Cartilage-Hair Hypoplasia (CHH), a rare ribosomopathy characterized by immune deficiency, carries a markedly increased risk of early-onset malignancy, particularly lymphoma. However, the molecular drivers of malignant transformation in CHH, and the contribution of viruses to this process, remain poorly defined. We performed targeted virome sequencing of 41 DNA viruses on FFPE tumor samples (primarily lymphomas) from 15 CHH patients and three malignancy-matched controls per patient. Subsequent analyses comprised Epstein-Barr Virus (EBV) quantification via qPCR, intra-host minor variant (MV) profiling, and high-resolution mapping of viral integration sites using ViroJoin. EBV was the only pathogen consistently detected across all CHH tumors, with viral loads exceeding those of controls by more than 400-fold. Aggregate analysis of all full-length EBV genomes revealed minimal intra-host diversity and sparse structural variations, of which inversions were the most common. Strikingly, we detected a non-random pattern of EBV integration into the host genome, with junctions frequently clustering near viral promoters, particularly within LMP1. Integrations localized preferentially to host genes, occurring 1.3-fold more frequently within genes and 8.2-fold closer to them than expected by chance. Our findings identify a distinct genomic signature associated with EBV-positive lymphomas, characterized by non-random EBV integrations into the host genome. We propose that these ectopic viral sequences may act as cis-regulatory elements, potentially dysregulating host gene expression and contributing to malignant transformation and disease severity. These results underscore the importance of virome surveillance for early risk stratification in high-risk populations.

BACKGROUND:Pulmonary complications are a major cause of morbidity after allogeneic hematopoietic stem cell transplantation (HSCT). Late-onset non-infectious pulmonary complications (LONIPCs), especially bronchiolitis obliterans syndrome (BOS), are difficult to diagnose, particularly in paediatric patients. METHODS:In this retrospective single-center study, 14 of 325 paediatric HSCT recipients (4.3%) who developed severe pulmonary symptoms between 1999 and 2016 were analyzed. Lung biopsies were correlated with high-resolution computed tomography (HRCT) and pulmonary function tests (PFTs). Fourteen postmortem biopsies from HSCT patients without pulmonary symptoms served as controls. RESULTS:Histology showed BOS in eight patients, cryptogenic organizing pneumonia (COP) in three, and interstitial fibrosis in three. None of the controls had findings suggestive of LONIPCs. All patients with BOS exhibited obstructive spirometry results, while restrictive changes occurred in COP and fibrosis. HRCT findings, including bronchial wall thickening and dilation, were frequent but non-specific. The incidence of LONIPCs and BOS was 4% and 2%, respectively. CONCLUSIONS:BOS was the most common late-onset pulmonary complication after paediatric HSCT. Obstructive PFT changes correlated well with histological BOS, whereas HRCT findings lacked specificity. Regular pulmonary function monitoring appears more reliable than imaging for early detection and may help prevent progression to irreversible lung disease. IMPACT:This study highlights the diagnostic value of combining functional and histological assessment in children after HSCT. Underscores the limitations of HRCT in detecting early BOS. Supports routine pulmonary function surveillance as a non-invasive strategy to improve long-term outcomes.

Aim To evaluate the longitudinal coagulation profile after allogeneic hematopoietic stem cell transplantation (HSCT) in pediatric patients with hematological malignancies. Methods Several coagulation variables were measured at predetermined time points for two years after HSCT in 30 pediatric patients. Results At six months post-HSCT, endothelial activation was reflected by 1.4-fold increase in circulating von Willebrand factor activity (p < 0.05), and by 2-fold increase in thrombin-antithrombin complex levels (p < 0.05), suggesting sustained coagulation system activity. In six patients with chronic graft-versus-host disease (cGVHD), specifically in those having gastrointestinal (GI) tract cGVHD, we observed continued longitudinal alterations in the coagulation system. The activities of both, coagulation factors (FV, FVII, FVIII, fibrinogen), and natural anticoagulants (antithrombin and protein C) were higher than prior to conditioning (p < 0.05) at most time points in patients with cGVHD. Moreover, fibrin turnover marker D-dimer was elevated from 6 to 18 months after HSCT (p < 0.05). Conclusion Pediatric patients undergoing HSCT demonstrate prolonged derangement of the coagulation system, with a new alleviating balance after 6 months post-HSCT. However, in patients with cGVHD, and in particular when cGVHD affects the GI tract, the persisting derangement of coagulation suggest its contributing role in cGVHD and related complications.

The central nervous system (CNS) is an important sanctuary site for acute lymphoblastic leukaemia (ALL). Sensitive biomarkers are needed to guide CNS treatment intensity and identify patients at risk of CNS relapse. Currently, cerebrospinal fluid (CSF) cell counts and cytology are used to stage patients as CNS1 (no detectable CNS leukaemia), CNS2 (≤5 white blood cells (WBC)/µl, ≥2 visible blasts on cytospin), and CNS3 (>5 WBC/µl with blasts or overt clinical CNS involvement). However, most CNS relapses occur in CNS1 patients, and the prognostic value of CNS2 disease is disputed. Wide variations in CNS2 rates between and even within countries indicate a lack of diagnostic accuracy. CSF-FLOW is a scientific sub-study within the ALLTogether1 trial for children and young adults (1-45 years of age) with newly diagnosed ALL (ClinicalTrials.gov ID: NCT04307576). CSF-FLOW builds on data indicating that CSF flow cytometry (FCM) identifies patients at higher risk of relapse even among CNS1 patients and can divide patients with a traumatic lumbar puncture (TLP: >10 red cells/µl of CSF) into TLP- (no blasts on FCM) and TLP+ (with blasts) groups with prognostic relevance. CSF-FLOW aims to: 1) evaluate the prognostic impact of CSF FCM in a large independent cohort with sufficient power to accurately stratify CNS relapse risk; 2) determine the utility of CSF FCM in improving conventional CNS classification; 3) identify key parameters influencing assay performance to develop a standardised clinical grade assay protocol. Aim 1 requires long follow-up. Here we report the results of aims 2 and 3. As of April 22, 2024, CSF-FLOW recruited 1869 children from 12 European countries (57.1% males; 73.5% ≤10 years old). Using conventional staging criteria, 67% of patients were CNS1 (n = 1249), 10% CNS2 (n = 186), 2.1% CNS3 (n = 40), 11.4% TLP- (n = 213), 5.6% TLP+ (n = 104), and 3.8% inconclusive (n = 71). 1348 patients had a day 1 CSF (collected in Transfix/stabilisation buffer) FCM result, 20.5% of whom had >10 leukaemia associated immunophenotype (LAIP) events detectable (= CSF FCM+). CSF FCM+ was commoner in T-cell than B-cell precursor (BCP) ALL (41.6% vs 17.5%, p < 0.001) and in TLP patients compared to non-TLP (35.2% vs 17.6%, p < 0.001). 55.2% of BCP patients diagnosed as CNS2 by cytology were confirmed by FCM, whilst 44.8% had no detectable leukemic blasts by FCM. These could be false negatives due to technical issues such as sample delays (see below), or false positives due to misidentification of T lymphocytes as leukemic cells on cytology. We investigated CD3+ cell counts (by FCM) in BCP patients with discrepant results. The mean CD3+ count was 101 (range 0-782) indicated up to 90% of patients would have ≥2 CD3+ T cells on the cytology slide, indicating a high likelihood of false positive results. FCM+ rates were significantly higher when larger CSF sample volumes were used (range = 45-5000 µl; p = 0.007). Despite use of Transfix, CSF FCM- patients had a significantly longer delay (days) between sample withdrawal and testing than CSF FCM+ (p = 0.04). Varying FCM rates between countries were mainly explainable by differences in sample volumes and analytical delays. Patients underwent serial CSF sampling at days 1, 15 and 29 of treatment. Clearance kinetics varied by immunophenotype with 1.9% (21/1127) BCP and 13% (21/162) T-ALL patients still FCM+ at day 15 (p < 0.001). At day 29, 1% (11/1116) BCP and 3.1% (5/161) T-ALL patients were still FCM+ (p = n.s). Clearance at day 15 also varied by TLP status, with a higher rate of FCM+ in TLP patients compared to non-TLP (5.9% vs 2.8%; p = 0.04). Patients still FCM+ at day 15 had a slightly higher day 1 CSF blast count/µl (p < 0.001). Longer follow up is needed to assess the impact of flow positivity and clearance on outcome. Overall, these results confirm that FCM is more sensitive and specific than cytospin-based methodologies and suggest that FCM can increase the accuracy of conventional CNS2 classification by reducing false positives due to T cells. With longer follow-up, CSF-FLOW is adequately powered to develop risk-prediction algorithms for patients at high and low risk of CNS-involving relapses. However, prior to universal adoption of FCM as a clinical-grade biomarker, our findings stress the importance of developing standardized protocols indicating required sample volumes, maximal sample transit times and identification of optimal blast thresholds for prognostic significance.

We studied the associations between inflammation-related proteins in circulation and complications after pediatric allogenic hematopoietic stem cell transplantation (HSCT), to reveal proteomic signatures or individual soluble proteins associated with specific complications after HSCT. We used a proteomics method called Proximity Extension Assay to repeatedly measure 180 different proteins together with clinical variables, cellular immune reconstitution and blood viral copy numbers in 27 children (1-18 years of age) during a 2-year follow-up after allogenic HSCT. Protein profile analysis was performed using unsupervised hierarchical clustering and a regression-based method, while the Bonferroni-corrected Mann-Whitney U-test was used for time point-specific comparison of individual proteins against outcome. At 6 months after allogenic HSCT, we could identify a protein profile pattern associated with occurrence of the complications such as chronic graft-versus-host disease, viral infections, relapse and death. When protein markers were analyzed separately, the plasma concentration of the inhibitory and cytotoxic T-cell surface protein FCRL6 (Fc receptor-like 6) was higher in patients with cytomegalovirus (CMV) viremia [log2-fold change 1.5 (P = 0.00099), 2.5 (P = 0.00035) and 2.2 (P = 0.045) at time points 6, 12 and 24 months]. Flow cytometry confirmed that FCRL6 expression was higher in innate-like gamma delta T cells, indicating that these cells are involved in controlling CMV reactivation in HSCT recipients. In conclusion, the potentially druggable FCRL6 receptor on cytotoxic T cells appears to have a role in controlling CMV viremia after HSCT. Furthermore, our results suggest that system-level analysis is a useful addition to the studying of single biomarkers in allogenic HSCT. In this study, the cytotoxic T-cell inhibitory FCRL6 (Fc receptor-like 6) emerged as a potentially relevant biomarker or a therapy target for cytomegalovirus reactivation after pediatric hematopoietic stem cell transplantation (HSCT). Furthermore, the proteomic approach revealed several potential other biomarkers that showed different kinetics in patients with and without complications after HSCT. image

The aim of this study was to identify pitfalls in ovarian tissue cryopreservation protocol from referral to surgical procedures and to analyze factors associated with chemotherapy exposure of the cryopreserved tissue and decreased ovarian function in a cohort of young girls at high risk of infertility. The study population comprised 200 girls eligible for ovarian tissue cryopreservation between 2002 and 2020 at the Children's Hospital of the University Central Hospital of Helsinki (Finland). Analyses included the evaluation of the proportion of patients who underwent ovarian tissue cryopreservation, factors associated with patient selection and timing of ovarian tissue cryopreservation, and ovarian function during long-term follow-up in relation to oncological treatments. Lack of counseling was identified as the major reason for not receiving ovarian tissue cryopreservation. A longer interval from scheduling gonadotoxic therapy to cryopreservation correlated with a higher exposure to alkylating agents of the ovarian tissue. The long-term ovarian function was mainly influenced by age at the time of gonadotoxic treatment. Current selection criteria for ovarian tissue cryopreservation should be implemented in order to stratify patients at risk of infertility and timely identify those at higher risk, especially in relation to age and pubertal stage. Efforts to increase healthcare providers’ awareness and facilitate guided timing in relation to the treatment protocols are needed to guarantee early access to ovarian tissue cryopreservation for all patients at high risk of infertility. Lay summary Girls affected by cancer may undergo aggressive treatments to cure the disease, such as chemotherapy and radiotherapy, which can harm the ovaries. These treatments often result in the destruction of the ovaries and infertility. Nowadays, an option exists to help these girls recover their fertility after the cancer has been successfully treated. A fragment or an entire ovary can be removed by surgery and frozen before the treatments begin. When the girls are well and wish as adults to start a family, this fragment can be reimplanted back into the remaining ovary to restore fertility. This technique is called ovarian tissue cryopreservation. In this article, we report on the experience of ovarian tissue cryopreservation at the Children’s Hospital in Finland for 200 girls undergoing cancer treatment with a high risk of subsequent infertility. We analyzed the proportion of girls who had ovarian tissue cryopreservation performed among those exposed to aggressive treatments and investigated the reasons why some of them did not undergo the procedure. We also examined the time passing before the procedure was done to identify potential avoidable sources of delay. Finally, we explored how the ovaries of all the girls functioned during the time after the cancer diagnosis and looked at this in relation to their cancer treatments and ovarian tissue freezing.

Abstract Introduction Transitioning to adulthood often involves achieving independence from the parental home. We assessed whether the likelihood of leaving the parental home, cohabitation, and marriage was similar between patients who experienced a hematologic malignancy at a young age and their peers. Methods We identified 11,575 patients diagnosed with a hematologic malignancy under the age of 20 years between 1971 and 2011 in Denmark, Finland, and Sweden, 57,727 country‐, age‐, and sex‐matched population comparisons and 11,803 sibling comparisons and obtained annual information on family and marital status by linking to the statistical institute databases. Hazard ratios (HR) for leaving the parental home, cohabitation and marriage were estimated using Cox proportional hazards modeling. Results Young adults with a history of a hematologic malignancy were slightly less likely to leave the parental home (HR 0.89; 95% confidence interval [CI] 0.86–0.92; HR 0.87 [95% CI 0.82–0.92]), cohabit with a nonmarital partner (HR 0.83 [95%CI 0.78–0.87]; HR 0.84 [95% CI 0.77–0.92]) and be married (HR 0.87 [95% CI 0.82–0.91]; HR 0.86 [95% CI 0.79–0.93]), compared with population comparisons and siblings, respectively. Conclusions Our findings provide reassurance that young adults with a history of a hematologic malignancy show only a slight decrease in their likelihood of gaining independence from their childhood family and forming close interpersonal relationships compared to peers. While most patients are coping well in the long term, integrating structured psychosocial support into long‐term follow‐up is recommended to facilitate a timely and adequate transition into adulthood.

Background: Childhood cancer survivors face various adverse consequences. This Nordic register-based cohort study aimed to assess whether survivors of childhood cancer are more likely to have low income than their peers. Methods: We identified 17,392 childhood cancer survivors diagnosed at ages 0 to 19 between 1971 and 2009 with 83,221 age-, sex-, and country-matched population comparisons. Annual disposable income at ages 20 to 50 years was retrieved from statistical offices (for 1990-2017) and categorized into low income and middle/high income. The number of transitions between income categories were assessed using binomial regression analyses. Results: The prevalence of annual low income among childhood cancer survivors was 18.1% and 15.6% among population comparisons (risk ratio [RR] 1.17; 95% confidence interval [CI] 1.16-1.18). Compared to population comparisons, childhood cancer survivors were 10% (95% CI 8%-11%) less likely to transition from low to middle/high income and 12% (10%-15%) more likely to transition from middle/high to low income during follow-up. Among those initially in the low income category, survivors were 7% (95% CI 3%-11%) more likely to remain in the low income category. If the initial category was middle/high income, childhood cancer survivors were 10% (95% CI 8%-11%) less likely to remain in the middle/high income and 45% (37%-53%) more likely to transition to the low income category permanently. Conclusions: Childhood cancer survivors are at higher risk for low income in adulthood than their peers. These disparities might be reduced by continued career counseling along with support in managing within the social security system.

Background: In 2014, germline signal transducer and activator of transcription (STAT) 3 gain-of-function (GOF) mutations were first described to cause a novel multisystem disease of early-onset lymphoproliferation and autoimmunity. Objective: This pivotal cohort study defines the scope, natural history, treatment, and overall survival of a large global cohort of patients with pathogenic STAT3 GOF variants. Methods: We identified 191 patients from 33 countries with 72 unique mutations. Inclusion criteria included symptoms of immune dysregulation and a biochemically confirmed germline heterozygous GOF variant in STAT3. Results: Overall survival was 88%, median age at onset of symptoms was 2.3 years, and median age at diagnosis was 12 years. Immune dysregulatory features were present in all patients: lymphoproliferation was the most common manifestation (73%); increased frequencies of double-negative (CD4-CD8-) T cells were found in 83% of patients tested. Autoimmune cytopenias were the second most common clinical manifestation (67%), followed by growth delay, enteropathy, skin disease, pulmonary disease, endocrinopathy, arthritis, autoimmune hepatitis, neurologic disease, vasculopathy, renal disease, and malignancy. Infections were reported in 72% of the cohort. A cellular and humoral immunodeficiency was observed in 37% and 51% of patients, respectively. Clinical symptoms dramatically improved in patients treated with JAK inhibitors, while a variety of other immunomodulatory treatment modalities were less efficacious. Thus far, 23 patients have undergone bone marrow transplantation, with a 62% survival rate. Conclusion: : STAT3 GOF patients present with a wide array of immune-mediated disease including lymphoproliferation, autoimmune cytopenias, and multisystem autoimmunity. Patient care tends to be siloed, without a clear treatment strategy. Thus, early identification and prompt treatment implementation are lifesaving for STAT3 GOF syndrome. (J Allergy Clin Immunol 2023;151:1081-95.)

Background:Cartilage-hair hypoplasia (CHH) is a syndromic inborn error of immunity caused by variants in the RMRP gene. Disease manifestations vary, and their ability to predict outcome is uncertain. The optimal management of infants with CHH who do not fulfill classical severe combined immunodeficiency (SCID) criteria is unknown. Objective:We described longitudinal changes in lymphocyte counts during childhood and explored correlations of early childhood clinical and laboratory features with clinical outcomes on long-term follow-up of CHH patients. Methods:Immunologic laboratory parameters, birth length, the presence of Hirschsprung disease, and severe anemia correlated to the primary end points of respiratory and severe infections. We implemented traditional statistical methods and machine learning techniques. Results:Thirty-two children with CHH were followed up for 2.7 to 22.1 years (median, 8.2 years, in total 331.3 patient-years). None of the patients had classical SCID. Median lymphocyte subclass counts, apart from CD16+/56+ cells, were subnormal throughout childhood, but did not show age-related decline seen in healthy children. Low immunoglobulin levels were uncommon and often transient. Respiratory and/or severe infections developed in 14 children, 8 of whom had low naive T-cell counts, absent T-cell receptor excision circles, and/or partial "leaky" SCID-level lymphopenia. Shorter birth length correlated with lower lymphocyte counts and the occurrence of infections. Of the laboratory parameters, decreased naive T-cell counts and abnormal lymphocyte proliferation responses contributed most to the development of severe infections. In addition, all participants with absent T-cell receptor excision circles developed severe infections. Opportunistic infections occurred only in children with leaky SCID-level lymphopenia. Conclusions:Shorter birth length and a combination of laboratory abnormalities can predict the development of severe infections in children with CHH.

Allogeneic hematopoietic stem cell transplantation (aHSCT) represents a therapeutic choice for high-risk and relapsed leukemia at a young age. In this retrospective population-based study, we evaluated cardiovascular complications after aHSCT (N = 272) vs conventional therapy (N = 1098) among patients diagnosed with acute lymphoblastic or acute myeloid leukemia below 35 years between 1985 and 2004. Additionally, siblings from a prior comparison group served as population controls (N = 39 217). Childhood leukemia and aHSCT was associated with a 16-fold HR for developing arterial hypertension (HR 16.8, 95%CI 1.5-185.5) compared with conventional therapy. A 2-fold HR for any cardiovascular complication was observed after AYA leukemia and aHSCT vs conventional treatment (HR 2.7, 95% CI 1.4-5.1). After AYA leukemia and aHSCT, the HR of cardiac arrhythmia was significantly elevated vs conventional therapy (HR 14.4, 95% CI 1.5-125.2). Moreover, after aHSCT in childhood, elevated hazard ratios (HRs) were found for cardiomyopathy/ cardiac insufficiency (HR 105.0, 95% CI 10.0-1100.0), cardiac arrhythmia, and arterial hypertension (HR 20.1, 95%CI 2.5-159.7 and HR 20.0, 95%CI 4.1-97.4) compared with healthy controls. After adolescent and young adult (AYA) leukemia and aHSCT, markedly increased HRs were observed for cardiac arrhythmia (HR 29.2, 95%CI 6.6-129.2), brain vascular thrombosis/ atherosclerosis and cardiomyopathy/cardiac insufficiency (HR 23.4, 95%CI 7.1-77.4 and HR 19.2, 95%CI 1.5-245.2) compared with healthy controls. As the cumulative incidence for cardiovascular complications rose during the follow-up of childhood and AYA leukemia patients, long-term cardiovascular surveillance is warranted to optimize the quality of life after childhood and AYA leukemia following both conventional treatment and aHSCT.

Objective Our objective was to study kinetics and associations between inflammation related proteins in circulation after pediatric allogenic hematopoietic stem cell transplantation (HSCT) to reveal proteomic signatures or individual soluble proteins associated with specific complications post HSCT.Methods We used a proteomics method called Proximity Extension Assay to repeatedly measure 180 different proteins together with clinical variables, cellular immune reconstitution, and blood viral copy numbers in 27 children aged 1-18 years during a two-year follow up after allogenic HSCT. Protein profile analysis was done using unsupervised hierarchical clustering and a regression-based method, while Bonferroni-corrected Mann-Whitney U test was used for time point specific comparison of individual proteins against outcome.Results At 6 months after allogenic HSCT, we could identify a protein profile pattern that was associated with occurrence of the complications chronic graft-versus-host disease, viral infections, relapse, and death. When protein markers were analyzed separately, the plasma concentration of the inhibitory and cytotoxic T cell surface protein FCRL6 (Fc receptor-like 6) was higher in patients with CMV viremia (log2-fold change 1.5 (p=9.9 x 10-4), 2.5 (p=3.5 x 10-4) and 2.2 (p=0.045) at time points 6, 12 and 24 months). Flow cytometry confirmed that FCRL6 expression was higher in innate-like T cells, indicating that these cells have a role𝛾𝛿 in controlling CMV reactivation in HSCT recipients.Conclusions The potentially druggable FCRL6 receptor on cytotoxic T cells appears to have role in controlling CMV viremia post-HSCT. Our results suggests that system level analysis is a useful addition to the studying of single biomarkers in allogeneic HSCT.### Competing Interest StatementThe authors have declared no competing interest.### Funding StatementAA reports funding from Finska Lakaresallskapet and Lastentautien Tutkimussaatio. MSV reports funding from the Academy of Finland (grant number 322123). EK reports funding from Lastentautien tutkimussaatio; University of Helsinki research funds and Helsinki University Hospital Governmental Funding for Research. LLE reports funding from the European Research Council ERC (677943); European Union Horizon 2020 research and innovation programme (955321); Academy of Finland (310561; 314443; 329278; 335434; 335611 and 341342); Sigrid Juselius Foundation; Biocenter Finland and ELIXIR Finland. XH and PH report no competing financial interests.### Author DeclarationsI confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.YesThe details of the IRB/oversight body that provided approval or exemption for the research described are given below:Ethics Committee of the Helsinki University Hospital (permit number: HUS/2306/2016) gave ethical approval for this work.I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.YesI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).YesI have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.YesAll data produced in the present study are available upon reasonable request to the authors

Background Chronic lung problems are a rare but serious complication of allogeneic hematopoietic stem cell transplantation (HSCT). We studied clinical phenotypes and polysomnography appearance of breathing abnormality in late onset non-infectious pulmonary complications (NIPS). Methods We reviewed Finnish national reference database between the years 1999 and 2016. We identified 12 children with most severely decreased pulmonary function and performed polysomnography and 24 aged-matched controls out of 325 performed pediatric allogeneic HSCTs. Results All patients with NIPS had severely decreased pulmonary function already at 6 months post HSCT with median FEV 1 value 42% (interquartile range (IQR) 30–52%) of predicted normal values. Seven children had obstructive and five children more restrictive lung function. Children with obstructive lung function showed laborious breathing (7/7), decreased oxygenation and ventilation-to-perfusion mismatch (6/7), or REM-sleep-related hypoventilation (4/7) on polysomnography. Children with restrictive lung function (5/12) did not show sleep-related breathing disorder. Conclusions Children going through allogeneic HSCT who develop severe chronic obstructive lung function are more likely to present with sleep-related hypoxia and hypoventilation than children with restrictive lung function. Impact Children with severe obstructive lung function and chronic lung graft-versus-host disease following hematopoietic stem cell transplantation are more likely to present with sleep-related mild hypoxia and hypoventilation than children with restrictive lung disease. To our knowledge there are no reports on sleep-related breathing disorders and ventilatory function measured by polysomnography in children with pulmonary complications after allogeneic HSCT. Polysomnography may add to the differential diagnostics between patients with BOS and other non-infectious pulmonary complications.

Background: Cartilage-hair hypoplasia (CHH) is an autosomal recessive disorder characterized by short stature, hypotrichosis, combined immunodeficiency, and macrocytic anemia. CHH is caused by germline mutations in the RMRP gene encoding the RNA component of the mitochondrial RNA processing endoribonuclease. CHH is heavily enriched in the Finnish (1 in 23000 births) and the Amish (1 in 1340 births) populations. Transient macrocytic anemia is common in children with CHH, whereas severe hypoplastic macrocytic anemia is only present in 10% of pediatric CHH patients and can be treated with allogeneic hematopoietic stem cell transplantation (HSCT). The mechanism behind hypoplastic anemia in CHH is unknown: while erythroid differentiation from hematopoietic stem cells is impaired in vitro in CHH, immune dysregulation may also play a role in this phenotype. Clonal hematopoiesis is a common phenomenon of aging. Patients with inherited and immune-mediated bone marrow failure (BMF) show distinct spectra of clonal hematopoiesis mutations, reflecting context-specific selection of hematopoietic stem cell clones. However, the spectrum of clonal hematopoiesis is yet to be characterized in CHH. Methods: To assess the landscape of somatic alterations in hematopoietic cells in CHH, we performed whole exome sequencing (WES) on twelve bone marrow samples of four pediatric (age 4 to 13 years) and eight adult (age 20 to 52 years) unrelated subjects with CHH. Three children with CHH had severe hypoplastic anemia at the time of DNA sampling and three patients underwent HSCT during follow-up. Seven adults with CHH had normal blood counts and no severe immune phenotypes despite other clinical manifestations of CHH. Matched skin fibroblast samples were available for five CHH adults in the cohort for whom we performed tumor-normal variant calling. For the remaining cases, variant calling was based on tumor-only samples and stringent filtering to exclude germline variants. Additionally, we queried the FINRISK dataset, a Finnish cohort comprising WES and SNP microarray data from 10 129 participants, for the presence of CHH associated RMRP variants and evaluated their association with clonal hematopoiesis of indeterminate potential (CHIP) and mosaic chromosomal alterations (mCAs). Results: The median WES coverage of the bone marrow samples was 445x (347-505). Eleven out of 12 patients were homozygous for the RMRP founder variant n.71A>G and one patient was compound heterozygous for two pathogenic RMRP variants. We observed no somatic reversion of the germline RMRP variants. Two pediatric patients had variants in the CHIP genes: CHH1 (age 13 years) with TP53 hotspot variant R175C (variant allele frequency, VAF 0.006) and CHH2 (age 4 years) with BCORL1 P1681Qfs*20 (VAF 0.025). One fifty-year-old patient had a DNMT3A splicing variant c.1555-1G>C (VAF 0.022), likely consistent with CHIP observed in older general population. To identify clonal hematopoiesis outside the classical CHIP genes, we performed conservative filtering of the remaining somatic variant calls, resulting in a list of 36 high-confidence coding variants (VAF >0.02). These variants were present in 10 out of 12 patients; no recurrent genetic alterations were observed. Finally, the analysis of the FINRISK dataset revealed eleven participants with RMRP disease-associated variants; each participant had one heterozygous RMRP variant. No enrichment of CHIP variants or mCAs were observed in carriers of RMRP variants. Conclusion: We observed TP53 and BCORL1 mutations in the bone marrow samples of pediatric patients with CHH. In comparison to other CHIP-associated conditions, BCORL1 variants are disproportionately represented in immune-mediated aplastic anemia, potentially suggestive of similar immune-mediated origin of hypoplastic anemia in CHH. TP53 mutations are abundant in inherited BMF syndromes; however and in contrast to classical inherited BMF syndromes, CHH is not associated with increased risk of myeloid malignancies. No enrichment of classical or non-classical clonal hematopoiesis mutations were observed in adults with clinical CHH diagnosis or in RMRP variant carriers in the population-level FINRISK cohort. This is consistent with transient selection pressure on hematopoietic stem cells in childhood CHH. To our knowledge, our study is the first attempt to characterize the spectrum of clonal hematopoiesis in CHH.

BackgroundAdolescents with chronic diseases are shown to be vulnerable for risky sexual behavior. Childhood cancer patients seem to engage in risky health behaviors as frequently as general population, but little is known about sexual issues in this group of patients.Material and methodsWe characterized the risk for sexually transmitted diseases (STD) in a Finnish population-based cohort of over 6,000 childhood cancer patients diagnosed with cancer under the age of 20 years between 1971 and 2009, compared with over 30,000 age- and sex -matched population comparisons. The data were constructed through linkage between national cancer, population, infectious diseases, and hospital discharge registries. We estimated hazard ratios (HRs) with 95% confidence intervals (CIs) using Cox regression modeling with attained age as the underlying time scale.ResultsChildhood cancer patients had a decreased risk for having an infection with chlamydia, the most common STD in our cohort, when comparing with population comparisons (HR 0.77, 95% CI 0.69-0.86). The risk was lowest among male patients (HR 0.64, 95% CI 0.53-0.79) and patients with central nervous system (CNS) tumors (HR 0.46, 95% CI 0.33-0.63). The overall risk for cervical dysplasia was slightly increased among female cancer patients when compared with their population comparisons (HR 1.28, 95% CI 1.02-1.60). Greatest risk elevation was found among patients diagnosed with cancer in ages 10-14 years (HR 2.31, 95% CI 1.46-3.65) and patients with lymphoma (HR 1.95, 95% CI 1.20-3.16). The risk for all explored outcomes seemed to be decreased among patients with CNS tumors.ConclusionsOur findings highlight the importance of integrating sexual issues as a part of psychosocial support and having a systematic transition program in the follow-up care of childhood cancer patients.

Central nervous system (CNS) toxicity is common at diagnosis and during treatment of pediatric acute lymphoblastic leukemia (ALL). We studied CNS toxicity in 1,464 children aged 1.0–17.9 years, diagnosed with ALL and treated according to the Nordic Society of Pediatric Hematology and Oncology ALL2008 protocol. Genome-wide association studies, and a candidate single-nucleotide polymorphism (SNP; n=19) study were performed in 1,166 patients. Findings were validated in an independent Australian cohort of children with ALL (n=797) in whom two phenotypes were evaluated: diverse CNS toxicities (n=103) and methotrexate-related CNS toxicity (n=48). In total, 135/1,464 (9.2%) patients experienced CNS toxicity for a cumulative incidence of 8.7% (95% confidence interval: 7.31–10.20) at 12 months from diagnosis. Patients aged ≥10 years had a higher risk of CNS toxicity than had younger patients (16.3% vs. 7.4%; P<0.001). The most common CNS toxicities were posterior reversible encephalopathy syndrome (n=52, 43 with seizures), sinus venous thrombosis (n=28, 9 with seizures), and isolated seizures (n=16). The most significant SNP identified by the genome-wide association studies did not reach genomic significance (lowest P-value: 1.11x10-6), but several were annotated in genes regulating neuronal functions. In candidate SNP analysis, ATXN1 rs68082256, related to epilepsy, was associated with seizures in patients <10 years (P=0.01). ATXN1 rs68082256 was validated in the Australian cohort with diverse CNS toxicities (P=0.04). The role of ATXN1 as well as the novel SNP in neurotoxicity in pediatric ALL should be further explored.