COVID-19 disease in children and adolescents following allogeneic hematopoietic stem cell transplantation: A report from the Turkish pediatric bone marrow transplantation study group.

BACKGROUND: Data on the risk factors and outcomes for pediatric patients with SARS-CoV-2 infection (COVID-19) following hematopoietic stem cell transplantation (HSCT) are limited. OBJECTIVES: The study aimed to analyze the clinical signs, risk factors, and outcomes for ICU admission and mortality in a large pediatric cohort who underwent allogeneic HSCT prior to COVID-19 infection. METHOD: In this nationwide study, we retrospectively reviewed the data of 184 pediatric HSCT recipients who had COVID-19 between March 2020 and August 2022. RESULTS: The median time from HSCT to COVID-19 infection was 209.0 days (IQR, 111.7-340.8; range, 0-3845 days). The most common clinical manifestation was fever (58.7%). While most patients (78.8%) had asymptomatic/mild disease, the disease severity was moderate in 9.2% and severe and critical in 4.4% and 7.6%, respectively. The overall mortality was 10.9% (n: 20). Deaths were attributable to COVID-19 in nine (4.9%) patients. Multivariate analysis revealed that lower respiratory tract disease (LRTD) (OR, 23.20, p: .001) and lymphopenia at diagnosis (OR, 5.21, p: .006) were risk factors for ICU admission and that HSCT from a mismatched donor (OR, 54.04, p: .028), multisystem inflammatory syndrome in children (MIS-C) (OR, 31.07, p: .003), and LRTD (OR, 10.11, p: .035) were associated with a higher risk for COVID-19-related mortality. CONCLUSION: While COVID-19 is mostly asymptomatic or mild in pediatric transplant recipients, it can cause ICU admission in those with LRTD or lymphopenia at diagnosis and may be more fatal in those who are transplanted from a mismatched donor and those who develop MIS-C or LRTD.

A large single-center cohort of bare lymphocyte syndrome: Immunological and genetic features in Turkey.

Major histocompatibility complex class II (MHC-II) deficiency or bare lymphocyte syndrome (BLS) is a rare, early-onset, autosomal recessive, and life-threatening inborn error of immunity. We aimed to assess the demographic, clinical, laboratory, follow-up, and treatment characteristics of patients with MHC-II deficiency, together with their survival. We retrospectively investigated 21 patients with MHC-II deficiency. Female/male ratio was 1.63. The median age at diagnosis was 16.3 months (5 months-9.7 years). Nineteen patients (90.5%) had parental consanguinity. Pulmonary diseases (pneumonia, chronic lung disease) (81%), diarrhoea (47.6%), and candidiasis (28.6%) were common. Four (19%) had autoimmunity, two developed septic arthritis, and three (14%) developed bronchiectasis in the follow-up. Three patients (14%) had CMV viraemia, one with bilateral CMV retinitis. Eight (38.1%) had lymphocytopenia, and four (19%) had neutropenia. Serum IgM, IgA, and IgG levels were low in 18 (85.7%), 15 (71.4%), and 11 (52.4%) patients, respectively. CD4+ lymphocytopenia, a reversed CD4+/CD8+ ratio, and absent/low HLA-DR expressions were detected in 93.3%, 86.7%, and 100% of the patients, respectively. Haematopoietic stem cell transplantation (HSCT) was performed on nine patients, and four died of septicaemia and ARDS after HSCT. The present median age of patients survived is 14 years (1-31 years). Genetic analysis was performed in 10 patients. RFX5 homozygous gene defect was found in three patients (P1, P4 and P8), and RFXANK (P2 and P14) and RFXAP (P18 and P19) heterozygous gene defects were found in each two patients, respectively. This large cohort showed that BLS patients have severe combined immunodeficiency (SCID)-like clinical findings. Flow cytometric MHC-II expression study is crucial for the diagnosis, differential diagnosis with SCID, early haematopoietic stem cell transplantation (HSCT), and post-HSCT follow-up. Genetic studies are required first for matched family donor evaluation before HSCT and then for genetic counselling.

Predictors of kidney complications and analysis of hypertension in children with allogeneic hematopoietic stem cell transplantation.

BACKGROUND: This study aimed to determine incidence of kidney complications in pediatric allogeneic hematopoietic stem cell transplantation (HSCT) patients. METHODS: Pediatric allogeneic HSCT patients were included. Post-transplantation urinary system complications were collected from medical records and glomerular filtration rates at last visit compared with clinical parameters. Additionally, 24-h ambulatory blood pressure monitoring was performed. RESULTS: The study included 165 pediatric patients. Acute kidney injury (AKI) developed in 125 (75.8%) patients of whom 54 (43.2%) had stage 1, 36 (28.8%) stage 2, and 35 (28%) stage 3 AKI. Primary malignant disease and viral infection post-HSCT were associated with increased risk of AKI (OR: 4; 95%CI: 1.2-13, p = 0.022 and OR: 2.9; 95%CI: 1.2-6.8, p = 0.014, respectively). Mean duration of post-HSCT follow-up was 4.4 ± 2.5 years, during which time 8 patients had chronic kidney disease (CKD) (stage 1, 4 patients; stage 2, 3 patients; stage 3, 1 patient). CKD incidence was higher in patients in whom stem cell product was bone marrow + cord blood and mobilized peripheral blood, compared to bone marrow alone (40-37.5% versus 5.1%, p = 0.002). Based on 24-h ABPM, 14.7% and 7.4% of patients with normal office blood pressure had pre-hypertension and hypertension, respectively. In patients with albuminuria/severe albuminuria, daytime and nighttime systolic SDS scores were higher than those without albuminuria/severe albuminuria (p = 0.010 and p = 0.004, respectively). CONCLUSIONS: Incidence of AKI is higher in pediatric HSCT patients with primary malignant disease and those with documented viral infection. Our study highlights the beneficial role of 24-h ABPM as a routine part of standard care of pediatric HSCT recipients.

Alterations in Hematopoietic and Mesenchymal Stromal Cell Components of the Osteopetrotic Bone Marrow Niche.

Osteopetrosis is a rare inherited disease characterized by impaired osteoclast activity causing defective bone resorption and bone marrow aplasia. It is fatal in early childhood unless hematopoietic stem cell transplantation is performed. But, the transplant course is complicated with engraftment failure. Recently, osteoclasts have been described as the potential regulators of hematopoietic stem cell (HSC) niche. Here we investigated the alterations in the HSC and mesenchymal stromal cell (MSC) components of osteopetrotic niche and their interactions to mimic the stem cell dynamics/trafficking in the BM niche after HSC transplantation. Induced pluripotent stem cells were generated from peripheral blood mononuclear cells of patients with osteopetrosis carrying TCIRG1 mutation. iPSC lines were differentiated into hematopoietic and myeloid progenitors, then into osteoclasts using a step-wise protocol. We first demonstrated a shift toward monocyte-macrophages lineage regarding hematopoietic differentiation potential of osteopetrotic iPSC-derived hematopoietic progenitors (HPCs) and phenotypically normal and functionally defective osteoclast formation. The expression of the genes involved in HSC homing and maintenance (Sdf-1, Jagged-1, Kit-L, and Opn) in osteopetrotic MSCs recovered significantly after coculture with healthy HPCs. Similarly, the restoration of phenotype, impaired differentiation, and migratory potential of osteopetrotic iHPCs were observed upon interaction with healthy MSCs. Our results establish significant alterations in both MSC and HPC compartments of the osteopetrotic niche, and support the impact of functionally impaired osteoclasts in defective niche formation.

Chitosan Channels Stuffed with Mesenchyme Originated Stem/Progenitor Cells for Renovate Axonal Regeneration in Complete Spinal Cord Transection.

AIM: To examine the implantation of chitosan channels stuffed with mesenchyme-originated stem/progenitor cells (MSPCs) derived from adult rats in a spinal cord transection model. The level of axonal regeneration, the effect of chitosan channels on the survival of MSPCs, and the functional recovery results were also evaluated. MATERIAL AND METHODS: Chitosan channels stuffed with MSPCs were implanted at the level of T8 in a transected rat spinal cord. MSPCs were harvested from the pelvic bone marrow of adult rats, and the MSPC?chitosan channel group was compared with three control groups. The axonal regeneration capacity, the effect of chitosan channels on the survival of MSPCs, and the functional recovery results were compared among four groups. The survival of MSPCs was evaluated using histopathological techniques and electron microscopy, axonal regeneration/germination was evaluated by confocal microscopy, and locomotor function was assessed for 4 weeks using the Basso, Beattie, and Bresnahan locomotor score. RESULTS: The MSPC-chitosan channel group exhibited enhanced survival of transplanted MSPCs compared with MSPCs transplanted directly into the lesion cavity, although no significant difference was detected in locomotor function between the treatment and control groups. The MSPC-chitosan channel group demonstrated thicker myelination of axons than the other groups. CONCLUSION: Chitosan channels promoted the survival of transplanted MSPCs and created a tissue bridge after complete spinal cord transection. They also induced axonal regeneration and germination. No significant improvement in functional recovery was found between the groups.

Effects of multimodal exercise on clinical status and patient-reported outcomes in children undergoing hematopoietic stem cell transplantation.

There are limited data available regarding effectiveness of exercise training in children undergoing hematopoietic stem cell transplantation (HSCT). We aimed to investigate effects of multimodal exercise program on clinical status and patient-reported outcomes including pain, fatigue, depression, and quality of life (QOL) level of children and their parents' QOL level. Twenty-six children undergoing HSCT participated in this study. Clinical status, pain, fatigue, depression, and QOL level of children were assessed three times: before HSCT, at discharge, and one month later. For intervention group (IG, n = 15), multimodal exercise program was performed five days a week, throughout hospitalization and children were advised to continue exercise program at home. For control group (CG, n = 11), being active as much as possible was advised. The number of painful day and pain intensity was significantly lower in IG than in CG during hospitalization (p < .05). Depression level decreased in IG at the time points (p ˂ .05); however, there was no significantly difference between groups. The QOL level was higher in IG than CG only at control measurements (p ˂ .05). In addition, QOL level of the parents decreased in both groups (p ˂ .05). There was no statistically difference between groups in terms of other clinical variables. The multimodal supervised exercise program has positive effects on children's pain and QOL level. Exercise program was also well tolerated by children during hospitalization. In addition, QOL levels of the parents were also negatively affected during hospitalization, and interventions aiming to increase QOL level of the parents should be considered.

Osteopetrotic induced pluripotent stem cells derived from patients with different disease-associated mutations by non-integrating reprogramming methods.

BACKGROUND: Autosomal recessive osteopetrosis is a genetically and phenotypically heterogeneous disease, caused by defects in osteoclast formation and function. The only available treatment is allogeneic stem cell transplantation that has still high morbidity and mortality. The goal of the present study was to generate iPSCs from bone marrow-derived MSCs of osteopetrosis patients with three most common mutations by using two different integration-free gene transfer methods and compare their efficiencies. The secondary objective was to select the most appropriate integration-free production method for our institutional iPSC bank using this rare disease as a prototype. METHODS: Two different integration-free gene transfer methods (episomal and Sendai viral vectors) were tested and compared on the same set of patient samples exhibiting three different mutations associated with osteopetrosis. Generated iPSCs were characterized by standard assays, including immunophenotyping, immunocytochemistry, RT-PCR, embryoid body, and teratoma assays. Karyotype analyses were performed to evaluate genetic stability. RESULTS: iPSC lines exhibiting typical ESC-like colony morphology were shown to express pluripotency markers by immunofluorescence staining. Over 90% of the cells were found positive for SSEA-4 and OCT3/4 and negative/weak positive for CD29 by flow cytometry. Immunohistochemical staining of teratoma and spontaneously differentiated embryoid body sections confirmed their trilineage differentiation potential. All iPSC lines expressed pluripotency-related genes. Karyotype analyses were found normal. Direct sequencing of PCR-amplified DNA showed that disease-related mutations were retained in the patient-specific iPSCs. CONCLUSION: Generation of iPSC using SeV and episomal DNA vectors have several advantages over other methods like the ease of production, reliability, high efficiency, and safety, which is required for translational research. Furthermore, owing to the pluripotency and self-renewal capacity, patient-specific iPSCs seem to be ideal cell source for the modeling of a rare genetic bone disease like osteopetrosis to identify osteoclast defects, leading to clinical heterogeneity in osteopetrosis patients, especially among those with different mutations in the same gene.

Pediatric bone marrow transplantation: Psychopathologic features in recipients along with siblings.

OBJECTIVE: To analyze the development of psychopathology in recipients along with their donor and nondonor siblings and the relationship with the bone marrow transplantation (BMT) process. METHODS: All children were interviewed using the Kiddie Schedule for Affective Disorders and Schizophrenia to assess psychopathology. The depression and anxiety symptoms and self-esteem of children and adolescents were evaluated using the Children's Depression Inventory, State-Trait Anxiety Inventory for Children, State-Trait Anxiety Inventory, and Rosenberg Self-Esteem Scale. RESULTS: In this study, the depressive symptom level was found significantly higher in the donor group compared with the nondonor group. State anxiety symptoms were higher in the BMT group (P < .05). There were no significant differences in trait anxiety symptoms. Self-respect was higher in children in the donor group compared with those in the BMT group (P < .05). During the transplant process, children with bone marrow transplants had a higher prevalence of depression, anxiety disorder, and attention-deficit/hyperactivity disorder, and nondonor siblings had a higher prevalence of depressive disorder, anxiety disorder, and attention-deficit/hyperactivity disorder compared with society in general. CONCLUSION: Physicians should deal with the family as a whole, not just their patient, and should be aware of the psychiatric risk of other siblings during the assessment.

The effect of poly(3-hydroxybutyrate-co-3- hydroxyhexanoate) (PHBHHx) and human mesenchymal stem cell (hMSC) on axonal regeneration in experimental sciatic nerve damage.

This study is designed to evaluate the treatment effect of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) and human mesenchymal stem cells (hMSC) on axonal regeneration in experimental rat sciatic nerve damage, and compare the results of this modality with autologous nerve grafting. In Spraque-Dawley albino rats, 10-mm-long experimental nerve gaps were created. Three groups were constituted, the gap was repaired with autologous nerve graft (autograft group), PHBHHx nerve graft alone (PHBHHx alone group), and PHBHHx nerve graft with hMSCs inside (PHBHHx with hMSC group), respectively. The results were evaluated with functional recovery, electrophysiological evaluation, and histological evaluation either with light microscopy and transmission electron microscopy for axonal regeneration and myelin formation. In functional evaluation, autograft and PHBHHx with hMSC groups showed functional improvement with time, whereas PHBHHx alone group did not. Electrophysiological evaluation showed better results in autograft and PHBHHx with hMSC groups when compared to PHBHHx alone group. There was no statistical difference between autograft and PHBHHx with hMSC groups. Histological evaluation showed regenerated axons in each group. Autograft group was better than the others, and PHBHHx with hMSC group was better than PHBHHx alone group both for axonal regeneration and myelin formation. This study showed that the nerve grafts which were prepared from PHBHHx with oriented nanofiber three-dimensional surfaces aided to nerve regeneration, either used alone or with hMSC. PHBHHx provided better nerve regeneration when used with hMSCs inside than alone, and reached the same statistical treatment effect in functional evaluation and electrophysiological evaluation when compared to autografting.

Oxidative protein damage with carbonyl levels and nitrotyrosine expression after chemotherapy in bone marrow transplantation patients.

Protein oxidation is defined as the covalent modification ofa protein, induced either directly by reactive oxygen species/reactive nitrogen species or indirectly by reaction with secondary by-products of oxidative stress. Protein carbonyls are the most commonly measured products of protein oxidation. Additionally, nitrotyrosine is a product of tyrosine nitration mediated by reactive nitrogen species such as peroxynitrite anion and nitrogen dioxide. Samples were collected before the preparative regimen (10 days before transplantation; day ­10), on transplantation day (day 0), and after transplantation (days 7, 14, and 28) from 16 pediatric allogeneic hematopoietic stem cell transplantation (HSCT) patients.The erythrocyte 3-nitrotyrosine expression was shown to be significantly increased after chemotherapy. In accordance, the mean plasma carbonyl levels on days 14 and 28 were significantly higher than on the other days. High dose chemotherapy applied in the preparative regimen of HSCT may be responsible for this long-term oxidation of plasma proteins. These results show that high-dose chemotherapy resulted in protein oxidation both in plasma and in erythrocytes in HSCT patients.

Excessive naked megakaryocyte nuclei in myelodysplastic syndrome mimicking idiopathic thrombocytopenic purpura: a complicated pre- and post-transplantation course.

A boy 3 years 7 months old with thrombocytopenia and history of intracranial hemorrhage who underwent bone marrow transplantation is presented. He was refractory to steroids, immunoglobulin G, vincristine, azathioprine, cyclosporine A, interleukin-11, chemotherapy, and splenectomy. Idiopathic thrombocytopenic purpura was excluded by light /electron microscopic and flow cytometric findings; the diagnosis of refractory cytopenia, a subgroup of pediatric myelodysplastic syndrome, was made. Naked megakaryocyte nuclei were 55.38 +/- 28.2% vs. 31.67 +/- 23.22% of all megakaryocytes in the patient and the control group of 9 patients with idiopathic thrombocytopenic purpura, respectively (p = .016). The posttransplatation course was complicated by delayed platelet engraftment, bronchiolitis obliterans associated with pneumocystis carinii pneumonia, which resolved completely.

Dysplasia and disorder of cell membrane entirety in iron-deficiency anemia.

Peripheral blood smears of 43 patients (26 males, median age 18 months, range: 6-180 months) with nutritional iron-deficiency anemia (IDA) were examined for the presence of trilineage hematological dysplasia. Twelve patients were reexamined for dysplastic findings after achieving a normal Hb and hematocrit level for age by the end of 2-3 months of iron treatment. A control group of 17 age-matched healthy children were also included. Neutrophils with loss of membrane entirety and protrusions were remarkable in 34/43 (79%) in the IDA group versus 1/12 (8%) after iron treatment and none of the control group. Microspherocytes were seen in 9/43 (21%) of IDA patients. Additionally, trilienage dysplasia was observed in the bone marrow samples available in 3 of the patients. It has been shown that iron-deficiency results in cellular DNA and RNA alterations, cell-cycle G1/S phase arrest, and apoptosis. Rac GTPases have been shown to control actin cytoskeleton, influencing cell polarity, microtubule dynamics, and the cytoskeletal organization of hematopoietic cells. Thus, the findings described above in neutrophils and red cells suggest a plausible link between iron and the Rac GTPase gene family. It may be a new avenue for iron waiting for proof.

Hematopoietic stem cell transplantation from a donor with Klinefelter syndrome for Wiskott-Aldrich syndrome.

WAS is a rare X-linked recessive disorder characterized by primary progressive T cell immunodeficiency, impaired antipolysaccharide antibody response, thrombocytopenia with small platelet, and eczematoid dermatitis. Untreated patients with typical WAS have poor prognosis with the major causes of death being infection, bleeding, lymphoproliferative disorders, and malignancy. Due to the increased risk of infectious and hemorrhagic episodes the best results with HSCT are achieved in patients less than five yr of age and are recommended as early as possible. Here, we report a three-yr-old boy with WAS who underwent UCB and BMT from his genotypically identical brother with Klinefelter syndrome.

Allogeneic hematopoietic stem cell transplantation in pediatric chronic myelogenous leukemia cases: Hacettepe experience.

Recently, there are emerging reports on the beneficial effect of imatinib mesylate for pediatric CML patients; however, the general recommendation is that high-risk CML patients with a human leukocyte antigen-identical donor should be transplanted within the first 12 months after diagnosis. Herein, the data of 16 allogeneic HSCT in 14 children with CML were analyzed retrospectively. In the present study, three-yr EFS was 54.1+/-10.8% and three-yr OS was found as 80.7+/-12.5%.

[Evaluation of differentiation potential of human bone marrow-derived mesenchymal stromal cells to cartilage and bone cells]. / Insan kemik iligi kaynakli mezenkimal stromal hücrelerin kikirdak ve kemik hücrelerine farklilasma potansiyelinin degerlendirilmesi.

OBJECTIVES: This study was designed to identify the characteristics and surface antigen properties of mesenchymal stromal cells (MSC) isolated and cultured from bone marrow of healthy subjects and to assess their differentiation potential to osteoblast and chondroblast lineage cells. METHODS: Mononuclear cells were isolated by density-gradient separation from 1-3 ml of bone marrow collected from 10 donors of bone transplantation aged between 4 months and 18 years. These mononuclear cells were cultured in flasks containing 10% fetal calf serum, which resulted in growth of fibroblast-like cells showing adhesion onto the culture flask. Physical properties of the cells were identified and flow cytometric immunophenotyping was performed to specify surface antigen properties. Differentiation of mesenchymal stromal cells in specific media to chondroblasts and osteoblasts was evaluated. Osteoblasts and chondroblasts were stained with Alizarin red and Alcian blue, respectively, and microphotographed. RESULTS: In vitro yield of MSCs showed no age-related differences in terms of morphological and adhesive properties. While cells of stromal origin showed strong positivity (90% to 99%) to characteristic CD105, CD44, CD166, CD29, CD90, and CD73 antibodies, hematopoietic cells remained negative (0% to 5%) to CD45, CD34, CD14, and HLA-DR antibodies. It was observed that MSCs produced in cell-specific media differentiated to osteoblasts and chondroblasts in all passages (p1-15) tested, including late passages. CONCLUSION: It seems that the use of MSCs would provide promising treatment strategies in bone marrow transplantation, inherited diseases, and organ repair; in in vitro assessment of biological effects of biomaterials in orthopedics; and in repair of bone and cartilage injuries.