Epilepsy after acute central nervous system complications of pediatric hematopoietic cell transplantation: A retrospective, multicenter study.

BACKGROUND: Acute central nervous system (CNS) complications are common and well described among pediatric patients undergoing haematopoietic cell transplantation (HCT). However, their long-term outcomes are not known. The aim of this study is to describe the incidence, characteristics, and risk factors of long-term epilepsy in pediatric patients with acute CNS complications of HCT. METHODS: This retrospective study included pediatric patients who developed acute CNS complications from autologous or allogeneic HCT between 2000 and 2022. Clinical, therapeutic and prognostic data including long-term outcomes were analyzed. A diagnosis of epilepsy was provided if unprovoked seizures occurred during follow-up. RESULTS: Ninety-four patients (63 males, 31 females, median age 10 years, range 1-21 years) were included. The most common acute CNS complications were posterior reversible encephalopathy syndrome (n = 43, 46 %) and infections (n = 15, 16 %). Sixty-five patients (69 %) had acute symptomatic seizures, with 14 (16 %) having one or more episodes of status epilepticus (SE). Nine patients (9.6 %) were diagnosed with long-term focal epilepsy during the follow-up (5-year cumulative incidence from the acute complication, 13.3 %). Acute symptomatic SE during neurological complications of HCT was associated with an increased risk of long-term epilepsy (OR=14, 95 % CI 2.87-68.97). CONCLUSIONS: A higher occurrence of epilepsy has been observed in our cohort compared to the general population. Acute symptomatic SE during HCT was associated with a higher risk of long-term epilepsy. Pediatric patients with CNS complications during HCT could benefit from specific neurological follow-up. Further studies are needed to characterize mechanisms of epileptogenesis in pediatric patients undergoing HCT.

Donor Cell Acute Myeloid Leukemia after Hematopoietic Stem Cell Transplantation for Chronic Granulomatous Disease: A Case Report and Literature Review.

The patient reported here underwent hematopoietic stem cell transplantation (HSCT) due to chronic granulomatous disease (CGD) caused by biallelic mutations of the NCF1 gene. Two years later, he developed AML, which was unexpected and was recognized via sex-mismatched chromosomes as deriving from the donor cells; the patient was male, and the donor was his sister. Donor cell leukemia (DCL) is very rare, and it had never been reported in patients with CGD after HSCT. In the subsequent ten years, the AML relapsed three times and the patient underwent chemotherapy and three further HSCTs; donors were the same sister from the first HSCT, an unrelated donor, and his mother. The patient died during the third relapse. The DCL was characterized since onset by an acquired translocation between chromosomes 9 and 11, with a molecular rearrangement between the MLL and MLLT3 genes-a quite frequent cause of AML. In all of the relapses, the malignant clone had XX sex chromosomes and this rearrangement, thus indicating that it was always the original clone derived from the transplanted sister's cells. It exhibited the ability to remain quiescent in the BM during repeated chemotherapy courses, remission periods and HSCT. The leukemic clone then acquired different additional anomalies during the ten years of follow-up, with cytogenetic results characterized both by anomalies frequent in AML and by different, non-recurrent changes. This type of cytogenetic course is uncommon in AML.

The Clinical Impact of Methotrexate-Induced Stroke-Like Neurotoxicity in Paediatric Departments: An Italian Multi-Centre Case-Series.

Introduction: Stroke-like syndrome (SLS) is a rare subacute neurological complication of intrathecal or high-dose (≥500 mg) Methotrexate (MTX) administration. Its clinical features, evoking acute cerebral ischaemia with fluctuating course symptoms and a possible spontaneous resolution, have elicited interest among the scientific community. However, many issues are still open on the underlying pathogenesis, clinical, and therapeutic management and long-term outcome. Materials and Methods: We retrospectively analyzed clinical, radiological and laboratory records of all patients diagnosed with SLS between 2011 and 2021 at 4 National referral centers for Pediatric Onco-Hematology. Patients with a latency period that was longer than 3 weeks between the last MTX administration of MTX and SLS onset were excluded from the analysis, as were those with unclear etiologies. We assessed symptom severity using a dedicated arbitrary scoring system. Eleven patients were included in the study. Results: The underlying disease was acute lymphoblastic leukemia type B in 10/11 patients, while fibroblastic osteosarcoma was present in a single subject. The median age at diagnosis was 11 years (range 4-34), and 64% of the patients were women. Symptoms occurred after a mean of 9.45 days (± 0.75) since the last MTX administration and lasted between 1 and 96 h. Clinical features included hemiplegia and/or cranial nerves palsy, paraesthesia, movement or speech disorders, and seizure. All patients underwent neuroimaging studies (CT and/or MRI) and EEG. The scoring system revealed an average of 4.9 points (± 2.3), with a median of 5 points (maximum 20 points). We detected a linear correlation between the severity of the disease and age in male patients. Conclusions: SLS is a rare, well-characterized complication of MTX administration. Despite the small sample, we have been able to confirm some of the previous findings in literature. We also identified a linear correlation between age and severity of the disease, which could improve the future clinical management.

Posterior Reversible Encephalopathy Syndrome in infants and young children.

AIM: The aim of this study was to describe the characteristics of Posterior Reversible Encephalopathy Syndrome (PRES) in infants and young children (<6 years) and to compare them with the older pediatric population affected by PRES. METHODS: we retrospectively reviewed records of 111 children (0-17 years) diagnosed with PRES from 2000 to 2018 in 6 referral pediatric hospitals in Italy. The clinical, radiological and EEG features, as well as intensive care unit (ICU) admission rate and outcome of children aged <6 years were compared to those of older children (6-17 years). Factors associated with ICU admission in the whole pediatric cohort with PRES were also evaluated. RESULTS: Twenty-nine patients younger than 6 years (26%) were enrolled with a median age at onset of PRES of 4 years (range: 6 months-5 years). Epileptic seizures were the most frequent presentation at the disease onset (27/29 patients). Status epilepticus (SE) was observed in 21/29 patients: in detail, 11 developed convulsive SE and 10 presented nonconvulsive SE (NCSE). SE was more frequent in children <6 years compared with older children (72% vs 45%) as well as NCSE (35% vs 10%). Seventeen children aged <6 years required ICU admission. Prevalence of ICU admissions was higher within younger population compared to older (59% vs 37%). In the whole study population SE was significantly associated with ICU admission (p = 0.001). CONCLUSIONS: PRES in children < 6 years differs from older children in clinical presentation suggesting a more severe presentation at younger age.

FANCA, TP53, and del(5q)/RPS14 alterations in a patient with T-cell non-Hodgkin lymphoma and concomitant Fanconi anemia and Li-Fraumeni syndrome.

We traced the neoplastic history (from 5 to 11 years of age) of a child with concomitant Fanconi anemia and Li-Fraumeni syndrome. Interestingly, the patient developed a highly malignant T-cell non-Hodgkin lymphoma (NHL), which does not represent the typical tumor type in the two aforementioned syndromes, presumably due to the underlying genomic instability. By using a combination of molecular and immunohistochemical approaches, we characterized the accumulation of multiple genetic alterations in a single patient, with both germline (parentally inherited biallelic FANCA variants and a likely de novo nonsense variant in TP53) and somatic (TP53 loss of heterozygosity and 5q interstitial deletion) contributions. Our findings support the interplay of TP53 and FANC genes in DNA damage response pathways and further highlight the genetic heterogeneity of lymphomas as well as the contribution of genomic instability to lymphomagenesis.

Management of PTLD After Hematopoietic Stem Cell Transplantation: Immunological Perspectives.

Post-transplant lymphoproliferative disorders (PTLDs) are life-threatening complications of iatrogenic immune impairment after allogeneic hematopoietic stem cell transplantation (HSCT). In the pediatric setting, the majority of PTLDs are related to the Epstein-Barr virus (EBV) infection, and present as B-cell lymphoproliferations. Although considered rare events, PTLDs have been increasingly observed with the widening application of HSCT from alternative sources, including cord blood and HLA-haploidentical stem cell grafts, and the use of novel agents for the prevention and treatment of rejection and graft-vs.-host disease. The higher frequency initially paralleled a poor outcome, due to limited therapeutic options, and scarcity of controlled trials in a rare disease context. In the last 2 decades, insight into the relationship between EBV and the immune system, and advances in early diagnosis, monitoring and treatment have changed the approach to the management of PTLDs after HSCT, and significantly ameliorated the prognosis. In this review, we summarize literature on the impact of combined viro-immunologic assessment on PTLD management, describe the various strategies for PTLD prevention and preemptive/curative treatment, and discuss the potential of novel immune-based therapies in the containment of this malignant complication.

Neonatal vesiculopustular eruption in Down syndrome and transient myeloproliferative disorder: A case report and review of the literature.

Transient myeloproliferative disorder (TMD) is a spontaneously resolving clonal myeloid proliferation characterized by circulating megakaryoblasts in the peripheral blood that is restricted to neonates with Down syndrome (DS) or those with trisomy 21 mosaicism. Cutaneous manifestations of TMD are observed in only 5% of affected neonates and present as a diffuse eruption of erythematous, crusted papules, papulovesicles, and pustules, often with prominent and initial facial involvement. We describe the case of a male infant with DS and TMD, associated with a vesiculopustular eruption, which appeared on day 36 of life, and review previous cases.

Brain Imaging Findings and Neurologic Complications after Allogenic Hematopoietic Stem Cell Transplantation in Children.

Hematopoietic stem cell transplantation (HSCT) is the only therapy for a subset of patients with malignant and nonmalignant diseases. Central nervous system (CNS) complications continue to be an important cause of morbidity and significantly contribute to mortality after HSCT. These complications include infections, cerebrovascular lesions, therapy-induced diseases, metabolic disturbances, and post-HSCT carcinogenesis. Following HSCT, three phases can be identified on the basis of the patient's immune status: the pre-engraftment period (<30 days after HSCT), the early postengraftment period (30-100 days after HSCT), and the late postengraftment period (>100 days after HSCT). There is a distinct relationship between the patient's degree of immunodeficiency after HSCT and the incidence of various complications that may occur. Early diagnosis of CNS complications is crucial for successful management and a good prognosis, and computed tomography and magnetic resonance imaging play an important role in achieving these goals. The global increase in the use of HSCT requires radiologists to be familiar with CNS complications, their relationship to the patient's immune status, and their imaging appearances. This article describes the clinical background of HSCT; reviews the incidence, causes, and timeline of brain complications in children who underwent allogenic HSCT; and identifies the characteristic imaging findings of these disorders. ©RSNA, 2018.

Pre- and post-transplant minimal residual disease predicts relapse occurrence in children with acute lymphoblastic leukaemia.

Relapse remains the leading cause of treatment failure in children with acute lymphoblastic leukaemia (ALL) undergoing allogeneic haematopoietic stem cell transplantation (HSCT). We retrospectively investigated the prognostic role of minimal residual disease (MRD) before and after HSCT in 119 children transplanted in complete remission (CR). MRD was measured by polymerase chain reaction in bone marrow samples collected pre-HSCT and during the first and third trimesters after HSCT (post-HSCT1 and post-HSCT3). The overall event-free survival (EFS) was 50%. The cumulative incidence of relapse and non-relapse mortality was 41% and 9%. Any degree of detectable pre-HSCT MRD was associated with poor outcome: EFS was 39% and 18% in patients with MRD positivity <1 × 10-3 and ≥1 × 10-3 , respectively, versus 73% in MRD-negative patients (P < 0·001). This effect was maintained in different disease remissions, but low-level MRD had a very strong negative impact only in patients transplanted in second or further CR. Also, MRD after HSCT enabled patients to be stratified, with increasing MRD between post-HSCT1 and post-HSCT3 clearly defining cohorts with a different outcome. MRD is an important prognostic factor both before and after transplantation. Given that MRD persistence after HSCT is associated with dismal outcome, these patients could benefit from early discontinuation of immunosuppression, or pre-emptive immuno-therapy.

Whole exome sequencing in the differential diagnosis of Diamond-Blackfan anemia: Clinical and molecular study of three patients with novel RPL5 and mosaic RPS19 mutations.

Diamond-Blackfan anemia (DBA) is a rare congenital disorder presenting remarkable phenotypic overlap with other inherited bone marrow failure syndromes, making differential diagnosis challenging and its confirmation often reached with great delay. By whole exome sequencing, we unraveled the presence of pathogenic variants affecting genes already known to be involved in DBA pathogenesis (RPL5 and RPS19) in three patients with otherwise uncertain clinical diagnosis, and provided new insights on DBA genotype-phenotype correlations. Remarkably, the RPL5 c.482del frameshift mutation has never been reported before, whereas the RPS19 c.3G>T missense mutation, although previously described in a 2-month-old DBA patient without malformations and refractory to steroid therapy, was detected here in the mosaic state in different bodily tissues for the first time in DBA patients.

Treosulfan-based conditioning regimen for allogeneic haematopoietic stem cell transplantation in children with sickle cell disease.

Although allogeneic haematopoietic stem cell transplantation (HSCT) still represents the only consolidated possibility of cure for sickle cell disease (SCD) patients, its use has been limited by the risk of morbidity and mortality associated with conventional myeloablative therapy. The introduction of treosulfan to replace busulfan in conditioning regimens has recently been explored by virtue of its lower toxicity profile. We report our experience with a treosulfan/thiotepa/fludarabine conditioning for human leucocyte antigen (HLA)-matched sibling or unrelated donor-HSCT in 15 children with SCD, and compare patient outcomes with those of a historical cohort (15 patients) given a busulfan-based regimen. Engraftment was achieved in 28 out of 30 patients (93%), with one case of graft failure in either group. The conditioning regimen was well tolerated in both groups, with no cases of grade III-IV regimen-related toxicity. The 7-year overall survival (OS) and disease-free survival (DFS) for the whole cohort were 100% and 93%, respectively, with a 93% DFS in both busulfan and treosulfan groups. No SCD-related adverse events occurred after engraftment in patients with complete or mixed donor chimerism. This retrospective analysis suggests that a treosulfan-based conditioning regimen is able to ensure engraftment with excellent OS/DFS and low regimen-related toxicity in patients with SCD.

Adolescent and adult uterine volume and uterine artery Doppler blood flow among subjects treated with bone marrow transplantation or chemotherapy in pediatric age: a case-control study.

OBJECTIVE: To compare uterine and ovarian volumes and uterine artery (UA) Doppler blood flow among women who were treated with antineoplastic regimens when pediatric aged versus healthy controls. DESIGN: Case-control study. SETTING: Tertiary obstetric and gynecologic center. PATIENT(S): One hundred twenty-seven women who were treated for childhood cancer with bone marrow transplantation (BMT) and∖or chemotherapy and total body irradiation (TBI) and 64 age-matched healthy controls. INTERVENTION(S): Ultrasonographic and clinical evaluations. MAIN OUTCOME MEASURE(S): Uterine and ovarian volume, detection of follicles, and UA pulsatility index (PI). RESULT(S): Median uterus and ovarian volumes were reduced by 64% (95% CI, 56.6-70.6) and 83.6% (95% CI, 79.6-86.7), respectively, among cases compared with controls. Median UA PI among cases was increased by 30.3% (95% CI, 19.6-40.8) compared with controls. Ovarian follicles were identified in 24 (18.9%) of 127 cases and 25 (39%) of 64 controls. Uterine volume was reduced after TBI (percent reduction 81.9%; 95% CI, 71.8-87.8) or busulfan (percentage reduction 67.4%; 95% CI, 58.5-75.6) compared with those who had not received a conditioning regimen (percentage reduction 24.4%; 95% CI, 7.6-38.2). The only factors independently associated with reduced uterine and ovarian volumes compared with controls were TBI, busulfan, and BMT. The worst effect on UA PI resulted from BMT and a diagnosis of hematologic disease. CONCLUSION(S): Bone marrow transplantation as main treatment and TBI and busulfan as conditioning regimens had the worst effect on uterine and ovarian sizes compared with controls. These data should be considered in counseling families on preserving future fertility in children undergoing BMT.

Donor multipotent mesenchymal stromal cells may engraft in pediatric patients given either cord blood or bone marrow transplantation.

OBJECTIVE: Multipotent mesenchymal stromal cells (MSCs) are endowed with multilineage differentiative potential and immunomodulatory properties. It is still a matter of debate whether donor MSCs have sustained engraftment potential in host bone marrow (BM) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). The aim of this study was to analyze the donor/recipient origin of MSCs in children receiving allogeneic either BM or cord blood (CB) transplantation. METHODS: Thirty-seven pediatric patients undergoing allo-HSCT for either a malignant or a nonmalignant disorder were enrolled in the study; 19 received CB and 18 BM transplantation. Results were compared with those obtained in 14 adults given BM transplantation for either malignant or nonmalignant disorders. MSCs were grown from BM aspirates obtained 1-17 and 2-192 months after allo-HSCT in pediatric and adult patients, respectively. MSC samples at the third-fourth passage were phenotypically characterized. Donor/recipient origin of MSCs was assessed by amelogenin assay and microsatellite analysis. RESULTS: MSCs could be grown from 30 of 37 children; at the third-fourth passage MSCs resulted positive (> or = 98%) for CD73, CD105, CD106, CD29, CD13, CD44 and negative (< or = 1%) for CD34, CD45, CD14. Mixed chimerism with donor cells was observed in 4 BM and 5 CB transplantation recipients, respectively; full recipient chimerism was detected in the remaining children. Full recipient MSC chimerism was observed also in all assessable (12/14) adult patients. CONCLUSIONS: BM of pediatric patients might be a more favorable milieu than that of adults for sustained engraftment of transplanted MSCs. MSCs able to engraft in the host can be transferred with cryopreserved CB units.

Homozygosity for human leucocyte antigen-C ligands of KIR2DL1 is associated with increased risk of relapse after human leucocyte antigen-C-matched unrelated donor haematopoietic stem cell transplantation.

Human leucocyte antigen (HLA)-C molecules regulate the function of natural killer cells and may be subdivided into two groups, C(1) and C(2), based on their specificity for inhibitory killer immunoglobulin-like receptors. We analysed the impact of the HLA-C genotype on outcome of HLA-C-matched unrelated donor haematopoietic stem cell transplantation (URD-HSCT) recipients. HLA-C(2) homozygous patients (n = 18) had lower probability of overall survival (P = 0.01) and disease-free survival (P = 0.02), resulting from increased relapse rate (P = 0.02) when compared with both HLA-C(1) homozygous (n = 43) and HLA-C(1),C(2) heterozygous (n = 50) subgroups. Patients lacking HLA-C(1) should, therefore, be considered at increased risk of relapse following HLA-C-matched URD-HSCT.