A high prevalence of neutrophil-specific antibodies in ELANE-mutated severe congenital neutropenia.

An assay for neutrophil-specific antibodies is frequently used in the workup of chronic severe neutropenia and is suggestive of autoimmune, or sporadically alloimmune neutropenia, rather than severe congenital neutropenia (SCN). We analyzed a neutropenia consortium database for the outcomes of antibody testing initiated before receiving genetic diagnosis in Polish SCN cohort. Test results, performed in a single reference laboratory, were available for 14 patients with ELANE-mutated SCN or cyclic neutropenia, and were frequently positive (36%). We note that the trigger for genetic studies in severe neutropenia should not be affected by antibody-positivity and should be clinically driven.

Four Decades of Carrier Detection and Prenatal Diagnosis in Hemophilia A: Historical Overview, State of the Art and Future Directions.

Hemophilia A (HA), a rare recessive X-linked bleeding disorder, is caused by either deficiency or dysfunction of coagulation factor VIII (FVIII) resulting from deleterious mutations in the F8 gene encoding FVIII. Over the last 4 decades, the methods aimed at determining the HA carrier status in female relatives of HA patients have evolved from phenotypic studies based on coagulation tests providing merely probabilistic results, via genetic linkage studies based on polymorphic markers providing more accurate results, to next generation sequencing studies enabling highly precise identification of the causative F8 mutation. In parallel, the options for prenatal diagnosis of HA have progressed from examination of FVIII levels in fetal blood samples at weeks 20-22 of pregnancy to genetic analysis of fetal DNA extracted from chorionic villus tissue at weeks 11-14 of pregnancy. In some countries, in vitro fertilization (IVF) combined with preimplantation genetic diagnosis (PGD) has gradually become the procedure of choice for HA carriers who wish to prevent further transmission of HA without the need to undergo termination of pregnancies diagnosed with affected fetuses. In rare cases, genetic analysis of a HA carrier might be complicated by skewed X chromosome inactivation (XCI) of her non-hemophilic X chromosome, thus leading to the phenotypic manifestation of moderate to severe HA. Such skewed XCI may be associated with deleterious mutations in X-linked genes located on the non-hemophilic X chromosome, which should be considered in the process of genetic counseling and PGD planning for the symptomatic HA carrier. Therefore, whole exome sequencing, combined with X-chromosome targeted bioinformatic analysis, is highly recommended for symptomatic HA carriers diagnosed with skewed XCI in order to identify additional deleterious mutations potentially involved in XCI skewing. Identification of such mutations, which may profoundly impact the reproductive choices of HA carriers with skewed XCI, is extremely important.

Isolated central nervous system relapses in patients with high-risk neuroblastoma -clinical presentation and prognosis: experience of the Polish Paediatric Solid Tumours Study Group.

Although isolated central nervous system (CNS) relapses are rare, they may become a serious clinical problem in intensively treated patients with high-risk neuroblastoma (NBL). The aim of this study is the presentation and assessment of the incidence and clinical course of isolated CNS relapses. Retrospective analysis involved 848 NBL patients treated from 2001 to 2019 at 8 centres of the Polish Paediatric Solid Tumours Study Group (PPSTSG). Group characteristics at diagnosis, treatment and patterns of relapse were analysed. Observation was completed in December 2020. We analysed 286 high risk patients, including 16 infants. Isolated CNS relapse, defined as the presence of a tumour in brain parenchyma or leptomeningeal involvement, was found in 13 patients (4.5%; 8.4% of all relapses), all of whom were stage 4 at diagnosis. Isolated CNS relapses seem to be more common in young patients with stage 4 MYCN amplified NBL, and in this group they may occur early during first line therapy. The only or the first symptom may be bleeding into the CNS, especially in younger children, even without a clear relapse picture on imaging, or the relapse may be clinically asymptomatic and found during routine screening. Although the incidence of isolated CNS relapses is not statistically significantly higher in patients after immunotherapy, their occurrence should be carefully monitored, especially in intensively treated infants, with potential disruption of the brain-blood barrier.

Challenges in the interpretation of a germline TERT variant in a patient with juvenile myelomonocytic leukemia.

Dyskeratosis congenita (DC) is a bone marrow failure syndrome with extrahematopoietic abnormalities. DC is a paradigmatic telomere biology disorder (TBD) caused by germline mutations in genes responsible for telomere maintenance including TERT. Cryptic TBD is a bone marrow failure syndrome due to premature telomere shortening but without additional symptoms, frequently clinically indistinguishable from severe aplastic anemia (SAA) or hypoplastic myelodysplastic syndrome. We present the complex diagnostic pathway in a boy with a rare germline p.Thr726Met TERT variant with previous reports of SAA association and compromised enzymatic function who presented with juvenile myelomonocytic leukemia, which is a rare myelodysplastic/myeloproliferative neoplasm of childhood.

Vaccination in children with chronic severe neutropenia - review of recommendations and a practical approach.

While the management of childhood neutropenia associated with a modifiable factor should be appropriate for the primary cause, there are misconceptions regarding the management of severe congenital neutropenia, immune neutropenia and cases classified as "idiopathic". Antibiotic prophylaxis or granulocyte-colony stimulating factor (G-CSF) are prescribed by specialists in pediatric hematology or immunology, whereas immunization may be conducted by primary care physicians should clear recommendations by provided. There is a belief that severe neutropenia, as an immunodeficiency, is associated with compromised effectiveness and increased rate of complications of immunization. The immunization might be delayed or omitted, increasing the risk of unnecessary infection. We discuss the available data and recommendations regarding vaccination of children with chronic severe neutropenia. While there are virtually no studies addressing the safety and effectiveness of vaccination in neutropenia, expert opinions provide information on immunization policy in "phagocytic cells defects" or explicitly neutropenia. There are no contraindications for inactivated vaccines in neutropenia. Live bacterial vaccines are contraindicated. While in general the vaccination with live viral vaccines is encouraged, occasionally neutropenia might be associated with defects of adaptive immunity, which would preclude the administration of such vaccines. Although this should be easily phenotypically identified, we propose assessing immunoglobulin levels and performing a low-cost flow cytometry test for major lymphocyte subpopulations to exclude significant defects in adaptive immunity before administration of live viral vaccines to such patients. This can improve the adherence of patients' guardians and physicians to proposed vaccination policy and the professional and legal safety associated with the procedure.

Uncommon reasons of the digestive tract-related paraneoplastic syndromes in children with neuroblastic tumors: three case reports.

AIM OF THE STUDY: presentation of the uncommon paraneoplastic syndromes related to the gastrointestinal tract that may occur in children with neuroblastic tumors and their impact on the disease course. MATERIAL AND METHODS: Retrospective analysis of three cases of patients mainly with digestive tract-related symptoms, who were originally admitted to the gastroenterology department from 2013 to 2016 and were finally diagnosed with neuroblastic tumors. RESULTS: The clinical data analysis showed that the symptoms from gastrointestinal tract were dominant in analyzed subjects. The first case is a girl with weight loss, bloating and severe diarrhea, admitted to the hospital in a state of dehydration. The laboratory tests revealed severe hypokalemia. Finally, vasoactive intestinal peptide (VIP) secreting ganglioneuroblastoma was diagnosed and effective surgery was performed. The second case was also a girl who suffered from the incidents of watery diarrhea and flatulence. The tumor was detected by computerized tomography scan. The 3rd stage of ganglioneuroblastoma was diagnosed. The patient required chemotherapy, radiotherapy and surgery treatment. The third child was a boy, hospitalized due to abdominal pain, constipation and weakness. During the diagnostic process, the 4th stage of neuroblastoma was recognized. The chemotherapy, surgery, radiotherapy and immunotherapy were applied. CONCLUSIONS: In children with common abdominal symptoms as chronic flatulence, diarrhea or severe constipation of unknown etiology, the neuroblastic tumors should be considered.

Severe Hyponatremia in a Single-Center Series of 84 Homogenously Treated Children With Acute Lymphoblastic Leukemia.

Electrolyte abnormalities are hallmark metabolic disturbances during the treatment of acute lymphoblastic leukemia (ALL). Hyponatremia is an ominous laboratory sign in the setting of neoplasia. We analyzed the incidence, risk factors, associations, specific interventions and outcomes of severe hyponatremia in a single-center series of children with ALL. The incidence of severe hyponatremia, defined as serum sodium levels below 130 mmol/L on at least 2 of 3 consecutive days, was 11.9%. History of hyponatremia episode is associated with neurologic complications (P=0.023) and the presence of overt central nervous system leukemia (CNS3) at diagnosis (P=0.005). Most observed hyponatremia episodes resolved relatively quickly, rarely requiring specific treatment. All but 1 hyponatremia episodes occurred in the induction or reinduction phases, but none before the administration of cytotoxic drugs, pointing to the role of therapy complications rather than leukemia per se. Most patients received vincristine shortly before hyponatremia onset, and vincristine has been previously strongly implicated in hyponatremia. We also suggest a role for imatinib. Although every patient with severe hyponatremia requires swift and thorough diagnostics a serious sequelae in the setting of pediatric ALL is rare. Hyponatremia association with neurotoxicity likely points to vincristine hypersensitivity in the subgroup of patients with both complications.

Congenital neutropenia: From lab bench to clinic bedside and back.

Neutropenia is a hematological condition characterized by a decrease in absolute neutrophil count (ANC) in peripheral blood, typically classified in adults as mild (1-1.5 × 109/L), moderate (0.5-1 × 109/L), or severe (< 0.5 × 109/L). It can be categorized into two types: congenital and acquired. Congenital severe chronic neutropenia (SCN) arises from mutations in various genes, with different inheritance patterns, including autosomal recessive, autosomal dominant, and X-linked forms, often linked to mitochondrial diseases. The most common genetic cause is alterations in the ELANE gene. Some cases exist as non-syndromic neutropenia within the SCN spectrum, where genetic origins remain unidentified. The clinical consequences of congenital neutropenia depend on granulocyte levels and dysfunction. Infants with this condition often experience recurrent bacterial infections, with approximately half facing severe infections within their first six months of life. These infections commonly affect the respiratory system, digestive tract, and skin, resulting in symptoms like fever, abscesses, and even sepsis. The severity of these symptoms varies, and the specific organs and systems affected depend on the genetic defect. Congenital neutropenia elevates the risk of developing acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS), particularly with certain genetic variants. SCN patients may acquire CSF3R and RUNX1 mutations, which can predict the development of leukemia. It is important to note that high-dose granulocyte colony-stimulating factor (G-CSF) treatment may have the potential to promote leukemogenesis. Treatment for neutropenia involves antibiotics, drugs that boost neutrophil production, or bone marrow transplants. Immediate treatment is essential due to the heightened risk of severe infections. In severe congenital or cyclic neutropenia (CyN), the primary therapy is G-CSF, often combined with antibiotics. The G-CSF dosage is gradually increased to normalize neutrophil counts. Hematopoietic stem cell transplants are considered for non-responders or those at risk of AML/MDS. In cases of WHIM syndrome, CXCR4 inhibitors can be effective. Future treatments may involve gene editing and the use of the diabetes drug empagliflozin to alleviate neutropenia symptoms.

The paradox of autoimmunity and autoinflammation in inherited neutrophil disorders - in search of common patterns.

Congenital defects of neutrophil number or function are associated with a severe infectious phenotype that may require intensive medical attention and interventions to be controlled. While the infectious complications in inherited neutrophil disorders are easily understood much less clear and explained are autoimmune and autoinflammatory phenomena. We survey the clinical burden of autoimmunity/autoinflammation in this setting, search for common patterns, discuss potential mechanisms and emerging treatments.

An Asymptomatic, Ectopic Mass as a Presentation of Adrenocortical Carcinoma Due to a Novel Germline TP53 p.Phe338Leu Tetramerisation Domain Variant.

Adrenocortical carcinoma (ACC) is a rare cancer in childhood. ACC is frequently associated with germline TP53 variants, with founder effects especially due to the p.Arg337His mutation. ACC leads to the secretion of adrenocortical hormones, resulting in endocrine syndromes, which is the usual trigger for establishing the diagnosis. We present a surprising ACC pathology in a non-secreting, ectopic retroperitoneal tumour in a 4-year-old boy, successfully controlled with chemotherapy and mitotane after microscopically incomplete tumour resection with spillage. Genomic analysis (gene panel sequencing and copy-number microarray) demonstrated a novel p.Phe338Leu tetramerisation domain (TD) TP53 variant in the proband and his cancer-free mother and a monoallelic deletion encompassing the TP53 locus in cancer tissue, consistent with cancer-predisposition syndrome. While the recurrent p.Arg337His variant translates into high ACC risk, residue 338 and, in general, TD domain variants drive heterogeneous clinical scenarios, despite generally being considered less disruptive than TP53 DNA-binding domain mutations.

Venetoclax Use in Paediatric Haemato-Oncology Centres in Poland: A 2022 Survey.

Venetoclax, the best established BH3-mimetic, is a practice-changing proapoptotic drug in blood cancers in adults. In paediatrics the data are fewer but exciting results were recently presented in relapsed or refractory leukaemias demonstrating significant clinical activity. Importantly, the in-terventions could be potentially molecularly guided as vulnerabilities to BH3-mimetics were re-ported. Currently venetoclax is not incorporated into paediatric treatment schedules in Poland but it has been already used in patients that failed conventional therapy in Polish paediatric haemato-oncology departments. The aim of the study was to gather clinical data and correlates of all paediatric patients treated so far with venetoclax in Poland. We set out to gather this experience to help choose the right clinical context for the drug and stimulate further research. The questionnaire regarding the use of venetoclax was sent to all 18 Polish paediatric haemato-oncology centres. The data as available in November 2022 were gathered and analysed for the diagnoses, triggers for the intervention, treatment schedules, outcomes and molecular associations. We received response from 11 centres, 5 of which administered venetoclax to their patients. Clinical benefit, in most cases consistent with hematologic complete remission (CR), was reported in 5 patients out of ten, whereas 5 patient did not show clinical benefit from the intervention. Importantly, patients with CR included subtypes expected to show venetoclax vulnerability, such as poor-prognosis ALL with TCF::HLF fusion. We believe BH3-mimetics have clinical activity in children and should be available to pae-diatric haemato-oncology practitioners in well-selected applications.

Subcutaneous immunoglobulin replacement therapy in a patient with 18q deletion syndrome, primary immune deficiency, and type 1 diabetes.

18q deletion syndrome (OMIM #601808) results from a deletion of a part of a long arm of 18 chromosome and is characterized by mental retardation and congenital malformations. We present an exceptional case of a 12-year-old girl with severe phenotype of 18q deletion syndrome, frequent infections, type 1 diabetes, autoimmune thyroiditis, and vitiligo. At first, the patient was diagnosed with selective immunoglobulin A (sIgAD) which explained her susceptibility to both infections and autoimmunity. With time, sIgAD progressed to common variable immune deficiency-like (CVID-like) disorder. She had a minimum of 12 infections per year, approximately twice as many courses of different antibiotics and up to three hospitalizations annually, making the treatment of diabetes difficult. Due to safety issues (increased risk of adverse reaction to blood products) and patient's convenience, subcutaneous IgG (SCIG) replacement therapy was initiated. We noticed a substantial decrease in the number of infections and improvement of metabolic control of diabetes.

Pulmonary Exacerbation of Undiagnosed Toxocariasis in Intensively-Treated High-Risk Neuroblastoma Patients.

Toxocariasis is one of the most common zoonoses, with high seroprevalence in apparently healthy individuals. Neuroblastoma is an aggressive childhood cancer. The cure rates are improving due to dose-dense chemotherapy, progress in surgical practice, myeloablative therapy with autologous stem cell transplantation, and recently, anti-GD2 immunotherapy. This is associated with a burden of complications, some of which are relatively specific for neuroblastoma treatment. Based on previous reports of Toxocara canis infection in high-risk neuroblastoma patients and cases of pulmonary exacerbation from our center in this disease, we propose that toxocariasis is a specific complication of intensive pediatric cancer treatment and advocate for active surveillance.

Severe, Reversible Acute Lung Injury During Autologous Hematopoietic Stem Cell Mobilization After Filgrastim in a Child With Neuroblastoma: A Case Report.

Peripheral blood hematopoietic stem cell mobilization is widely performed in a variety of clinical facilities and is believed to be a safe outpatient procedure. In this report, we describe a child with neuroblastoma who developed an extremely severe acute lung injury after granulocyte colony-stimulating factor was used for peripheral hematopoietic stem cell mobilization. A 3-year-old boy with a medical history of patent foramen ovale and secundum atrial septal defect was diagnosed with an MYCN-amplified neuroblastoma and treated with chemotherapy. During stem cell mobilization with filgrastim, the boy was in very good clinical condition, with a peripheral white blood cell (WBC) count of 57.17 K/µL, but he suddenly deteriorated, and nausea, seizures, and nystagmus were observed. The patient developed dyspnea with hemoptysis, and lung computed tomography showed bilateral asymmetrical pulmonary opacification demonstrating an anteroposterior density gradient. Because of rapidly progressing circulatory and respiratory failure, the child was hospitalized in the intensive care unit. Corticosteroid therapy, broad-spectrum antibiotic therapy, and cardiovascular support with mechanical ventilation were immediately instituted, and the child recovered without sequelae. The presented case emphasizes that life-threatening complications can occur during granulocyte colony-stimulating factor administration, and patient surveillance is warranted, especially if high leukocyte counts are observed or the patient exhibits cardiopulmonary signs.

Six molecular patterns leading to hemophilia A phenotype in 18 females from Poland.

INTRODUCTION: Female hemophilia is an intriguing rare disorder and few larger reports on its genetic etiology are available. While historically the diagnosis was satisfactorily reached by factor VIII activity assays, the clinical and potentially therapeutic heterogeneity of female hemophilia calls for comprehensive molecular diagnosis in each case. Currently, the genetic investigations are not a part of routine, state-funded, diagnostics in Poland, and thus molecular epidemiological data are missing. AIM: We set out to perform a comprehensive genetic analysis of Polish females with hemophilia A. PATIENTS/METHODS: Eighteen females with hemophilia A (including 2 with severe and 5 with moderate hemophilia phenotype) consented for genetic diagnostics. To establish F8 mutations, we used next-generation sequencing of a panel of genes associated with hematological disorders, standard assays for recurrent intragenic F8 inversions and MLPA when deletions were suspected. When appropriate we also used karyotyping, genomic microarrays and X chromosome inactivation assays. RESULTS: While abnormally skewed X-chromosome inactivation combined with a F8 variant on the active allele was, as expected, the most common genetic etiology, a number of other genetic scenarios were unraveled. This included: misdiagnosis (molecular diagnosis of vWd), Turner syndrome, compound heterozygosity and androgen insensitivity syndrome (a phenotypical 46,XY female with a novel androgen receptor gene mutation). We report 3 novel F8 mutations. CONCLUSION: Every case of female hemophilia warrants full genomic diagnostics, as this may change the diagnosis or reveal broader morbidity than a coagulation disorder (Turner syndrome, androgen insensitivity, or cardiovascular morbidity that we described previously in a SHAM syndrome carrier).

Dynamic changes in specific anti-L-asparaginase antibodies generation during acute lymphoblastic leukemia treatment.

BACKGROUND: L-asparaginase (L-asp) remains one of the key components of acute lymphoblastic leukemia therapy. Immune reactions to the drug are associated with its diminished activity. The aim of the study was to determine the level of IgM, IgG and IgE-class anti-L-asp antibodies during the induction and reinduction phases of acute lymphoblastic leukemia therapy and their influence on L-asp activity. METHODS: The study group comprised 65 patients treated for acute lymphoblastic leukemia in one pediatric oncology center. L-asp antibodies were assessed using ELISA at the end of the induction and reinduction phases. L-asp activity was assessed prior to each drug administration by colorimetry. RESULTS: At the end of the first exposure to L-asp antibodies were detected in 35 patients (54%). In the reinduction phase of the treatment anti-L-asp antibodies were found in 38/55 patients (69%). In the induction phase patients with inadequate L-asp activity had higher IgM concentrations (median 5.88 versus 2.81 µg/mL, p = 0.03). In the reinduction phase IgG and IgM levels correlated inversely with L-asp activity. Patients with L-asp allergy had higher levels of IgG (median 61.6 versus 18.36 µg/mL, p = 0.01), whereas higher IgE levels were noted in the group of patients with inadequate drug activity (median 0.91 versus 0.64 µg/mL, p = 0.03). CONCLUSIONS: Subsequent exposure to L-asp in the treatment of acute lymphoblastic leukemia was associated with the increase of anti-L-asp antibodies in all studied classes. However, the changes observed in specific classes of antibodies were not distinctive for L-asp hypersensitivity or inactivation, suggesting that the mechanism is more complex.

Unfavorable Outcome of Neuroblastoma in Patients With 2p Gain.

Background: Amplification of the MYCN oncogene is the most unfavorable genetic factor in neuroblastoma patients. However, knowledge about the clinical impact of low-level multiplication of MYCN is still insufficient. Therefore, we aimed to investigate the disease course in patients with different copy number status of MYCN. Materials and Methods: We examined 105 children diagnosed with neuroblastoma from 2010 to 2018 in five pediatric oncology centers in Poland. We determined the MYCN status at diagnosis by the interphase FISH examination and assessed the clinical outcome in patients. Results: A total of 35% of tumors presented with chromosome 2 numerical changes, 20% had MYCN amplification and 16% revealed 2p gain. Unexpectedly, we observed very low overall survival and event free survival (EFS) rates in neuroblastomas with 2p gain, which were comparable with patients with MYCN amplification. Conclusions: The 2p gain alteration should be reported as a strong unfavorable prognostic marker in neuroblastoma patients.