1 and RAG2 genes was identified. TRAF6, a tumor necrosis factor receptor-associated family member, plays an important role in T cell signaling and in RANKL-dependent osteoclast differentiation and activation but its role in human OP has not been previously reported. The RAG proteins are essential for recombination of B and T cell receptors, and for the survival and differentiation of these cells. This is the first study to report a homozygous deletion of TRAF6 as a cause of human disease.

Optimizing the process of fertility preservation in pediatric female cancer patients - a multidisciplinary program.

BACKGROUND: Current evidence indicates sub-optimal incidence of fertility preservation (FP) in eligible patients. We present herein our designated multidisciplinary program for FP in pediatric and adolescent population and present our data on FP in female patients. METHODS: Pediatric patients (age 0-18) who were candidate for highly gonadotoxic treatments were referred to FP program for a multidisciplinary discussion and gonadal risk-assessment followed by either oocyte cryopreservation or ovarian cryopreservation (OCP) for female patients, and sperm banking for male patients. The OCP protocol consists of aspiration of oocytes from small antral follicles and in-vitro maturation followed by cryopreservation, as well as ovarian tissue cryopreservation. RESULTS: The establishment of a designated FP program resulted in a significant increase in referral and subsequent FP procedures of all eligible patients. Sixty-two female patients were referred for FP discussion during a period of 36 months; 41 underwent OCP; 11 underwent oocyte cryopreservation and six were declined due to parental decision. The median age was 13.2y (range 18 months-18y). Thirty-two (51.6 %) were chemotherapy-naïve. Seventeen patients (27 %) had sarcoma, 16 patients (26 %) had acute leukemia. The mean number of mature oocytes that were eventually vitrified was significantly higher in chemotherapy-naïve patients compared with chemotherapy-exposed patients (mean 12 oocytes (1-42) versus 2 (0-7)). CONCLUSION: Multidisciplinary programs that encompass experts of all relevant fields, skilled laboratory resources and a facilitated path appear to maximize the yield. We observed a considerable higher referral rates following launching a designated program and earlier OCP in chemo-naïve patients that culminated in a better fertility preservation procedure.

Cryopreservation of in vitro matured oocytes in addition to ovarian tissue freezing for fertility preservation in paediatric female cancer patients before and after cancer therapy.

STUDY QUESTION: Is a protocol that combines in vitro maturation of germinal vesicle-stage oocytes and their vitrification with freezing of cortical ovarian tissue feasible for use in fertility preservation for both chemotherapy-naive paediatric patients as well as patients after initiation of cancer therapy? SUMMARY ANSWER: Follicle-containing ovarian tissue as well as oocytes that can undergo maturation in vitro can be obtained from paediatric patients (including prepubertal girls) both before and after cancer therapy. WHAT IS KNOWN ALREADY: Anticancer therapy reduces the number of follicles/oocytes but this effect is less severe in young patients, particularly the paediatric age group. Autotransplantation of ovarian tissue has yielded to date 60 live births, including one from tissue that was cryostored in adolescence. However, it is assumed that autografting cryopreserved-thawed ovarian cortical tissue poses a risk of reseeding the malignancy. Immature oocytes can be collected from very young girls without hormonal stimulation and then matured in vitro and vitrified. We have previously shown that there is no difference in the number of ovarian cortical follicles between paediatric patients before and after chemotherapy. STUDY DESIGN, SIZE, DURATION: A prospective study was conducted in a cohort of 42 paediatric females with cancer (before and after therapy initiation) who underwent fertility preservation procedures in 2007-2014 at a single tertiary medical centre. PARTICIPANTS/MATERIALS, SETTING, METHODS: The study group included girls and adolescent females with cancer: 22 before and 20 after chemotherapy. Following partial or complete oophorectomy, immature oocytes were either aspirated manually ex vivo from visible small antral follicles or filtered from spent media. Oocytes were incubated in oocyte maturation medium, and those that matured at 24 or 48 h were vitrified. Ovarian cortical tissue was cut and prepared for slow-gradual cryopreservation. Anti-Mullerian hormone (AMH) levels were measured in serum before and after oophorectomy. MAIN RESULTS AND ROLE OF CHANCE: Ovarian tissue was successfully collected from 78.7% of the 42 patients. Oocytes were obtained from 20 patients before chemotherapy and 13 after chemotherapy. The youngest patients from whom oocytes were retrieved were aged 2 years (two atretic follicles) and 3 years. Of the 395 oocytes collected, ∼30% were atretic (29.6% in the pre-chemotherapy group, 37% in the post-chemotherapy group). One hundred twenty-one oocytes (31%) were matured in vitro and vitrified: 67.8% from patients before chemotherapy, the rest after chemotherapy. Mature oocytes suitable for vitrification were obtained from 16/20 patients before chemotherapy and from 12/13 patients after chemotherapy (maturation rate, 32 and 26.4%, respectively). There were significant correlations of the number of vitrified oocytes with patient age (more matured oocytes with older age) (P = 0.001) and with pre-oophorectomy AMH levels (P = 0.038 pre-chemotherapy group, P = 0.029 post-chemotherapy group). Oocytes suitable for vitrification were obtained both by manual aspiration of antral follicles (45%) and from rinse solutions after dissection. There were significantly more matured oocytes in the pre-chemotherapy group from aspiration than in the post-chemotherapy group after both aspiration (P < 0.033) and retrieval from rinsing fluids (P < 0.044). The number of pre-antral follicles per histological section did not differ in the pre- versus post-chemotherapy. AMH levels dropped by approximately 50% after ovarian removal in both groups, with a significant correlation between pre- and post-oophorectomy levels (P = 0.002 pre-chemotherapy group, P = 0.001 post-chemotherapy group). LIMITATIONS, REASONS FOR CAUTION: There were no patients between 5 years and 10 years old in the post-chemotherapy group, which might have affected some results and correlations. Oocytes from patients soon after chemotherapy might be damaged, and caution is advised when using them for fertility-restoration purposes. The viability, development capability and fertilization potential of oocytes from paediatric patients, especially prepubertal and after chemotherapy, are unknown, in particular oocytes recovered from the media after the tissue dissection step. WIDER IMPLICATIONS OF THE FINDINGS: Although more oocytes were collected and matured from chemotherapy-naïve paediatric patients, ovarian tissue and immature oocytes were also retrieved from young girls in whom cancer therapy has already been initiated. Our centre has established a protocol for potential maximal fertility preservation in paediatric female patients with cancer. Vitrified-in vitro-matured oocytes may serve as an important gamete source in paediatric female patients with cancer because the risk of reseeding the disease is avoided. Further studies are needed on the fertility-restoring potential of oocytes from paediatric and prepubertal patients, especially after exposure to chemotherapy. STUDY FUNDING/COMPETING INTERESTS: The study was conducted as part of the routine procedures for fertility preservation at our IVF unit. No funding outside of the IVF laboratory was received. Funding for the AMH measurements was obtained by a research grant from the Israel Science Foundation (to B.-A.I., ISF 13-1873). None of the authors have competing interests. TRIAL REGISTRATION NUMBER: N/A.

Treosulfan-based conditioning regimens for allogeneic haematopoietic stem cell transplantation in children with non-malignant diseases.

An increasing number of children with non-malignant diseases can be cured by allogeneic haematopoietic stem cell transplantation (HSCT). Treosulfan (L-treitol-1,4-bis-methanesulfonate) is being used more frequently for conditioning, owing to its' lower toxicity profile compared with conventional myeloablative regimens. A retrospective analysis was performed of children registered in the EBMT database, who received treosulfan before HSCT between January 2005 and 2010, to identify possible dose-related toxicity and determine the incidence of engraftment, treatment-related mortality and overall survival (OS). Results from 316 transplants from 11 different countries are presented. Ninety-five (30%) were under 1 year of age at the time of transplant. OS was 83% and event-free survival was 76%; 3-year OS and event-free survival of infants below 1 year were 79% and 73%, respectively. No association was found with age at transplant, dose of treosulfan given, other agents used in combination with treosulfan, donor type, stem cell source, or second or subsequent transplant. In this report of the largest number of children to date receiving treosulfan for non-malignant diseases, treosulfan is shown to be a safe and effective agent even for those under 1 year of age at the time of transplant. Further prospective studies are needed using precisely defined protocols with pharmacokinetic monitoring and detailed chimerism analysis. In addition, long-term studies will be vital to determine long-term effects, for example, on fertility in comparison with other regimens.

Recommendations on hematopoietic stem cell transplantation for inherited bone marrow failure syndromes.

Allogeneic hematopoietic stem cell transplantation (HSCT) offers the potential to cure patients with an inherited bone marrow failure syndrome (IBMFS). However, the procedure involves the risk of treatment-related mortality and may be associated with significant early and late morbidity. For these reasons, the benefits should be carefully weighed against the risks. IBMFS are rare, whereas case reports and small series in the literature illustrate highly heterogeneous practices in terms of indications for HSCT, timing, stem cell source and conditioning regimens. A consensus meeting was therefore held in Vienna in September 2012 on behalf of the European Group for Blood and Marrow Transplantation to discuss HSCT in the setting of IBMFS. This report summarizes the recommendations from this expert panel, including indications for HSCT, timing, stem cell source and conditioning regimen.

Treatment of Patients with Obese Type 2 Diabetes with Tantalus-DIAMOND® Gastric Electrical Stimulation: Normal Triglycerides Predict Durable Effects for at Least 3 Years.

The objectives of the present work are to evaluate long-term benefit of nonexcitatory gastric electrical stimulation (GES) by the DIAMOND(®) device on glycemic control and body weight in patients with type 2 diabetes inadequately controlled with oral agents and to determine the magnitude of the modulating effects of fasting plasma triglyceride (FTG) levels on these effects of GES. Sixty one patients with type 2 diabetes [HbA1c > 7.0% (53 mmol/mol) to < 10.5% (91 mmol/mol)] were implanted with the DIAMOND(®) GES device and treated with meal-mediated antral electrical stimulation for up to 36 months. The effects of baseline HbA1c and FTG on glycemic control, body weight, and systolic blood pressure were measured. GES reduced mean HbA1c by 0.9% and body weight by 5.7%. The effects were greater in patients with normal fasting plasma triglycerides (NTG) as compared to those with hypertriglyceridemia. The mean decrease in HbA1c in patients with NTG averaged 1.1% and was durable over 3 years of follow-up. ANCOVA indicated that improvement in HbA1c was a function of both baseline FTG group (p = 0.02) and HbA1c (p = 0.001) and their interaction (p = 0.01). Marked weight loss (≥ 10%) was observed in a significant proportion of NTG patients by 12 months of treatment and persisted through the 3 years. GES improves glycemic control and reduces body weight by a triglyceride-dependent mechanism in patients with type 2 diabetes inadequately controlled on oral agents. It is postulated that this is through a gut-brain interaction that modulates effects on the liver and pancreatic islets.

Paediatric reduced intensity conditioning: analysis of centre strategies on regimens and definitions by the EBMT Paediatric Diseases and Complications and Quality of Life WP.

The aim of this analysis was to explore the diversity of reduced intensity conditioning (RIC) in paediatric allo-SCT in daily practice across Europe. Data from the European Group for Blood and Marrow Transplantation (EBMT) Promise database from 1994 to 2008 were supplemented by a survey of EBMT centres performing paediatric allo-SCT on the current policy asking for the underlying diseases and for the drug combinations. Records from 161 centres from 30 countries were analysed and 139 various RIC regimens were reported. More centres applied RIC for malignant rather than for non-malignant diseases. In general, fludarabine (FLU)-based regimens predominated except for BU-based regimens in myeloid malignancies and haemoglobinopathies. Treosulfan (TREO) was mainly applied for unspecified malignant diseases and for haemophagocytic diseases. FLU-based regimens revealed the greatest number of different combinations. Correlating the number of regimens with the number of treating centres revealed the lowest variety in FLU and the highest variety in TBI and TREO. FLU/melphalane and FLU/CY were the most frequent combinations. This extreme heterogeneity in RIC may influence both the efficacy and the safety of the procedures, which requires further investigation. Optimization and standardization of RIC is the final goal to provide a platform for future prospective studies.

Negative selection by apoptosis enriches progenitors in naïve and expanded human umbilical cord blood grafts.

The influence of TNF-α and Fas-ligand (FasL) on viability and function was evaluated in fresh- and expanded-umbilical cord blood (UCB) cells. CD34(+) progenitors and T cells display outstanding survival, whereas ~30% and >50% B lymphocytes and myeloid cells undergo spontaneous apoptosis within 24 and 48 h, respectively. Although the impact of exposure to toxic doses of FasL and TNF-α was undetectable in measurements of apoptosis; removal of dead cells after 2 days of incubation with the ligands revealed a twofold increase in frequency of colony-forming cells (CFU). The sensitivity of progenitors to apoptosis was also unaffected by Fas cross-linking following TNF-induced upregulation of the receptor, increasing CFU frequency without impairing SCID repopulating cell (SRC) activity. Most significant enrichment in CD34(+) progenitors and corresponding increase in CFU frequency were observed when FasL was applied during the final week of ex vivo expansion under the influence of nicotinamide, without impairing SRC activity. These data emphasize differential sensitivities of UCB progenitors and lineage-positive cells to apoptotic signaling mediated by the Fas and TNF receptors, which might be useful in improving the efficiency of ex vivo expansion and improving UCB cell engraftment.

Apoptotic signaling through Fas and TNF receptors ameliorates GVHD in mobilized peripheral blood grafts.

Mobilized peripheral blood (mPB) is a prevalent source of hematopoietic progenitors for transplantation; however, allogeneic and haploidentical transplants are often accompanied by severe GVHD. Following the observation that murine GVHD is ameliorated by pretransplant donor cell exposure to Fas-ligand (FasL) without host-specific sensitization, we assessed the susceptibility of mPB cells to spontaneous and receptor-induced apoptosis as a possible approach to GVHD prophylaxis. Short incubation for 4 h resulted in spontaneous apoptosis of 50% of the T and B lymphocytes and 60% myeloid cells. Although expression of Fas and TNF-R1 was proportionate to fractional apoptosis, cell death was dominated by spontaneous apoptosis. Functional assays revealed that the death receptors modulated mPB graft composition as compared with incubation in medium, without detectable quantitative variations. Removal of dead cells increased the frequency of mPB myeloid progenitors (P<0.001 vs medium), and recipients of mPB exposed to death ligands displayed reduced GVHD (P<0.01 vs medium) and improved survival following lipopolysacharide stimulation. mPB grafts exposed to the apoptotic challenge retained SCID reconstituting potential and graft versus tumor activity. These data emphasize that short-term exposure of mPB grafts to an apoptotic challenge is effective in reduction of GVHD effector activity.

Early immunisation with dendritic cells after allogeneic bone marrow transplantation elicits graft vs tumour reactivity.

BACKGROUND: Perspectives of immunotherapy to cancer mediated by bone marrow transplantation (BMT) in conjunction with dendritic cell (DC)-mediated immune sensitisation have yielded modest success so far. In this study, we assessed the impact of DC on graft vs tumour (GvT) reactions triggered by allogeneic BMT. METHODS: H2K(a) mice implanted with congenic subcutaneous Neuro-2a neuroblastoma (NB, H2K(a)) tumours were irradiated and grafted with allogeneic H2K(b) bone marrow cells (BMC) followed by immunisation with tumour-inexperienced or tumour-pulsed DC. RESULTS: Immunisation with tumour-pulsed donor DC after allogeneic BMT suppressed tumour growth through induction of T cell-mediated NB cell lysis. Early post-transplant administration of DC was more effective than delayed immunisation, with similar efficacy of DC inoculated into the tumour and intravenously. In addition, tumour inexperienced DC were equally effective as tumour-pulsed DC in suppression of tumour growth. Immunisation of DC did not impact quantitative immune reconstitution, however, it enhanced T-cell maturation as evident from interferon-γ (IFN-γ) secretion, proliferation in response to mitogenic stimulation and tumour cell lysis in vitro. Dendritic cells potentiate GvT reactivity both through activation of T cells and specific sensitisation against tumour antigens. We found that during pulsing with tumour lysate DC also elaborate a factor that selectively inhibits lymphocyte proliferation, which is however abolished by humoral and DC-mediated lymphocyte activation. CONCLUSION: These data reveal complex involvement of antigen-presenting cells in GvT reactions, suggesting that the limited success in clinical application is not a result of limited efficacy but suboptimal implementation. Although DC can amplify soluble signals from NB lysates that inhibit lymphocyte proliferation, early administration of DC is a dominant factor in suppression of tumour growth.

Fasting plasma triglycerides predict the glycaemic response to treatment of type 2 diabetes by gastric electrical stimulation. A novel lipotoxicity paradigm.

BACKGROUND: Non-stimulatory, meal-mediated electrical stimulation of the stomach (TANTALUS-DIAMOND) improves glycaemic control and causes modest weight loss in patients with Type 2 diabetes who are inadequately controlled on oral anti-diabetic medications. The magnitude of the glycaemic response in clinical studies has been variable. A preliminary analysis of data from patients who had completed 6 months of treatment indicated that the glycaemic response to the electrical stimulation was inversely related to the baseline fasting plasma triglyceride level. METHOD: An analysis of 40 patients who had had detailed longitudinal studies for 12 months. RESULTS: Twenty-two patients with fasting plasma triglycerides ≤ 1.7 mmol/l had mean decreases in HbA1c after 3, 6 and 12 months of gastric contraction modulation treatment of -15 ± 2.1 mmol/mol (-1.39 ± 0.20%), -16 ± 2.2 mmol/mol (-1.48 ± 0.20%) and -14 ± 3.0 mmol/mol (-1.31 ± 0.26%), respectively. In contrast, 18 patients with fasting plasma triglyceride > 1.7 mmol/l had mean decreases in HbA1c of -7 ± 1.7 mmol/mol (-0.66 ± 0.16%), -5 ± 1.6 mmol/mol (-0.44 ± 0.18%) and -5 ± 1.7 mmol/mol (-0.42 ± 0.16%), respectively. Pearson's correlation coefficient between fasting plasma triglyceride and decreases in HbA1c at 12 months of treatment was 0.34 (P < 0.05). Homeostasis model assessment of insulin resistance was unchanged during 12 months of treatment in patients with high baseline fasting triglycerides, while it progressively improved in patients with low fasting plasma triglycerides. Patients with low fasting plasma triglycerides had a tendency to lose more weight than those with high fasting plasma triglycerides, but this did not achieve statistical significance. CONCLUSIONS: The data presented suggest the existence of a triglyceride lipotoxic mechanism that interferes with gastric/neural mediated pathways that can regulate glycaemic control in patients with type 2 diabetes. The data suggest the existence of a triglyceride lipotoxic pathway that interferes with gastric/neural mediated pathways that can regulate glycaemic control.

Immunomodulation with dendritic cells and donor lymphocyte infusion converge to induce graft vs neuroblastoma reactions without GVHD after allogeneic bone marrow transplantation.

BACKGROUND: Mounting evidence points to the efficacy of donor lymphocyte infusion (DLI) and immunisation with tumour-pulsed dendritic cells (DC) in generating graft vs leukaemia reactions after allogeneic bone marrow transplantation (BMT). We assessed the efficacy of DLI and DC in generating potent graft vs neuroblastoma tumour (GVT) reactions following allogeneic BMT. METHODS: Mice bearing congenic (H2K(a)) Neuro-2a tumours were grafted with allogeneic (H2K(b)) T-cell-depleted bone marrow cells. Tumour-pulsed donor DC (DC(Neuro2a)) were inoculated (on day +7) in conjunction with donor (H2K(b)) and haploidentical (H2K(a/b)) lymphocytes. RESULTS: Murine Neuro-2a cells elicit immune reactions as efficient as B lymphoma in major histocompatibility complex antigen-disparate mice. Lymphopenia induced by conditioning facilitates GVT, and transition to adaptive immunity is enhanced by simultaneous infusion of and DC(Neuro2a) and lymphocytes devoid of graft vs host (GVH) activity (H2K(a/b)). In variance, the efficacy of DC-mediated immunomodulation was diminished by severe graft vs host disease (GVHD), showing mechanistic dissociation and antagonising potential to GVT. CONCLUSIONS: The GVHD is not a prerequisite to induce GVT reactivity after allogeneic BMT, but is rather detrimental to induction of anti-tumour immunity by DC-mediated immunomodulation. Simultaneous inoculation of tumour-pulsed donor DC and DLI synergise in stimulation of potent GVT reactions to the extent of eradication of established NB tumours.

Regulatory functions of TRAIL in hematopoietic progenitors: human umbilical cord blood and murine bone marrow transplantation.

The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) signaling pathway has selective toxicity to malignant cells. The TRAIL receptors DR4 and DR5 are expressed at low levels in human umbilical cord blood cells (3-15%) and are upregulated by incubation with the cognate ligand, triggering apoptosis in 70-80% of receptor-positive cells (P<0.001). Apoptosis is not induced in hematopoietic progenitors, as determined from sustained severe combined immunodeficiency reconstituting potential and clonogenic activity. Furthermore, elimination of dead cells after incubation with TRAIL for 72 h results in a threefold enrichment in myeloid progenitors. Exposure to TRAIL in semisolid cultures showed synergistic activity of DR4 and granulocyte/macrophage colony-stimulating factor in recruiting lineage-negative (lin(-)) and CD34(+) progenitors and in promoting the formation of large colonies. In murine bone marrow, approximately 30% of lin(-) cells express TRAIL-R2 (the only murine receptor), and the receptor is upregulated after transplantation in cycling and differentiating donor cells that home to the host marrow. However, this receptor is almost ubiquitously expressed in the most primitive (lin(-)SCA-1(+)c-kit(+)) progenitors, and stimulates the clonogenic activity of lin(-) cells (P<0.001), suggesting a tropic function after transplantation. It is concluded that TRAIL does not trigger apoptosis in hematopoietic progenitors, and upregulation of its cognate receptors under stress conditions mediates tropic signaling that supports recovery from hypoplasia.

Outcome of antibiotic lock technique for persistent central venous catheter-associated coagulase-negative Staphylococcus bacteremia in children.

The purpose of this study was to assess the long-term effectiveness of the antibiotic lock technique (ALT) in conjunction with systemic antibiotics for the salvage of long-term central venous catheter (CVC)-associated coagulase-negative Staphylococcus (CONS) bloodstream infections (BSIs) in children. A retrospective study of children with CVC-associated CONS BSIs treated with systemic vancomycin and ALT with vancomycin was carried out. The primary outcome was the immediate and 3-month success rate of salvage of the CVC. During the study period, 23 patients had persistent CONS bacteremia and were treated with ALT and systemic vancomycin. Of the 23 vancomycin lock treatments, eight catheters were removed during the acute event because of persistent bacteremia, six had relapse of CONS bacteremia within 30 days, and two had relapse within 90 days. Only seven CVCs (30%) were salvaged. Long-term transcutaneous CVCs (Hickman CVCs) were significantly associated with higher salvage rates than implantable ports (75% vs. 18%, P = 0.05). ALT with vancomycin for CVC-associated bacteremia has a limited long-term effectiveness, especially with implantable ports. Larger prospective studies are needed for the long-term evaluation of this technique.

Quantitative monitoring of multi-donor chimerism: a systematic, validated framework for routine analysis.

Despite therapeutic advantages, double-donor (DD) HSCTs present technical problems for molecular chimerism (CHM) monitoring. These DD chimeras contain three matched DNAs, so that the genomes of donor(s) and recipient often share the same alleles. In the STR assay, shared recipient/donor alleles are common and have identical physico-chemical properties. As a consequence of the latter, they co-migrate in the same band ('shared peak'), which prevents measuring each allele separately. Without individual allelic measurements, the direct calculation of the chimeric recipient/donor DNA ratio is precluded. This is the first study to document and systematically examine these problems. Its goal was to provide a validated framework for accurate, routine monitoring based on a stepwise analytic paradigm for approximating percent CHM (%CHM) from shared STR-alleles. Analysis of STR-DNA from DD loci showed that at least four of six alleles were typically shared. Despite such extensive allelic sharing, we show how simple arithmetic procedures can be applied for standardized calculation of %CHM based on peak measurements. Criteria for selecting loci suitable for such analysis are provided. Validation of the computational results required analyzing 18 'informative' loci with pre-established reference values for %CHM. In all cases, the results for %CHM, calculated from peak measurements, were +/-5% of the reference value. The conclusions of the study are as follows: (1) Multi-donor chimeras, with shared alleles, can be accurately and simply analyzed within the usual limits of STR measurement error; (2) by examining these various facets of DD CHM analysis, this novel study has provided a basis for standardized, routine quantitative monitoring using the STR/VNTR assay.