Prognostic factors for survival in children who relapsed after allogeneic hematopoietic stem cell transplantation for acute leukemia.

BACKGROUND: Post-transplant relapse has a dismal prognosis in children with acute leukemia undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). Data on risk factors, treatment options, and outcomes are limited. PROCEDURE: In this retrospective multicenter study in which a questionnaire was sent to all pediatric transplant centers reporting relapse after allo-HSCT for a cohort of 938 children with acute leukemia, we analyzed 255 children with relapse of acute leukemia after their first allo-HSCT. RESULTS: The median interval from transplantation to relapse was 180 days, and the median follow-up from relapse to the last follow-up was 1844 days. The 3-year overall survival (OS) rate was 12.0%. The main cause of death was disease progression or subsequent relapse (82.6%). The majority of children received salvage treatment with curative intent without a second HSCT (67.8%), 22.0% of children underwent a second allo-HSCT, and 10.2% received palliative therapy. Isolated extramedullary relapse (hazard ratio (HR): 0.607, P = .011) and relapse earlier than 365 days post-transplantation (HR: 2.101, P < .001 for 0-180 days; HR: 1.522, P = .041 for 181-365 days) were found in multivariate analysis to be significant prognostic factors for outcome. The type of salvage therapy in chemosensitive relapse was identified as a significant prognostic factor for OS. CONCLUSION: A salvage approach with curative intent may be considered for patients with post-transplant relapse, even if they relapse in the first year post-transplantation. For sustainable remission, a second allo-HSCT may be recommended for patients who achieve complete remission after reinduction treatment.

PKNOX2 expression and regulation in the bone marrow mesenchymal stem cells of Fanconi anemia patients and healthy donors.

HOX and TALE transcription factors are important regulators of development and homeostasis in determining cellular identity. Deregulation of this process may drive cancer progression. The aim of this study was to investigate the expression of these transcription factors in the bone marrow derived mesenchymal stem cells (BM-MSCs) of Fanconi anemia (FA) patients, which is a cancer-predisposing disease. Expression levels of HOX and TALE genes in BM-MSCs were obtained from FA patients and healthy donors by RT-qPCR and highly conserved expression levels were observed between patient and donor cells, except PKNOX2, which is a member of TALE class. PKNOX2 was significantly downregulated in FA cells compared to donors (P < 0.05). PKNOX2 expression levels did not change with diepoxybutane (DEB), a DNA crosslinking agent, in either donor or FA cells except one patient's with a truncation mutation of FANCA. A difference of PKNOX2 protein level was not obtained between FA patient and donor BM-MSCs by western blot analysis. When human TGF-ß1 (rTGF-ß1) recombinant protein was provided to the cultures, PKNOX2 as well as TGF-ß1 expression increased both in FA and donor BM-MSCs in a dose dependent manner. 5 ng/mL rTGF-ß stimulation had more dominant effect on the gene expression of donor BM-MSCs compared to FA cells. Decreased PKNOX2 expression in FA BM-MSCs may provide new insights into the molecular pathophysiology of the disease and TGF-ß1 levels of the microenvironment may be the cause of PKNOX2 downregulation.

The clinical and laboratory evaluation of familial hemophagocytic lymphohistiocytosis and the importance of hepatic and spinal cord involvement: a single center experience.

Familial hemophagocytic lymphohistiocytosis is an autosomal recessive, life-threatening condition characterized by defective immune response. A retrospective analysis was performed on 57 patients diagnosed with familial hemophagocytic lymphohistiocytosis at Hacettepe University Pediatric Hematology Department, Ankara, Turkey. Mutation analysis was performed on 37 patients, and of these: 11 had UNC13D, 10 had PRF1 and 3 had STX11 gene mutation. Of these patients, 44% were found to have central nervous system involvement on admission and spinal cord involvement was also seen in 5 patients. Remission was achieved in 24 patients with the treatment, in a median time of 76 days (min-max: 15-705 days). Time to remission was prolonged 3.1 times in patients with a ferritin level 1500 mg/dL or more. When patients were grouped according to age [Group 1 (≤ 2 years), Group 2 (>2 years)]; patients in Group 1 had higher ferritin and aspartate aminotransferase levels but lower fibrinogen levels. The 5-year survival rate was also lower in Group 1. When patients in Group 1 were divided into two sub-groups according to hepatic involvement, the 5-year survival rate of patients who had hepatic involvement was significantly lower than those patients without hepatic involvement (0.7%, 27%, respectively) (P=0.002). The 5-year survival rate of patients who underwent hematopoietic stem cell transplantation was significantly higher than the patients who didn't (44%, 16%, respectively) (P=0.02). In conclusion, age two years and under, ferritin level above 1500 mg/dL, spinal cord or hepatic involvement should be considered as poor prognostic factors in familial hemophagocytic lymphohistiocytosis.

The Effects of Hypericum perforatum L. on the Proliferation, Osteogenic Differentiation, and Inflammatory Response of Mesenchymal Stem Cells from Different Niches.

The aim of this study is to demonstrate and compare the differentiation, proliferation, migration and inflammatory behavior of dental pulp- and bone marrow-derived mesenchymal stem cells (DP-MSCs and BM-MSCs) in response to a Hypericum perforatum ethanol extract. Using xCELLigence, a real-time monitoring system, a dose of 10 µg/mL was found to be the most efficient concentration for vitality. The IC50 values and doubling time were calculated. The results showed that H. perforatum L. was able to accelerate osteogenic differentiation in DP-MSCs, but calcium granulation was impaired in BM-MSCs. H. perforatum L.-induced migration increased when compared to the TNF-α-induced migration in a Transwell migration assay, and the IL-6 cytokine levels between cells also differed. It can be suggested that tissue memory is an important factor in MSCs, and that they differ in their response to external factors. In conclusion, H. perforatum L. can be considered an excellent osteoinductive agent for DP-MSCs but should not be used for BM-MSCs. Tissue-specific osteoinductive agents should be discussed in future studies.

Factors associated with bone marrow stem cell yield for pediatric allogeneic stem cell transplantation: The impact of donor characteristics.

The aim of this study was to investigate the effects of donor characteristics on CD34+ cell yield in BM harvest. Between April 2010 and November 2013, consecutive donors who underwent BM harvesting in our BM transplantation unit were retrospectively investigated. Donors were classified into two groups: those who donated BM without mobilization (steady-state BM donors) and those who received G-CSF for stem cell mobilization (G-CSF-primed BM donors). Donor characteristics (age, gender, race, body weight, BMI, and laboratory factors including donor's leukocyte, platelet, and monocyte) and their relationship with total nuclear cell and CD34+ cell numbers has been evaluated. A total of 64 healthy related donors (29 males/35 females, median age 11.2 years; 49 [76.6%] younger than 18 and 36 [56.3%] younger than 12 years) were included in the study. The median CD34+ cell yield in the harvest was 0.12×106 /L (0.02-0.21) in SS-BM donors and 0.18×106 /L (0.09-0.67) in GP-BM donors (P=.03). Median of CD34+ cell count given to recipients was 2.6×106 /recipient body weight (1.3-19.3) in SS-BM yields and 3.8×106 /recipient body weight (1.1-10.2) in GP-BM yields, respectively. Multiple regression analysis showed that donor height and pre-G-CSF platelet were the most important parameters to obtain a sufficient BM harvest. Our data suggest that the shorter donors and the donors with higher thrombocyte counts may offer more hematopoietic stem cell. The height and thrombocyte count of the donors should be taken into consideration before planning the targeted CD34+ cell count especially for pediatric donors.

Hematopoietic cell transplantation activity of Turkey in 2014: Ongoing increase in HCT rates.

Hematopoietic cell transplantation is an established treatment option with curative potential for a variety of clinical conditions. The last decade especially witnessed a remarkable increase in HCT activity in Turkey. In 2014, 696 pediatric and 2631 adult (total 3327) HCT were performed in Turkey. Corresponding transplant rates per 10 million inhabitants for autologous-HCT and allogeneic-HCT were 226 and 202, respectively. Total HCT procedures in Turkey increased 177% in the last 5 years and 791% in the last 14 years. This report focuses mainly on HCT activity of Turkey in 2014 based on the national HCT registry and presents a general picture of national HCT activity.

Mesenchymal stem cell application in children with subacute sclerosing panencephalitis.

Subacute sclerosing panencephalitis (SSPE) is a serious, often fatal disease that responds poorly to current treatment modalities. Recently, the ability of mesenchymal stem cells (MSCs) to produce neurotrophic factors and inflammatory molecules has placed them among potential treatment agents for neurological conditions. We report the results of four patients treated with MSC for SSPE. The patients were followed up clinically, and by periodical laboratory evaluations, magnetic resonance imaging (MRI), and electroencephalography. One patient deteriorated to stage III of the disease, two patients remained in the same stage, and one died from disease progression and respiratory problems. Neurological findings and electroencephalography scores were consistent with the clinical course of the patient whereas MRI showed new inflammatory lesions in two patients. This is the first report of the application of MSC in SSPE. No benefit is demonstrated.

Clinical outcomes and graft characteristics in pediatric hematopoietic stem cell transplantation: Effect of granulocyte-colony stimulating factor priming.

In this study, we aimed to determine the effect(s) of G-CSF priming on graft and transplantation parameters and compare these findings with those obtained without priming. A total of 64 pediatric patients transplanted from HLA-matched family donors were enrolled in the study. Twenty-nine patients received G-CSF primed marrow (G-BM group) and 35 patients received steady state bone marrow (S-BM group). Number of total nucleated cells (TNC) and CD34(+) cells, CFU-GM colony number, neutrophil and platelet engraftment times, total length of stay in hospital, overall and disease free survival, and occasions of acute and chronic GvHD has been compared between these two groups. Granulocyte colony stimulating factor primed bone marrow (G-BM) yielded higher numbers of CD34(+) cells, TNCs, and CFU-GM colony numbers compared to those obtained in S-BM. The neutrophil engraftment time, platelet engraftment time, length of stay in hospital, overall survival and disease free survival were not different between G-BM and S-BM groups. Also the cumulative incidence of grades II-IV acute and chronic GvHD were similar. It was observed that the use of G-CSF did not increase the risk of acute or chronic GvHD. We concluded that use of G-CSF for stem cell mobilization is an effective and safe method in children.

Evaluation of Cardiac Markers in Children Undergoing Hematopoietic Stem Cell Transplantation.

BACKGROUND: Early life-threatening cardiotoxicity and cardiac death have been reported after hematopoietic stem cell transplantation (HSCT). The purpose of the current study was to evaluate cardiac toxicity of conventional chemotherapy followed by HSCT with cardiac markers: heart-type fatty acid binding protein (H-FABP), glycogen phosphorylase BB (GPBB), high sensitive C reactive protein (hsCRP) cardiac troponin I, (cTnI), creatine kinase MB (CK-MB mass) and myoglobin. METHODS: A total of 20 children who underwent HSCT for malignant and non-malignant diseases were included in this study. Blood samples were collected from all patients in 0th, 7th and 21st day for evaluating these cardiac biomarkers. The patients' echocardiography was assessment before and after one-month of HSCT. RESULTS: Serum 21st H-FABP level was significantly higher when compared with the 0th day H-FABP level (P < 0.05) . 7th day hsCRP level was significantly higher than 0th and 21st day levels (P < 0.05). Interestingly, 7th day GPBB level was significantly lower than 0th and 21st day levels (P < 0.05). Myoglobin, CK-MB mass and cTnI biomarkers remained within the reference range in all patients. CONCLUSIONS: This study showed that H-FABP and hsCRP both seem to be promising markers for evaluation of cardiotoxicity in HSCT process and probably superior to GPBB, cTnI, CK-MB mass and myoglobin.

Successful treatment of severe myasthenia gravis developed after allogeneic hematopoietic stem cell transplantation with plasma exchange and rituximab.

Myasthenia gravis is among the rare complications after allogeneic hematopoietic stem cell transplantation and is usually associated with chronic GVHD. Herein, we report a 2-year and 10 months of age female with Griscelli syndrome, who developed severe myasthenia gravis at post-transplant +22nd month and required respiratory support with mechanical ventilation. She was unresponsive to cyclosporine A, methylprednisolone, intravenous immunoglobulin, and mycophenolate mofetil and the symptoms could only be controlled after plasma exchange and subsequent use of rituximab, in addition to cyclosporine A and mycophenolate mofetil maintenance. She is currently asymptomatic on the 6th month of follow-up.

Neurological complications after allogeneic hematopoietic stem cell transplantation in children, a single center experience.

In this study, we retrospectively examined the data of children who underwent allo-HSCT from HLA-matched family donors. We analyzed the incidence, etiological factors, clinical characteristics, possible reasons, risk factors, and follow-up of neurologic complications. BU-based conditioning regimens were used in most of the cases (n = 62). The median duration of follow-up for the 89 patients was 20 months (range 1-41 months). Eleven percent of transplanted children developed one or more neurological symptoms after HSCT with a median observation time of two months (range -6 days to 18 months). The median age of the four girls and six boys with neurological complication was 13 yr (range 5.3-17.6 yr). Cylosporine A neurotoxicity was diagnosed in five children, four of them were PRES. The rest of complications were BU and lorazepam toxicity, an intracranial hemorrhage, a sinovenous thrombosis, and a transient ischemic attack during extracorpereal photopheresis. No difference was found between groups of neurological complication according to age, gender, diagnosis, hospitalization time, neutrophil and platelet engraftment time, stem cell source, and conditioning regimen, acute and chronic GVHD or VOD. Neurological complication was the cause of death in one patient (1.1%).

Do two different stem cell grafts: G-CSF stimulated and unstimulated bone marrow differ according to hematopoietic colony forming capacity?

The study was designed to compare colony forming capacity of granulocyte-colony stimulating factor (G-CSF) stimulated bone marrow (G-BM) with standard unstimulated bone marrow (U-BM) of healthy donors of pediatric patients. CFU-Assay results of 26 healthy donors of pediatric patients undergoing allogeneic hematopoietic stem cell transplantation (HSCT) were analyzed retrospectively. 13 of donors received 10 µg/kg per day of G-CSF as a single injection for 3 consecutive days and other 13 of donors had unstimulated BM. Colony forming capacity of hematopoietic stem cells evaluated with Colony Forming Unit-Assay (CFU-Assay) with in semi-solid agar culture medium after 14-18 days of culture period. CFU-Assay results of G-BM and U-BM (expressed as means) were; Burst Forming Unit-Erythroid (BFU-E): 15.20 × 10(4)/kg and 8.38 × 10(4)/kg, Colony Forming Unit-Granulocyte Macrophage (CFU-GM): 10.35 × 10(4)/kg and 5.67 × 10(4)/kg, Colony Forming Unit-Erythroid (CFU-E): 0.59 × 10(4)/kg and 0.33 × 10(4)/kg, CFU-Granulocyte Erythroid Macrophage Megakaryocyte (CFU-GEMM): 0.52 × 10(4)/kg and 0.53 × 10(4)/kg respectively. BFU-E and CFU-GM capacity of G-BM was increased and statistically significantly different than standard U-BM (p ⩽ 0.01). In conclusion, increased colony forming capacity of hematopoietic stem cells of G-BM when compared with standard unstimulated BM could be a major advantage for transplantation.

Successful allogeneic hemopoietic stem cell transplantation in a case of Wiskott-Aldrich syndrome and non-Hodgkin lymphoma.

WAS is a severe X-linked recessive disorder characterized by microthrombocytopenia, eczema, and immunodeficiency. A six-yr-old boy with WAS diagnosed as B-cell NHL (Stage III) localized in the liver who underwent successful HSCT from HLA-one antigen mismatch sibling donor has been presented here. His conditioning regimen included ATG, busulfan, and fludarabine. He received 2.3 × 10(6) /kg CD 34+ stem cells and 11 × 10(8) /kg nucleated cells at day 0. Neutrophil engraftment was achieved at day +14 and platelet engraftment at day +20. He has been in CR for more than two yr after transplantation. Thus, HSCT is an effective treatment for children with WAS even after development of lymphoma.

Use of mesenchymal stem cells and darbepoetin improve ischemia-induced acute kidney injury outcomes.

BACKGROUND: Interest has recently been focused on the possible role of bone marrow-originating stem cells and the therapeutic role of erythropoietin in the recovery of ischemia-induced acute kidney injury (AKI). The aim of the present study was to compare treatment with mesenchymal stem cells (MSCs) to treatment with darbepoetin-α (DPO) or both concomitantly in a rat model of ischemia/reperfusion (I/R) AKI. METHODS: Forty male Sprague-Dawley rats were included, and 28 of them were randomly assigned to controls (treated with serum physiologic) or one of the three treatment groups treated with either DPO, MSCs, or both (MSCs and DPO concomitantly) after the induction of I/R injury. Hematocrit, serum creatinine, and BUN levels were obtained at 0, 24, 48, and 72 h of surgery, and renal tissue was obtained at 72 h after nephrectomy for histological analysis. Tissue injury was quantified by standardized histological scoring systems, using light and electron microscopes. RESULTS: Treatment with MSCs or DPO improved renal function compared with controls. However, the improvement observed in renal function in the MSC/DPO group was better than that in the other groups. Histological analysis demonstrated that tissue injury was significantly decreased in rats in the MSC or DPO groups compared to that of the controls; however the best recovery was observed in rats treated with MSCs and DPO concomitantly. CONCLUSION: These results suggest that concomitant application of DPO and MSCs may be a potential novel renoprotective therapy for patients after having sustained an ischemic renal insult.

Thalassemia-free and graft-versus-host-free survival: outcomes of hematopoietic stem cell transplantation for thalassemia major, Turkish experience.

We report the national data on the outcomes of hematopoietic stem cell transplantation (HSCT) for thalassemia major (TM) patients in Turkey on behalf of the Turkish Pediatric Stem Cell Transplantation Group. We retrospectively enrolled 1469 patients with TM who underwent their first HSCT between 1988 and 2020 in 25 pediatric centers in Turkey. The median follow-up duration and transplant ages were 62 months and 7 years, respectively; 113 patients had chronic graft versus host disease (cGVHD) and the cGVHD rate was 8.3% in surviving patients. Upon the last visit, 30 patients still had cGvHD (2.2%). The 5-year overall survival (OS), thalassemia-free survival (TFS) and thalassemia-GVHD-free survival (TGFS) rates were 92.3%, 82.1%, and 80.8%, respectively. cGVHD incidence was significantly lower in the mixed chimerism (MC) group compared to the complete chimerism (CC) group (p < 0.001). In survival analysis, OS, TFS, and TGFS rates were significantly higher for transplants after 2010. TFS and TGFS rates were better for patients under 7 years and at centers that had performed over 100 thalassemia transplants. Transplants from matched unrelated donors had significantly higher TFS rates. We recommend HSCT before 7 years old in thalassemia patients who have a matched donor for improved outcomes.

Mesenchymal stem cell therapy in necrotizing enterocolitis: a rat study.

We evaluated the potential therapeutic use of exogenous human bone marrow-derived mesenchymal stem cells (hBM-MSCs) in an experimental rat model of necrotizing enterocolitis (NEC). Thirty-six newborn Sprague-Dawley rats were randomly divided into three groups: NEC, NEC + hBM-MSC, and a control (control and control + hBM-MSC). NEC was induced by enteral formula feeding, exposure to hypoxia-hyperoxia, and cold stress. After NEC was induced, iron-labeled hBM-MSCs were administered by intraperitoneal injection. All pups were killed on the fourth day following injection, and the terminal ileum was excised for a histopathological and immunohistochemical evaluation. The pups in the NEC + hBM-MSC group showed significant weight gains and improvements in their clinical sickness scores (p < 0.01). Bowel damage severity observed in the histopathological evaluation was significantly lower in the NEC + hBM-MSC group than that in the NEC group (p = 0.012). The number of MSCs homing to the bowel was significantly higher in the NEC + hBM-MSC group than that in the control + hBM-MSC group. In conclusion, this is the first study that has evaluated the effectiveness of hBM-MSCs in a neonatal rat NEC model. MSCs reduced histopathological damage significantly.

Increased availability of family donors for hematopoietic stem cell transplantation in a population with increased incidence of consanguinity.

The study was planned to determine the frequency of parental and non-sibling family donor transplants in our center and to investigate the rate of familial donor availability at two HLA-typing laboratories in Turkey. Among 203 patients who underwent hematopoietic stem cell transplantation (HSCT), 151 (74.4%) received stem cells from siblings, 48 (23.6%) from non-sibling family donors, two (1.0%) from unrelated cord blood, and two (1.0%) autologous transplantation. Of these 48 patients received stem cells from non-sibling family donors; donors were mothers for 26 (12.8%), fathers for 20 (9.9%), and aunts for two (1.0%). The rate of transplants from parental donors was 22.6% in this patient population with increased frequency of inherited diseases (58.1%). Among these 203 patients, there was consanguinity between parents in 60.6% of the patients. Of 833 subjects applying as donor candidates to HLA-typing laboratories, 527 (63.3%) had HLA 6/6 identical family donors. Among 527 full-matched donors, 479 (90.9%) were sibling, 21 (4.0%) were fathers, and 17 (3.2%) were mothers. The remaining 10 (1.9%) were other relatives. The results have shown that the unfavorable factor of consanguinity marriage may increase the availability of family donors for HSCT in particularly developing countries where large donor registries are lacking.

Serological response to influenza vaccine after hematopoetic stem cell transplantation.

Vaccination is the best strategy to prevent influenza infection that is a potential cause of morbidity and mortality in immunosuppressed patients. Here, we evaluated the factors that may affect serological response to influenza vaccine in patients who have undergone hematopoetic stem cell transplantation (HSCT). Sixty-one HSCT recipients were included in the study during the 2007-2008 influenza season. Serum samples prior to vaccination and 6-10 weeks after vaccination were collected. Samples were assayed for antibodies to influenza virus A/H1N1, A/H3N2, and B strains by hemagglutination-inhibition assay. The patients were followed in terms of clinical symptoms up to the next influenza season and for adverse effects within a month after vaccination. Overall, pre-vaccine seroprotection rate against all vaccine antigens (A/H1N1, A/H3N2, and B antigens) was 45.1%, post-vaccine seroprotection rate 91% and seroconversion rate was 28.3%. Seroconversion rates were found to be low against B in patients who were vaccinated in the late influenza season (p = 0.018; respectively). Five patients (10.9%) had no immune response against H1N1. Adverse events were reported in 19.6% (n = 9/46) of the patients. In conclusion, the patients should be vaccinated as early as possible in the influenza season, before they are exposed to the virus.

Deferasirox use after hematopoietic stem cell transplantation in pediatric patients with beta-thalassemia major: preliminary results.

There are limited data on the posttransplantation pharmacological treatment of iron overload in ex-thalassemic patients and the current approach is phlebotomy. The authors chelated 2 ex-thalassemic patients after hematopoietic stem cell transplantation with deferasirox for 6 and 24 months. Although serum ferritin levels decreased, cardiac and hepatic iron load, measured by T2* magnetic resonance imaging (MRI), showed decrease in iron overload in these organs. The drug was tolerated well by both patients and no adverse effect on donor hematopoiesis was observed. This preliminary study demonstrates that deferasirox is well tolerated in these patients and will be a good potential therapy when more data have been obtained from larger studies.