Gut microbiota diversity before allogeneic hematopoietic stem cell transplantation as a predictor of mortality in children.

The correlation existing between gut microbiota diversity and survival after allogeneic hematopoietic stem cell transplantation (allo-HSCT) has so far been studied in adults. Pediatric studies question whether this association applies to children as well. Stool samples from a multicenter cohort of 90 pediatric allo-HSCT recipients were analyzed using 16S ribosomal RNA amplicon sequencing to profile the gut microbiota and estimate diversity with the Shannon index. A global-to-local networking approach was used to characterize the ecological structure of the gut microbiota. Patients were stratified into higher- and lower-diversity groups at 2 time points: before transplantation and at neutrophil engraftment. The higher-diversity group before transplantation exhibited a higher probability of overall survival (88.9% ± 5.7% standard error [SE] vs 62.7% ± 8.2% SE; P = .011) and lower incidence of grade 2 to 4 and grade 3 to 4 acute graft-versus-host disease (aGVHD). No significant difference in relapse-free survival was observed between the 2 groups (80.0% ± 6.0% SE vs 55.4% ± 10.8% SE; P = .091). The higher-diversity group was characterized by higher relative abundances of potentially health-related microbial families, such as Ruminococcaceae and Oscillospiraceae. In contrast, the lower-diversity group showed an overabundance of Enterococcaceae and Enterobacteriaceae. Network analysis detected short-chain fatty acid producers, such as Blautia, Faecalibacterium, Roseburia, and Bacteroides, as keystones in the higher-diversity group. Enterococcus, Escherichia-Shigella, and Enterobacter were instead the keystones detected in the lower-diversity group. These results indicate that gut microbiota diversity and composition before transplantation correlate with survival and with the likelihood of developing aGVHD.

Development and Initial Validation of the ONCOREUM Score to Differentiate Childhood Cancer with Arthropathy from Juvenile Idiopathic Arthritis.

OBJECTIVE: To develop and validate a weighted score, the ONCOREUM score, that aids physicians in differentiation of cancer with arthropathy from juvenile idiopathic arthritis (JIA). STUDY DESIGN: Data were extracted from the ONCOREUM Study, a multicenter, cross-sectional investigation aimed at comparing children with cancer and arthropathy to children with JIA. Three statistical approaches were applied to develop the ONCOREUM score and assess the role of each variable in the diagnosis of cancer with arthropathy, including 2 approaches based on multivariable stepwise selection (models 1 and 2) and 1 approach on a Bayesian model averaging method (model 3). The ß coefficients estimated in the models were used to assign score points. Considering that not missing a child with cancer is a mandatory clinical objective, discriminating performance was assessed by fixing sensitivity at 100%. Score performance was evaluated in both developmental and validation samples (representing 80% and 20% of the study population, respectively). RESULTS: Patients with cancer and arthropathy (49 with solid tumors and 46 with hematologic malignancies without peripheral blasts) and 677 patients with JIA were included. The highest area under the receiver operating characteristic (ROC) curve (AUC) in the validation data set was yielded by model 1, which was selected to constitute the ONCOREUM score. The score ranged from -18 to 21.8, and the optimal cutoff obtained through ROC analysis was -6. The sensitivity, specificity, and AUC of the cutoff in the validation sample were 100%, 70%, and 0.85, respectively. CONCLUSIONS: The ONCOREUM score is a powerful and easily applicable tool that may facilitate early differentiation of malignancies with articular complaints from JIA.

Real-World Comparison of Isavuconazole and Voriconazole in Terms of the Need for Dosage Adjustments Guided by Clinical Pharmacological Advice During Primary Prophylaxis of Invasive Fungal Infections in Pediatric Patients with Hemato-Oncological Malignancies.

BACKGROUND: Limited evidence concerning optimal azole dosing regimens currently exists for antifungal prophylaxis in hemato-oncological pediatric patients. METHODS: Hemato-oncological children receiving intravenous or oral isavuconazole or voriconazole for primary antifungal prophylaxis at IRCCS Azienda Ospedaliero-Universitaria of Bologna during November 2020 to October 2021 and undergoing CPA programs based on real-time therapeutic drug monitoring (TDM) were retrospectively analyzed. CPAs for isavuconazole and voriconazole and the number of dosage adjustments were collected. Normalized trough concentrations [(C min )/dose/kg] were calculated for both drugs at each TDM assessment, and the coefficient of variation was determined. The efficacy and safety of the drugs were evaluated. RESULTS: Sixteen hemato-oncological pediatric patients received azole prophylaxis (mean age and weight: 9.1 ± 4.9 years and 32.6 ± 16.0 kg; 6 isavuconazole and 10 voriconazole). Sixty and 89 CPAs were delivered as isavuconazole and voriconazole, respectively. Dosage adjustments were needed in 3.3% of cases for isavuconazole and 53.9% of cases for voriconazole ( P < 0.001). At first TDM, achievement of the desired target during standard dosing regimens was higher for isavuconazole (83.3%) than for voriconazole (10.0%; P = 0.008). Dispersion of normalized concentrations was higher for voriconazole (CV = 139.1% vs. CV = 79.4%). Elevation of ALT and aspartate aminotransferase levels between baseline and the third month was higher in patients receiving voriconazole (median, 28 vs. 90 U/L; P = 0.038, and 19 vs. 65.5 U/L; P = 0.002). CONCLUSIONS: Our findings suggest that there is limited variability in isavuconazole exposure in hemato-oncological pediatric patients receiving azole prophylaxis , resulting in a low need for CPA-guided dosage adjustments.

Refractory immune thrombocytopenia successfully treated with bortezomib in a child with 22q11.2 deletion syndrome, complicated by Evans syndrome and hypogammaglobulinemia.

Treatment of refractory autoimmune cytopenias (AICs) and Evans syndrome (ES) represent a great challenge in pediatric setting, where an underlying primary immunodeficiency is recurrent. Frequently, second or third line treatments are employed, with an increased risk of toxicity and infections. The advent of novel drugs is the object of research in order to modify the management of these patients.We report a case of successful use of bortezomib in a child with 22q11.2 deletion syndrome and CVID-like phenotype with a multi-refractory severe ES. Last flares were prolonged and dominated by severe and symptomatic ITP, refractory to different courses of high dose steroid and IVIG, mofetil mycophenolate, thrombopoietin receptor agonists, sirolimus, and rituximab. Persistence of AICs in subjects with depletion of CD20 + B-cells and IgG strengthens the hypothesis about the production of autoantibodies by terminally differentiated plasma-cells, not targetable from immunosuppressants and rituximab.In the attempt to enhance plasma-cells inhibition, the child was addressed to bortezomib, with a good response at 6 month follow-up without side effects. Nowadays, the use of bortezomib in ES/AICs is based only on small retrospective studies and case reports. Despite the lack of long term follow-up, our work highlights the potential role of bortezomib in the management of pediatric patients with multi-resistant AICs secondary to immune-system impairment.

Clinical utility of measuring Epstein-Barr virus-specific cell-mediated immunity after HSCT in addition to virological monitoring: results from a prospective study.

Lack of virus-specific cell-mediated immunity (CMI) is associated with worse viral infection outcome in hematopoietic stem cell transplantation (HSCT). We aimed to evaluate the role of immunological monitoring of Epstein-Barr virus (EBV) infection in addition to virological one in 33 adult and 18 pediatric allogeneic HSCT recipients. Virological monitoring of infection was performed on whole blood samples by a quantitative real-time PCR assay. Immunological monitoring was performed by Enzyme-linked ImmunoSPOT assay, evaluating EBV-specific CMI, at fixed time-points and when EBV DNAemia was ≥ 10,000 copies/mL. Fifty-one percent of patients developed a post-transplant EBV infection and reduced-intensity conditioning regimen was the only factor associated to infection (P = 0.023). Lack of EBV-specific CMI during active EBV infection was associated with a greater severity of infection. Patients without EBV-specific CMI showed higher median peak level of EBV DNAemia than patients with EBV-specific CMI (P = 0.014), and consequently received more frequently, at EBV DNAemia peak, anti-CD20 therapy (0 versus 54.5%, P = 0.002). No patients with EBV-specific CMI versus 27.2% without EBV-specific CMI developed EBV-related complications (P = 0.063), including two lethal EBV-related post-transplant lymphoproliferative disorders. Combined immunological and virological measurements could improve EBV infection management in HSCT, anticipating the beginning of preemptive treatment from the EBV DNAemia peak to the finding of the lack of EBV-specific CMI.

A New Formulation of an Old Drug: A Potential New Therapy in the Management of Oral cGvHD.

Oral chronic graft versus host disease (cGVHD) is often refractory to systemic therapies. Additional topical treatment is commonly required. The potency of the agent, the vehicle and formulation in which it is delivered are all critical factors in determining the effectiveness of topical therapies. High potency of budesonide, combined with its very low bioavailability when absorbed through mucosal surfaces, increased the potential role in topical application for oral cGVHD. Viscous formulation increases mucosal contact time resulting in a greater decrease in mucosal inflammation. This short communication suggests that oral viscous budesonide should be considered as a potential new therapy in the management of oral cGVHD.

Spleen nodules: a potential hallmark of Visceral Leishmaniasis in young children.

BACKGROUND: Visceral leishmaniasis (VL) is a severe disease caused by Leishmania infantum in the Mediterranean basin, and is associated with considerable morbidity and mortality. Infantile VL may begin suddenly, with high fever and vomiting, or insidiously, with irregular daily fever, anorexia, and marked splenomegaly. Delays in diagnosis of VL are common, highlighting the need for increased awareness of clinicians for VL in endemic European countries. CASE PRESENTATION: We report 4 cases of young children in northern Italy presenting with persistent fever of unknown origin and diagnosed with VL by serological and molecular methods. At the time of diagnosis, these patients showed an unusual echographic pattern characterized by multiple iso-hypoechoic nodules associated with splenomegaly. CONCLUSION: We suggest that detection of spleen nodules represents a signature of VL in infants, thus helping to diagnose systemic Leishmania infantum infection in children.

Ruxolitinib for the treatment of acute and chronic graft-versus-host disease in children: a systematic review and individual patient data meta-analysis.

Steroid-refractory graft-versus-host disease (SR-GvHD) represents a major complication of pediatric allogenic hematopoietic stem cell transplantation. Ruxolitinib, a selective JAK 1-2 inhibitor, showed promising results in the treatment of SR-GvHD in adult trial, including patients >12 years old. This systematic review aims to evaluate ruxolitinib use for SR-GvHD in the pediatric population. Among the 12 studies included, ruxolitinib administration presented slight differences. Overall response rate (ORR) ranged from 45% to 100% in both acute and chronic GvHD. Complete response rates (CR) varied from 9% to 67% and from 0% to 28% in aGvHD and cGvHD, respectively. Individual-patient meta-analysis from 108 children under 12 years showed an ORR and CR for aGvHD of 74% and 56%, respectively, while in cGvHD ORR was 78% but with only 11% achieving CR. Treatment-related toxicities were observed in 20% of patients, including cytopenia, liver toxicity, and infections. Age, weight, graft source, previous lines of therapy, and dose did not significantly predict response, while a higher rate of toxicities was observed in aGvHD patients. In conclusion, ruxolitinib shows promising results in the treatment of SR-GvHD in children, including those under 12 years. Specific pediatric perspective trials are currently ongoing to definitely assess its efficacy and safety.

Healthcare migration in Italian paediatric haematology-oncology centres belonging to AIEOP.

BACKGROUND: In Italy, there is a network of centres headed by the Italian Association of Pediatric Hematology and Oncology (AIEOP) for the diagnosis and treatment of paediatric cancers on almost the entire national territory. Nevertheless, migration of patients in a hospital located in a region different from that of residence is a widespread habit, sometimes motivated by several reasons. The aim of this paper is to assess the impact of migration of children with cancer to AIEOP centres in order to verify their optimal distribution throughout the national territory. METHODS: To this purpose, we used information on 41,205 registered cancer cases in the database of Mod.1.01 Registry from AIEOP centres, with age of less than 20 years old at diagnosis, diagnosed from 1988 to 2017. Patients' characteristics were analysed and compared using the X2 or Fisher's exact test or Mann-Whitney test, when appropriate. Survival distributions were estimated using the method of Kaplan and Meier, and the log-rank test was used to examine differences among subgroups. RESULTS: Extra-regional migration involved overall 19.5% of cases, ranging from 23.3% (1988-1997) to 16.4% (2008-2017) (p < 0.001). In leukaemias and lymphomas we observed a mean migration of 8.8% overall, lower in the North (1.2%) and Centre (7.8%) compared to the South & Isles (32.3%). In the case of solid tumours, overall migration was 25.7%, with 4.2% in the North, 17.2% in the Centre and 59.6% in the South & Isles. For regions with overall levels of migration higher than the national average, most migration cases opted for AIEOP centres of close or even neighbouring regions. Overall survival at 10 years from diagnosis results 69.9% in migrants vs 78.3% in no migrants (p < 0.001). CONCLUSIONS: There is still a certain amount of domestic migration, the causes of which can be easily identified: migration motivated by a search for high specialization, migration due to lack of local facilities, or regions in which no AIEOP centres are present, which makes migration obligatory. Better coordination between AIEOP centres could help to reduce so-called avoidable migration, but technical and political choices will have to be considered, with the active participation of sector technicians.

The role of presepsin in pediatric patients with oncological and hematological diseases experiencing febrile neutropenia.

Febrile neutropenia (FN) represents one of the main complications of pediatric patients with oncological and hematological diseases. In these patients, it is crucial to identify bacterial infections. The aim of this study is to evaluate presepsin as an early biomarker of bacterial infections during FN. We compared patients with oncological and hematological diseases and a 2:1 age-matched healthy control group. In the FN group, we evaluated 4 biomarkers, namely, C reactive protein (CRP), procalcitonin (PCT), interleukin 6 (IL6) and presepsin at the onset of fever (T0) and 48 h after T0 (T1). In the control group, we only evaluated presepsin. We enrolled a total of 41 children with oncological and hematological diseases disease experiencing 50 FN episodes and 100 healthy patients in the control group. In patients with FN, we found that presepsin was significantly higher than in the control group (p < 0.001). However, in the FN group, we did not find a statistically significant difference between patients with and without bacteremia (p = 0.989 at T0, p = 0.619 at T1). Presepsin values at T1 were higher in patients experiencing an unfavorable outcome (p = 0.025). This study shows that presepsin increases in neutropenic patients, but it only revealed useful in predicting an unfavorable outcome 48 h from the onset of fever.

Treatment of steroid-refractory graft versus host disease in children.

Systemic steroids are still the first-line approach in acute graft-versus-host disease (aGvHD), and the backbone of chronic GvHD management. Refractoriness to steroid represent a major cause of morbidity and non-relapse mortality after hematopoietic stem cell transplantation (HSCT). In both backgrounds, several second-line immunosuppressive agents have been tested with variable results in terms of efficacy and toxicity. Solid evidence regarding these approaches is still lacking in the pediatric setting where results are mainly derived from adult experiences. Furthermore, the number of treated patients is limited and the incidence of acute and chronic GvHD is lower, resulting in a very heterogeneous approach to this complication by pediatric hematologists. Some conventional therapies and anti-cytokine monoclonal antibodies used in the adult setting have been evaluated in children. In recent years, the increasing understanding of the biological mechanisms underpinning the pathogenesis of GvHD justified the efforts toward the adoption of targeted therapies and non-pharmacologic approaches, with higher response rates and lower immunosuppressive effects. Moreover, many questions regarding the precise timing and setting in which to integrate these new approaches remain unanswered. This Review aims to critically explore the current evidence regarding novel approaches to treat SR-GvHD in pediatric HSCT recipients.

Levofloxacin prophylaxis and parenteral nutrition have a detrimental effect on intestinal microbial networks in pediatric patients undergoing HSCT.

The gut microbiome (GM) has shown to influence hematopoietic stem cell transplantation (HSCT) outcome. Evidence on levofloxacin (LVX) prophylaxis usefulness before HSCT in pediatric patients is controversial and its impact on GM is poorly characterized. Post-HSCT parenteral nutrition (PN) is oftentimes the first-line nutritional support in the neutropenic phase, despite the emerging benefits of enteral nutrition (EN). In this exploratory work, we used a global-to-local networking approach to obtain a high-resolution longitudinal characterization of the GM in 30 pediatric HSCT patients receiving PN combined with LVX prophylaxis or PN alone or EN alone. By evaluating the network topology, we found that PN, especially preceded by LVX prophylaxis, resulted in a detrimental effect over the GM, with low modularity, poor cohesion, a shift in keystone species and the emergence of modules comprising several pathobionts, such as Klebsiella spp., [Ruminococcus] gnavus, Flavonifractor plautii and Enterococcus faecium. Our pilot findings on LVX prophylaxis and PN-related disruption of GM networks should be considered in patient management, to possibly facilitate prompt recovery/maintenance of a healthy and well-wired GM. However, the impact of LVX prophylaxis and nutritional support on short- to long-term post-HSCT clinical outcomes has yet to be elucidated.

Effectiveness of Quinolone Prophylaxis in Pediatric Acute Leukemia and Hematopoietic Stem Cell Transplantation: A Systematic Review and Meta-analysis.

The effectiveness of quinolone prophylaxis in high-risk hematological pediatric patients is controversial. A systematic review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, including studies that involved children and young adults undergoing chemotherapy for acute leukemia or hematopoietic stem cell transplantation (HSCT) who received quinolone prophylaxis compared with no prophylaxis. A meta-analysis was performed on bloodstream infections and neutropenic fever. Data regarding the impact of prophylaxis on overall survival, antibiotic exposure, antibiotic-related adverse effects, antibiotic resistance, Clostridium difficile infections, fungal infections, length of hospitalization, and costs were reviewed in the descriptive analysis. Sixteen studies were included in the qualitative analysis, and 10 of them met the criteria for quantitative analysis. Quinolone prophylaxis was effective in reducing the rate of bloodstream infections and neutropenic fever in pediatric acute leukemia compared with no prophylaxis, but it had no significant effect in HSCT recipients. Prophylaxis was associated with a higher rate of bacterial resistance to fluoroquinolones and higher antibiotic exposure.

Antimicrobial Stewardship Interventions in Pediatric Oncology: A Systematic Review.

Antimicrobial stewardship programs represent efficacious measures for reducing antibiotic overuse and improving outcomes in different settings. Specific data on pediatric oncology are lacking. We conducted a systematic review on the PubMed and Trip databases according to the PRISMA guidelines, searching for reports regarding antimicrobial stewardship in pediatric oncology and hematology patients. The aim of the study was to summarize the present literature regarding the implementation of antimicrobial stewardship programs or initiatives in this particular population, and provide insights for future investigations. Nine papers were included in the qualitative analysis: three regarding antifungal interventions, five regarding antibacterial interventions, and one regarding both antifungal and antibacterial stewardship interventions. Variable strategies were reported among the included studies. Different parameters were used to evaluate the impact of these interventions, including days of therapy per 1000-patient-days, infections with resistant strains, safety analysis, and costs. We generally observed a reduction in the prescription of broad-spectrum antibiotics and an improved appropriateness, with reduced antibiotic-related side effects and no difference in infection-related mortality. Antibiotic stewardship programs or interventions are effective in reducing antibiotic consumption and improving outcomes in pediatric oncology hematology settings, although stewardship strategies differ substantially in different institutions. A standardized approach needs to be implemented in future studies in order to better elucidate the impact of stewardship programs in this category of patients.

In-Depth Immunological Typization of Children with Sickle Cell Disease: A Preliminary Insight into Its Plausible Correlation with Clinical Course and Hydroxyurea Therapy.

Sickle cell disease (SCD) is a condition of functional hypo-/a-splenism in which predisposition to bacterial infections is only a facet of a wide spectrum of immune-dysregulation disorders forming the clinical expression of a peculiar immunophenotype. The objective of this study was to perform an in-depth immunophenotypical characterization of SCD pediatric patients, looking for plausible correlations between immunological biomarkers, the impact of hydroxyurea (HU) treatment and clinical course. This was an observational case−control study including 43 patients. The cohort was divided into two main groups, SCD subjects (19/43) and controls (24/43), differing in the presence/absence of an SCD diagnosis. The SCD group was split up into HU+ (12/19) and HU− (7/19) subgroups, respectively receiving or not a concomitant HU treatment. The principal outcomes measured were differences in the immunophenotyping between SCD patients and controls through chi-squared tests, t-tests, and Pearson's correlation analysis between clinical and immunological parameters. Leukocyte and neutrophil increase, T-cell depletion with prevalence of memory T-cell compartment, NK and B-naïve subset elevation with memory and CD21low B subset reduction, and IgG expansion, significantly distinguished the SCD HU− subgroup from controls, with naïve T cells, switched-memory B cells and IgG maintaining differences between the SCD HU+ group and controls (p-value of <0.05). The mean CD4+ central-memory T-cell% count was the single independent variable showing a positive correlation with vaso-occlusive crisis score in the SCD group (Pearson's R = 0.039). We report preliminary data assessing plausible clinical implications of baseline and HU-related SCD immunophenotypical alterations, which need to be validated in larger samples, but potentially affecting hypo-/a-splenism immuno-chemoprophylactic recommendations.

Febrile Neutropenia Duration Is Associated with the Severity of Gut Microbiota Dysbiosis in Pediatric Allogeneic Hematopoietic Stem Cell Transplantation Recipients.

Febrile neutropenia (FN) is a common complication in pediatric patients receiving allogeneic hematopoietic stem cell transplantation (HSCT). Frequently, a precise cause cannot be identified, and many factors can contribute to its genesis. Gut microbiota (GM) has been recently linked to many transplant-related complications, and may also play a role in the pathogenesis of FN. Here, we conducted a longitudinal study in pediatric patients receiving HSCT from three centers in Europe profiling their GM during the transplant course, particularly at FN onset. We found that a more stable GM configuration over time is associated with a shorter duration of fever. Moreover, patients with longer lasting fever exhibited higher pre-HSCT levels of Collinsella, Megasphaera, Prevotella and Roseburia and increased proportions of Eggerthella and Akkermansia at the engraftment. These results suggest a possible association of the GM with the genesis and course of FN. Data seem consistent with previous reports on the relationship of a so-called "healthy" GM and the reduction of transplant complications. To our knowledge, this is the first report in the pediatric HSCT setting. Future studies are warranted to define the underling biological mechanisms and possible clinical implications.

Off-Label Use of Letermovir as Preemptive Anti-Cytomegalovirus Therapy in a Pediatric Allogeneic Peripheral Blood Stem Cell Transplant.

Despite the effectiveness of the currently available antiviral drugs in treating cytomegalovirus (CMV) infection, high rates of adverse effects are associated with their use. Moreover, a problem of increasing importance is the emergence of drug-resistant CMV infection. Here, we describe the first case of off-label use of letermovir (LMV) as preemptive antiviral therapy, in a pediatric allogeneic peripheral blood stem cell transplant recipient with ganciclovir-resistant CMV infection who was intolerant to foscarnet and unable to achieve viral clearance after seven doses of cidofovir. After the administration of LMV, a gradual reduction in viral load was observed and within 6 weeks of LMV treatment, after more than 6 months of positive CMV-DNAemia, the patient cleared the infection. No adverse effects associated with LMV were observed during treatment. In this pediatric study case, the off-label use of LMV for the treatment of CMV infection has been well tolerated and proved to be effective in leading to the suppression of viral replication.

Musculoskeletal manifestations of childhood cancer and differential diagnosis with juvenile idiopathic arthritis (ONCOREUM): a multicentre, cross-sectional study.

BACKGROUND: Presenting symptoms of childhood cancers might mimic those of rheumatic diseases. However, the evidence available to guide differential diagnosis remains scarce. Preventing wrong or delayed diagnosis is therefore important to avoid incorrect administration of glucocorticoid or immunosuppressive therapy and worsening of prognosis. As such, we aimed to assess the prevalence and characteristics of presenting musculoskeletal manifestations in patients at cancer onset and to identify the factors that differentiate childhood malignancies with arthropathy from juvenile idiopathic arthritis. METHODS: We did a multicentre, cross-sectional study at 25 paediatric haemato-oncology centres and 22 paediatric rheumatology centres in Italy. We prospectively recruited patients who were younger than 16 years that were newly diagnosed with cancer or juvenile idiopathic arthritis. We excluded patients with glucocorticoid pre-treatment (>1 mg/kg per day of oral prednisone or equivalent for ≥2 consecutive weeks). We collected data for patients with a new diagnosis of cancer or juvenile idiopathic arthritis using an electronic case report form on a web-based platform powered by the Cineca Interuniversity Consortium. The primary outcome was to describe the frequency and characteristics of musculoskeletal manifestations at cancer onset; and the secondary outcome was to identify factors that could discriminate malignancies presenting with arthropathy, with or without other musculoskeletal symptoms, from juvenile idiopathic arthritis using multivariable logistic regression analysis. FINDINGS: Between May 1, 2015, and May 31, 2018, 1957 patients were eligible, of which 1277 (65%) had cancer and 680 (35%) had juvenile idiopathic arthritis. Musculoskeletal symptoms occurred in 324 (25% [95% CI 23·0-27·8]) of 1277 patients with cancer, of whom 207 had arthropathy. Patients with malignant bone tumours had the highest frequency of musculoskeletal symptoms (53 [80%] of 66), followed by patients with Langerhans histiocytosis (16 [47%] of 34), leukaemia (189 [32%] of 582), soft-tissue sarcomas (16 [24%] of 68), and neuroblastoma (21 [19%] of 109). In the 324 patients with cancer and musculoskeletal symptoms, the most common complaints were joint pain (199 [61%]), followed by limb bone pain (112 [35%]). Joint involvement had a prevalent monoarticular pattern (100 [48%] of 207) and oligoarticular pattern (86 [42%] had 2-4 joints involved and 20 [10%] had >4 joints involved), with the most frequently involved joints being the hip (88 [43%] of 207) and knee (81 [39%]). On multivariable analysis, limb bone pain was the independent variable most strongly associated with cancer (odds ratio [OR] 87·80 [95% CI 18·89-408·12]), followed by weight loss (59·88 [6·34-565·53]), thrombocytopenia (12·67 [2·40-66·92]), monoarticular involvement (11·30 [4·09-31·19]), hip involvement (3·30 [1·13-9·61]), and male sex (2·40 [1·03-5·58]). Factors independently associated with juvenile idiopathic arthritis were morning stiffness (OR 0·04 [95% CI 0·01-0·20]), joint swelling (0·03 [0·01-0·09]), and involvement of the small hand joints (0·02 [0-1·05]). INTERPRETATION: Our study provides detailed information about presenting musculoskeletal manifestations of childhood cancers and highlights the clinical and laboratory features that are most helpful in the differential diagnosis with juvenile idiopathic arthritis. FUNDING: Associazione Lorenzo Risolo.

Genomic complexity and dynamics of clonal evolution in childhood acute myeloid leukemia studied with whole-exome sequencing.

Despite significant improvement in treatment of childhood acute myeloid leukemia (AML), 30% of patients experience disease recurrence, which is still the major cause of treatment failure and death in these patients. To investigate molecular mechanisms underlying relapse, we performed whole-exome sequencing of diagnosis-relapse pairs and matched remission samples from 4 pediatric AML patients without recurrent cytogenetic alterations. Candidate driver mutations were selected for targeted deep sequencing at high coverage, suitable to detect small subclones (0.12%). BiCEBPα mutation was found to be stable and highly penetrant, representing a separate biological and clinical entity, unlike WT1 mutations, which were extremely unstable. Among the mutational patterns underlying relapse, we detected the acquisition of proliferative advantage by signaling activation (PTPN11 and FLT3-TKD mutations) and the increased resistance to apoptosis (hyperactivation of TYK2). We also found a previously undescribed feature of AML, consisting of a hypermutator phenotype caused by SETD2 inactivation. The consequent accumulation of new mutations promotes the adaptability of the leukemia, contributing to clonal selection. We report a novel ASXL3 mutation characterizing a very small subclone (<1%) present at diagnosis and undergoing expansion (60%) at relapse. Taken together, these findings provide molecular clues for designing optimal therapeutic strategies, in terms of target selection, adequate schedule design and reliable response-monitoring techniques.