Outcome of primary hemophagocytic lymphohistiocytosis: a report on 143 patients from the Italian Registry.

Primary hemophagocytic lymphohistiocytosis (pHLH) is a severe, life-threatening hyperinflammatory syndrome caused by defects in genes of the granule-dependent cytotoxic pathway. Here we investigated the clinical presentation and outcome in a large cohort of 143 patients with pHLH diagnosed in the last 15 years and enrolled in the Italian registry. The median age at diagnosis was 12 months (IQR 2-81), and ninety-two patients (64%) fulfilled the HLH-2004 criteria. Out of 111 patients who received first-line combined therapy (HLH-94, HLH-2004, Euro-HIT protocols), 65 (59%) achieved complete response (CR) and 21 (19%) partial response (PR). Thereafter, 33 patients (30%) reactivated, and 92 (64%) received HSCT, 78 of whom (85%) survived and were alive at a median follow-up from diagnosis of 67 months. Thirty-six patients (25%) died before HSCT and 14 (10%) after. Overall, 93 patients (65%) were alive after a median follow-up of 30 months. Unadjusted predictors of non-response were age.

First Case of VIM-1-like-Producing Pseudomonas putida Bacteremia in an Oncohematological Pediatric Patient in Italy.

Bacterial infections caused by multidrug-resistant (MDR) Gram-negatives are of great concern worldwide, as they are frequently associated with high mortality and morbidity rates. To date, two cases of VIM-2 metallo-ß-lactamase (MBL)-producing Pseudomonas putida bacteremia have been ever reported in France and Spain between 2004 and 2010. Here, we present the first case of VIM-1-like-producing P. putida isolated in blood culture collected from an oncohematological pediatric patient admitted to Bambino Gesù Children's Hospital (IRCCS) in Rome, Italy.

Achievement of operational tolerance in a pediatric liver transplant recipient following successful hematopoietic stem cell transplantation from a different donor.

Hematopoietic stem cell transplantation (HSCT)-based approaches are increasingly investigated strategies to induce tolerance in recipients of solid allografts. However, in the majority of cases, these approaches rely on the infusion of hematopoietic stem cells recovered from the same solid organ donor. In this report, we describe the case of a boy who received liver transplantation from a deceased donor, who had successfully underwent allogeneic HSCT from an unrelated donor for hepatitis-associated aplastic anemia. In this patient, it was possible to permanently withdraw post-HSCT immune suppression without causing any sign of liver graft dysfunction. To the best of our knowledge, this is the first case of operational tolerance documented in a patient who received combined liver transplantation and HSCT from different donors.

Human leukocyte antigen evolutionary divergence influences outcomes of paediatric patients and young adults affected by malignant disorders given allogeneic haematopoietic stem cell transplantation from unrelated donors.

High genetic heterogeneity in the human leukocyte antigen (HLA) increases the likelihood of efficient immune response to pathogens and tumours. As measure of HLA diversity, HLA evolutionary divergence (HED) has been shown to predict the response of tumours to immunotherapy and haematopoietic stem cell transplantation (HSCT) in adults. We retrospectively investigated the association of HED with outcomes of 153 paediatric/young adults patients, treated for malignant disorders with HSCT from 9-10/10 HLA-matched unrelated donors. HED was calculated as pairwise genetic distance between alleles in patient HLA-A, -B, -C, -DRB1, -DQB1 and -DPB1, using the locus median to stratify patients with 'high' or 'low' HED. Patients with high HED-B and -DRB1 showed significantly improved disease-free survival (DFS), especially when combined (70.8% vs 53.7% p = 0.008). High HED-B + -DRB1 was also associated with improved overall survival (OS) (82.1 vs 66.4% p = 0.014), and concomitant reduction of non-relapse-mortality (5.1% vs 21.1% p = 0.006). The impact on OS and DFS of combined HED-B + -DRB1 was confirmed in multivariate analysis [hazard ratio (HR) 0.39, p = 0.009; and HR 0.45, p = 0.007 respectively]. Only high HED scores for HLA-DPB1 were associated, in univariate analysis, with reduced incidence of relapse (15.9% vs 31.1%, p = 0.03). These results support HED as prognostic marker in allogeneic HSCT and, if confirmed in larger cohorts, would allow its use to inform clinical risk and potentially influence clinical practice.

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.

A Prospective, Multicenter Study of Closed-System Extracorporeal Photopheresis for Children with Steroid-Refractory Acute Graft-versus-Host Disease.

Therapy for steroid-refractory (SR) acute graft-versus-host disease (aGVHD) involves intensive immunosuppression, which is associated with significant risk of infection. Extracorporeal photopheresis (ECP) is used to treat SR-aGVHD and is considered more immunomodulatory than immunosuppressive. However, pediatric data are mostly retrospective and often involve multistep ECP that includes apheresis followed by separate photosensitizing/reinfusion on another device. This study aimed to prospectively evaluate the efficacy and safety of a single-device ECP system in children with SR-aGVHD. In this open-label multicenter phase 3 study of the Therakos CellEx Photopheresis System in children/young adults age 1 to 21 years with SR-aGVHD. Patients were treated 3 times per week for 4 weeks, then twice weekly through week 12 while maintaining standard aGVHD prophylaxis. The primary efficacy endpoint was the proportion of patients achieving an overall response (OR) at day +28 without the addition of next-line systemic treatment. Secondary endpoints included the proportion of patients achieving OR at weeks 8 and 12; the mean weekly steroid dose at weeks 4, 8, and 12; and treatment-emergent adverse events (TEAEs). Twenty-nine children (median age, 8 years) were enrolled. OR was 55% by day 28, 74% by week 8, and 79% by week 12. Progressive improvements were observed in the skin and the gastrointestinal tract. The mean steroid dose was decreased from 1.54 mg/kg/day at baseline to 0.90 mg/kg/day at week 4; 35% of patients achieved a >50% steroid dose reduction by week 4, and 75% achieved a >50% steroid dose reduction by week 12. Of the 168 TEAEs reported among 25 patients (86%), 28 events (17%) were infections and 14 events (8%) were considered likely treatment related (all nonserious). Of 627 ECP treatments administered in children and young adults, 68% required blood priming. TEAEs related to Uvadex or ECP were rare, hypocalcemia was the most common (3 events total). Three deaths occurred and were deemed unrelated to ECP by the investigators. Use of the Therakos CellEx Photopheresis System was effective in children with SR-aGVHD, with more than one-half experiencing improvement by day 28 and further responses observed over 12 weeks. Very few TEAEs were attributable to ECP, and no new safety signals were observed.

ALK-positive histiocytosis: a new clinicopathologic spectrum highlighting neurologic involvement and responses to ALK inhibition.

ALK-positive histiocytosis is a rare subtype of histiocytic neoplasm first described in 2008 in 3 infants with multisystemic disease involving the liver and hematopoietic system. This entity has subsequently been documented in case reports and series to occupy a wider clinicopathologic spectrum with recurrent KIF5B-ALK fusions. The full clinicopathologic and molecular spectra of ALK-positive histiocytosis remain, however, poorly characterized. Here, we describe the largest study of ALK-positive histiocytosis to date, with detailed clinicopathologic data of 39 cases, including 37 cases with confirmed ALK rearrangements. The clinical spectrum comprised distinct clinical phenotypic groups: infants with multisystemic disease with liver and hematopoietic involvement, as originally described (Group 1A: 6/39), other patients with multisystemic disease (Group 1B: 10/39), and patients with single-system disease (Group 2: 23/39). Nineteen patients of the entire cohort (49%) had neurologic involvement (7 and 12 from Groups 1B and 2, respectively). Histology included classic xanthogranuloma features in almost one-third of cases, whereas the majority displayed a more densely cellular, monomorphic appearance without lipidized histiocytes but sometimes more spindled or epithelioid morphology. Neoplastic histiocytes were positive for macrophage markers and often conferred strong expression of phosphorylated extracellular signal-regulated kinase, confirming MAPK pathway activation. KIF5B-ALK fusions were detected in 27 patients, whereas CLTC-ALK, TPM3-ALK, TFG-ALK, EML4-ALK, and DCTN1-ALK fusions were identified in single cases. Robust and durable responses were observed in 11/11 patients treated with ALK inhibition, 10 with neurologic involvement. This study presents the existing clinicopathologic and molecular landscape of ALK-positive histiocytosis and provides guidance for the clinical management of this emerging histiocytic entity.

Case Report: Early Association of Vemurafenib to Standard Chemotherapy in Multisystem Langerhans Cell Histiocytosis in a Newborn: Taking a Chance for a Better Outcome?

Langerhans cell histiocytosis (LCH) is due to aberrant monoclonal proliferation and accumulation of dendritic cells, ranging from a self-limiting local condition to a rapidly progressive multisystem disease with poor prognosis. Pathogenic cells originate from a myeloid-derived precursor characterized by an activation of the MAPK/ERK signaling pathway in about 70% of cases. In particular, BRAF V600E mutation is usually associated with a more severe clinical course and poor response to chemotherapy. We report on a newborn with multisystem LCH in life-threatening medical conditions. At diagnosis, the patient was successfully treated with the early association of BRAF inhibitor Vemurafenib to standard chemotherapy representing a new approach in first-line treatment. A rapid clinical improvement with a prompt fever regression from day 2 and complete resolution of skin lesions by week 2 were observed; laboratory data normalized as well. Vemurafenib was discontinued after 12 months of treatment. No signs of relapse occurred after 12 months of discontinuation. This case indicates that early combination of target therapy with standard treatment may induce rapid response and prolonged disease remission without significant toxicities in infants. This approach represents a valid and safe option as first-line treatment in multisystem disease, especially in high-risk patients.

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.

ALK-rearranged histiocytosis: Report of two cases with involvement of the central nervous system.

AIMS: Histiocytoses are a heterogeneous group of localized or disseminated diseases. Clinical presentation and patients' outcome vary greatly, ranging from mild to life-threatening disorders. Rare cases of systemic or localized histiocytosis harboring ALK rearrangement have been reported. METHODS: Two cases of CNS histiocytosis were thoroughly investigated by implementing multiple molecular tests, i.e. FISH, RT-qPCR, NGS analysis. RESULTS: In a 10-month old girl (patient #1), MRI showed two left hemispheric lesions and a right fronto-mesial lesion histologically consisting of a moderately cellular infiltrative proliferation, composed by CD68(PGM1)+/CD163+ spindle cells. ALK 5'/3'-imbalance and a KIF5B(exon 24)-ALK(exon 20) fusion were documented by RT-qPCR and NGS analysis, respectively. A subsequent CT scan showed multiple hepatic and pulmonary lesions. The patient was started on chemotherapy (vinblastine) associated to an ALK-inhibitor (Alectinib) with remarkable response. In a 11-year-old girl (patient #2), MRI showed a right frontal 1.5 cm lesion. Neuropathological examination revealed a histiocytic proliferation composed by medium sized CD68(PGM1)+/HLA-DR+ cells, showing moderate ALK1 positivity. ALK rearrangement and a KIF5B(exon 24)-ALK(exon 20) fusion were demonstrated also in this case. Subsequent CT, 18F-FDG-PET and MRI scans showed the presence of a single right femoral lesion, proved to be a fibrous cortical defect. CONCLUSIONS: In ALK-histiocytoses, CNS involvement may occur as part of a systemic disease or, rarely, as its only primary disease localization, which could remain otherwise asymptomatic. The diagnosis often relies on neuropathological examination of brain biopsy, which may pose a diagnostic challenge due to the variable histopathological features. An integrated histological and molecular approach in such cases is recommended.

HLA-haploidentical TCRαß+/CD19+-depleted stem cell transplantation in children and young adults with Fanconi anemia.

We report on the outcome of 24 patients with Fanconi anemia (FA) lacking an HLA matched related or unrelated donor, given an HLA-haploidentical T-cell receptor αß (TCRαß+) and CD19+ cell-depleted hematopoietic stem cell transplantation (HSCT) in the context of a prospective, single-center phase 2 trial. Sustained primary engraftment was achieved in 22 (91.6%) of 24 patients, with median time to neutrophil recovery of 12 days (range, 9-15 days) and platelet recovery of 10 days (range, 7-14 days). Cumulative incidences of grade 1 to 2 acute graft-versus-host disease (GVHD) and chronic GVHD were 17.4% (95% confidence interval [CI], 5.5%-35.5%) and 5.5% (95% CI, 0.8%-33.4%), respectively. The conditioning regimen, which included fludarabine, low-dose cyclophosphamide and, in most patients, single-dose irradiation was well tolerated; no fatal transplant-related toxicity was observed. With a median follow-up of 5.2 years (range, 0.3-8.7 years), the overall and event-free survival probabilities were 100% and 86.3% (95% CI, 62.8%-95.4%), respectively (2 graft failures and 1 case of poor graft function were considered as events). The 2 patients who experienced primary graft failure underwent a subsequent successful HSCT from the other parent. This is the first report of FA patients given TCRαß+/CD19+-depleted haplo-HSCT in the context of a prospective trial, and the largest series of T-cell-depleted haplo-HSCT in FA reported to date. This trial was registered at www.clinicaltrials.gov as #NCT01810120.

Monocyte-macrophage polarization and recruitment pathways in the tumour microenvironment of B-cell acute lymphoblastic leukaemia.

B-cell acute lymphoblastic leukaemia (B-ALL) reprograms the surrounding bone marrow (BM) stroma to create a leukaemia-supportive niche. To elucidate the contribution of immune cells to the leukaemic microenvironment, we investigated the involvement of monocyte/macrophage compartments, as well as several recruitment pathways in B-ALL development. Immunohistochemistry analyses showed that CD68-expressing macrophages were increased in leukaemic BM biopsies, compared to controls and predominantly expressed the M2-like markers CD163 and CD206. Furthermore, the "non-classical" CD14+ CD16++ monocyte subset, expressing high CX3CR1 levels, was significantly increased in B-ALL patients' peripheral blood. CX3CL1 was shown to be significantly upregulated in leukaemic BM plasma, thus providing an altered migratory pathway possibly guiding NC monocyte recruitment into the BM. Additionally, the monocyte/macrophage chemoattractant chemokine ligand 2 (CCL2) strongly increased in leukaemic BM plasma, possibly because of the interaction of leukaemic cells with mesenchymal stromal cells and vascular cells and due to a stimulatory effect of leukaemia-related inflammatory mediators. C5a, a macrophage chemoattractant and M2-polarizing factor, further appeared to be upregulated in the leukaemic BM, possibly as an effect of PTX3 decrease, that could unleash complement cascade activation. Overall, deregulated monocyte/macrophage compartments are part of the extensive BM microenvironment remodelling at B-ALL diagnosis and could represent valuable targets for novel treatments to be coupled with classical chemotherapy.

ERAP1 and ERAP2 Enzymes: A Protective Shield for RAS against COVID-19?

Patients with coronavirus disease 2019 (COVID-19) have a wide variety of clinical outcomes ranging from asymptomatic to severe respiratory syndrome that can progress to life-threatening lung lesions. The identification of prognostic factors can help to improve the risk stratification of patients by promptly defining for each the most effective therapy to resolve the disease. The etiological agent causing COVID-19 is a new coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that enters cells via the ACE2 receptor. SARS-CoV-2 infection causes a reduction in ACE2 levels, leading to an imbalance in the renin-angiotensin system (RAS), and consequently, in blood pressure and systemic vascular resistance. ERAP1 and ERAP2 are two RAS regulators and key components of MHC class I antigen processing. Their polymorphisms have been associated with autoimmune and inflammatory conditions, hypertension, and cancer. Based on their involvement in the RAS, we believe that the dysfunctional status of ERAP1 and ERAP2 enzymes may exacerbate the effect of SARS-CoV-2 infection, aggravating the symptomatology and clinical outcome of the disease. In this review, we discuss this hypothesis.

Langerhans cell histiocytosis in a young patient with Pitt-Hopkins syndrome.

Pitt-Hopkins syndrome (PTHS, MIM #610954) is a rare neurodevelopmental disease characterized by the association of intellectual disability, characteristic facial gestalt and episodes of abnormal and irregular breathing. PTHS is due to heterozygous loss-of-function variants in the TCF4 gene (transcription factor 4, MIM #602272) encoding for a basic helix-loop-helix transcription factor. TCF4 is highly expressed during early development of the nervous system, and it is involved in cellular differentiation and proliferation. Since the first clinical description in 1978, less than 200 PTHS patients have been described. A comprehensive phenotype, especially regarding cancer predisposition, is not yet well defined. We report the case of a 7-year-old boy affected by PTHS with a 4-week history of progressive swelling of the frontal bones diagnosed with Langerhans cell histiocytosis.

Cord blood transplantation for acute leukemia.

INTRODUCTION: Umbilical cord blood transplantation (UCBT) is a suitable alternative for patients with acute leukemia (AL) in need of an allograft and who lack an HLA-matched donor. Single-institution and registry studies have shown that, in both children and adults with AL, the outcome of UCBT is comparable to that of matched unrelated donor. At the same time, these studies have highlighted some limitations of UCBT, such as increased early mortality and delayed recovery of both hematopoietic and immune compartment, which hamper a more widespread adoption of this approach. AREAS COVERED: In this review, we will analyze the current results of UCBT in children and adults with AL, including comparisons with other hematopoietic stem cell sources and transplant strategies. We will also discuss important factors to be considered when selecting UCB units, as well as future strategies to further improve the outcome of UCBT recipients. EXPERT OPINION: The utilization of UCBT for the treatment of AL patients has decreased in recent years. However, recent clinical data suggesting that UCBT might offer better results in patients with minimal residual disease, as well as innovative strategies to facilitate engraftment, reduce transplant-related mortality, and optimize anti-leukemic activity, may pave the way toward a second youth for use of UCB cells.