The application of a multidisciplinary approach in the diagnosis of Castleman disease and Castleman-like lymphadenopathies: A 20-year retrospective analysis of clinical and pathological features

BACKGROUND

Castleman disease (CD) comprises a group of rare and heterogeneous haematological disorders, including unicentric (UCD) and multicentric (MCD) forms, the latter further subdivided into HHV8-MCD, POEMS-MCD and idiopathic-MCD (iMCD). However, according to the Castleman Disease Collaborative Network guidelines, the diagnosis of CD can only be achieved through collaboration between clinicians and pathologists.

METHODS

We applied these clinical and pathological criteria and implement with clonality testing to a retrospective cohort of 48 adult and paediatric Italian patients diagnosed with reactive lymphadenitis with CD-like histological features.

RESULTS

We confirmed the diagnosis of CD in 60% (29/48) of the cases, including 12 (41%) UCD and 17 (59%; five HHV8-MCD, three POEMS-MCD and nine iMCD) MCD. Of the remaining 19 cases (40%) with multiple lymphadenopathy, 5 (26%) were classified as autoimmune diseases, 1 (5%) as autoimmune lymphoproliferative disorder, 1 (5%) as IgG4-related disease, 11 (83%) as reactive lymphadenitis and 1 (5%) as nodal marginal zone lymphoma.

CONCLUSIONS

Our study emphasizes the importance of the multidisciplinary approach to reactive lymphadenitis with CD-like features in order to achieve a definitive diagnosis and choose the appropriate treatment.

Identification of a robust DNA methylation signature for Fanconi anemia

Fanconi anemia (FA) is a clinically variable and genetically heterogeneous cancer-predisposing disorder representing the most common bone marrow failure syndrome. It is caused by inactivating predominantly biallelic mutations involving >20 genes encoding proteins with roles in the FA/BRCA DNA repair pathway. Molecular diagnosis of FA is challenging due to the wide spectrum of the contributing gene mutations and structural rearrangements. The assessment of chromosomal fragility after exposure to DNA cross-linking agents is generally required to definitively confirm diagnosis. We assessed peripheral blood genome-wide DNA methylation (DNAm) profiles in 25 subjects with molecularly confirmed clinical diagnosis of FA (FANCA complementation group) using Illumina's Infinium EPIC array. We identified 82 differentially methylated CpG sites that allow to distinguish subjects with FA from healthy individuals and subjects with other genetic disorders, defining an FA-specific DNAm signature. The episignature was validated using a second cohort of subjects with FA involving different complementation groups, documenting broader genetic sensitivity and demonstrating its specificity using the EpiSign Knowledge Database. The episignature properly classified DNA samples obtained from bone marrow aspirates, demonstrating robustness. Using the selected probes, we trained a machine-learning model able to classify EPIC DNAm profiles in molecularly unsolved cases. Finally, we show that the generated episignature includes CpG sites that do not undergo functional selective pressure, allowing diagnosis of FA in individuals with reverted phenotype due to gene conversion. These findings provide a tool to accelerate diagnostic testing in FA and broaden the clinical utility of DNAm profiling in the diagnostic setting.

Neutralizing IFNγ improves safety without compromising efficacy of CAR-T cell therapy in B-cell malignancies

Chimeric antigen receptor T (CAR-T) cell therapy may achieve long-lasting remission in patients with B-cell malignancies not responding to conventional therapies. However, potentially severe and hard-to-manage side effects, including cytokine release syndrome (CRS), neurotoxicity and macrophage activation syndrome, and the lack of pathophysiological experimental models limit the applicability and development of this form of therapy. Here we present a comprehensive humanized mouse model, by which we show that IFNγ neutralization by the clinically approved monoclonal antibody, emapalumab, mitigates severe toxicity related to CAR-T cell therapy. We demonstrate that emapalumab reduces the pro-inflammatory environment in the model, thus allowing control of severe CRS and preventing brain damage, characterized by multifocal hemorrhages. Importantly, our in vitro and in vivo experiments show that IFNγ inhibition does not affect the ability of CD19-targeting CAR-T (CAR.CD19-T) cells to eradicate CD19+ lymphoma cells. Thus, our study provides evidence that anti-IFNγ treatment might reduce immune related adverse effect without compromising therapeutic success and provides rationale for an emapalumab-CAR.CD19-T cell combination therapy in humans.

Case report: A new pathogenic variant of LRBA deficiency with a complex phenotype and Rosai-Dorfman disease

We reported a new pathogenic variant of LRBA deficiency with a complex phenotype-neonatal diabetes, very early-onset inflammatory bowel disease, and polyarthritis-who presented with lymph node enlargement. A case of Rosai-Dorfman's disease (RDD) was confirmed. The occurrence of an RDD lesion in LRBA-deficiency has never been reported so far.

LncOb rs10487505 variant is associated with leptin levels in pediatric non-alcoholic fatty liver disease

BACKGROUND

Low and high leptin levels are associated with non-alcoholic fatty liver disease (NAFLD). The LncOb rs10487505 variant has been associated with body mass index (BMI), and the C allele was reported as leptin-lowering. We evaluated the association of rs10487505 with leptin levels, liver histology, and surgery-induced weight loss in youths with NAFLD.

METHODS

One-hundred five obese youths with NAFLD, of whom 19 undergoing laparoscopic sleeve gastrectomy (LSG), were analyzed for rs10487505 and leptin circulating levels.

RESULTS

The G allele frequency was lower in youths with NAFLD than in controls (p = 0.049). No difference was found in anthropometrics, biochemistry and histology between G allele carriers and CC homozygotes, except for leptin levels (p = 0.016). Leptin correlated with body weight, BMI, BMI-z score, waist circumference, insulin resistance/sensitivity, and triglycerides (p ≤ 0.01). A multivariable regression model including body weight and homeostasis model assessment of insulin resistance was a good predictor of plasma leptin (R² = 0.45), and the addition of genotype to the model increased the R² to 0.50. Following LSG, leptin levels and body weight were more reduced in G allele carriers (p < 0.05).

CONCLUSIONS

LncOb rs10487505 variant was associated with pediatric NAFLD and high leptin levels, and with weight and leptin reduction after LSG in youths.

IMPACT

The interplay of environment, genetics and epigenetics is crucial inflating the risk of non-alcoholic fatty liver disease (NAFLD). Several long non-coding RNA (LncRNAs) are found associated with NAFLD pathogenesis. Here, we evaluated the impact of the genetic variant rs10487505 in LncOb which is involved in the regulation of leptin gene expression. The LncOb rs10487505 is associated with increased levels of leptin, but not with liver histology, in youths with NAFLD. The LncOb rs10487505 was also associated with the significant decrease of leptin and body weight after bariatric surgery.

A Pediatric Case of High-Grade Secretory Carcinoma of the Maxillary Sinus With ETV6::NTRK3 Gene Fusion, Therapeutic Implications, and Review of the Literature

Secretory carcinoma (SC) is a salivary gland tumor with a generally low grade microscopic appearance, a characteristic immunophenotype, and a recurrent translocation leading to ETV6::NTRK3 fusion gene. Rare cases are reported in children. The maxillary sinus is an unusual localization. SC have an overall favorable prognosis, but cases with high grade morphology have been described in adult population and are related to a more aggressive clinical course. We present a pediatric case of secretory carcinoma involving the maxillary sinus with high grade morphology, with a review of the literature of secretory carcinomas with high grade component.

Common bone marrow signature in COVID-19-associated multisystem inflammatory syndrome in children: A first-wave small case series experience

The hyper-inflammatory response, also known as multisystem inflammatory syndrome in children (MIS-C), represents a major concern in children with SARS-CoV-2 infection. We report bone marrow features of three patients with MIS-C who were diagnosed during the first wave of the SARS-CoV-2 pandemic. A bone marrow evaluation was performed at onset of the inflammatory condition in order to exclude secondary hemophagocytic lymphohistiocytosis (sHLH). The bone marrows of the patients presented common features: the erythroid and megakaryocytic lineages were prominently affected and hemophagocytosis was moderately increased, differently than observed in sHLH. Megakaryocytopoiesis was increased, representing a peculiar feature of MIS-C differing from sHLH. SARS-CoV-2 RT-PCR and viral panel were studied in bone marrow aspiration samples. MIS-C is a rare complication of SARS-CoV-2 infections in children. An immuno-dysregulation considering both innate and adaptive immunity together with vascular inflammation and endothelial dysfunction play a major role. Our observations, although limited due to the small sample size, suggest that there are unique features in the bone marrow of patients with MIS-C that are likely secondary to immuno-dysregulation, and there are notable differences in bone marrow features compared to those reported in sHLH.

Liquid Biopsy with Detection of NRASQ61K Mutation in Cerebrospinal Fluid: An Alternative Tool for the Diagnosis of Primary Pediatric Leptomeningeal Melanoma

Primary leptomeningeal melanoma (PLMM) is a very rare disease in childhood with a poor prognosis. NRAS^Q16K mutation frequently drives malignant transformation in this population, so its evaluation should be considered in childhood PLMM diagnosis. In the presented case, the mutation was detected by Sanger sequencing performed on DNA extracted from cerebrospinal fluid neoplastic cells. Liquid biopsy has been shown to be a safe and reliable technique for the diagnosis of PLMM. Its use can potentially be extended to other neoplasms of the central nervous system bearing well-defined molecular mutations, sparing the patient invasive surgery and finally allowing a more rapid diagnosis and early initiation of targeted therapies.

Prominent Follicular Keratosis in Multiple Intestinal Atresia with Combined Immune Deficiency Caused by a TTC7A Homozygous Mutation

Multiple intestinal atresia with combined immune deficiency (MIA-CID) is an autosomal recessive syndrome due to mutations in the TTC7A gene implicated in the polarization of intestinal and thymic epithelial cells. MIA-CID is lethal in the first year of life in the majority of patients. Dermatological manifestations have been reported in a few cases. We describe a child affected with MIA-CID due to a previously unreported TTC7A homozygous missense mutation. Surgery for bowel occlusion was performed in the first days of life. The patient was totally dependent on parenteral nutrition since birth and presented severe diarrhea and recurrent infections. He underwent hematopoietic stem cell transplantation at 17 months with complete donor engraftment and partial immunity improvement. In the second year of life, he progressively developed diffuse papular follicular keratoses on ichthyosiform skin, nail clubbing, and subungual hyperkeratosis. Histopathology showed hyperkeratosis with follicular plugging and scattered apoptotic keratinocytes, visualized at an ultrastructural examination. Our findings expand the spectrum of dermatological manifestations which can develop in MIA-CID patients. Examination of further patients will allow defining whether keratinocyte apoptosis is also a disease feature.

Brentuximab vedotin in combination with bendamustine in pediatric patients or young adults with relapsed or refractory Hodgkin lymphoma

Although children and young adults with Hodgkin's lymphoma usually have a favorable prognosis, patients with primary refractory disease and some subsets of relapsed patients still have a dismal outcome. Brentuximab vedotin (BV) in combination with bendamustine may represent a suitable salvage therapy; data on 32 patients aged less than 25 years were retrospectively analyzed. Patients received up to six cycles of treatment of BV 1.8 mg/kg on day 1 and bendamustine 90-120 mg/m² on days 2 and 3. At the end of treatment, the overall response rate was 81%. The 3-year overall and progression-free survivals are 78.1% and 67%, respectively.

Higher Levels of Plasma Hyaluronic Acid and N-terminal Propeptide of Type III Procollagen Are Associated With Lower Kidney Function in Children With Non-alcoholic Fatty Liver Disease

OBJECTIVE

Hyaluronic acid (HA) and N-terminal propeptide of type III procollagen (PIIINP) are two non-invasive biomarkers of liver fibrosis in non-alcoholic fatty liver disease (NAFLD). We examined the relationships of plasma levels of HA and PIIINP with kidney function in children with NAFLD.

METHODS

Plasma HA and PIIINP levels were measured using two commercially available enzyme-linked immunosorbent assay kits in a cohort of 106 Caucasian overweight or obese children with biopsy-proven NAFLD. Glomerular filtration rate (eGFR) was estimated using the Bedside Schwartz equation. Genotyping for the patatin-like phospholipase domain-containing protein-3 (PNPLA3) rs738409 variant was performed using an allelic discrimination assay.

RESULTS

Children with fibrosis F2 had significantly higher plasma PIIINP and HA levels than those with F0 or F1 fibrosis. Liver fibrosis was positively associated with plasma HA and PIIINP, as well as with the presence of the risk allele G of PNPLA3 rs738409 variant, and negatively with eGFR. Moreover, eGFR showed significant inverse associations with HA and PIIINP levels, as well as the presence of G of PNPLA3 rs738409, and liver fibrosis stage. Notably, our multivariable regression models showed that higher plasma PIIINP (standardized beta coefficient: -0.206, P = 0.011) and HA levels (standardized beta coefficient: -0.531, P < 0.0001) were associated with lower eGFR values, even after adjustment for age, sex, systolic blood pressure, PNPLA3 rs738409 genotype, and any stage of liver fibrosis.

CONCLUSIONS

Higher levels of HA and PIIINP were associated with lower eGFR values in Caucasian children with biopsy-proven NAFLD, independently of PNPLA3 rs738409 genotype and other potential confounding factors.

Changes in Total Homocysteine and Glutathione Levels After Laparoscopic Sleeve Gastrectomy in Children with Metabolic-Associated Fatty Liver Disease

PURPOSE

Paediatric obesity is a well-known risk factor for metabolic-associated fatty liver disease (MAFLD). The aim of this study was to evaluate the effects of laparoscopic sleeve gastrectomy (LSG) on the levels of total homocysteine (tHcy) and total glutathione (tGSH) plasma levels in children with MAFLD.

MATERIAL AND METHODS

Twenty-four children with severe obesity who underwent LSG were included in the study. The metabolic parameters, systemic inflammatory markers, one-carbon metabolism products, ultrasound and histological improvement were evaluated at baseline (T0M) and after 12 months from LSG (T12M).

RESULTS

The patients exhibited a significant amelioration of several metabolic parameters at T12M. A significant reduction of steatosis was observed at ultrasound (from 72.7% of moderate-severe grade to 0% severe steatosis), accompanied by a statistically significant improvement of ballooning, portal and lobular inflammation and fibrosis. A statistically significant decrease of tumour necrosis factor circulating levels was also observed (T0M median = 290.3, IQR = 281.0-317.0 pg/mL; T12M median = 260.4, IQR = 240.0-279.0 pg/mL; p < 0.0001). After 12 months from LSG, a significant increase of mean plasma levels of tHcy(T0M mean = 15.7 ± 4.1 μmol/L; T12M mean = 21.1 ± 9.3 μmol/L; p = 0.0146) was also observed. The increase of tHcy showed no causal link with the improvement of MAFLD-related inflammatory, metabolic and histological pattern.

CONCLUSION

LSG in children with obesity induces an improvement of MAFLD-related metabolic derangement and liver damage, but also a mild hyperhomocysteinemia that should be avoided to prevent cardiovascular risk.

Stimulation of Treg Cells to Inhibit Osteoclastogenesis in Gorham-Stout Disease

Gorham-Stout disease (GSD) is a very rare syndrome displaying excessive bone erosion and vascular lesion. Due to the rarity of the disease and to the limited studies, its etiopathogenesis is not entirely known. The involvement of immune system in the progressive osteolysis was recently suggested. Indeed, extensive reciprocal interactions between the immune and skeletal systems have been demonstrated. This study aimed to evaluate alterations of immune cells in GSD. An increase of CD8+ cells and reduction of CD4+ and CD4+CD25+CD127^low cells was revealed in patients. Interestingly, patients’ regulatory T cells maintain the ability to respond to extracellular stimuli and to regulate osteoclastogenesis; GSD cells proliferate under aCD3/CD28 signal reaching similar levels to those observed in control culture and exert their immunomodulatory activity on effector T cells. GSD Treg cells preserved their inhibitory effects on the osteoclastogenesis. These results suggest that stimulation of Treg cells could open the way for the identification and testing of new therapeutic approaches for patients affected by GSD.

Dysregulated miRNAs in bone cells of patients with Gorham-Stout disease

Gorham-Stout disease (GSD) is a very rare disease characterized by increased bone erosion with angiomatous proliferation. The mechanisms underlying this disorder have not been deeply investigated. Due to its rarity, no guidelines are currently available for treatment and management of GSD. We recently evaluated the cellular alterations of the bone remodeling in patients showing that osteoclast precursors displayed increased ability to differentiate into osteoclasts and that affected osteoclasts resorb bone more actively than control cells. Moreover, osteoblasts isolated from a patient showed a defective ability to form mineralized nodules. In this paper, we investigated the molecular pathways involved in the cellular defects of GSD bone cells. For this study, we recruited nine patients and performed miRNome analysis of bone cells. Between the 178 miRNAs robustly expressed in GSD osteoclasts, significant modulation of three miRNAs (miR-1246, miR-1-3p, and miR-137-3p) involved in the regulation of osteoclast formation and activity or in the angiomatous proliferation was found in patients' cells. Interestingly, miR-1246 was also up-regulated in serum exosomes from patients. Analysis of miRNAs from patient osteoblasts suggested alteration of miR-204a-5p, miR-615-3p and miR-378a-3p regulating osteoblast function and differentiation. The resulting miRNA pattern may help to understand better the mechanisms involved in GSD and to identify new potential therapeutic targets for this rare disease.

Magnetic Resonance Imaging during Proton Therapy Irradiation Allows for the Early Response Assessment of Pediatric Chordoma

Chordoma in pediatric patients is very rare. Proton therapy has become a gold standard in the treatment of these neoplasms, as high dose escalation can be achieved regarding the target while maximizing the sparing of the healthy tissues near the tumor. The aim of the work was to assess the evolution of morphological sequences during treatment using T1/T2-weighted magnetic resonance imaging (MRI) for the early response assessment of a classic chordoma of the skull base in a pediatric patient who had undergone surgical excision. Our results demonstrated a significant quantitative reduction in the residual nodule component adhered to the medullary bulb junction, with an almost complete recovery of normal anatomy at the end of the irradiation treatment. This was mainly shown in the T2-weighted MRI. On the other hand, the classic component of the lesion was predominantly present and located around the tooth of the axis. The occipital condyles were morphologically and dimensionally stable for the entire irradiation period. In conclusion, the application of this type of monitoring methodology, which is unusual during the administration of a proton treatment for chordoma, highlighted the unexpected early response of the disease. At the same time, it allowed the continuous assessment of the reliability of the treatment plan.

Congenital self-healing reticulohistiocytosis in a newborn: unusual oral and cutaneous manifestations

Background

Congenital self-healing reticulohistiocytosis (CSHRH), also called Hashimoto-Pritzker disease, is a rare and benign variant of Langerhans cell histiocytosis, characterized by cutaneous lesions without extracutaneous involvement.

Case presentation

We present a case of CSHRH with diffuse skin lesions and erosions in the oral mucosa, present since birth and lasting for 2 months, and we perform a review of the literature on Pubmed in the last 10 years.

Conclusions

Our case confirm that lesions on oral mucosa, actually underestimated, may be present in patients with CSHRH. Patients affected by CSHRH require a close follow-up until the first years of life, due to the unpredictable course of Langerhans cell histiocytosis, in order to avoid missing diagnosis of more aggressive types of this disorder.

CD28.OX40 co-stimulatory combination is associated with long in vivo persistence and high activity of CAR.CD30 T-cells

The prognosis of many patients with chemotherapy-refractory or multiply relapsed CD30⁺ non-Hodgkin lymphoma (NHL) or Hodgkin lymphoma (HL) still remains poor, and novel therapeutic approaches are warranted to address this unmet clinical need. In light of this consideration, we designed and pre-clinically validated a chimeric antigen receptor (CAR) construct characterized by a novel anti-CD30 single- chain variable-fragment cassette, linked to CD3ζ by the signaling domains of two co-stimulatory molecules, namely CD28.4-1BB or CD28.OX40. We found that CAR.CD30 T cells exhibit remarkable cytolytic activity in vitro against both HL and NHL cell lines, with sustained proliferation and pro-inflammatory cytokine production, even after multiple and sequential lymphoma-cell challenges. CAR.CD30 T cells also demonstrated anti-lymphoma activity in two in vivo xenograft immune-deficient mouse models of metastatic HL and NHL. We observed that administration of CAR.CD30 T cells, incorporating the CD28.OX40 co-stimulatory domains and manufactured in the presence of interleukin 7 and interleukin 15, were associated with the best overall survival in the treated mice, along with establishment of a long-term immunological memory able to protect mice from further tumor re-challenge. Our data indicate that, in the context of in vivo systemic metastatic xenograft mouse models, the co-stimulatory machinery of CD28.OX40 is crucial for improving persistence, in vivo expansion and proliferation of CAR.CD30 T cells upon tumor encounter. The CD28.OX40 co-stimulatory combination is ultimately responsible for the anti-tumor efficacy of the approach, paving the way to translate this therapeutic strategy into clinical use for patients with CD30⁺ HL and NHL.

GD2 redirected CAR T and activated NK-cell-mediated secretion of IFNγ overcomes MYCN-dependent IDO1 inhibition, contributing to neuroblastoma cell immune escape

Immune escape mechanisms employed by neuroblastoma (NB) cells include secretion of immunosuppressive factors disrupting effective antitumor immunity. The use of cellular therapy to treat solid tumors needs to be implemented. Killing activity of anti-GD2 Chimeric Antigen Receptor (CAR) T or natural killer (NK) cells against target NB cells was assessed through coculture experiments and quantified by FACS analysis. ELISA assay was used to quantify interferon-γ (IFNγ) secreted by NK and CAR T cells. Real Time PCR and Western Blot were performed to analyze gene and protein levels modifications. Transcriptional study was performed by chromatin immunoprecipitation and luciferase reporter assays on experiments of mutagenesis on the promoter sequence. NB tissue sample were analyzed by IHC and Real Time PCR to perform correlation study. We demonstrate that Indoleamine-pyrrole 2,3-dioxygenase1 (IDO1), due to its ability to convert tryptophan into kynurenines, is involved in NB resistance to activity of immune cells. In NB, IDO1 is able to inhibit the anti-tumor effect displayed by of both anti-GD2 CAR (GD2.CAR) T-cell and NK cells, mainly by impairing their IFNγ production. Furthermore, inhibition of MYCN expression in NB results into accumulation of IDO1 and consequently of kynurenines, which negatively affect the immune surveillance. Inverse correlation between IDO1 and MYCN expression has been observed in a wide cohort of NB samples. This finding was supported by the identification of a transcriptional repressive role of MYCN on IDO1 promoter. The evidence of IDO1 involvement in NB immune escape and its ability to impair NK and GD2.CAR T-cell activity contribute to clarify one of the possible mechanisms responsible for the limited efficacy of these immunotherapeutic approaches. A combined therapy of NK or GD2.CAR T-cells with IDO1 inhibitors, a class of compounds already in phase I/II clinical studies, could represent a new and still unexplored strategy capable to improve long-term efficacy of these immunotherapeutic approaches.

Identification of neuroblastoma cell lines with uncommon TAZ+/mesenchymal stromal cell phenotype with strong suppressive activity on natural killer cells

Background

Neuroblastoma (NB) is the most common, extracranial childhood solid tumor arising from neural crest progenitor cells and is a primary cause of death in pediatric patients. In solid tumors, stromal elements recruited or generated by the cancer cells favor the development of an immune-suppressive microenvironment. Herein, we investigated in NB cell lines and in NB biopsies, the presence of cancer cells with mesenchymal phenotype and determined the immune-suppressive properties of these tumor cells on natural killer (NK) cells.

Methods

We assessed the mesenchymal stromal cell (MSC)-like phenotype and function of five human NB cell lines and the presence of this particular subset of neuroblasts in NB biopsies using flow-cytometry, immunohistochemistry, RT-qPCR, cytotoxicity assays, western blot and silencing strategy. We corroborated our data consulting a public gene-expression dataset.

Results

Two NB cell lines, SK-N-AS and SK-N-BE(2)C, exhibited an unprecedented MSC phenotype (CD105⁺/CD90⁺/CD73⁺/CD29⁺/CD146⁺/GD2⁺/TAZ⁺). In these NB-MSCs, the ectoenzyme CD73 and the oncogenic/immune-regulatory transcriptional coactivator TAZ were peculiar markers. Their MSC-like nature was confirmed by their adipogenic and osteogenic differentiation potential. Immunohistochemical analysis confirmed the presence of neuroblasts with MSC phenotype (CD105⁺/CD73⁺/TAZ⁺). Moreover, a public gene-expression dataset revealed that, in stage IV NB, a higher expression of TAZ and CD105 strongly correlated with a poorer outcome.

Among the NB-cell lines analyzed, only NB-MSCs exhibited multifactorial resistance to NK-mediated lysis, inhibition of activating NK receptors, signal adaptors and of NK-cell cytotoxicity through cell-cell contact mediated mechanisms. The latter property was controlled partially by TAZ, since its silencing in NB cells efficiently rescued NK-cell cytotoxic activity, while its overexpression induced opposite effects in non-NB-MSC cells.

Conclusions

We identified a novel NB immunoregulatory subset that: (i) displayed phenotypic and functional properties of MSC, (ii) mediated multifactorial resistance to NK-cell-induced killing and (iii) efficiently inhibited, in coculture, the cytotoxic activity of NK cells against target cells through a TAZ-dependent mechanism. These findings indicate that targeting novel cellular and molecular components may disrupt the immunomodulatory milieu of the NB microenvironment ameliorating the response to conventional treatments as well as to advanced immunotherapeutic approaches, including adoptive transfer of NK cells and chimeric antigen receptor T or NK cells.

Interaction between SNAI2 and MYOD enhances oncogenesis and suppresses differentiation in Fusion Negative Rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is an aggressive pediatric malignancy of the muscle, that includes Fusion Positive (FP)-RMS harboring PAX3/7-FOXO1 and Fusion Negative (FN)-RMS commonly with RAS pathway mutations. RMS express myogenic master transcription factors MYOD and MYOG yet are unable to terminally differentiate. Here, we report that SNAI2 is highly expressed in FN-RMS, is oncogenic, blocks myogenic differentiation, and promotes growth. MYOD activates SNAI2 transcription via super enhancers with striped 3D contact architecture. Genome wide chromatin binding analysis demonstrates that SNAI2 preferentially binds enhancer elements and competes with MYOD at a subset of myogenic enhancers required for terminal differentiation. SNAI2 also suppresses expression of a muscle differentiation program modulated by MYOG, MEF2, and CDKN1A. Further, RAS/MEK-signaling modulates SNAI2 levels and binding to chromatin, suggesting that the differentiation blockade by oncogenic RAS is mediated in part by SNAI2. Thus, an interplay between SNAI2, MYOD, and RAS prevents myogenic differentiation and promotes tumorigenesis.

Case Report: EBV Chronic Infection and Lymphoproliferation in Four APDS Patients: The Challenge of Proper Characterization, Therapy, and Follow-Up

Activated PI3K-kinase Delta Syndrome (APDS) is an autosomal-dominant primary immunodeficiency (PID) caused by the constitutive activation of the PI3Kδ kinase. The consequent hyperactivation of the PI3K-Akt-mTOR pathway leads to an impaired T- and B-cells differentiation and function, causing progressive lymphopenia, hypogammaglobulinemia and hyper IgM. Patients with APDS show recurrent sinopulmonary and chronic herpes virus infections, immune dysregulation manifestations, including cytopenia, arthritis, inflammatory enteropathy, and a predisposition to persistent non-neoplastic splenomegaly/lymphoproliferation and lymphoma. The recurrence of the lymphoproliferative disorder and the difficulties in the proper definition of malignancy on histological examination represents the main challenge in the clinical management of APDS patients, since a prompt and correct diagnosis is needed to avoid major complications. Targeted therapies with PI3Kδ-Akt-mTOR pathway pharmacologic inhibitors (i.e., Rapamycin, Theophylline, PI3K inhibitors) represent a good therapeutic strategy. They can also be used as bridge therapies when HSCT is required in order to control refractory symptoms. Indeed, treated patients showed a good tolerance, improved immunologic phenotype and reduced incidence/severity of immune dysregulation manifestations. Here, we describe our experience in the management of four patients, one male affected with APDS1 (P1) and the other three, a male and two females, with APDS2 (P2, P3, P4) presenting with chronic EBV replication, recurrent episodes of immune dysregulation manifestations and lymphomas. These cases highlighted the importance of a tailored and close follow-up, including serial endoscopic and lymph nodes biopsies control to detect a prompt and correct diagnosis and offer the best therapeutic strategy.

Abstract B35: Liaison between SNAI2 and MYOD enhances oncogenesis and suppresses differentiation in fusion-negative rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is a pediatric malignancy of the muscle, and patients with high-risk fusion-negative RMS (FN-RMS), the major subtype of this disease, are associated with RAS pathway activating mutations and have a poor survival rate of &lt;30%. RMS cells express the myogenic master transcription factors MYOD and MYOG and yet are unable to differentiate. Here, we report an oncogenic role for SNAI2, which is highly expressed in FN-RMS, that blocks differentiation and promotes tumor growth through inhibition of a MYOD, MYOG, and MEF2 program. HiC analyses of the tridimensional-structure around the SNAI2 locus in IMR-90 cells find that it is regulated by a 1.2 mb enhancer regulatory region. In RMS tumors, MYOD can engage multiple SNAI2 enhancers and directly induce SNAI2 expression, while SNAI2 knockdown in RMS RD and JR1 results in increased expression of MYOD, indicating that SNAI2 in turn can repress MYOD expression. Employing two validated shRNAs to knock down SNAI2 in FN-RMS RD, JR1, and RD18 cells, we find that SNAI2 plays an oncogenic role by blocking myogenic differentiation and promoting growth both in vitro and in vivo in murine xenograft experiments. SNAI2 knockdown potentiates vincristine treatments and expands differentiation and greatly reduces tumor growth in vivo. In order to understand molecularly how SNAI2 blocks differentiation and promotes growth, we optimized ChIP-seq experiments in FN-RMS RD, JR1, and SMS-CTR cells to define genome-wide chromatin binding of SNAI2 and MYOD, with or without SNAI2 knockdown. Our ChIP-sequencing experiments confirmed that SNAI2 binds EBoxes, including the SNAI2 motif and motifs that MYOD and MYOG engage. Importantly, combining ChIPseq and RNAseq analyses, we discovered that SNAI2 preferentially binds EBox elements associated with enhancer elements and regulates gene expression by dampening enhancer function. SNAI2 competes with MYOD at a subset of myogenic enhancers associated with terminal differentiation, thus blocking differentiation in FN-RMS cells while potentially enabling progrowth effects of MYOD. SNAI2 also downregulates the expression of a MYOG, MEF2A/C/D, and CDKN1A differentiation program that is suppressed in FN-RMS cells, which upon reactivation along with MYOD drives robust differentiation and inhibits tumor xenograft growth in mice. Finally, we establish that SNAI2 function is downstream of the RAS program involved in blocking differentiation. In summary, SNAI2, through inhibition of a MYOD, MYOG, MEF2, and CDNK1A program, blocks tumor differentiation and promotes growth in FN-RMS.

Citation Format: Silvia Pomella, Prethish Sreenivas, Berkley E. Gryder, Long Wang, Matteo Cassandri, Kunal Baxi, Nicole R. Hensch, Elena Carcarino, Young Song, Marielle Yohe, Bruno Amadio, Ignazio Caruana, Cristiano De Stefanis, Rita De Vito, Franco Locatelli, Yidong Chen, Eleanor Y. Chen, Peter Houghton, Javed Khan, Rossella Rota, Myron S. Ignatius. Liaison between SNAI2 and MYOD enhances oncogenesis and suppresses differentiation in fusion-negative rhabdomyosarcoma [abstract]. In: Proceedings of the AACR Special Conference on the Advances in Pediatric Cancer Research; 2019 Sep 17-20; Montreal, QC, Canada. Philadelphia (PA): AACR; Cancer Res 2020;80(14 Suppl):Abstract nr B35.

Proteomic Profiling of Retinoblastoma-Derived Exosomes Reveals Potential Biomarkers of Vitreous Seeding

Retinoblastoma (RB) is the most common tumor of the eye in early childhood. Although recent advances in conservative treatment have greatly improved the visual outcome, local tumor control remains difficult in the presence of massive vitreous seeding. Traditional biopsy has long been considered unsafe in RB, due to the risk of extraocular spread. Thus, the identification of new biomarkers is crucial to design safer diagnostic and more effective therapeutic approaches. Exosomes, membrane-derived nanovesicles that are secreted abundantly by aggressive tumor cells and that can be isolated from several biological fluids, represent an interesting alternative for the detection of tumor-associated biomarkers. In this study, we defined the protein signature of exosomes released by RB tumors (RBT) and vitreous seeding (RBVS) primary cell lines by high resolution mass spectrometry. A total of 5666 proteins were identified. Among these, 5223 and 3637 were expressed in exosomes RBT and one RBVS group, respectively. Gene enrichment analysis of exclusively and differentially expressed proteins and network analysis identified in RBVS exosomes upregulated proteins specifically related to invasion and metastasis, such as proteins involved in extracellular matrix (ECM) remodeling and interaction, resistance to anoikis and the metabolism/catabolism of glucose and amino acids.

Neuroblastoma-secreted exosomes carrying miR-375 promote osteogenic differentiation of bone-marrow mesenchymal stromal cells

Bone marrow (BM) is the major target organ for neuroblastoma (NB) metastasis and its involvement is associated with poor outcome. Yet, the mechanism by which NB cells invade BM is largely unknown. Tumour microenvironment represents a key element in tumour progression and mesenchymal stromal cells (MSCs) have been recognized as a fundamental part of the associated tumour stroma. Here, we show that BM-MSCs isolated from NB patients with BM involvement exhibit a greater osteogenic potential than MSCs from non-infiltrated BM. We show that BM metastasis-derived NB-cell lines secrete higher levels of exosomal miR-375, which promotes osteogenic differentiation in MSCs. Of note, clinical data demonstrate that high level of miR-375 correlates with BM metastasis in NB patients. Our findings suggest, indeed, a potential role for exosomal miR-375 in determining a favourable microenvironment in BM to promote metastatic progression. MiR-375 may, thus, represent a novel biomarker and a potential target for NB patients with BM involvement.

Ectopic ACTH Secretion in a Child With Metastatic Ewing's Sarcoma: A Case Report

Ectopic ACTH syndrome is rare in pediatric age. Sarcomas that cause Ectopic ACTH Syndrome (EAS) are even more uncommon. Currently, only three cases of EAS caused by Ewing' sarcoma have been reported. We detail a 10-year-old boy with Cushing's syndrome symptoms caused by ectopic ACTH production by a metastatic Ewing's sarcoma of the right ischio-pubic and ileo-pubic branches. The rapid appearance of cushingoid symptoms, with significant weight gain, acne, hirsutism, and hypercortisolism were implications of ectopic ACTH production as paraneoplastic Cushing's Syndrome. The very high levels of ACTH and non-suppression at the high dose dexamethasone test confirmed the clinical suspicion. We underline the possibility EAS was caused by an ACTH-secreting tumor, including soft tissue sarcomas.

DNA Methylation Profiling for Diagnosing Undifferentiated Sarcoma with Capicua Transcriptional Receptor (CIC) Alterations

Undifferentiated soft tissue sarcomas are a group of diagnostically challenging tumors in the pediatric population. Molecular techniques are instrumental for the categorization and differential diagnosis of these tumors. A subgroup of recently identified soft tissue sarcomas with undifferentiated round cell morphology was characterized by Capicua transcriptional receptor (CIC) rearrangements. Recently, an array-based DNA methylation analysis of undifferentiated tumors with small blue round cell histology was shown to provide a highly robust and reproducible approach for precisely classifying this diagnostically challenging group of tumors. We describe the case of an undifferentiated sarcoma of the abdominal wall in a 12-year-old girl. The patient presented with a voluminous mass of the abdominal wall, and multiple micro-nodules in the right lung. The tumor was unclassifiable with current immunohistochemical and molecular approaches. However, DNA methylation profiling allowed us to classify this neoplasia as small blue round cell tumor with CIC alterations. The patient was treated with neoadjuvant chemotherapy followed by complete surgical resection and adjuvant chemotherapy. After 22 months, the patient is disease-free and in good clinical condition. To put our experience in context, we conducted a literature review, analyzing current knowledge and state-of-the-art diagnosis, prognosis, and clinical management of CIC rearranged sarcomas. Our findings further support the use of DNA methylation profiling as an important tool to improve diagnosis of non-Ewing small round cell tumors.

Dissecting the mechanisms of bone loss in Gorham-Stout disease

Gorham-Stout disease (GSD) is a rare disorder characterized by progressive osteolysis and angiomatous proliferation. Since the mechanisms leading to bone loss in GSD are not completely understood, we performed histological, serum, cellular and molecular analyses of 7 patients. Increased vessels, osteoclast number and osteocyte lacunar area were revealed in patients' bone biopsies. Biochemical analysis of sera showed high levels of ICTP, Sclerostin, VEGF-A and IL-6. In vitro experiments revealed increased osteoclast differentiation and activity, and impaired mineralization ability of osteoblasts. To evaluate the involvement of systemic factors in GSD, control cells were treated with patients' sera and displayed an increase of osteoclastogenesis, bone resorption activity and a reduction of osteoblast function. Interestingly, GSD sera stimulated the vessel formation by endothelial cells EA.hy926. These results suggest that bone cell autonomous alterations with the cooperation of systemic factors are involved in massive bone loss and angiomatous proliferation observed in GSD patients.

The Contribution of the Adipose Tissue-Liver Axis in Pediatric Patients with Nonalcoholic Fatty Liver Disease after Laparoscopic Sleeve Gastrectomy

OBJECTIVE

To evaluate the histopathologic modifications in liver and visceral adipose tissue (VAT), and to correlate these changes with clinical measures, adipokine production, and proinflammatory cytokines in a population of adolescents with obesity with nonalcoholic fatty liver disease (NAFLD) who underwent laparoscopic sleeve gastrectomy (LSG).

STUDY DESIGN

Twenty adolescents with obesity who underwent LSG and with biopsy-proven NAFLD were included. Patients underwent clinical evaluation and blood tests at baseline and 1 year after the surgical procedure. Liver and VAT specimens were processed for routine histology, immunohistochemistry, and immunofluorescence.

RESULTS

In adolescents with obesity and NAFLD, hepatic histologic alterations were uncorrelated with VAT inflammation. LSG induced in both liver and VAT tissue histopathology amelioration and macrophage profile modification that were correlated with body mass index and improvement in insulin resistance. The adipokine profile in liver and VAT was associated with weight loss and histologic improvement after LSG. Serum proinflammatory cytokines were correlated with liver and VAT histopathology and IL-1β and IL-6 levels were independently predicted by liver necroinflammatory grade.

CONCLUSIONS

This study suggests a unique adipose tissue/fatty liver crosstalk in pediatric patients. LSG induces a similar pattern of histologic improvement in the liver and in VAT. Besides VAT, our results strengthen the role of the liver in adipocytokine production and its contribution to systemic inflammation in pediatric patients with NAFLD.

Pediatric gastrointestinal stromal tumor: Report of two novel patients harboring germline variants in SDHB and SDHC genes

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract and rarely occur in pediatric patients. 85% of pediatric GISTs and 15% of adult GISTs lack of KIT or PDGFRA mutations. 40% of these "wild-type" GISTs present loss of function mutations in genes encoding for the subunits of the succinate dehydrogenase (SDH) complex. Germline mutations in SDH complex genes have been described in patients with the Carney-Stratakis syndrome (CSS), a rare inherited condition that predisposes to GIST and paraganglioma. We report two pediatric patients with multifocal GIST, harboring respectively a novel and a previously reported loss-of-function germline variant, in SDHC and SDHB genes.

EGFR inhibition for metastasized cutaneous squamous cell carcinoma in dystrophic epidermolysis bullosa

Dystrophic epidermolysis bullosa (DEB) is a hereditary skin fragility disorder, characterized by trauma-induced blistering followed by soft tissue fibrosis. One of the most feared complications is the early development of aggressive cutaneous squamous cell carcinomas (SCC). For patients with locally advanced or metastasized SCCs treatment with cetuximab, a monoclonal antibody against epidermal growth factor receptor (EGFR), has been proposed and so far, treatment of five DEB patients with cetuximab has been published. With this report, we extend the spectrum of EB patients treated with cetuximab by adding two additional patients. Taking together all DEB cases treated with cetuximab, we propose that cetuximab should be administered as early as possible, since it seems to be more efficient and is accompanied by rather mild adverse effects. We also show that EGFR is frequently expressed in DEB-associated SCCs, although there were noticeable differences in the level of expression, which may influence responsiveness to EGFR-targeting therapies. Although only limited experiences with targeted cancer treatments in EB exist, such reports highlight the treatments' effects in this specific cohort and assist our therapeutic decisions.

Role of interferon-γ in immune-mediated graft failure after allogeneic hematopoietic stem cell transplantation

Pathophysiology of graft failure (GF) occurring after allogeneic hematopoietic stem cell transplantation (HSCT) still remains elusive. We measured serum levels of several different cytokines/chemokines in 15 children experiencing GF, comparing their values with those of 15 controls who had sustained donor cell engraftment. Already at day +3 after transplantation, patients developing GF had serum levels of interferon (IFN)-γ and CXCL9 (a chemokine specifically induced by IFNγ) significantly higher than those of controls (8859±7502 vs. 0 pg/mL, P=0.03, and 1514.0±773 vs. 233.6±50.1 pg/mlL, P=0.0006, respectively). The role played by IFNγ in HSCT-related GF was further supported by the observation that a rat anti-mouse IFNγ-neutralizing monoclonal antibody promotes donor cell engraftment in Ifngr1-/-mice receiving an allograft. In comparison to controls, analysis of bone marrow-infiltrating T lymphocytes in patients experiencing GF documented a predominance of effector memory CD8+ cells, which showed markers of activation (overexpression of CD95 and downregulation of CD127) and exhaustion (CD57, CD279, CD223 and CD366). Finally, we obtained successful donor engraftment in 2 out of 3 children with primary hemophagocytic lymphohistiocytosis who, after experiencing GF, were re-transplanted from the same HLA-haploidentical donor under the compassionate use coverage of emapalumab, an anti-IFNγ monoclonal antibody recently approved by the US Food and Drug Administration for treatment of patients with primary hemophagocytic lymphohistiocytosis. Altogether, these results suggest that the IFNγ pathway plays a major role in GF occurring after HSCT. Increased serum levels of IFNγ and CXCL9 represent potential biomarkers useful for early diagnosis of GF and provide the rationale for exploring the therapeutic/preventive role of targeted neutralization of IFNγ.

Next-Generation Sequencing Reveals A JAGN1 Mutation in a Syndromic Child With Intermittent Neutropenia

BACKGROUND

Jagunal homolog 1 (JAGN1) gene was identified as a novel responsible for severe congenital neutropenia. The protein encoded by this gene is required for neutrophil differentiation, survival and function in microbial activity. JAGN1-deficient human neutrophils are characterized by alterations in trafficking within the endoplasmic reticulum and golgi compartments because of ultrastructural defects in endoplasmic reticulum and susceptibility to apoptosis.

OBSERVATIONS

We report a patient exhibiting an intermittent neutropenia, for which a next-generation sequencing revealed a homozygous mutation in the JAGN1 gene.

CONCLUSIONS

The patient extends the clinical variability associated to JAGN1 mutations, and this case highlights the importance of genetic investigations in patients with suspected neutropenia.

Angioma serpiginosum: a case report and review of the literature

Background

Angioma serpiginosum is a rare vascular anomaly whose pathogenesis is still unknown. It is characterized by the onset of vascular reddish macules and papules during childhood, lesions are usually monolateral with a linear serpiginous pattern. It is rarely associated with extracutaneous findings. This entity has not yet been included in the classification of the International Society for the Study of Vascular Anomalies.

Case presentation

We describe the first Italian report of angioma serpiginosum with a congenital symmetrical presentation. The patient had a further extension of macules during puberty involving both of the soles. No extracutaneous manifestations were present. Diagnosis was confirmed with dermoscopy and light microscopy that revealed the typical clusters of dilated, thickened and PAS+ capillaries in the upper dermis. Moreover, Immunohistochemistry showed positive WT-1 staining. Genetic analysis with next generation sequencing did not detected any mutation.

Conclusions

Our patient presented a peculiar symmetrical and planar extension with a serpiginous linear pattern. The proliferative nature of this condition has been widely discussed in literature. In our case immunohistochemistry was positive for Wilms tumor-1, a new endothelial marker expressed during angiogenesis in reparative processes and endothelial tumors.

Clinical evolution, histological and immunohistochemical findings suggest that angioma serpiginosum should be considered as a vascular proliferation. For these reasons we think it should be included in the international classification as a tumor.

First Case of Patient With Two Homozygous Mutations in MYD88 and CARD9 Genes Presenting With Pyogenic Bacterial Infections, Elevated IgE, and Persistent EBV Viremia

We described for the first time a female patient with the simultaneous presence of two homozygous mutations in MYD88 and CARD9 genes presenting with pyogenic bacterial infections, elevated IgE, and persistent EBV viremia. In addition to defective TLR/IL1R-signaling, we described novel functional alterations into the myeloid compartment. In particular, we demonstrated a defective production of reactive oxygen species exclusively in monocytes upon E. coli stimulation, the inability of immature mono-derived DCs (iDCs) to differentiate into mature DCs (mDCs) and the incapacity of mono-derived macrophages (MDMs) to resolve BCG infection in vitro. Our data do not provide any evidence for digenic inheritance in our patient, but rather for the association of two monogenic disorders. This case illustrates the importance of using next generation sequencing (NGS) to determine the most accurate and early diagnosis in atypical clinical and immunological phenotypes, and with particular concern in consanguineous families. Indeed, besides the increased susceptibility to recurrent invasive pyogenic bacterial infections due to MYD88 deficiency, the identification of CARD9 mutations underline the risk of developing invasive fungal infections emphasizing the careful monitoring for the occurrence of fungal infection and the opportunity of long-term antifungal prophylaxis.

Expression profiles of exosomal miRNAs isolated from plasma of patients with desmoplastic small round cell tumor

AIM

Desmoplastic small round cell tumor (DSRCT) is a rare, aggressive mesenchymal tumor, lacking biomarkers for diagnosis, treatment stratification and prognosis. We investigated the exosomal miRNA profile in plasma samples collected from DSRCT patients, evaluating their potential as circulating biomarkers for this tumor.

PATIENTS & METHODS

We isolated exosomes from plasma of three DSRCT adolescents and four age-matched healthy controls; expression of circulating miRNAs was quantified by qPCR.

RESULTS

We identified 55 miRNAs significantly modulated compared with healthy controls. Among these miRNAs, 14 were highly dysregulated in at least one patient and 5 were expressed in all patients.

CONCLUSION

To our knowledge, this is the first report describing exosomal miRNAs as promising biomarkers to characterize disease status in DSRCT patients.

Burkitt lymphoma in a patient with Kabuki syndrome carrying a novel KMT2D mutation

Kabuki syndrome (KS) is an extremely rare genetic disorder, mainly caused by germline mutations at specific epigenetic modifier genes, including KMT2D. Because the tumor suppressor gene KMT2D is also frequently altered in many cancer types, it has been suggested that KS may predispose to the development of cancer. However, KS being a rare disorder, few data are available on the incidence of cancer in KS patients. Here, we report the case of a 5-year-old boy affected by KS who developed Burkitt lymphoma (BL). Genetic analysis revealed the presence of a novel heterozygous mutation in the splice site of the intron 4 of KMT2D gene in both peripheral blood-extracted DNA and tumour cells. In addition, the tumour sample of the patient was positive for the classical somatic chromosomal translocation t(8;14) involving the c-MYC gene frequently identified in BL. We propose that the mutated KMT2D gene contributes to the development of both KS and BL observed in our patient and we suggest that strict surveillance must be performed in KS patients.

Liver zonation in children with non-alcoholic fatty liver disease: Associations with dietary fructose and uric acid concentrations

BACKGROUND & AIMS

As dietary components are delivered directly to the periportal zone of the liver lobule, there is the potential for greater injury in this zone (zone 1) compared to the perivenous zone (zone 3). We investigated the associations between dietary fructose consumption and uric acid concentrations and differential zonal injury in periportal and perivenous zones.

METHODS

A total of 271 children's histological images were scored in 5 periportal and 5 perivenous zones for steatosis, ballooning, inflammation and fibrosis severity. Dietary fructose consumption (g/d) was assessed and uric acid measured in serum. Logistic regression was undertaken to test associations between both high fructose consumption and hyperuricaemia, and histological disease in periportal and perivenous zones.

RESULTS

Children with a mean age of 12.5 years were included in the study. Inflammation (mean ± SD) was increased in the periportal vs perivenous zones (0.78 ± 0.43 vs 0.41 ± 0.48, P = .041). There were non-significant trends towards greater steatosis, ballooning and fibrosis in the periportal zone. In the fully adjusted models, high fructose intake was associated with disease in both zones. Example for periportal and perivenous zones, respectively, steatosis 1.56 (1.12, 2.49) and 1.21 (1.09, 2.73); inflammation 4.29 (2.31, 5.88) and 3.69 (2.14, 4.56); and fibrosis 2.72 (1.43, 3.76) and 1.96 (1.24, 2.37). Hyperuricaemia (uric acid ≥5.9 mg/dL) was associated with inflammation in the periportal zone 1.71 (1.17, 2.35); and was associated with steatosis and fibrosis in both zones; for example, for periportal and perivenous zones, respectively, steatosis 2.98 (1.65, 3.23) and 1.14 (1.05, 1.99); and fibrosis, 2.65 (1.35, 2.99) and 1.31 (1.13, 2.17).

CONCLUSIONS

High fructose consumption is associated with disease severity in both lobular zones and hyperuricaemia may be associated with more severe disease in the periportal zone.

Hepatic farnesoid X receptor protein level and circulating fibroblast growth factor 19 concentration in children with NAFLD

BACKGROUND & AIMS

Treatment with the farnesoid X receptor (FXR) agonist obeticholic acid is ineffective in some patients with non-alcoholic steatohepatitis (NASH) but the explanation is uncertain. We investigated hepatic FXR expression, and measurements of fibroblast growth factor 19 (FGF19) and bile acids (BAs) in children with NAFLD to investigate relationships with NASH.

METHODS

33 children with NAFLD who underwent diagnostic liver biopsy were studied. Hepatic FXR protein levels and circulating FGF19 concentrations were compared with those analysed in five control subjects with proven normal liver histology. NASH was defined by the Paediatric NAFLD Histological Score (PNHS). Binary logistic regression with adjustment for covariates and potential confounders was undertaken to test factors independently associated with: a) NASH and b) hepatic FXR protein levels.

RESULTS

Mean ± SD age was 13.7 ± 1.9 years. Nineteen patients had NASH (PNHS ≥ 85) and 14 did not have NASH (PNHS < 85). Hepatic FXR level and plasma FGF19 concentration varied ~10-fold and 5-fold, respectively, between groups, and was highest in control subjects, intermediate in NAFLD without NASH, and lowest in NASH (between group differences P < .001 and P < .01 respectively). NASH was independently associated with both FXR protein levels (OR = 0.18, 95% CI 0.09, 0.38) and FGF19 concentration (OR = 0.55, 95% CI 0.20, 0.89).

CONCLUSIONS

FXR protein levels vary markedly between normal liver, NAFLD without NASH, and NASH. Low levels of FXR are independently associated with NASH.

A Case Report of Fatal Necrotizing Encephalitis and Acute HBV Infection: Coincidence or Comorbidity?

We report the first fatal pediatric case of encephalitis associated with hepatitis B virus (HBV) infection. A Caucasian, previously healthy, and vaccinated 7-year-old girl was evaluated at our hospital for fever, vomiting, tremors, and loss of consciousness. At admission, she underwent brain computed tomographic scan, electroencephalogram, lumbar puncture, and blood examination. In 12 hours, her clinical condition deteriorated and the patient entered coma and died. A laboratory error was useful to reach a predeath diagnosis, showing HBV–DNA on blood. Autopsy confirmed HBV–PCR DNA in brain, lymphnodes, lungs, liver, and spleen. We generally do not search HBV–DNA in organic fluid of Italian children with encephalitis, as they are currently all vaccinated. Consequently, as a teaching lesson, we would suggest not to take anything obvious.

Quantitative Multiplexed Imaging Analysis Reveals a Strong Association between Immunogen-Specific B Cell Responses and Tonsillar Germinal Center Immune Dynamics in Children after Influenza Vaccination

Generation of Ag-specific humoral responses requires the orchestrated development and function of highly specialized immune cells in secondary lymphoid organs. We used a multiparametric approach combining flow cytometry, confocal microscopy, and histocytometry to analyze, for the first time to our knowledge in children, tonsils from seasonal influenza-vaccinated children. We used these novel imaging assays to address the mucosal immune dynamics in tonsils investigating the spatial positioning, frequency, and phenotype of immune cells after vaccination. Vaccination was associated with a significantly higher frequency of follicular helper CD4 T cells compared with the unvaccinated control group. The imaging analysis revealed that potential suppressor (FOXP3^hi) CD4 T cells are mainly located in extrafollicular areas. Furthermore, a significantly reduced frequency of both follicular and extrafollicular FOXP3^hi CD4 T cells was found in the vaccine group compared with the control group. Levels of circulating CXCL13 were higher in those vaccinated compared with controls, mirroring an increased germinal center reactivity in the tonsils. Notably, a strong correlation was found between the frequency of tonsillar T follicular helper cells and tonsillar Ag-specific Ab-secreting cells. These data demonstrate that influenza vaccination promotes the prevalence of relevant immune cells in tonsillar follicles and support the use of tonsils as lymphoid sites for the study of germinal center reactions after vaccination in children.

Clinical impact of miR-223 expression in pediatric T-Cell lymphoblastic lymphoma

Although probability of event-free survival in pediatric lymphoblastic T-cell lymphoma (T-LBL) is about 75%, survival in relapsed patients is very poor, so the identification of new molecular markers is crucial for treatment optimization. Here, we demonstrated that the over-expression of miR-223 promotes tumor T-LBL cell growth, migration and invasion in vitro. We found out that SIK1, an anti-metastatic protein, is a direct target of miR-223 and consequently is significantly reduced in miR-223-overexpressing tumor cells. We measured miR-223 expression levels at diagnosis in tumor biopsies from 67 T-LBL pediatric patients for whom complete clinical and follow up data were available, and we found that high miR-223 expression (above the median value) is associated with worse prognosis (PFS 66% vs 94%, P=0.0036). In addition, the multivariate analysis, conducted taking into account miR-223 expression level and other molecular and clinical characteristics, showed that only high level of miR-223 is an independent factor for worse prognosis. MiR-223 represents a promising marker for treatment stratification in pediatric patients with T-LBL and we provide the first evidence of miR-223 potential role as oncomir by SIK1 repression.

Src nuclear localization and its prognostic relevance in human osteosarcoma

Osteosarcoma is the most common malignant bone tumor in children and young adults. The identification of proteins which exhibit different subcellular localization in low- versus high-risk osteosarcoma can be instrumental to obtain prognostic information and to develop innovative therapeutic strategies. Beside the well-characterized membrane and cytoplasmic localization of Src protein, this study evaluated the prognostic relevance of its so-far unknown nuclear compartmentalization. We analyzed the subcellular distribution of total and activated (pY418) Src in a tissue microarray including 60 osteosarcoma samples. Immunohistochemical analyses revealed a variable pattern of Src expression and localization, ranging from negative to high-stained nuclei combined with a substantial cytoplasmic staining for total and activated forms. The analysis of Kaplan-Meier survival curves in relationship to the diverse permutations of cytoplasmic and nuclear staining suggested a correlation between Src subcellular localization and the overall survival (OS) of osteosarcoma patients. In order to explain this different subcellular localization, normal osteoblasts and three osteosarcoma cell lines were used to investigate the molecular mechanism. Once confirmed a variable Src localization also in these cell lines, we demonstrated a correlation between the N-myristoyltransferase enzymes expression and activity and the Src nuclear content. In conclusion, these results described a so-far unknown Src nuclear localization in osteosarcoma cells, suggesting that the combined detection of nuclear and cytoplasmic Src levels can be used as a prognostic marker for osteosarcoma patient survival. A correlation between the N-myristoyltransferase enzymes and the Src subcellular localization was described as well.

Serum uric acid concentrations and fructose consumption are independently associated with NASH in children and adolescents

BACKGROUND & AIMS

Recent research has suggested that dietary fructose intake may increase serum uric acid (UA) concentrations. Both UA concentration and fructose consumption maybe also increase in NAFLD. It is not known whether dietary fructose consumption and UA concentration are independently associated with non-alcoholic steatohepatitis (NASH). Our aim was to investigate the factors associated with NASH in children and adolescents with proven NAFLD, and to test whether UA concentrations and fructose consumption are independently associated with NASH.

METHODS

Obese children with NAFLD were studied (n=271). NASH was diagnosed by a NAFLD activity score ⩾5 and the fatty liver inhibition of progression (FLIP) algorithm. Fructose consumption (g/day) was assessed by food frequency questionnaire, and UA (mg/dl) was measured in serum. Binary logistic regression with adjustment for covariates and potential confounders was undertaken to test factors independently associated with NASH.

RESULTS

NASH occurred in 37.6% of patients. Hyperuricaemia (UA ⩾5.9mg/dl) was present in 47% of patients with NASH compared with 29.7% of non-NASH patients (p=0.003). Both UA concentration (OR=2.488, 95% CI: 1.87-2.83, p=0.004) and fructose consumption (OR=1.612, 95% CI 1.25-1.86, p=0.001) were independently associated with NASH, after adjustment for multiple (and all) measured confounders. Fructose consumption was independently associated with hyperuricaemia (OR=2.021, 95% CI: 1.66-2.78, p=0.01). These data were confirmed using the FLIP algorithm.

CONCLUSIONS

Both dietary fructose consumption and serum UA concentrations are independently associated with NASH. Fructose consumption was the only factor independently associated with serum UA concentration.

LAY SUMMARY

Currently, it is not known whether dietary fructose consumption and uric acid (UA) concentration are linked with non-alcoholic steatohepatitis (NASH) in children and adolescents. Our aim was to test whether UA concentrations and fructose consumption are independently associated with NASH in children and adolescents with proven non-alcoholic fatty liver disease (NAFLD). We show that both dietary fructose consumption and serum UA concentrations are independently associated with NASH and fructose consumption was independently linked with high serum UA concentrations.

Docosahexanoic Acid Plus Vitamin D Treatment Improves Features of NAFLD in Children with Serum Vitamin D Deficiency: Results from a Single Centre Trial

BACKGROUND

There are no licensed treatments for non alcoholic fatty liver disease (NAFLD) in adults or children. In NAFLD, several studies have shown a benefit of omega-3 fatty acid treatment on lipid profile, insulin-sensitivity and hepatic steatosis and it has also been suggested that Vitamin D treatment has potential antifibrotic properties in liver disease.

TRIAL DESIGN

To date, however, there are no studies that have tested the combination of Docosahexanoic acid (DHA) and vitamin D treatment which may benefit the whole spectrum of disease in NAFLD. Our aim therefore, was to test the effect of daily DHA (500 mg) plus vitamin D (800 IU) treatment, in obese children with biopsy-proven NAFLD and vitamin D deficiency, in a randomized, double-blind placebo-controlled trial.

METHODS

The 41/43 patients completed the study (18-treatment, 23-placebo). At 12 months: i) the main outcome was liver histology improvement, defined by NAS; ii) the secondary outcome was amelioration of metabolic parameters.

RESULTS

DHA plus vitamin D treatment reduced the NAFLD Activity Score (NAS), in the treatment group (5.4 v1.92; p<0.001 for baseline versus end of study). There was no change in fibrosis score, but a reduction of the activation of hepatic stellate cells (HSC) and fibrillar collagen content was noted (3.51±1.66 v. 1.59±1.37; p = 0.003) in treatment group. Moreover, the triglycerides (174.5 vs. 102.15 mg/dl), ALT (40.25 vs. 24.5 UI/l) and HOMA-IR (4.59 vs. 3.42) were all decreased with treatment.

CONCLUSION

DHA plus vitamin D treatment improved insulin-resistance, lipid profile, ALT and NAS. There was also decreased HSC activation and collagen content with treatment.

Human B-cell memory is shaped by age- and tissue-specific T-independent and GC-dependent events

Switched and IgM memory B cells execute different and noninterchangeable functions. We studied memory B cells in children of different ages, in peripheral blood and spleen and compared them with those of children born asplenic or unable to build germinal centers. We show that, whereas switched memory B cells are mostly generated in the germinal centers at all ages, IgM memory B cells can be distinct in three types with different developmental history. Innate IgM memory B cells, the largest pool in infants, are generated in the spleen by a germinal center-independent mechanism. With age, if the spleen is present and germinal centers are functional, innate IgM memory B cells are remodelled and accumulate somatic mutations. The third type of IgM memory B cell is a by-product of the germinal center reaction. Our data suggest that the B-cell memory developmental program is implemented during the first 5-6 years of life.