Vitamin D3 Stimulates Proliferation Capacity, Expression of Pluripotency Markers, and Osteogenesis of Human Bone Marrow Mesenchymal Stromal/Stem Cells, Partly through SIRT1 Signaling.

The biology of vitamin D3 is well defined, as are the effects of its active metabolites on various cells, including mesenchymal stromal/stem cells (MSCs). However, the biological potential of its precursor, cholecalciferol (VD3), has not been sufficiently investigated, although its significance in regenerative medicine-mainly in combination with various biomaterial matrices-has been recognized. Given that VD3 preconditioning might also contribute to the improvement of cellular regenerative potential, the aim of this study was to investigate its effects on bone marrow (BM) MSC functions and the signaling pathways involved. For that purpose, the influence of VD3 on BM-MSCs obtained from young human donors was determined via MTT test, flow cytometric analysis, immunocytochemistry, and qRT-PCR. Our results revealed that VD3, following a 5-day treatment, stimulated proliferation, expression of pluripotency markers (NANOG, SOX2, and Oct4), and osteogenic differentiation potential in BM-MSCs, while it reduced their senescence. Moreover, increased sirtuin 1 (SIRT1) expression was detected upon treatment with VD3, which mediated VD3-promoted osteogenesis and, partially, the stemness features through NANOG and SOX2 upregulation. In contrast, the effects of VD3 on proliferation, Oct4 expression, and senescence were SIRT1-independent. Altogether, these data indicate that VD3 has strong potential to modulate BM-MSCs' features, partially through SIRT1 signaling, although the precise mechanisms merit further investigation.

Risk of reactivated toxoplasmosis in haematopoietic stem cell transplant recipients: a prospective cohort study in a setting withholding prophylaxis.

OBJECTIVES: Reactivation of latent toxoplasmosis may be life-threatening in haematopoietic stem cell transplant (HSCT) recipients. We conducted an 8-year-long prospective study on the diagnosis and monitoring of reactivated toxoplasmosis in paediatric HSCT recipients. The primary objective was to determine the incidence of reactivated toxoplasmosis in a setting that withholds prophylaxis until engraftment. The second objective was to identify the subgroups of HSCT recipients particularly prone to reactivation who may benefit the most from regular PCR follow-up. METHODS: Serological and qPCR screening targeting the Toxoplasma 529 bp gene was performed before HSCT, and continued by weekly monitoring after HSCT for a median time of 104 days. RESULTS: Reactivated toxoplasmosis was diagnosed in 21/104 (20.2%), predominantly in allo- (19/75) and rarely in auto-HSCT (2/29) recipients. Over 50% (14/21) of cases were diagnosed during the first month after HSCT, while awaiting engraftment without prophylaxis. Toxoplasma disease evolved in only three (14.3%, 3/21) patients, all treated by allo-HSCT. Reactivation was more frequent in patients treated for acute lymphoblastic leukaemia (3/27, p 0.03) and especially, in recipients of haploidentical stem cells (10/20, p 0.005). Seronegative status of the donor (where was known) contributed to 75% (12/16) cases of reactivated toxoplasmosis after allo-HSCT. DISCUSSION: The presented results show that peripheral blood-based qPCR, both before and after HSCT, is a valuable asset for the diagnosis of reactivated toxoplasmosis, whereas the results of serology in recipients should be interpreted with caution. Weekly qPCR monitoring, at least until successful engraftment and administration of prophylaxis, allows for prompt introduction of specific treatment.

Factors Associated With Cytomegalovirus Infection in Pediatric Allogeneic Hematopoietic Stem Cell Transplant Recipients: A Prospective Single-Center Study.

OBJECTIVES: The human cytomegalovirus is a notorious pathogen in the pediatric transplant setting. Although studies on factors in complicity with cytomegalovirus infection abound, the roles of age, sex, allogeneic hematopoietic stem cell transplant modality, and type of underlying disease (malignant vs nonmalignant) with regard to cytomegalovirus infection and viral load in children are seldom explored. Our aim was to examine the significance of these factors on cytomegalovirus infection and viral load in Serbian pediatric recipients of allogeneic hematopoietic stem cell transplant. MATERIALS AND METHODS: Thirty-two pediatric recipients of allogeneic hematopoietic stem cell transplant to treat various malignant and nonmalignant disorders were prospectively monitored for cytomegalovirus infection. The real-time quantitative polymerase chain reaction was used for pathogen detection and quantitation. Demographic and virologic parameters were statistically analyzed with SPSS statistics software (version 20). RESULTS: Cytomegalovirus DNA was detected in 23 patients (71.9%). Infection occurred significantly more often (P = .015) in patients with haploidentical donors. The opposite was noted for matched sibling grafts (P = .006). Viral load was higher in female patients (P = .041) and children with malignant diseases (P = .019).There was no significant relationship between viral infection or load and medical complications. CONCLUSIONS: Transplant recipients presented with a high incidence of cytomegalovirus viremia. The modality of allogeneic hematopoietic stem cell transplant was associated with the frequency of cytomegalovirus infection. Age, sex, type of underlying disease, and medically relevant events were not conducive to occurrences of viremia. Notably, we observed substantial viral loads in female patients and patients with neoplastic diseases. Studies comprising larger populations are needed to better understand these results.

Cytomegalovirus glycoprotein B and N genotypes in pediatric recipients of the hematopoietic stem cell transplant.

Clinical significance of the cytomegalovirus (CMV) genotypes in patients undergoing allogeneic hematopoietic stem cell transplant (HSCT) has been evaluated mostly in adults. The studies of diverse CMV glycoprotein B (gB) and N (gN) genotype variants in transplanted children and adolescents are lacking. We analyzed the investment of gB and gN genotype variants in the HSCTed children and their relation to clinical complications and disease outcome. The cohort included forty two pediatric recipients of the HSCT. Patients positive for CMV DNAemia (24/42, 57.1%) were genotyped. The gB4 and gN1 genotype variants predominated and were evidenced in 7/18 (38.9%) and 9/19 (47.4%) patients, respectively. The graft-versus-host disease (GvHD) predominated in children with viremia (p < 0.05). Frequencies of the gB and gN genotypes contrasted those reported in recent studies. The GvHD scaled strongly with CMV reactivation whereas viral loads were uncorrelated to medical complications and treatment outcomes.

Complex karyotype with cryptic FUS gene rearrangement and deletion of NR3C1 and VPREB1 genes in childhood B-cell acute lymphoblastic leukemia: A case report.

B-cell acute lymphoblastic leukemia (B-ALL) is a hematopoietic malignancy characterized by overproduction of immature B-lymphoblasts. B-ALL is the most common pediatric tumor and remains the leading cause of mortality in children and adolescents. Molecular and cytogenetic analyses of B-ALL revealed recurrent genetic and structural genomic alterations which are routinely applied for diagnosis, prognosis and choice of treatment regimen. The present case report describes a 4-year-old female diagnosed with B-ALL. GTG-banding at low resolution revealed an abnormal clone with 46,XX,?t(X;19)(q13;q13.3),der(9) besides normal cells. Molecular cytogenetics demonstrated a balanced translocation between chromosomes 16 and 19, and an unbalanced translocation involving chromosomes 5 and 9. A locus-specific probe additionally identified that the FUS gene in 16p11.2 was split and its 5' region was translocated to subband 19q13.33, whereas the 3' region of the FUS gene remained on the derivative chromosome 16. Overall, this complex karyotype included four different chromosomes and five break events. Further analyses, including array-comparative genomic hybridization, additionally revealed biallelic deletion of the tumor suppressor genes CDKN2A/B, and deletion of the NR3C1 and VPREB1 genes. The patient passed away under treatment due to sepsis.

BIRC3 alterations in chronic and B-cell acute lymphocytic leukemia patients.

Deletions within chromosome 11q22-23, are considered among the most common chromosomal aberrations in chronic lymphocytic leukemia (CLL), and are associated with a poor outcome. In addition to the ataxia telangiectasia mutated (ATM) gene, the baculoviral IAP repeat-containing 3 (BIRC3) gene is also located in the region. BIRC3 encodes a negative regulator of the non-canonical nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) protein. Disruption of BIRC3 is known to be restricted to CLL fludarabine-refractory patients. The aim of the present study was to determine the frequency of copy number changes of BIRC3 and to assess its association with two known predictors of negative CLL outcome, ATM and tumor protein 53 (TP53) gene deletions. To evaluate the specificity of BIRC3 alterations to CLL, BIRC3 copy numbers were assessed in 117 CLL patients in addition to 45 B-cell acute lymphocytic leukemia (B-ALL) patients. A commercially available multiplex ligation dependent probe amplification kit, which includes four probes for the detection of TP53 and four probes for ATM gene region, was applied. Interphase-directed fluorescence in situ hybridization was used to apply commercially available probes for BIRC3, ATM and TP53. High resolution array-comparative genomic hybridization was conducted in selected cases. Genetic abnormalities of BIRC3 were detected in 23/117 (~20%) of CLL and 2/45 (~4%) of B-ALL cases. Overall, 20 patients with CLL and 1 with B-ALL possessed a BIRC3 deletion, whilst 3 patients with CLL and 1 with B-ALL harbored a BIRC3 duplication. All patients with an ATM deletion also carried a BIRC3 deletion. Only 2 CLL cases possessed deletions in BIRC3, ATM and TP53 simultaneously. Evidently, the deletion or duplication of BIRC3 may be observed rarely in B-ALL patients. BIRC3 duplication may occur in CLL patients, for which the prognosis requires additional studies in the future. The likelihood that TP53 deletions occur simultaneously with BIRC3 and/or ATM aberrations is low. However, as ATM deletions may, but not always, associate with BIRC3 deletions, each region should be considered in the future diagnostics of CLL in order to aid treatment decisions, notably whether to treat with or without fludarabine.

A cryptic three-way translocation t(10;19;11)(p12.31;q13.31;q23.3) with a derivative Y-chromosome in an infant with acute myeloblastic leukemia (M5b).

Acute myeloid leukemia (AML) is a heterogeneous disease characterized by the malignant transformation of hematopoietic precursors to a pathogenic cell clone. Chromosomal band 11q23 harboring MLL (=mixed lineage leukemia) gene is known to be involved in rearrangements with variety of genes as activating partners of MLL in different AML subtypes. Overall, an unfavorable prognosis is associated with MLL abnormalities. Here we investigated an 11-month-old male presenting with hyperleukocytosis being diagnosed with AML subtype FAB-M5b. In banding cytogenetics a der(19)t(19;?)(q13.3;?) and del(Y)(q11.23) were found as sole aberrations. Molecular cytogenetics revealed that the MLL gene was disrupted and even partially lost due to a t(10;19;11)(p12.31;q13.31;q23.3), an MLL/MLLT10 fusion appeared, and the der(Y) was an asymmetric inverted duplication with breakpoints in Yp11.2 and Yq11.23. The patient got hematopoietic stem cell transplantation from his haploidentical mother. Still three months afterwards 15% of blasts were detected in bone marrow and later the patient was lost during follow-up. The present case highlights the necessity to exclude MLL rearrangements, even when there seems to be no actual hint from banding cytogenetics.

Subclinical hypothyroidism in children and adolescents after hematopoietic stem cells transplantation without irradiation.

BACKGROUND/AIM: Although total body irradiation (TBI) was considered to be the primary cause of thyroid dysfunction following hematopoietic stem cells transplantation (HSCT), a significant prevalence of subclinical hypothyroidism after HSCT with chemotherapy-only conditioning regimens has been observed in several studies. The aim of this study was to assess changes in thyroid stimulating hormone (TSH) levels in children after HSCT, without the use of irradiation at any time in the course of the treatment. METHODS: Our cohort consisted of 41 children and adolescents who underwent autologous or allogeneic HSCT and were available for follow-up for at least one year after transplantation. Irradiation was not performed in any of the subjects, neither during pretransplatation therapy, nor during conditioning. The median duration of follow-up was 2.9 years. The indications for HSCT were hematologic malignancy (41.5%), solid malignant tumor (34.1%), and other disorders (24.4%). The thyroid status of all the subjects was assessed prior to HSCT and after follow-up period. RESULTS: Thyroid dysfunction after HSCT was present in 27 (65.8%) subjects. Subclinical hypothyroidism was the most common abnormality, presenting in 23 (56.1%) patients, primary hypothyroidism was present in one (2.4%) patient, while 3 (7.3%) subjects had low free T4 with normal TSH values. Significantly (p < 0.01) higher elevations in TSH levels were present in the patients who received chemotherapy for the underlying disease prior to HSCT. CONCLUSION: Our findings emphasize the need for long-term monitoring of thyroid function following HSCT, regardless of whether or not irradiation was used.

Bone marrow processing for transplantation using Cobe Spectra cell separator.

Concentration of bone marrow aspirates is an important prerequisite prior to infusion of ABO incompatible allogeneic marrow and prior to cryopreservation and storage of autologous marrow. In this paper we present our experience in processing 15 harvested bone marrow for ABO incompatible allogeneic and autologous bone marrow (BM) transplantation using Cobe Spectra® cell separator. BM processing resulted in the median recovery of 91.5% CD34+ cells, erythrocyte depletion of 91% and volume reduction of 81%. BM processing using cell separator is safe and effective technique providing high rate of erythrocyte depletion and volume reduction, and acceptable recovery of the CD34+ cells.

Monitoring of pediatric patients with malignant hematological diseases after allogeneic HSCT: Serbian experience.

We describe the implementation of short tandem repeats-polymerase chain reaction (STR-PCR) chimerism analyses coupled with reverse transcription PCR detection of recurrent translocations characteristic for childhood leukemia in monitoring of patients after allogeneic hematopoietic stem cell transplantation in Serbia and the first clinical results thereof. Chimerism and minimal residual disease were regularly analyzed from blood and marrow samples of 26 pediatric patients taken after stem cell transplantation with a median follow-up of 17.6 months. Our results demonstrate that STR-based chimerism monitoring is sufficient in establishing the origin of engrafted cells after transplantation and in detecting graft rejection, but more specific and more sensitive method is necessary for identifying patients with threatening leukemia relapse.

Mobilization and harvesting of peripheral blood stem cells in pediatric patients with solid tumors.

Survival of patients with high-risk pediatric solid tumors has improved with the introduction of a high-dose chemotherapy regimen and autologous stem cell rescue. Here, we present our data regarding the evaluation of the efficacy and safety of hematopoietic stem cell mobilization and harvesting in children with solid tumors. From November 2002 to March 2010, 85 children underwent autologous peripheral blood stem cell collection; 35 (41.1%) of them weighed less than 20 kg and were diagnosed with neuroblastoma, Wilms' tumor, medulloblastoma, yolk sac sarcoma, or non-Hodgkin's lymphoma. The mobilization regimens included disease-specific chemotherapy plus granulocyte colony-stimulating factor in most of the patients. The median age and weight at the time of apheresis was 36 months and 13.5 kg, respectively. Large-volume leukapheresis was performed with the aim of reducing the psychological and financial impact of leukapheresis by reducing the number of procedures while collecting a large number of cells. The median number of mobilization and leukapheresis procedures per case was one. The pre-apheresis CD34+ cell count ranged from 2 to 845 µL, with a median of 24 µL. A median of four patient blood volumes was processed per procedure, lasting 279 min (range, 113-420 min). A radial catheter was used for harvesting in 35 procedures (71.4%). The median yield of CD34+ cells was 6.6×10(6) /kg per patient. The targeted dose of 5×10(6) /kg CD34+ cells was realized in 80% of patients. The tolerance of peripheral blood stem cell collection in our patients was good. In conclusion, the collection of peripheral blood stem cells is an effective and safe procedure, even when conducted on the youngest children.

Veno-occlusive disease in pediatric patients after hematopoietic stem cell transplantation: relevance of activated coagulation and fibrinolysis markers and natural anticoagulants.

Prediction of veno-occlusive disease (VOD), its precise diagnosis, and treatment have been the subject of various studies, but still remain unclear. Our goal was to investigate the levels of activated coagulation and fibrinolysis markers and natural anticoagulants in pediatric patients with VOD after hematopoietic stem cell transplantation (HSCT). We investigated 47 pediatric patients: 20 with neuroblastoma, 17 with leukemias, and 10 with lymphomas and measured the values of antithrombin (AT), protein C (PC), fibrinogen (FI), thrombin AT complex, prothrombin fragments 1+2 (F1+2), and D-dimer from day -7 to day +30 post-HSCT. Patients were monitored for the occurrence of VOD, and it occurred in 10 patients at a median post-HSCT day of 17.5 (range: 2 to 28 d). In the VOD group, at baseline the levels of FI were significantly lower, and on days +7 and +14 a relevant difference existed in F1+2 levels. The levels of PC were significantly lower on day +14. Logistic multivariate regression analysis between the groups showed significantly different D-dimer levels on day +14. On day +30, the levels of PC, AT, and F1+2 were different between these 2 groups of patients. The levels of D-dimer and F1+2 were increased, and PC and FI decreased before the clinical onset of VOD. The parameter differences may have a predictive value in VOD onset, which makes them candidates to be routinely monitored in patients after HSCT.

Coagulation disturbances in paediatric patients with hepatic veno-occlusive disease after stem cells transplantation.

INTRODUCTION: Hepatic veno-occlusive disease (VOD) is a life threatening complication after stem cells transplantation (SCT). Its prediction, precise diagnosis and treatment remain unclear. OBJECTIVE: Our goals were to determine the incidence, outcome and changes in haemostatic parameters in patients with VOD. Also, we tried to determine coagulation disturbances and their practical significance in early diagnosis of such patients. METHODS: We prospectively evaluated all consecutive VOD patients after SCT, aged 3 months to 17 years, from February 2004 to July 2008 treated at the Mother and Child Health Institute of Serbia "Dr Vukan Cupic" (IMD). All patients were diagnosed according to the Seattle criteria. The values of PT, aPTT, fibrinogen, FVIII, AT and vWF were measured on the day prior to the initiation of conditioning regiment and on the days 1, 7 and 14 from the moment of VOD diagnosis. Laboratory testing was performed in the IMD haemostasis laboratory and results were statistically evaluated. RESULTS: During the study period 74 SCT were performed at IMD. VOD developed 11 patients; 10 of 46 were autologous and 1 of 28 allogeneic SCT patients. In our group of patients the incidence of VOD was 14.8%. VOD was classified as mild in 7, moderate in 1 and severe in 3 patients. At the moment of establishing the diagnosis all patients had a significantly increased activity of vWF, FVIII and fibrinogen, and decreased AT. All of them were dependent on platelet transfusions. CONCLUSION: Platelet transfusion dependence suggests coagulation activation with great significance and indicates a possible development of VOD. Our results also suggest that monitoring coagulation parameters levels in the first five days from the establishment of diagnosis may have a significant predictive value for VOD outcome.