Hematopoietic Stem Cell Transplantation in ARPC1B Deficiency.

Mutations in the ARPC1B isoform component of human actin-related protein 2/3 complex have been recently associated with an inborn error of immunity characterized by combined immunodeficiency, allergies, autoinflammation, and platelet abnormalities. Currently, indications on the management of this novel disease and information on its outcome are lacking. We report the first case series of 7 children with a homozygous mutation in ARPC1B gene who underwent allogeneic-HSCT (allo-HSCT). All patients presented an early clinical onset, characterized by recurrent infections, failure to thrive and gastrointestinal bleeding episodes complicated with neonatal hemorrhagic enteritis in 3 cases, and macrophage activating syndrome in 2. Allo-HSCT was performed at the median age of 1.83 years after a myeloablative conditioning regimen in all cases. Engraftment occurred in all patients with full donor chimerism in 6 out of 7. The clinical course after engraftment was uneventful in 3 out of 7 children; 2 patients developed a grade 1-2 acute graft-versus-host disease (GvHD), and 1 patient a grade 1 chronic-GvHD. JC virus-related progressive multifocal leukoencephalopathy was diagnosed in one patient 13 months after haploidentical-HSCT and successfully managed with donor-derived viral-specific T-cell infusion. Only one patient had a fatal outcome 3 months after HSCT because of sepsis, after veno-occlusive disease, and transplant-associated microangiopathy. At a median follow-up of 19 months (range 3-110), 6 out of 7 patients are alive and disease-free. The severity of the clinical phenotype at diagnosis and the high survival rate, with limited transplant-related morbidity, strongly support the indication to allo-HSCT for patients with this diagnosis.

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.

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.

Voriconazole Antifungal Prophylaxis in Children With Malignancies: A Nationwide Study.

BACKGROUND: Antifungal prophylaxis (AFP) is recommended in at-risk hematology-oncology patients. We evaluated the safety of AFP with voriconazole (VRC) in pediatric hematology/oncology patients. MATERIALS AND METHODS: A retrospective study of VRC AFP in children with malignancies hospitalized in all 7 Greek pediatric hematology/oncology centers during 2008 to 2012 was conducted. Patients' demographics, outcome, and adverse event (AE) data were recorded. RESULTS: Four hundred twenty-nine VRC AFP courses in 249 patients (median age 6 y, 55% boys) were studied. The most common underlying diseases were acute lymphoblastic leukemia (51%), non Hodgkin lymphoma (8.6%), and acute myeloid leukemia (7.7%). The median number of VRC courses per patient was 1.7, whereas the median VRC dose was 7 mg/kg (range, 5 to 7 mg/kg) every 12 hours. During the last 2 weeks before AFP, 51% of the patients had received corticosteroids, 43% suffered from severe neutropenia, and 17.3% from mucositis. The median duration of VRC AFP was 17 days (range, 1 to 31 d). A single breakthrough fungemia due to Candida glabrata was recorded. Only 1 patient died due to the underlying disease. The most common AEs reported in 70/429 (16.3%) courses with ≥1 AE were elevated liver enzymes (50%), hypokalemia (24.3%), and ophthalmological disorders (14.3%). The median time of AE onset was 5 days (range, 1 to 21 d). Among 70 AEs reported, 38.5%, 48.4%, and 12.8% were of grade I, II, and III, respectively. CONCLUSIONS: VRC prophylaxis in pediatric hematology/oncology patients appears to be well tolerated.

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.

The Prognostic Effect of CDKN2A/2B Gene Deletions in Pediatric Acute Lymphoblastic Leukemia (ALL): Independent Prognostic Significance in BFM-Based Protocols.

One of the most frequent genes affected in pediatric ALL is the CDKN2A/2B gene, acting as a secondary cooperating event and playing an important role in cell-cycle regulation and chemosensitivity. Despite its inclusion in combined CNA (copy-number alterations) classifiers, like the IKZF1plus entity and the UKALL CNA profile, the prognostic impact of the individual gene deletions outside the context of a combined CNA evaluation remains controversial. Addressing the CDKN2A/2B deletions' additive prognostic effect in current risk-stratification algorithms, we present a retrospective study of a Greek pediatric ALL cohort comprising 247 patients studied over a 24-year period (2000-2023). Herein, we provide insight regarding the correlation with disease features, MRD clearance, and independent prognostic significance for this ALL cohort treated with contemporary BFM-based treatment protocols. Within an extended follow-up time of 135 months, the presence of the CDKN2A/2B deletions (biallelic or monoallelic) was associated with inferior EFS rates (65.1% compared to 91.8% for the gene non-deleted subgroup, p < 0.001), with the relapse rate accounting for 22.2% and 5.9%, respectively (p < 0.001). The presence of the biallelic deletion was associated with the worst outcomes (EFS 57.2% vs. 89.6% in the case of any other status, monoallelic or non-deleted, p < 0.001). Survival differences were demonstrated for B-ALL cases (EFS 65.3% vs. 93.6% for the non-deleted B-ALL subgroup, p < 0.001), but the prognostic effect was not statistically significant within the T-ALL cohort (EFS 64.3 vs. 69.2, p = 0.947). The presence of the CDKN2A/2B deletions clearly correlated with inferior outcomes within all protocol-defined risk groups (standard risk (SR): EFS 66.7% vs. 100%, p < 0.001, intermediate risk (IR): EFS 77.1% vs. 97.9%, p < 0.001, high risk (HR): EFS 42.1% vs. 70.5% p < 0.001 for deleted vs non-deleted cases in each patient risk group); additionally, in this study, the presence of the deletion differentiated prognosis within both MRD-positive and -negative subgroups on days 15 and 33 of induction. In multivariate analysis, the presence of the CDKN2A/2B deletions was the most important prognostic factor for relapse and overall survival, yielding a hazard ratio of 5.2 (95% confidence interval: 2.59-10.41, p < 0.001) and 5.96 (95% confidence interval: 2.97-11.95, p < 0.001), respectively, designating the alteration's independent prognostic significance in the context of modern risk stratification. The results of our study demonstrate that the presence of the CDKN2A/2B deletions can further stratify all existing risk groups, identifying patient subgroups with different outcomes. The above biallelic deletions could be incorporated into future risk-stratification algorithms, refining MRD-based stratification. In the era of targeted therapies, future prospective controlled clinical trials will further explore the possible use of cyclin-dependent kinase inhibitors (CDKIs) in CDKN2A/2B-affected ALL pediatric subgroups.

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.

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.

Low usage rate of banked sibling cord blood units in hematopoietic stem cell transplantation for children with hematological malignancies: implications for directed cord blood banking policies.

Directed sibling cord blood banking is indicated in women delivering healthy babies who already have a sibling with a disease that is potentially treatable with an allogeneic cord blood transplant. We evaluated the effectiveness of a national directed cord blood banking program in sibling HLA-identical stem cell transplantation for hematological malignancies and the factors influencing the usage rate of the stored cord blood units. Fifty families were enrolled from which, 48 cord blood units were successfully collected and 2 collections failed due to damaged cord/placenta at delivery. Among enrolled families 4 children needed transplantation; however, only one was successfully transplanted using the collected cord blood unit containing 2×10(7) nucleated cells/kg in conjunction with a small volume of bone marrow from the same HLA-identical donor. Two children received grafts from matched unrelated donors because their sibling cord blood was HLA-haploidentical, while the fourth one received bone marrow from his HLA-identical brother, since cord blood could not be collected due to damaged cord/placenta at delivery. With a median follow-up of 6 years (range, 2-12) for the 9 remaining HLA-matched cord blood units, none from the prospective recipients needed transplantation. The low utilization rate of sibling cord blood in the setting of hematopoietic stem cell transplantation for pediatric hematological malignant diseases necessitates the development of directed cord blood banking programs that limit long-term storage for banked cord blood units with low probability of usage such as non-HLA-identical or identical to patients who are in long-term complete remission.

Successful bone marrow transplantation in a pediatric patient with chronic myeloid leukemia from a HLA-identical sibling selected by preimplantation HLA testing.

We report successful bone marrow transplantation in an 11-year-old male with chronic myeloid leukemia from his HLA-identical sibling selected by preimplantation HLA testing. Because collection of cord blood failed, the transplantation was performed when the donor reached the age of 19 months, and sufficient bone marrow could be harvested safely. The patient was BCR/ABL negative at the time of transplantation after complete molecular response to imatinib. Currently, 16 months post-transplantation he is well and in complete molecular remission. This report describes preimplantation HLA-genotyping to deliver a matched sibling donor for successful transplantation of a malignant disorder.

Diagnostic Capacity for Invasive Fungal Infections in the Greek Paediatric Haematology-Oncology Units: Report from the Infection Working Group of the Hellenic Society of Paediatric Haematology-Oncology.

An audit based on a specific questionnaire was attempted, in order to investigate the mycology laboratory diagnostic capacity for invasive fungal diseases (IFDs) in Greek Paediatric Haematology-Oncology departments/units. The study provided the relevant information for the years 2019 and 2020 and included data from all units, concerning culture-based methods and direct microscopy, phenotypic and molecular identification, sensitivity testing, serology and molecular diagnosis, as well as therapeutic drug monitoring. The target was mostly to reveal the level of laboratory coverage for hospitalised paediatric patients, independently of the possibility of performing the tests in the host hospital, or otherwise to refer the specimens elsewhere. In total, the current study demonstrated that the most important facilities and services regarding the IFD diagnostics for paediatric haematology-oncology patients in Greece are available and relatively easily accessible, with a reasonable turnaround time. Acting as an initial registry for further improvements, the audit can serve as a valuable approach to the actual situation and future perspectives. A national clinical mycology network under the auspices of the relevant scientific societies will probably facilitate collaboration between all the departments (clinical and laboratory) involved in invasive fungal infections and provide an easier approach to any necessary test for any hospitalised patient.

Candidemia in Children with Malignancies: Report from the Infection Working Group of the Hellenic Society of Pediatric Hematology-Oncology.

Candidemia is an important cause of morbidity and mortality especially in immunocompromised and hospitalized patients. We retrospectively collected data of candidemia cases that occurred in the seven Hematology-Oncology Departments/Units of Greece and the Stem Cell Transplant Unit between 2015 and 2019. In total, 19 episodes of candidemia in 19 patients were recorded. The majority of the patients (78.9%) had at least one risk factor for candidemia. The most frequent risk factors associated with candidemia observed in our patients were prolonged duration of hospitalization (30 days, range 1-141), presence of a central venous catheter at diagnosis of candidemia (73.7%) and antibiotics use during the last two weeks (84.2%). Candida parapsilosis was the most common species isolated accounting for 42.1%, followed by C. albicans (26.3%) and C. famata (15.8%). Nearly all of the patients (84.2%) received antifungal monotherapy with liposomal amphotericin B or echinocandins. The central venous catheter was removed in 78.6% of patients and the median time between the first positive blood culture and catheter removal was 3 days (range 1-9). Mortality at 28 days was 26.3%. In conclusion, a predominance of non-albicans species was observed in our study in conformity with the global trend.

The role of HLA matching in unrelated donor hematopoietic stem cell transplantation for sickle cell disease in Europe.

We report the results of an analysis of unrelated allogeneic hematopoietic stem cell transplantations (HSCT) in 71 patients with sickle cell disease (SCD) transplanted in EBMT centers between 2005 and 2017. Median age was 9.3 years; graft type was bone marrow in 79% and peripheral blood in 21%. Recipient-donor HLA match at high resolution typing was 10/10 in 31, 9/10 in 20, and 8/10 in 4 patients; the other patients had intermediate resolution typing. The most frequent conditioning regimens were fludarabine-thiotepa-treosulfan (64%) or busulfan-cyclophosphamide (12%). Cumulative incidence of neutrophil engraftment was 92%; platelet engraftment was 90%. Eleven patients (15%) experienced graft failure. Grade II-IV acute graft-vs.-host disease (GvHD) was 23%; 3-year chronic GvHD was 23%. Three-year overall survival (OS) was 88 ± 4%. GRFS was 62 ± 6%. HLA matching was the most significant risk factor for OS: 3-year OS was 96 ± 4% in 10/10 group vs. 75 ± 10% in 9-8/10 (p = 0.042); GRFS was 69 ± 9% vs. 50 ± 12% (p = 0.114), respectively. In conclusion, unrelated donor HSCT is a valid option for SCD patients who lack an HLA-identical sibling donor, preferably in the context of clinical trials. Using a 10/10 HLA-matched unrelated donor yields better survival indicating that HLA matching is an important donor selection factor in this nonmalignant disease.

Resolution of Hematocolpos in Adolescents Affected with Graft vs Host Disease.

BACKGROUND: Bone marrow transplantation is a lifesaving procedure for a range of serious benign or malignant hematological conditions. A proportion of patients, however, will develop graft vs host disease (GVHD), acute or chronic, with serious long-term sequalae. CASES: We present 2 cases of hematocolpos that developed in adolescence because of vaginal synechiae due to GVHD. The condition was initially asymptomatic, resolved spontaneously at first and recurred. In 1 girl blunt lysis of the adhesions was performed with the patient under general anesthesia, followed thereafter by local hydrocortisone and estriol treatment. SUMMARY AND CONCLUSION: Genital symptoms might not be readily reported by adolescents after bone marrow transplantation. Physicians should be aware of possible late effects of GVHD on genitalia, inquire about symptoms, and be acquainted with addressing complications, such as vaginal obstruction.

Cytokine gene polymorphisms and graft-versus-host disease in children after matched sibling hematopoietic stem cell transplantation: a single-center experience.

Various polymorphisms in cytokine genes have recently been investigated as candidate risk factors in allogeneic hematopoetic stem cell transplantation (allo-HSCT). We retrospectively analyzed specific polymorphisms in genes for interleukin (IL)-10, IL-6, tumor-necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ) in a pediatric cohort of 57 histocompatibility leucocyte antigen (HLA)-identical sibling myeloablative transplants. Both recipient and donor genotypes were tested for association with graft-versus-host disease (GVHD) by statistical methods including Cox regression analysis. We found a significant association between the IL-10 promoter haplotype polymorphisms at positions -1082, -819 and -592 with the occurrence of severe (grades III-IV) acute GVHD (aGVHD). Recipients with the haplotype GCC had a statistically significant decreased risk of severe aGVHD (hazard risk (HR)=0.20, 95% confidence interval (CI): 0.06-0.67) in comparison with patients with other IL-10 haplotypes (P=0.008). Transplant-related mortality at 1 year was significantly lower in recipients with this haplotype (HR=0.17, 95% CI: 0.012-0.320) versus other IL-10 haplotypes (P=0.03), whereas overall survival was not influenced by IL-10 haplotype polymorphisms. In multivariate analysis, the presence of the IL-10 GCC haplotype was found as the only variable associated with a statistically significant decreased hazard of severe aGVHD development (P=0.02, HR=0.21, 95% CI: 0.05-0.78). These results suggest that pediatric patients possessing the IL-10 GCC haplotype may be protected from the occurrence of severe aGVHD in the setting of matched sibling HSCT.