Allogeneic hematopoietic stem cell transplantation in infants is associated with significant morbidity and mortality.

BACKGROUND: Infants are subjected to hematopoietic stem cell transplantation (HSCT) due to malignant and non-malignant diseases. However, specific data concerning the outcome and transplantation-related complications in infants, as a separate age group, are limited. Our aim was to evaluate the impact of infancy on the outcome, toxicity, and complications after HSCT. METHODS: We retrospectively analyzed data of 55 infants that underwent HSCT in our unit from May 1997 until February 2020, emphasizing on the probability of overall survival (OS) and the cumulative incidence (CI) of transplantation-related mortality (TRM) and complications. RESULTS: We report a probability of OS of 61%, a CI of TRM at day 100 and 365 post transplantation of 22% and 30%, respectively, and additionally a CI of graft failure, acute graft-versus-host disease (GvHD), and infectious complications, 18%, 44%, and 39%, respectively. No statistically significant association was detected between the above mentioned parameters and diagnosis, the use of myeloablative or non-myeloablative/reduced toxicity conditioning regimens or the type of donor. CONCLUSIONS: We conclude that HSCT in infancy is associated with significant mortality and morbidity. This is possibly attributed to endogenous, age-related factors. More specifically, infants may be at a higher risk of toxicities due to the immaturity of developing vital organs and the deficiency of the newly adopted immune system that predisposes them to infectious complications. The development of GvHD further augments the danger of infections, in a potential vice-versa relationship. Moreover, there are few data on pharmacokinetics of chemotherapy agents, making safe and efficacious drug administration hard.

Is Carbapenem-resistant Klebsiella pneumoniae Infection in Pediatric Bone Marrow Transplantation Recipients Inevitably Fatal?

Carbapenem resistance, most notably in Klebsiella pneumonia (KPC), results in infections associated with significant morbidity and mortality. Here we report 2 cases of adolescent patients with KPC infection after high-risk bone marrow transplantation, who eventually succumbed from other causes and review the epidemiology and treatment options for KPC infections in this vulnerable population.

Toxoplasma gondii: How fatal is it in pediatric allogeneic bone marrow transplantation setting?

Toxoplasmosis is a disease of the immunocompetent population. However, cases of toxoplasma infection associated with immunosuppression have been reported, especially the first months after transplantation. Limited data are available about toxoplasma infection, occurring even many months post-transplant in pediatric patients with nonmalignant and malignant diseases. We report the cases of three patients with early and late disseminated toxoplasmosis and review the literature.

Autosomal dominant hyper-IgE syndrome: When hematopoietic stem cell transplantation should be considered?

AD-HIES or Job's syndrome is a primary immunodeficiency, caused by dominant negative mutations in signal transducer and activator of transcription (STAT) 3. The syndrome is characterized by infectious, immunologic, and non-immunologic manifestations and is associated with significant morbidity, mortality, and development of lymphomas. What has not yet been elucidated is the role of HSCT in the disease treatment spectrum. We review published cases of patients with AD-HIES that underwent HSCT and attempt to clarify at what stage HSCT should be considered and what are the complications.

Reprogramming of bone marrow derived mesenchymal stromal cells to human induced pluripotent stem cells from pediatric patients with hematological diseases using a commercial mRNA kit.

The potential use of patient-specific induced pluripotent stem cells (hiPSCs) in the study and treatment of hematological diseases requires the setup of efficient and safe protocols for hiPSC generation. We aimed to adopt a reprogramming method for large-scale production of integration-free patient-specific hiPSC-lines in our stem cell processing laboratory, which supports a pediatric hematopoietic stem cell transplant unit located at a tertiary care children's hospital. We describe our 5-year experience in generation of hiPSC-lines from human bone marrow-derived mesenchymal stromal cells (BM-MSCs) using synthetic mRNAs encoding reprogramming factors. We generated hiPSC-lines from pediatric patients with ß-Thalassemia, Sickle Cell Anemia, Blackfan-Diamond Anemia, Severe Aplastic Anemia, DOCK8 Immunodeficiency and 1 healthy control. After optimization of the reprogramming procedure, average reprogramming efficiency of BM-MSCs was 0.29% (range 0.25-0.4). The complete reprogramming process lasted 14-16 days. Three to five hiPSC-colonies per sample were selected, expanded to 5 culture passages and then frozen. The whole procedure took an average time of 1.8 months (range 1.6-2.2). The hiPSC-lines expressed embryonic stem cell markers and exhibited pluripotency. This mRNA reprogramming method can be applicable in a hematopoietic stem cell culture lab setting and would be useful for the clinical translation of patient-specific hiPSCs.

Epidemiology of viral infections among children undergoing hematopoietic stem cell transplant: Α prospective single-center study.

BACKGROUND: Viral infections are a significant cause of morbidity and mortality in pediatric transplant populations. We analyzed the epidemiology of viral infections in pediatric hematopoietic stem cell transplant (HSCT) patients, including their incidence, associated risk factors, and outcome. METHODS: In a prospective study from September 2011 to September 2015, blood, urine, and stool specimens were monitored weekly from transplantation to day 100 or after if clinically suspected, by use of real-time polymerase chain reaction. Cytomegalovirus (CMV), Epstein-Barr virus (EBV), BK polyomavirus (BKV), Herpes simplex virus-1,2, Varicella zoster virus, Human herpes virus-6,7, and Adenovirus infections were monitored. All children and adolescents who underwent HSCT received long-term follow up in the regular outpatient clinics (range 2-48 months). RESULTS: A total of 192 HSCTs (autologous/allogeneic: 53/139) were performed in 165 subjects (median age: 5.6 years). Viruses most commonly isolated were CMV (46.1%), BKV (25.9%) and EBV (22.6%) and were more frequent in allogeneic versus autologous transplants (P < 0.05). Almost all high-risk allogeneic recipients developed EBV infections post-HSCT. EBV-PTLD was the only cause of death among those who developed viral disease. The factors significantly associated with the development of viral infections were recipient's advanced age, unrelated donor, mismatched graft and use of peripheral blood stem cells grafts. CONCLUSIONS: Viral infections were common among our pediatric recipients. Data suggest that monitoring of viral load may be significant to the prevention of viral disease. Particular demographic and transplantation characteristics were associated with the development of viral infections post-HSCT.

Successful long-term hematological and immunological reconstitution by autologous cord blood transplantation combined with post-transplant immunosuppression in two children with severe aplastic anemia.

aUCBT is a valuable curative option in pediatric patients with refractory idiopathic SAA and no available matched sibling or unrelated donors. Experience in the use of autologous cord blood units in patients with SAA is limited and private for-profit cord blood-banking programs are controversial. We report the successful treatment of two patients with SAA, aged 15 and 24 months, with autologous cord blood combined with immunosuppression. After conditioning with 200 mg/kg cyclophosphamide and ATG, 7.5 mg/kg, 32.2 × 107 /kg, and 3.8 × 107 /kg autologous cord blood nucleated cells were infused, respectively. One of our patients underwent transplantation after failure of IST. Both patients received post-transplant immunosuppression with cyclosporine for 12 months. They remain disease-free 6 years post-transplantation.

A prospective study on the epidemiology and clinical significance of viral respiratory infections among pediatric oncology patients.

Respiratory infections in oncology are both common and potentially severe. However, there is still a gap in the literature, regarding the epidemiology of viral respiratory infections in children with cancer. We prospectively enrolled 224 patients, from September 2012 to August 2015. The cohort included children with hematologic or solid malignancies receiving chemotherapy, or undergoing hemopoietic stem cell transplantation, outpatients/inpatients exhibiting signs/symptoms of febrile/afebrile upper/lower respiratory infection. Viral infection was diagnosed by detection of ≥1 viruses from a sample at time of enrollment, using the CLART® PneumoVir kit (GENOMICA, Spain). Α detailed questionnaire including demographics and medical history was also completed. Samples were processed in batches, results were communicated as soon as they became available. Children recruited in whom no virus was detected composed the no virus detected group. Viral prevalence was 38.4% in children presenting with respiratory illness. A single virus was found in 30.4%, with RSV being the most frequent. Viral coinfections were detected in 8%. Children with viral infection were more likely to be febrile upon enrollment and to present with lower respiratory signs/symptoms. They had longer duration of illness and they were more likely to receive antibiotics/antifungals. Only 22% of children with influenza received oseltamivir. Mortality was low (2.7%), however, pediatric intensive care unit (PICU) admission and death were correlated with virus detection. In our study mortality was low and PICU admission was related to virus identification. Further research is needed to clarify whether antibiotics in virus-proven infection are of value and underline the importance of oseltamivir's timely administration in influenza.

Bioassay for Determining Voriconazole Serum Levels in Patients Receiving Combination Therapy with Echinocandins.

Voriconazole levels were determined with high-performance liquid chromatography (HPLC) and a microbiological agar diffusion assay using a Candida parapsilosis isolate in 103 serum samples from an HPLC-tested external quality control program (n = 39), 21 patients receiving voriconazole monotherapy (n = 39), and 7 patients receiving combination therapy (n = 25). The results of the bioassay were correlated with the results obtained from the external quality control program samples and with the HPLC results in sera from patients on voriconazole monotherapy and on combination therapy with an echinocandin (Spearman's rank correlation coefficient [rs], > 0.93; mean ± standard error of the mean [SEM] % difference, <12% ± 3.8%).

Acute disseminated encephalomyelitis after allogeneic bone marrow transplantation for pure red cell aplasia - a case report and review of the literature.

ADEM is a rare inflammatory demyelinating disease of the CNS, which usually presents after a viral infection or a vaccination. We report a 15-yr-old boy who was diagnosed with ADEM after an HLA-identical sibling allogeneic BMT for transfusion-dependent PRCA. His course was complicated with GVHD affecting the skin and lungs. Five months post-BMT, he developed neurological symptoms including sudden mental status alteration, dysarthria, facial nerve palsy, and acute paraplegia. The MRI revealed multifocal hyperintense lesions mainly in the subcortical white matter of the cerebrum, the brainstem, the basal ganglia, and the thalami. CSF examination was normal. There was no laboratory evidence of infection. The typical MRI findings and an acute monophasic clinical course were consistent with the diagnosis of ADEM. Clinical and radiological improvement was observed after treatment with high-dose steroids and IVIG. Complete neurologic recovery was achieved six months after the onset of symptoms. We present a rare case of ADEM post-BMT and review of the literature.

Transient effect of anti-CD20 therapy in a child with 22q11.2 deletion syndrome and severe steroid refractory cytopenias: a case report.

We report on the development of steroid-refractory recurrent cytopenias in a child with 22q11.2 deletion syndrome. His first hematological complication was autoimmune hemolytic anemia at 3 months of age. Thereafter, he developed severe autoimmune cytopenias of all 3 hematological lineages with poor response to steroids and intravenous immunoglobulin. At the age of 2½ years, a course of anti-CD20 therapy (Rituximab) was given with transient hematological recovery. Because of persistent symptoms, bone marrow transplantation from a matched unrelated donor was performed. Although the data in the use of anti-CD20 therapy in children with 22q11.2 deletion syndrome and autoimmune cytopenias are limited, our experience suggests its potential benefit.

Integration of Transcriptome and MicroRNA Profile Analysis of iMSCs Defines Their Rejuvenated State and Conveys Them into a Novel Resource for Cell Therapy in Osteoarthritis.

Although MSCs grant pronounced potential for cell therapies, several factors, such as their heterogeneity restrict their use. To overcome these limitations, iMSCs (MSCs derived from induced pluripotent stem cells (iPSCs) have attracted attention. Here, we analyzed the transcriptome of MSCs, iPSCs and iMSCs derived from healthy individuals and osteoarthritis (OA) patients and explored miRNA-mRNA interactions during these transitions. We performed RNA-seq and gene expression comparisons and Protein-Protein-Interaction analysis followed by GO enrichment and KEGG pathway analyses. MicroRNAs' (miRNA) expression profile using miRarrays and differentially expressed miRNA's impact on regulating iMSCs gene expression was also explored. Our analyses revealed that iMSCs derivation from iPSCs favors the expression of genes conferring high proliferation, differentiation, and migration properties, all of which contribute to a rejuvenated state of iMSCs compared to primary MSCs. Additionally, our exploration of the involvement of miRNAs in this rejuvenated iMSCs transcriptome concluded in twenty-six miRNAs that, as our analysis showed, are implicated in pluripotency. Notably, the identified here interactions between hsa-let7b/i, hsa-miR-221/222-3p, hsa-miR-302c, hsa-miR-181a, hsa-miR-331 with target genes HMGA2, IGF2BP3, STARD4, and APOL6 could prove to be the necessary tools that will convey iMSCs into the ideal mean for cell therapy in osteoarthritis.

Severe hyperinsulinemia, decreased GLUT3 and GLUT4 expression, and increased retinol binding protein 4 in a patient with chronic graft-versus-host disease post bone marrow transplantation.

Hyperinsulinemia with or without DM2 is a frequent long-term sequela of BMT, especially following cGvHD. In this report, an extensive evaluation of a patient with cGvHD is described: glucose and insulin during OGTT, markers of inflammation, adiponectin and RBP4, body composition analysis, and the kinetics of GLUT3 and GLUT4 in circulating monocytes were evaluated. Hyperinsulinemia, associated with partial lipodystrophy, elevated RBP4, low adiponectin levels, and decreased expression of GLUT3 and GLUT4 were detected. The defects disclosed in this particular patient possibly explain, at least in part, the mechanisms underlying insulin resistance in patients undergoing BMT. It is not clear whether insulin resistance was caused by the drugs, the process itself, or the residual damage to the muscles and/or adipose tissue.

Update on the mechanism of action and on clinical efficacy of extracorporeal photopheresis in the treatment of acute and chronic graft versus host disease in children.

Extracorporeal photopheresis (ECP) has been used for treatment of steroid-refractory graft versus host disease (GVHD) with encouraging results. Although its exact mechanism of action is not fully understood, photoapheresed cells seem to induce a selective immune response directed against alloreactive T cell populations without causing generalized immunosuppression. Current pediatric experience with ECP for GVHD is available in the form of a few retrospective small studies concerning children with steroid refractory GVHD. Reviewing these data we conclude that ECP is a safe procedure, well tolerated even in low-weight pediatric patients, which warrants further evaluation in well-designed, prospective, controlled studies.

Extracorporeal photopheresis in the treatment of chronic graft-versus-host disease. The Hellenic experience: a study by the Hellenic association of hematology.

The Hellenic experience regarding the efficacy of extracorporeal photopheresis (ECP) in the treatment of 58 patients with chronic graft-versus-host disease (cGVHD) is presented in this article. All 58, except one patient, had failed at least one line of immunosuppressive treatment including steroids. Thirty-three out of 58 patients showed an objective overall response to ECP in a median time of 10 weeks after the onset of treatment. The cumulative incidence of overall response was 65.1%. In multivariate analysis, the presence of severe chronic GVHD was the only parameter associated with a significantly lower probability of response to treatment (RR=0.4, CI 95% 0.2-0.9, p=0.03). Responders to treatment with ECP were more likely to discontinue immunosuppression, had a lower probability of non-relapse mortality (RR=0.2, CI 95% 0.1-0.5, p=0.002), and a higher probability of overall survival (RR=7.8, CI 95% 3-20, p<0.001) in comparison with non-responders. Eight out of 58 patients experienced relapse of the original disease. The cumulative incidence of relapse in the group of responders to ECP was 6%, while it was 25% in the group of non-responders to ECP. In multivariate analysis, response to treatment with ECP was the only parameter statistically associated with a significantly decreased hazard of relapse (RR=0.1, CI 95% 0.1-0.7, p=0.02). ECP should be tested as first-line treatment in patients with cGVHD with the aim to minimize the duration of immunosuppression and the rate of relapse of the malignant disease.

Chronic myeloid leukemia (CML) in children: classical and newer therapeutic approaches.

Chronic myeloid leukemia (CML) represents a rare myeloproliferative disease among children where allogeneic stem cell transplantation (SCT) remains the curative gold standard. However, the impressive early cytogenetic and molecular responses achieved by tyrosine kinase inhibitors [TKIs (imatinib, nilotinib, and dasatinib)] as first-line or even sole treatment in adults, has led to their increasing use also among children. Due to limited data regarding long-term results of TKIs and especially those of second generation in pediatric cohorts, we would like to add clinical information in this rare series of patients by reporting on four children with CML over a 10-year period, focusing on TKIs, dose escalations and clinical responses.

Development of a Population Pharmacokinetic Model of Busulfan in Children and Evaluation of Different Sampling Schedules for Precision Dosing.

We develop a population pharmacokinetic model to describe Busulfan pharmacokinetics in paediatric patients and investigate by simulations the impact of various sampling schedules on the calculation of AUC. Seventy-six children had 2 h infusions every 6 h. A two-compartment linear model was found to adequately describe the data. A lag-time was introduced to account for the delay of the administration of the drug through the infusion pump. The mean values of clearance, central volume of distribution, intercompartmental clearance, and peripheral volume of distribution were 10.7 L/h, 39.5 L, 4.68 L/h and 17.5 L, respectively, normalized for a Body Weight (BW) of 70 kg. BW was found to explain a portion of variability with an allometric relationship and fixed exponents of 0.75 on clearance parameters and 1 on volumes. Interindividual variability for clearance and volume of distribution was found to be 28% and 41%, respectively, and interoccasion variability for clearance was found to be 11%. Three sampling schedules were assessed by simulations for bias and imprecision to calculate AUC by a non-compartmental and a model-based method. The latter was found to be superior in all cases, while the non-compartmental was unbiased only in sampling up to 12 h corresponding to a once-daily dosing regimen.

Rapid clinical-scale propagation of mesenchymal stem cells using cultures initiated with immunoselected bone marrow CD105+ cells.

Current clinical protocols used for isolation and purification of mesenchymal stem cells (MSC) are based on long-term cultures starting with bone marrow (BM) mononuclear cells. Using a commercially available immunoselection kit for enrichment of MSC, we investigated whether culture of enriched BM-CD105(+) cells could provide an adequate number of pure MSC in a short time for clinical use in the context of graft versus host disease and graft failure/rejection. We isolated a mean of 5.4 × 10(5) ± 0.9 × 10(5) CD105(+) cells from 10 small volume (10-25 ml) BM samples achieving an enrichment >100-fold in MSC. Seeding 2 × 10(3) immunoselected cells/cm(2) we were able to produce 2.5 × 10(8) ± 0.7 × 10(8) MSC from cultures with autologous serum enriched medium within 3 weeks. Neither haematopoietic nor endothelial cells were detectable even in the primary culture cell product. Expanded cells fulfilled both phenotypic and functional current criteria for MSC; they were CD29(+), CD90(+), CD73(+), CD105(+), CD45(-); they suppressed allogeneic T-cell reaction in mixed lymphocyte cultures and retained in vitro differentiation potential. Moreover, comparative genomic hybridization analysis revealed chromosomal stability of the cultured MSC. Our data indicate that adequate numbers of pure MSC suitable for clinical applications can be generated within a short time using enriched BM-CD105(+) cells.

Acute gastrointestinal graft-versus-host disease in pediatric patients: serum albumin on day 5 from initiation of therapy correlates with nonrelapse mortality and overall survival.

The aim of the present study was to identify factors associated with the risk of development of gastrointestinal acute graft-versus-host disease (GI-aGVHD), as well as to evaluate the impact of various baseline parameters on response to treatment, nonrelapse mortality (NRM), and overall survival (OS) in pediatric patients with GI-aGVHD after allogeneic hematopoietic stem cell transplantation (allo-SCT). We retrospectively analyzed 300 pediatric patients who underwent allo-SCT from HLA-matched related or volunteer unrelated donors in our institution. GI tract involvement was observed in 46 out of 133 patients with aGVHD grade II-IV. Severe aGVHD (grade III-IV) was more frequently observed among patients with GI-aGVHD in comparison with patients without GI involvement (P < .001). Treatment with steroids resulted in durable responses in 22/46 patients; 14 additional patients responded to salvage therapy, whereas 10 were refractory to all treatments administered. Using Cox regression analysis, we observed that serum albumin level ≥ 3 mg/dL on day 5 after the initiation of therapy with steroids was statistically significantly associated with decreased hazard of NRM and improved OS (P = .021 and P = .026, respectively). In our study, serum albumin level, early (+ day 5) after the onset of steroids in patients with GI-aGVHD, was a predictor of treatment outcome. Prospective randomized trials need to be performed to verify the predictive significance of serum albumin and the need for early intensification of immunosuppressive treatment.