Effective BRAF inhibitor vemurafenib therapy in a 2-year-old patient with sequentially diagnosed Langerhans cell histiocytosis and Erdheim-Chester disease

Erdheim-Chester disease (ECD) is a rare histiocytic disorder, characterized by the xanthomatous infiltration of tissues by CD68-positive and CD1a-/CD100-negative foamy histiocytes. In childhood, ECD is exceptionally rare, and only a dozen cases have been published so far. The cooccurence of Langerhans cell histiocytosis (LCH) and ECD is even rarer. Here, we report a 2-year-old boy, the youngest patient in the literature so far, who was diagnosed with concomitant BRAF mutation-positive LCH and ECD. In his case, conventional LCH treatment proved to be ineffective, but he is the youngest patient who was successfully treated with the BRAF inhibitor vemurafenib.

Successful nivolumab therapy in an allogeneic stem cell transplant child with post-transplant lymphoproliferative disorder

Primary CNS PTLD is an extremely rare complication after allogeneic HSCT. At our centre, an 11-year-old patient developed nausea, vomiting, and diplopy on day +82 following HSCT. On brain MRI, multiple white matter lesions were seen. Histology showed a diffuse large B-cell lymphoma with high load of EBV in tissue. Despite stopping immunosuppression, treatment with EBV-specific cytotoxic T cells, systemic rituximab, HD-MTX, and intrathecal chemotherapy, progression was observed. With a combination of HD-MTX and cytarabine, only a partial response could be achieved. Having all conventional modalities not only failed but resulted in significant toxicity, a salvage monotherapy with biweekly nivolumab has been instituted. The starting dose was 1.1 mg/kg, later escalated to 2.2 mg/kg. After 8 months of nivolumab therapy, PET-CT showed complete metabolic remission. Subsequently, the patient has been switched to a maintenance dosage of 1.1 mg/kg. No cytopenias, graft failure, GvHD, or any other alloimmune complications were seen during nivolumab therapy. In conclusion, nivolumab may be considered as an effective and safe option for CNS PTLD therapy when all other modalities have failed.

Switching reciprocity on and off in a magneto-optical x-ray scattering experiment using nuclear resonance of α-(57)Fe foils

Reciprocity is when the scattering amplitude of wave propagation satisfies a symmetry property, connecting a scattering process with an appropriate reversed one. We report on an experiment using nuclear resonance scattering of synchrotron radiation, which demonstrates that magneto-optical materials do not necessarily violate reciprocity. The setting enables us to switch easily between reciprocity and its violation. In the latter case, the exhibited reciprocity violation is orders of magnitude larger than achieved by previous wave scattering experiments.

What Is the Role of HSCT in Philadelphia-Chromosome-Positive and Philadelphia-Chromosome-Like ALL in the Tyrosine Kinase Inhibitor Era?

Previously, the outcome of paediatric Philadelphia-chromosome-positive (Ph+) ALL treated with conventional chemotherapy alone was poor, necessitating the use of haematopoietic stem cell transplantation (HSCT) for the best outcomes. The recent addition of tyrosine kinase inhibitors (TKIs) alongside the chemotherapy regimens for Ph+ ALL has markedly improved outcomes, replacing the need for HSCT for lower risk patients. An additional poor prognosis group of Philadelphia-chromosome-like (Ph-like) ALL has also been identified. This group also can be targeted by TKIs in combination with chemotherapy, but the role of HSCT in this population is not clear. The impact of novel targeted immunotherapies (chimeric antigen receptor T cells and bispecific or drug-conjugated antibodies) has improved the outcome of patients, in combination with chemotherapy, and made the role of HSCT as the optimal curative therapy for Ph+ ALL and Ph-like ALL less clear. The prognosis of patients with Ph+ ALL and persistent minimal residual disease (MRD) at the end of consolidation despite TKI therapy or with additional genetic risk factors remains inferior when HSCT is not used. For such high-risk patients, HSCT using total-body-irradiation-containing conditioning is currently recommended. This review aims to provide an update on the current and future role of HSCT for Ph+ ALL and addresses key questions related to the management of these patients, including the role of HSCT in first complete remission, MRD evaluation and related actions post HSCT, TKI usage post HSCT, and the putative role of HSCT in Ph-like ALL.

Chromosomal breakage tests in the differential diagnosis of Fanconi anemia and aplastic anemia

BACKGROUND

FA patients are hypersensitive to preconditioning of bone marrow transplantation.

OBJECTIVE

Assessment of the power of mitomycin C (MMC) test to assign FA patients.

METHODS

We analysed 195 patients with hematological disorders using spontaneous and two types of chromosomal breakage tests (MMC and bleomycin). In case of presumed Ataxia telangiectasia (AT), patients' blood was irradiated in vitro to determine the radiosensitivity of the patients.

RESULTS

Seven patients were diagnosed as having FA. The number of spontaneous chromosomal aberrations was significantly higher in FA patients than in aplastic anemia (AA) patients including chromatid breaks, exchanges, total aberrations, aberrant cells. MMC-induced ≥10 break/cell was 83.9 ± 11.4% in FA patients and 1.94 ± 0.41% in AA patients (p < .0001). The difference in bleomycin-induced breaks/cell was also significant: 2.01 ± 0.25 (FA) versus 1.30 ± 0.10 (AA) (p = .019). Seven patients showed increased radiation sensitivity. Both dicentric + ring, and total aberrations were significantly higher at 3 and 6 Gy compared to controls.

CONCLUSIONS

MMC and Bleomycin tests together proved to be more informative than MMC test alone for the diagnostic classification of AA patients, while in vitro irradiation tests could help detect radiosensitive-as such, individuals with AT.

Real World Posaconazole Pharmacokinetic Data in Paediatric Stem Cell Transplant Recipients

Background: Invasive fungal disease is a significant cause of morbidity and mortality in allogeneic hematopoietic stem cell transplant (alloHSCT) recipients. Posaconazole, a broad-spectrum triazole, is widely used as prophylaxis. Methods: We conducted a monocentric, retrospective study to present real-world data on posaconazole trough levels in paediatric alloHSCT patients. The main objective was to determine the required daily dose of posaconazole in paediatric patients. We analysed factors influencing posaconazole levels, and the association between posaconazole levels and breakthrough fungal infection. Results: Among 102 allogeneic HSCT recipients, we measured posaconazole plasma concentrations in 548 blood samples. The required daily doses to reach a target range of 0.7-2.0 mg/L were 15.22 (suspension), 7.52 (tablet), and 7.84 mg/kg (intravenous). Patients aged < 13 years needed higher doses to achieve the target range. The presence of enteral symptoms during prophylaxis was associated with lower plasma concentrations (p < 0.001), while co-administration of proton pump inhibitors did not (p = 0.09). Eight breakthrough infections occurred; low levels of posaconazole (<0.7 mg/L) were observed in five out of eight cases. The Cox regression model showed that higher mean plasma concentrations decreased the hazard of breakthrough infections. Conclusions: The tablet and intravenous formulations of posaconazole outperformed the suspension in terms of predictability. Our analyses on breakthrough infections and posaconazole plasma levels suggest an exposure-response relationship.

Bone Turnover Marker for the Evaluation of Skeletal Remodelling in Autosomal Recessive Osteopetrosis after Haematopoietic Stem Cell Transplantation: A Case Report

Background: Autosomal recessive osteopetrosis (ARO) is a rare genetic disorder of bone metabolism, primarily affecting the remodelling function of osteoclasts. Haematopoietic stem cell transplantation (HSCT) is the first-line treatment for ARO. Traditional tools for the assessment of therapeutic response, such as measuring donor chimerism, do not provide information on bone remodelling. The use of bone turnover markers (BTMs) might be ideal. Here, we report a case of a paediatric ARO patient undergoing successful HSCT. Methods: For the evaluation of donor-derived osteoclast activity and skeletal remodelling throughout the transplantation, the bone resorption marker β-CTX (β-C-terminal telopeptide) was used. Results: The low baseline level of β-CTX markedly increased after transplantation and remained in the elevated range even after 3 months. Donor-derived osteoclast activity reached its new baseline level around the 50th percentile range after 5 months and proved to be stable during the 15-month follow-up time. The apparent increase of the baseline osteoclast activity after HSCT was in consonance with the radiographic improvement of the disease phenotype and the correction of bone metabolic parameters. Despite the successful donor-derived osteoclast recovery, craniosynostosis developed, and reconstructive surgery had to be performed. Conclusions: The use of β-CTX may be of aid in assessing osteoclast activity throughout the transplantation. Further studies could help to establish the extended BTM profile of ARO patients using the available osteoclast- and osteoblast-specific markers.

Molecular Profiling Reveals Novel Gene Fusions and Genetic Markers for Refined Patient Stratification in Pediatric Acute Lymphoblastic Leukemia

Risk-adapted treatment protocols conferred remarkable improvement in the survival rates of pediatric acute lymphoblastic leukemia/lymphoma (ALL/LBL). Nevertheless, clinical management is still challenging in certain molecular subgroups and in the presence of alterations associated with an increased rate of relapse. In this study, disease-relevant genomic and transcriptomic profiles were established in a prospective, multicenter, real-world cohort involving 192 children diagnosed with ALL/LBL. Gene fusions were detected in 34.9% of B-ALL and 46.4% of T-ALL patients, with novel chimeric genes involving JAK2, KMT2A, PAX5, RUNX1, and NOTCH1, and with KMT2A-rearranged patients displaying the worst 3-year event-free survival (P = .019). Nonsynonymous mutations were uncovered in 74.9% of the analyzed patients, and pairwise scrutiny of genetic lesions revealed recurrent clonal selection mechanisms commonly converging on the same pathway (eg, Ras, JAK/STAT, and Notch) in individual patients. Investigation of matched diagnostic and relapse samples unraveled complex subclonal variegation, and mutations affecting the NT5C2, TP53, CDKN2A, and PIK3R1 genes, emerging at the time of relapse. TP53 and CREBBP mutations, even as subclonal aberrations, were associated with shorter 3-year event-free survival among all patients with B-ALL (TP53 mutant vs wild-type: P = .008, CREBBP mutant vs wild-type: P = .010), and notably, B-ALL patients showing no measurable residual disease on day 33 could be further stratified based on TP53 mutational status (P < .001). Our in-depth molecular characterization performed across all risk groups identified novel opportunities for molecularly targeted therapy in 55.9% of high-risk and 31.6% of standard/intermediate-risk patients.

Digital PCR-based quantification of miR-181a in the cerebrospinal fluid aids patient stratification in pediatric acute lymphoblastic leukemia

Despite remarkable improvements in the survival of pediatric acute lymphoblastic leukemia (ALL), sensitive detection and clinical management of central nervous system leukemia (CNSL) are still immensely challenging. Blast cells residing in the CNS but not circulating in the cerebrospinal fluid (CSF) remain undetected by current diagnostic methods, preventing a truly risk-adapted anti-leukemic treatment in this compartment. We examined the clinical applicability of the molecular marker microRNA (miR)-181a quantified in the cell-free CSF to evaluate the level of CNS involvement and to optimize patient stratification based on CNS status. Normalized copy number of miR-181a was longitudinally profiled using droplet digital PCR, and the results were compared with the degree of leukemic involvement of the CNS. After combining cytospin- and flow cytometry (FCM) data with miR-181a expression, we could stratify previously ambiguous cases and reclassify patients into a CNS-positive/miR-significant group (mean ± SE for miR-181a copies: 3300.70 ± 809.69) bearing remarkable infiltration as well as into CNS-minimal/miR-significant and CNS-minimal/miR-minimal groups differentiating putative, clinically significant occult CNSL cases (2503.50 ± 275.89 and 744.02 ± 86.81 copies, respectively, p = 1.13 × 10-6). In summary, miR-181a expression is a promising biomarker for CNSL detection, facilitating the robust identification of patients who could benefit from intensified CNS-directed therapy.

Case Report: A Child With Hemophilia A Serves as Donor for Hematopoietic Stem Cell Transplantation to Cure His Brother's Severe Aplastic Anemia

The first-line treatment of severe aplastic anemia is allogeneic hematopoietic stem cell transplantation with a matched sibling donor. However, co-morbidities of the identical donor can make donation difficult. We present a transplantation where in parallel with the patient's conditioning treatment, the preparation of the donor with severe hemophilia A required a special management with perioperative factor VIII substitution. Donation was successful without complications, and 18 months after transplantation, the patient and his donor are well without any long-term sequelae. To our knowledge, this is the first reported succesfull transplantation with hemophilic child serving as a bone marrow donor. The procedure did not mean a significant risk to donor health, so donors with hemophilia should not be excluded from donation.

[Late post-tracheostomy airway complications in patients with central nervous system injuries]

At decannulation or often weeks later some of the patients undergone long-term mechanical ventilation through tracheostoma reveal symptoms of airway stenosis. Posttracheostomy airway complications detected during the rehabilitation of 34 patients with central nervous system injury are presented. Endoscopic examinations (total 130) were performed with Olympus BF B3 and OES 20-type fiberscopes and Friedel-type rigid bronchoscopes under local or general anaesthesia. Stridor (20 cases) and possible decannulation (10 cases) were the main indications of the first endoscopic examinations. Stridor was caused by tracheal (12 cases) and laryngeal (8 cases) stenosis. With six patients decannulation was possible after the first endoscopy. Removal of granulomas and sutures was successful in 8 cases. Rigid bronchoscopic dilatations were temporarily successful in 7 cases, but in five of them it had to be repeated on emergency. Further therapeutic interventions were: recannulation (3 cases), retracheostomy (4 cases), implantation of silicon T-endoprothesis (5 cases), tracheal resection (4 cases). Three patients are discussed in details. Eliminating airway complications largely contributed to rehabilitation of the nervous and musculoskeletal system, improved the quality of life, and in acute cases it was a life-saving measure. In order to prevent the development of late airway complications or detect them in time, it is recommended to have an endoscopic protocol following every tracheostomy: 1. at the time of decannulation 2. at closing the trachea and 3. 2-3 months after decannulation.