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Key Points TCRαβ/CD19-depleted HLA-haploidentical HSCT is an effective strategy for children with several nonmalignant disorders.Patients given this type of transplant benefit from a low incidence of GVHD and TRM, with graft failure being the main obstacle., Visual Abstract, Several nonmalignant disorders (NMDs), either inherited or acquired, can be cured by allogeneic hematopoietic stem cell transplantation (HSCT). Between January 2012 and April 2020, 70 consecutive children affected by primary immunodeficiencies, inherited/acquired bone marrow failure syndromes, red blood cell disorders, or metabolic diseases, lacking a fully matched donor or requiring urgent transplantation underwent TCRαβ/CD19-depleted haploidentical HSCT from an HLA-partially matched relative as part of a prospective study. The median age at transplant was 3.5 years (range 0.3-16.1); the median time from diagnosis to transplant was 10.5 months (2.7 for SCID patients). Primary engraftment was obtained in 51 patients, while 19 and 2 patients experienced either primary or secondary graft failure (GF), the overall incidence of this complication being 30.4%. Most GFs were observed in children with disease at risk for this complication (eg, aplastic anemia, thalassemia). All but 5 patients experiencing GF were successfully retransplanted. Six patients died of infectious complications (4 had active/recent infections at the time of HSCT), the cumulative incidence of transplant-related mortality (TRM) being 8.5%. Cumulative incidence of grade 1-2 acute GVHD was 14.4% (no patient developed grade 3-4 acute GVHD). Only one patient at risk developed mild chronic GVHD. With a median follow-up of 3.5 years, the 5-year probability of overall and disease-free survival was 91.4% and 86.8%, respectively. In conclusion, TCRαβ/CD19-depleted haploidentical HSCT from an HLA-partially matched relative is confirmed to be an effective treatment of children with NMDs. Prompt donor availability, low incidence of GVHD, and TRM make this strategy an attractive option in NMDs patients. The study is registered at ClinicalTrial.gov as NCT01810120.

Immune Thrombocytopenia (ITP) is an autoimmune disease characterized by autoantibodies-mediated platelet destruction, a prevalence of M1 pro-inflammatory macrophage phenotype and an elevated T helper 1 and T helper 2 lymphocytes (Th1/Th2) ratio, resulting in impairment of inflammatory profile and immune response. Macrophages are immune cells, present as pro-inflammatory classically activated macrophages (M1) or as anti-inflammatory alternatively activated macrophages (M2). They have a key role in ITP, acting both as effector cells, phagocytizing platelets, and, as antigen presenting cells, stimulating auto-antibodies against platelets production. Eltrombopag (ELT) is a thrombopoietin receptor agonist licensed for chronic ITP to stimulate platelet production. Moreover, it improves T and B regulatory cells functions, suppresses T-cells activity, and inhibits monocytes activation. We analyzed the effect of ELT on macrophage phenotype polarization, proposing a new possible mechanism of action. We suggest it as a mediator of macrophage phenotype switch from the M1 pro-inflammatory type to the M2 anti-inflammatory one in paediatric patients with ITP, in order to reduce inflammatory state and restore the immune system function. Our results provide new insights into the therapy and the management of ITP, suggesting ELT also as immune-modulating drug.

Background: allogeneic HSCT is the only potentially curative treatment for many non-malignant diseases (NMD), either inherited or acquired. However, many patients lack an HLA-matched donor (familiar (MFD) or unrelated (MUD)) and the outcome of children transplanted from an HLA-haploidentical relative (haplo) was historically inferior to that of transplants from a MFD or a MUD. We previously published promising results in a cohort of 23 children with NMD given this type of allograft (Bertaina et al., Blood 2014), demonstrating a low transplant-related mortality (TRM) and high cure rates. Here, we report the outcome of a large cohort of children affected by NMD who received a TBdepl-haploHSCT at our Center (NCT01810120). Patients and methods: Between February 2011 and June 2020, 80 consecutive patients affected by NMD received TBdepl-haploHSCT from an HLA-partially matched relative at Ospedale Pediatrico Bambino Gesù in Rome, Italy. Patients had many different disorders (see Table for details on patient- and transplant-related characteristics). Median time from diagnosis to transplant for the whole cohort was 12 months (range 1-177), while it was 2.5 months (range 1.3-11.2) for SCID patients. All patients, including children with SCID, received a conditioning regimen, which varied according to the original disease. Pre-transplant anti-thymocyte globulins (from day -4 to day -2) were given to modulate bi-directional donor/recipient alloreactivity, while rituximab (on day -1) was administered to prevent PTLD. Moreover, no post-transplant pharmacological GvHD prophylaxis was given. Results: fifty-eight patients (72.5%) achieved primary donor cell engraftment, while 3 patients experienced secondary graft failure (GF); the cumulative incidence of either primary or secondary GF was 27.8% (95% CI 17.2-37.0). Median time to neutrophil and platelet recovery was 13.5 (range 9-33) and 10 days (range 7-51), respectively. As expected, GF occurred more frequently in children with disorders known to be associated with an increased GF risk (i.e., HLH, thalassemia, SAA or osteopetrosis) (see also Figure 1A). Three children (4%) experiencing GF died because of infectious complications before retransplant. Sixteen of the 22 patients with either primary or secondary GF were successfully retransplanted (2 with a mismatched unrelated cord blood unit, the other having received a second TBdepl-haploHSCT from either the same donor or the other parent). Since 3 other patients died [all because of infectious complications, 2 due to disseminated adenovirus infection and 1 to CMV pneumonia)], TRM is 7.8% (95% CI 1.6-13.7). Eighteen patients experienced acute GVHD of any grade, the cumulative incidence of this complication being 22% (95% CI 13.5-31.8); 10/18 patients developed grade II acute GVHD (no patient developed grade III or IV aGVHD), this resulting into a cumulative incidence of 12.9% (95% CI 6.6-21.4). Only one patient at risk developed mild chronic GVHD. Twenty-two and 7 patients developed clinically-relevant (i.e., with a viral load > 1000 copies/ml and/or requiring specific antiviral-treatment) CMV and adenovirus infection, respectively, at a median time of 4 (range 0-16) and 1 (range 1-4) weeks from HSCT. Time averaged area under the curve (i.e., viral burden under the curve/weeks at risk for infection) for CMV and ADV are reported in Figure 1B. With a median follow-up of 36 months (range 2 - 110), the 5-year probability of overall survival and event-free survival for the entire cohort of patients is 92.1% (95% CI 83.3-96.4) (Figure 1C) and 68.1% (95% CI 56.4-77.2), respectively. Considering the 16/22 given a successful 2nd allograft, the 5-year disease-free survival is 88.4% (95% CI 78.9-93.8). Details on reconstitution of CD3+, CD4+ and CD8+ lymphocytes are reported in Figure 1D. Conclusions: TBdepl-haploHSCT is an effective option for children with different NMD. GF (either primary or secondary) is a challenging problem in a sub-group of patients at risk (i.e., those with HLH, thalassemia, SAA or osteopetrosis): thus, new strategies to overcome this problem are desirable. However, a second transplant is able to rescue most of these patients. Prompt availability of this type of transplant, limiting infectious risk, low incidence of both acute and chronic GvHD preserving a good quality of life in patients makes this strategy an attractive choice in patients with NMD. Figure 1 Disclosures Merli: Bellicum Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; SOBI: Consultancy, Membership on an entity's Board of Directors or advisory committees; Jazz: Honoraria; Sanofi-Genzyme: Honoraria; Atara Therapeutics: Honoraria. Algeri:BlueBird Bio: Membership on an entity's Board of Directors or advisory committees; Atara Therapeutics: Membership on an entity's Board of Directors or advisory committees. Locatelli:Jazz Pharmaceeutical: Speakers Bureau; Medac: Speakers Bureau; Miltenyi: Speakers Bureau; Bellicum Pharmaceutical: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau.

Interferon-gamma (IFN-γ) plays a key role in the pathophysiology of hemophagocytic lymphohistiocytosis (HLH), and available evidence also points to a role in other conditions, including aplastic anemia (AA) and graft failure following allogeneic hematopoietic stem cell transplantation. Recently, the therapeutic potential of IFN-γ inhibition has been documented; emapalumab, an anti-IFN-γ monoclonal antibody, has been approved in the United States for treatment of primary HLH that is refractory, recurrent or progressive, or in patients with intolerance to conventional therapy. Moreover, ruxolitinib, an inhibitor of JAK/STAT intracellular signaling, is currently being investigated for treating HLH. In AA, IFN-γ inhibits hematopoiesis by disrupting the interaction between thrombopoietin and its receptor, c-MPL. Eltrombopag, a small-molecule agonist of c-MPL, acts at a different binding site to IFN-γ and is thus able to circumvent its inhibitory effects. Ongoing trials will elucidate the role of IFN-γ neutralization in secondary HLH and future studies could explore this strategy in controlling hyperinflammation due to CAR T cells.

Leukemia is the most common childhood malignancy, and it is often characterized by pallor, fatigue, cytopenia, and organomegaly; sometimes musculoskeletal symptoms, mainly characterized by diffuse bone pain in the lower extremities, are the onset clinical characteristics of the disease. In these cases, the disease may initially be misdiagnosed as reactive arthritis, osteomyelitis, or juvenile idiopathic arthritis delaying appropriate diagnosis and management. Even if leukopenia, thrombocytopenia, and a history of nighttime pain are reported to be the most important predictive factors for a pediatric leukemia, blood examinations can sometimes be subtle or within normal limits, and this represents a further diagnostic difficulty. Radiological findings of leukemic bone involvement are described in patients with musculoskeletal symptoms of acute lymphoblastic leukemia and often appear before hematologic anomalies, but they are not specific for the disease. However, they could be helpful to get the right diagnosis if integrated with other features; thus, it is important knowing them, and it is mandatory for the multidisciplinary comparison to talk about dubious cases even in an emergency setting. We describe 4 patients visited in the emergency department for musculoskeletal complaints and having radiological lesions and a final diagnosis of acute lymphoblastic leukemia, in whom the onset of the manifestations could mimic orthopedic/rheumatologic diseases.

Graft failure is a severe complication of allogeneic hematopoietic stem cell transplantation (HSCT). The mechanisms involved in this phenomenon are still not completely understood; data available suggest that recipient T lymphocytes surviving the conditioning regimen are the main mediators of immune-mediated graft failure. So far, no predictive marker or early detection method is available. In order to identify a non-invasive and efficient strategy to diagnose this complication, as well as to find possible targets to prevent/treat it, we performed a detailed analysis of serum of eight patients experiencing graft failure after T-cell depleted HLA-haploidentical HSCT. In this study, we confirm data describing graft failure to be a complex phenomenon involving different components of the immune system, mainly driven by the IFNγ pathway. We observed a significant modulation of IL7, IL8, IL18, IL27, CCL2, CCL5 (Rantes), CCL7, CCL20 (MIP3a), CCL24 (Eotaxin2), and CXCL11 in patients experiencing graft failure, as compared to matched patients not developing this complication. For some of these factors, the difference was already present at the time of infusion of the graft, thus allowing early risk stratification. Moreover, these cytokines/chemokines could represent possible targets, providing the rationale for exploring new therapeutic/preventive strategies.

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 αβ (TCRαβ+) 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 TCRαβ+/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.

TcRαβ/CD19-cell depleted HLA-haploidentical hematopoietic stem cell transplantation (haplo-HSCT) represents a promising new platform for children affected by acute leukemia in need of an allograft and lacking a matched donor, disease recurrence being the main cause of treatment failure. The use of zoledronic acid to enhance TcRγδ+ lymphocyte function after TcRαβ/CD19-cell depleted haplo-HSCT was tested in an open-label, feasibility, proof-of-principle study. Forty-six children affected by high-risk acute leukemia underwent haplo-HSCT after removal of TcRαβ+ and CD19+ B lymphocytes. No post-transplant pharmacological graft-versus-host disease (GvHD) prophylaxis was given. Zoledronic acid was administered monthly at a dose of 0.05 mg/kg/dose (maximum dose 4 mg), starting from day +20 after transplantation. A total of 139 infusions were administered, with a mean of 3 infusions per patient. No severe adverse event was observed. Common side effects were represented by asymptomatic hypocalcemia and acute phase reactions (including fever, chills, malaise, and/or arthralgia) within 24–48 h from zoledronic acid infusion. The cumulative incidence of acute and chronic GvHD was 17.3% (all grade I-II) and 4.8% (all limited), respectively. Patients given 3 or more infusions of zoledronic acid had a lower incidence of both acute GvHD (8.8 vs. 41.6%, p = 0.015) and chronic GvHD (0 vs. 22.2%, p = 0.006). Transplant-related mortality (TRM) and relapse incidence at 3 years were 4.3 and 30.4%, respectively. Patients receiving repeated infusions of zoledronic acid had a lower TRM as compared to those receiving 1 or 2 administration of the drug (0 vs. 16.7%, p = 0.01). Five-year overall survival (OS) and disease-free survival (DFS) for the whole cohort were 67.2 and 65.2%, respectively, with a trend toward a better OS for patients receiving 3 or more infusions (73.1 vs. 50.0%, p = 0.05). The probability of GvHD/relapse-free survival was significantly worse in patients receiving 1–2 infusions of zoledonic acid than in those given ≥3 infusions (33.3 vs. 70.6%, respectively, p = 0.006). Multivariable analysis showed an independent positive effect on outcome given by repeated infusions of zoledronic acid (HR 0.27, p = 0.03). These data indicate that the use of zoledronic acid after TcRαβ/CD19-cell depleted haploHSCT is safe and may result in a lower incidence of acute GvHD, chronic GvHD, and TRM.

Acute myeloid leukemia (AML) is a heterogeneous group of diseases, whose classification is based on lineage-commitment and genetics. Although rare in childhood, it is the most common type of acute leukemia in adults, accounting for 80% of all cases in this age group. The prognosis of this disease remains poor (especially in childhood, as compared to acute lymphoblastic leukemia); however, overall survival has significantly improved over the past 30 years. The health of the oral cavity is a remarkable reflection of the systemic status of an individual. Identification of the signs and symptoms of oral lesions can act as a warning sign of hidden and serious systemic involvement. Moreover, they may be the presenting feature of acute leukemia and provide important diagnostic indicators. Primary oral alterations are identified in up to 90% of cases of acute myeloid leukemia and consist of petechiae, spontaneous bleeding, mucosal ulceration, gingival enlargement with or without necrosis, infections, hemorrhagic bullae on the tongue, and cracked lips. Poor oral hygiene is a well-known risk factor for local and systemic infectious complications. Oro-dental complications due to AML treatment can affect the teeth, oral mucosa, soft and bone tissue, and contribute to opportunistic infections, dental decay, and enamel discoloration. The treatment of acute myeloid leukemia is still associated with high mortality and morbidity. The management is multimodal, involving aggressive multidrug chemotherapy and, in most cases, allogenic bone marrow transplantation. Periodontal and dental treatment for patients with leukemia should always be planned and concerted with hematologists.

Simple Summary GATA2 deficiency is considered one of the most common cancer predisposition syndromes determining myelodysplastic syndrome in children. Little is known of this recently described syndrome, often resulting in a misdiagnosis and unclear management. In this review, we describe GATA2 deficiency clinical presentation in order to focus on phenotypes that, in patients with myelodysplastic syndrome, may be suggestive of GATA2 deficiency. Moreover, due to the lack of clear guidelines, we performed an overview on literature data regarding management of GATA2-related myelodysplastic syndrome, in order to understand the best choice of treatment for these patients. Abstract Myelodysplastic syndromes (MDS) are hematopoietic disorders rare in childhood, often occurring in patients with inherited bone marrow failure syndromes or germinal predisposition syndromes. Among the latter, one of the most frequent involves the gene GATA binding protein 2 (GATA2), coding for a transcriptional regulator of hematopoiesis. The genetic lesion as well as the clinical phenotype are extremely variable; many patients present hematological malignancies, especially MDS with the possibility to evolve into acute myeloid leukemia. Variable immune dysfunction, especially resulting in B- and NK-cell lymphopenia, lead to severe infections, including generalized warts and mycobacterial infection. Defects of alveolar macrophages lead to pulmonary alveolar proteinosis through inadequate clearance of surfactant proteins. Currently, there are no clear guidelines for the monitoring and treatment of patients with GATA2 mutations. In patients with MDS, the only curative treatment is allogeneic hematopoietic stem cell transplantation (HSCT) that restores normal hematopoiesis preventing the progression to acute myeloid leukemia and clears long-standing infections. However, to date, the donor type, conditioning regimen, and the optimal time to proceed to HSCT, as well as the level of chimerism needed to reverse the phenotype, remain unclear highlighting the need for consensus guidelines.

Although recent advances in gene therapy are expected to increase the chance of disease cure in thalassemia major, at present hematopoietic stem cell transplantation (HSCT) remains the only consolidated curative approach for this disorder. The widest experience has been obtained in the HLA-matched family donor (MFD) setting, with probabilities of overall and thalassemia-free survival exceeding 90% and 85%, respectively. As for most patients a suitable MFD is not available, alternative donors (HLA-matched unrelated donor, unrelated cord blood, HLA-haploidentical relative) have been increasingly explored, translating into the expansion of the number of patients treatable with HSCT.

Background: Pediatric myelodysplastic syndromes (MDSs) are a heterogeneous group of clonal disorders, accounting for less than 5% of childhood hematologic malignancies. Usual indications to HSCT are: MDSs with excess of blasts, MDSs secondary to previously administered chemoradiotherapy and RCC associated with monosomy 7, complex karyotype, severe neutropenia, or erythrocyte/platelet transfusion dependence [Locatelli & Strahm, Blood 2018]. We previously demonstrated that TBdepl-haploHSCT is a suitable option for children with acute leukemia, with outcomes comparable to those reported in studies using either an HLA-identical sibling or an unrelated volunteer as donor. Here we present the results of this approach in children with MDSs. Patients and methods: Between February 2013 and February 2021, 23 children with MDSs other than juvenile myelomonocytic leukemia received TBdepl-haploHSCT from an HLA-partially matched relative at Ospedale Pediatrico Bambino Gesù, Rome, Italy or at IRCCS Fondazione Policlinico San Matteo, Pavia, Italy as part of a prospective study (#NCT01810120). All patients were prepared to the allograft using a fully-myeloablative conditioning regimen including a combination of cytotoxic drugs and/or total body irradiation (TBI). Anti-T-lymphocyte globulin (ATLG) was used before transplantation (12 mg/kg total dose, from days -5 to day -3) to modulate bi-directional donor/recipient alloreactivity. Rituximab (200 mg/sqm) was administered on day -1 to prevent post-transplantation EBV-induced lymphoproliferative disorders (PTLD). No patient received any post-transplant pharmacological GvHD prophylaxis. Results: Characteristics of patients enrolled in the study are shown in Table 1 (which reports also donor and graft characteristics). Median follow-up of surviving patients is 4.2 years (range: 0.5 - 8.5 years). Seventeen children were affected by refractory cytopenia of childhood (RCC) (2 cases occurring in the context of inherited bone marrow failure syndromes: one had GATA2 deficiency and the other SAMD9L mutation), while 1 and 5 were affected by MDS with excess of blasts 1 (EB1) and EB2 (one had GATA2 deficiency), respectively. Median time to neutrophil and platelet recovery was 14 (range 10-19) and 11 (range 9-14) days, respectively, with four patients (3 with RCC and 1 with EB2) experiencing primary graft failure, the cumulative incidence of this complication being 17.3% (95% CI 0.3-31.5). All these 4 patients were rescued with a second TBdepl-haploHSCT from the same or the other parent. Cumulative incidence of grade II-III acute GvHD was 11.4% (95% CI 0-25.2). One patient developed skin and gut GvHD after the second TBdepl-haploHSCT, while for all other patients skin was the sole organ involved; no case of grade IV GvHD was observed. One patient developed moderate chronic GvHD [cumulative incidence 5.2% (95% CI 0-14.8)], which completely resolved with low-dose steroids and ruxolitinib. Notably, no patient died for transplant-related complications. Six patients experienced CMV, 2 HHV-6 and 1 adenoviral infection/reactivation; one patient developed lung aspergillosis, which resolved with specific treatment. One patient affected by EB2, not in remission at time of transplant, relapsed 27 months after HSCT, the 5-year cumulative incidence of relapse being 7.1% (95% CI, 0-19.7); she eventually died after failing a second HSCT. The 5-year probability of overall and event-free survival were 92.3% (95% CI 56.6 -98.9) and 76.3% (95% CI 51.3-89.6) (Figure 1A and B), respectively. Five-year disease-free-survival was 90% (95% CI 47.3-98.5). Because of the low number of events, no prognostic factor related to OS and EFS was found. In particular, the MDS variant did not influence the patient's outcome. The median CD3+ cell count on day +30, +90, +180 and +360 were 113, 171, 558 and 1307/mcl, respectively. Conclusions: These data indicate that TBdepl-haploHSCT is a safe and effective transplant option also in children with MDS. Indeed, the low risk of both non-relapse mortality and acute/chronic GvHD makes this approach particularly attractive in the pediatric setting. Moreover, this haplo strategy compares favorably with T-cell replete approaches [Suo et al., 2020]. Figure 1 Figure 1. Disclosures Merli: JAZZ: Consultancy; SOBI: Consultancy. Locatelli: Miltenyl: Honoraria; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bellicum: Consultancy, Membership on an entity's Board of Directors or advisory committees; bluebird bio, Inc.: Consultancy; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees.

Summary Achieving complete remission (CR) in childhood relapsed/refractory acute lymphoblastic leukaemia (ALL) is a difficult task. Bortezomib, a proteasome inhibitor, has in vitro activity against ALL blasts. A phase I-II trial, reported by the Therapeutic Advances in Childhood Leukaemia and Lymphoma (TACL) consortium, demonstrated that bortezomib with chemotherapy has acceptable toxicity and remarkable activity in patients with relapsed ALL failing 2–3 previous regimens. We evaluated bortezomib in combination with chemotherapy in 30 and 7 children with B-cell precursor (BCP) and T-cell ALL, respectively. Bortezomib (1·3 mg/m2/dose) was administered intravenously on days 1, 4, 8, and 11. Chemotherapy agents were the same as those used in the TACL trial, consisting of dexamethasone, doxorubicin, vincristine and pegylated asparaginase. Three patients (8·1%) died due to infections. Twenty-seven patients (72·9%) achieved CR or CR with incomplete platelet recovery (CRp). Fourteen had minimal residual disease (MRD) lower than 0·1%. Twenty-two of 30 BCP-ALL patients (73·3%) and 5/7 patients (71%) with T-cell ALL achieved CR/CRp. The 2-year overall survival (OS) is 31·3%; CR/CRp patients with an MRD response had a remarkable 2-year OS of 68·4%. These data confirm that the combination of bortezomib with chemotherapy is a suitable/effective option for childhood relapsed/refractory ALL.

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.

GATA2 gene encodes a zinc finger transcription factor crucial for normal hematopoiesis. Its haploinsufficiency, caused by a great variety of heterozygous loss-of-function mutations, underlies one of the most common causes of inherited bone marrow failure, recognized as GATA2 deficiency. Its phenotype is characterized by a broad spectrum of clinical presentations, including: haematological malignancies; immunodeficiency leading to invasive viral, mycobacterial and fungal infections; recurrent warts; lymphedema; pulmonary alveolar proteinosis; deafness; and miscarriage. The onset of symptoms ranges from early childhood to late adulthood, more frequently between adolescence and early adulthood. The only curative treatment is allogenic hematopoietic stem cell transplantation (HSCT), that can restore the function of both hematopoietic and immune system and prevent lung deterioration. Currently, there are no consensus guidelines about the management of patients affected by GATA2 deficiency, especially with regard to the optimal time to proceed to HSCT.

Acute promyelocytic leukemia (APL) represents a paradigm of precision medicine. Indeed, in the last decades, the introduction of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) completely revolutionized the therapeutic approach to this previously highly fatal disorder. This entirely chemotherapy-free treatment, which provided excellent survival rates, has been initially validated in adults and, recently, translated in the pediatric setting. This review summarizes currently available data on the use of ATRA and ATO combination in pediatric APL, providing a particular focus on peculiar issues and challenges, such as the occurrence of pseudotumor cerebri and death during induction (early death), as well as the advantage offered by the ATO/ATRA combination in sparing long-term sequelae.

Juvenile myelomonocytic leukemia (JMML) is a clonal hematopoietic disorder of infancy/early childhood, resulting from oncogenic mutations in genes involved in the Ras pathway. As JMML often exhibits an aggressive course, the timing of diagnosis and treatment is critical to outcome. Areas covered: This review summarizes current approaches to diagnosis and treatment of JMML, highlighting most recent insights into genetic and epigenetic mechanisms underlying the disease, and providing an overview of novel potential therapeutic strategies. Expert commentary: At present, allogeneic HSCT remains the only potentially effective therapy, being able to cure more than 50% of patients, relapse representing the main cause of treatment failure. Prompt HSCT is recommended for all children with NF1, somatic PTPN11 and KRAS mutations, and for most children with somatic NRAS mutations. Conversely, a 'watch and wait' strategy should be adopted in children with germline CBL mutations, specific somatic NRAS mutation, and in Noonan syndrome patients, since spontaneous resolution has been reported to occur. Novel drugs targeting relevant nodes of JMML leukemogenesis have been explored in pre-HSCT window or at relapse. The use of 5-azacytidine, a DNA-hypomethylating agent reported to induce hematologic and molecular remission in some JMML children, is currently being investigated in clinical trials.

Eltrombopag is an orally bioavailable, non-peptide thrombopoietin receptor agonist capable of stimulating platelet production through the differentiation of CD34+ hematopoietic progenitor cells into committed CD41+ megakaryocyte precursors and proliferation of megakaryocyte progenitor cells.This drug has been tested in several clinical trials in adult patients with chronic immune thrombocytopenia (ITP), demonstrating the ability of the drug to reduce the burden of thrombocytopenia and its associated side effects. Two multicenter trials on eltrombopag in chronic ITP of childhood have been recently completed, showing that the drug is effective also in pediatric patients. Recent studies have suggested a potential role of eltrombopag in the treatment of thrombocytopenia associated with hepatitis-C virus infection. These studies have documented that adjunct treatment with eltrombopag can help avoid either dose reductions or withdrawal of pegylated interferon due to development of thrombocytopenia. Eltrombopag has shown efficacy also in patients with acquired severe aplastic anemia and myelodysplastic syndromes.Eltrombopag plays an important therapeutic role in many different conditions characterized by persistent thrombocytopenia. A more comprehensive definition of both long-term safety and benefits deriving from the use of eltrombopag will be obtained through prolonged observation of patients already enrolled in the different studies conducted so far and from future prospective controlled trials.

Introduction: Current challenges in the field of hematopoietic stem cell transplantation (HSCT) for hemoglobinopathies include the possibility of using alternative donors to expand the number of candidates to an allograft. Umbilical cord blood transplantation (UCBT) have extended the access to HSCT in patients lacking matched related or unrelated adult donors, and appears particularly appealing in non-malignant diseases by virtue of the associated low incidence of graft-versus-host disease (GVHD).Areas covered: Outcomes of patients with thalassemia or sickle cell disease given related UCBT is at least as good as that of patients receiving bone marrow (BM) allograft from human leucocyte antigen (HLA)-identical siblings, provided the UCB unit contains adequate cell dose. The experience with unrelated UCBT has been less encouraging, primarily due to low engraftment rates and delayed hematopoietic recovery. New promising approaches of ex vivo graft manipulation aimed at overcoming the drawback of cell dose li...

Although allogeneic haematopoietic stem cell transplantation (HSCT) still represents the only consolidated possibility of cure for sickle cell disease (SCD) patients, its use has been limited by the risk of morbidity and mortality associated with conventional myeloablative therapy. The introduction of treosulfan to replace busulfan in conditioning regimens has recently been explored by virtue of its lower toxicity profile. We report our experience with a treosulfan/thiotepa/fludarabine conditioning for human leucocyte antigen (HLA)-matched sibling or unrelated donor-HSCT in 15 children with SCD, and compare patient outcomes with those of a historical cohort (15 patients) given a busulfan-based regimen. Engraftment was achieved in 28 out of 30 patients (93%), with one case of graft failure in either group. The conditioning regimen was well tolerated in both groups, with no cases of grade III-IV regimen-related toxicity. The 7-year overall survival (OS) and disease-free survival (DFS) for the whole cohort were 100% and 93%, respectively, with a 93% DFS in both busulfan and treosulfan groups. No SCD-related adverse events occurred after engraftment in patients with complete or mixed donor chimerism. This retrospective analysis suggests that a treosulfan-based conditioning regimen is able to ensure engraftment with excellent OS/DFS and low regimen-related toxicity in patients with SCD.

Hematopoietic stem cell transplantation (HSCT) has significantly modified the natural history of many malignant and non-malignant disorders occurring in pediatric patients. In particular, allogeneic HSCT still represents the treatment of choice for life-threatening conditions, such as primary immune deficiencies or high-risk/relapsed leukemia, or the more effective option to improve the quality of life of patients with hemoglobinopathies. Continuous advances in transplantation outcomes achieved through the past three to four decades have led to the progressive expansion of the indications for HSCT, which is now used with success in several malignant and non-malignant disorders.

Allogeneic hematopoietic stem cell transplantation (HSCT) from an HLA-haploidentical relative (haplo-HSCT) is a suitable option for children with acute leukemia (AL) either relapsed or at high-risk of treatment failure. We developed a novel method of graft manipulation based on negative depletion of αβ T and B cells and conducted a prospective trial evaluating the outcome of children with AL transplanted with this approach. Eighty AL children, transplanted between September 2011 and September 2014, were enrolled in the trial. All children were given a fully myeloablative preparative regimen. Anti-T-lymphocyte globulin from day -5 to -3 was used for preventing graft rejection and graft-versus-host disease (GVHD); no patient received any posttransplantation GVHD prophylaxis. Two children experienced primary graft failure. The cumulative incidence of skin-only, grade 1-2 acute GVHD was 30%; no patient developed extensive chronic GVHD. Four patients died, the cumulative incidence of nonrelapse mortality being 5%, whereas 19 relapsed, resulting in a 24% cumulative incidence of relapse. With a median follow-up of 46 months for surviving patients, the 5-year probability of chronic GVHD-free, relapse-free survival (GRFS) is 71%. Total body irradiation-containing preparative regimen was the only variable favorably influencing relapse incidence and GRFS. The outcomes of these 80 patients are comparable to those of 41 and 51 children given transplantation from an HLA-identical sibling or a 10/10 allelic-matched unrelated donor in the same period. These data indicate that haplo-HSCT after αβ T- and B-cell depletion represents a competitive alternative for children with AL in need of urgent allograft. This trial was registered at www.clinicaltrials.gov as #NCT01810120.

We report the outcome of 12 consecutive pediatric patients with Fanconi anemia (FA) who had neither an HLA-identical sibling nor an HLA-matched unrelated donor and who were given T cell–depleted, CD34+ positively selected cells from a haploidentical related donor after a reduced-intensity, fludarabine-based conditioning regimen. Engraftment was achieved in 9 of 12 patients (75%), and the cumulative incidence of graft rejection was 17% (95% confidence interval [CI], 5% to 59%). Cumulative incidences of grades II to IV acute and chronic graft-versus-host disease were 17% (95% CI, 5% to 59%) and 35% (95% CI, 14% to 89%), respectively. The conditioning regimen was well tolerated, with no fatal regimen-related toxicity and 3 cases of grade III regimen-related toxicity. The cumulative incidence of transplant-related mortality was 17% (95% CI, 5% to 59%). The 5-year overall survival, event-free survival, and disease-free survival were 83% (95% CI, 62% to 100%), 67% (95% CI, 40% to 93%), and 83% (95% CI, 62% to 100%), respectively. These data demonstrate that a fludarabine-based conditioning regimen, followed by infusion of high doses of T cell–depleted stem cells, is able to ensure engraftment with good overall survival and disease-free survival, confirming the feasibility of haploidentical hematopoietic stem cell transplantation in FA. To the best of our knowledge, this is the largest series of hematopoietic stem cell transplantation from a haploidentical related donor in FA patients reported to date.

Background: Prophylactic platelet transfusion is commonly used to prevent life-threatening bleeding events in patients with severe thrombocytopenia associated with chemotherapy courses or hematopoietic stem cells transplantation (HSCT). In adults, the transfusion threshold for prophylaxis is usually set at 10x109plts/L, but in pediatric setting, it is still a matter of debate. Moreover, evidences from the PLADO trial (Slichter SJ et al. N Engl J Med. 2010) and recommendations form international guidelines (ICTMG, Nahirniak S et al. Transfus Med Rev. 2015) suggest two different platelet doses in Inpatients and Outpatients, but clinical experiences in children are still lacking. Aims: In order to confirm the safety of the recommended transfusion threshold, to test two different platelet doses in hospitalized patients and Outpatient setting and to optimize platelet clinical use, as a Children's Hospital, we applied, starting from January 2018, a new prophylactic platelet transfusion policy. Methods: Platelet dose was calculated based on body-surface area (BSA) of each patient (from age-standardized weight). As suggested by ICTMG, different platelets doses were given to Inpatients and Outpatients: (low-dose) 1.1x1011platelets per square meter (plts/m2) and (medium-dose) 2.2x1011plts/m2, respectively. The transfusion threshold for prophylaxis was set at 10x109plts/L, but higher threshold could be considered as per clinical decision (in presence of bleeding signs or risk factors for major bleeding). Patients with platelets refractoriness and newborns, were excluded from our study. Only major bleeding events (grade 3 or higher according to World Health Organization criteria) were collected during the study period. Results: From January 2018 to June 2019, 15278 platelet pediatric aliquots were transfused in our Hospital. Of all the aliquots, 8876 (58.1%) were obtained from apheresis procedures and 6402 (41.9%) from buffy-coat-derived pooled platelet concentrates. Almost 77% (11751) of the all aliquots were transfused in patients with onco-hematologic diseases. Among these, 9771 (64.0%) in the Inpatient group (N=547) and 1980 (13.0%) in the Outpatient group (N=385). Between Inpatients, 6794 (44.5%) aliquots were transfused in Onco-Hematology Ward and 2977 (19.5%) in the HSCT unit. During the study period, only 10 major bleeding events were observed. No fatal hemorrhagic episode was recorded and all of the bleedings occurred in hospitalized patients, and accounted for almost 2% of this population. Intracranial bleeding accounted for five out of six grade 4 bleeding episodes, and occurred in two patients with acute myelogenous leukemia, in one patient with Hodgkin lymphoma and in two patients with advance neuroblastoma. The other grade 4 bleeding event was a massive peritoneal and pleuric hemorrhage with a life-threatening haemodinamic instability in a patient with acute lymphoblastic leukemia (the main characteristics of these patients are reported in the table). Conclusions: our results show that a platelet transfusion policy based on recommendation mainly developed in adults may be safely applied also to pediatric patients with cancer or receiving HSCT. In fact, the lower dose used in Inpatient group resulted in a grade 4 bleeding rate similar to that observed in the PLADO trial (1.0% vs 0.7%). The double dose transfused in Oupatients was effective in preventing major bleeding events. Table. Disclosures No relevant conflicts of interest to declare.

Purpose of review Lack of a human leukocyte antigen (HLA)-matched family donor is a major obstacle limiting the use of allogeneic hematopoietic stem cell transplantation (HSCT) to cure thalassemia major. Use of alternative donors, if found well tolerated enough, may be a viable option for transplantation in this setting, allowing to expand the number of patients treatable by HSCT. This review will provide an overview of alternative HSCT approaches in thalassemia major. Recent findings With the introduction of high-resolution molecular HLA-typing techniques, the outcome of matched unrelated donor HSCT recipients has become comparable with that of patients given matched family donor HSCT. On the contrary, the use of unrelated cord blood transplantation has been limited by the risk of graft failure and slow hematopoietic recovery, although novel techniques of ex vivo graft manipulation are emerging as promising strategies for overcoming these obstacles. Although experience with haploidentical HSCT in thalassemia major is still limited, currently explored platforms hold the potential to extend the access to HSCT to thalassemia major patients lacking an HLA-matched either related or unrelated donor. Summary The significant advances achieved in transplantation techniques, both in the matched unrelated and in the haploidentical setting, are expected to significantly broaden the applicability of HSCT to patients with thalassemia major.

Fanconi Anemia (FA) is an inherited disorder characterized by the variable presence of multiple congenital somatic abnormalities, bone marrow failure and cancer susceptibility. Medulloblastoma (MB) has been described only in few cases of FA with biallelic inactivation in the tumor suppressor gene BRCA2/FANCD1 or its associated gene PALB2/FANCN. We report the case of a patient affected by Fanconi Anemia with Wilms tumor and unusual presentation of two medulloblastomas (MB1 and MB2). We identified a new pathogenetic germline BRCA2 mutation: c.2944_2944delA. Molecular analysis of MBs allowed us to define new features of MB in FA. MBs were found to belong to the Sonic Hedgehog (SHH) molecular subgroup with some differences between MB1 and MB2. We highlighted that MB in FA could share molecular aspects and hemispheric localization with sporadic adult SHH-MB. Our report provides new findings that shed new light on the genetic and molecular pathogenesis of MB in FA patients with implications in the disease management. Electronic supplementary material The online version of this article (doi:10.1186/s40364-015-0038-z) contains supplementary material, which is available to authorized users.

Summary Near infrared spectroscopy (NIRS) monitoring is a new challenge for clinicians who deal with early detection of dangerous hypoperfusion in the brain, as well as in splanchnic and renal districts in critically ill preterm infants. Previous studies performed on infants and children with congenital heart disease, demonstrated the efficacy of this non-invasive method in managing hypoperfusive states pre, post and during cardiac surgery. Its use has improved post surgery outcome. NIRS monitoring has been used also to assess therapeutic intervention utility. Early identification of silent hypoperfusion has made NIRS use in preterm infants very interesting for neonatologists, especially where other techniques have failed. In this work, literature on this topic has been carefully examined, particularly the “two site NIRS” use in preterm infants, to evaluate how regional splanchnic oxygen saturation changes, both in physiological events, such as enteral feeding and in hemodynamic disorders, that occur in patients with significant patent ductus and in hypoperfusive states that lead to necrotizing enterocolitis.

A 16-year-old girl was admitted for the first time to our department for acute, increasing left-sided chest pain and shortness of breath. Both physical and radiographic findings were compatible with pneumothorax (Figure 1), and thoracostomy tube drainage was performed as soon as the diagnosis was arrived at. Physical examination revealed hyperelastic and fragile skin, hypermobility of multiple joints, subluxation of the right temporomandibular joint, and ability to hyperextend and hyperabduct the fingers (Figure 2). The heart was tachycardic with a regular rhythm. Echocardiography was performed, and mitral valve prolapse was revealed. The period progressed uneventfully, and the thoracostomy tube drainage was removed after 3 days. The patient was discharged, but she was readmitted to our department 1 month later for progressively increasing chest pain. She denied any direct thoracic trauma. On physical examination, the vital signs were as follows: temperature 36°C, blood pressure 108/69 mm Hg, heart rate 84 beats/min, and room air oxygen saturation 94%. Laboratory values were as follows: white blood cell count = 8310/mm; hemoglobin = 11.8 g/dL; platelet count = 186 000/mm; C-reactive protein = 0.20 mg/dL. The chest X ray showed a left pneumothorax. After 20 days of discharge, the patient again showed the typical symptoms of pneumothorax. Video-assisted thoracoscopic surgery was performed, and the postoperative period progressed uneventfully. Her past medical history was remarkable for recurrent dislocations of the right coxo-femoral joint during sporting activities, and at 8 years of age, hip surgery was performed. At the age of 15 years, she was referred to a local hospital with chest pain, and spontaneous pneumothorax was identified. The clinical findings and the medical history were significant for Ehlers-Danlos syndrome (EDS). Indeed, a dermal biopsy was taken from the upper arm of the patient; a fibroblasts culture was done, and reduced synthesis of collagen type V was found, thus, confirming the diagnosis. At 2 years following surgery, the patient was free of respiratory symptoms.

Allogeneic hematopoietic stem cell transplantation (HSCT) is the only cure for marrow failure associated with dyskeratosis congenita (DC). Data on transplants from alternative donors are limited. We describe a boy with DC and severe aplastic anemia who underwent haploidentical T-cell depleted HSCT using a reduced-intensity conditioning regimen. He underwent engraftment without toxicity or GVHD. His posttransplant course was complicated by EBV reactivation, treated with rituximab and EBV-specific T lymphocytes. After 26 months, he is in complete chimerism, with normal blood count and no sign of GVHD or pulmonary dysfunction. To the best of our knowledge, this is the first report of DC successfully treated with allogeneic HSCT from a haploidentical family donor.

BK virus-related hemorrhagic cystitis is one of the major complications of hematopoietic stem cell transplantation. Because an immune reconstitution pattern of disease has been proposed as alternative pathogenetic model, in this study we focused on the link between BKV specific immune responses in the HSCT donor and the development of HC in paediatric HSCT recipients. We evaluated the frequency of IFN-γ-producing cells, by means of Elispot assay and flow cytometric measurement of T-cells CD8+/INFγ+, and specific cytotoxicity, in samples obtained from a cohort of 30 HLA-matched unrelated or haploidentical stem cell donors, divided into three groups, according to BKV positivity in urine and development of HC in recipients. We found that HSCT donors whose recipients developed HC have lower, though not statistically significant, levels of BKV-specific T cells, as compared with donors of recipient with isolated BK-viruria or without viruria. Although we cannot rule out that in some cases also immune reconstitution could play a role in the pathogenesis of HC, our preliminary data suggest that BKV-related HC may be related to low donor BKV-specific cytotoxic T cell transfer, perhaps coupled with impairment in BKV-specific T cell expansion posttransplant.

Background: Allogeneic HSCT from either an HLA-identical sibling or an unrelated donor is a potentially curative treatment for patients with hemoglobinopathies and erythroid disorders (ED), such as Thalassemia Major (TM), Sickle Cell Disease (SCD) and Diamond-Blackfan Anemia (DBA). The limited historical experience with HLA-haploidentical HSCT in this setting has reported a disease-free survival probability lower than that reported using HLA-matched donors. In the last few years, we have developed a novel method of graft manipulation, based on the selective depletion of α/β+ T-cells and CD19+ B-cells (ClinicalTrial.gov identifier: NCT01810120), which was shown to be safe and effective in children with multiple types of non-malignant disorders (Bertaina el al, Blood 2014). To further optimize this approach through the acceleration of the recovery of adaptive immunity, we designed an ongoing phase I/II trial aimed to test the safety and efficacy of post-transplant infusion of donor T-cells transduced with the iC9 suicide gene (BPX-501 cells) in children with either malignant or non-malignant disorders (ClinicalTrials.gov identifier: NCT02065869). As the transduced gene contains sequences for the CD19 marker, BPX-501 cells (CD3+/CD19+) can be easily tracked in peripheral blood. We report on 10 children with hemoglobinopathies and ED who were enrolled in the phase II portion of the study. Patients and methods: Five patients were males and 5 were females, and median age at diagnosis and at HSCT was 5.34 and 9.52 years (range 2.33-11.71), respectively. Seven patients had TM (all bo/bo), 2 DBA and 1 SCD. All 10 patients were transfusion-dependent and receiving iron-chelation therapy before haplo-HSCT. Among the thalassemia patients, 4 patients belonged to class I and 3 to class II of the Pesaro classification. All patients were transplanted from a parent. Median number of CD34+ and αβ+ T-cells infused was 22.5 x 106/kg and 0.3 x 105/kg, respectively. In all patients, conditioning regimen included busulfan (16 mg/Kg), thiotepa (10 mg/Kg) and fludarabine (160 mg/m2). Rabbit ATG (12 mg/Kg over 3 days, from day -4 to day -2) was administered to prevent graft-versus-host disease (GvHD) and graft failure and Rituximab (200 mg/ m2 on day -1) was administered to prevent EBV-related lymphoproliferative disorders. No post-transplantation GvHD prophylaxis was given. Median follow-up is 301 days (range 41-420 days). Basic phenotyping of circulating lymphocytes was assessed by flow cytometry on fresh heparinized peripheral blood samples at 10, 20, 30, 60, 90, 120 and 150 days post haplo-HSCT. Results: After haplo-HSCT, the median time to reach neutrophil and platelet recovery was 14 days (range 11-28) and 10 days (range 8-12), respectively. After engraftment of the allograft, BPX-501 cells were infused (dose: 1x106 cells/kg) at a median time of 13.5 days after HSCT (range 10-26). Nine of the 10 patients maintained sustained donor engraftment, reaching full chimerism. The patient who experienced secondary graft failure was successfully re-transplanted from the same parent and he is full donor chimeric with transfusion-independence. Grade I/II skin acute GvHD occurred in 2 patients (at 31 and 59 days after HSCT, respectively). There was no occurrence of chronic GVHD. Remarkably, no patient has died and none of the patients have been re-hospitalized after initial discharge. The last erythrocyte transfusion was administered on day +7 post-transplant (range 4-33 days). At last follow-up, the median hemoglobin value of these patients was 11.35 gr/dL (range 10.2-13.4). BPX-501 cells expanded after infusion and still persist in all patients at last follow-up. All children are alive and transfusion-independent. Details on T cell, NK cell and B cell recovery are shown in Figure 1 (Panel A-D). Conclusions: Children with hemoglobinopathies and DBA can benefit from curative haplo-HSCT after depletion of α/β T-cells followed by infusion of BPX-501 cells, which, expanding and persisting over time, contribute to speed immune recovery of adaptive T-cell immunity, thus rendering the procedure safer. Figure 1 Figure 1. Disclosures French: Bellicum Pharmaceuticals: Employment, Membership on an entity's Board of Directors or advisory committees. Moseley:Bellicum Pharmaceuticals: Employment, Membership on an entity's Board of Directors or advisory committees.

Background: Haplo-HSCT after depletion of α/β T and B cells is a suitable and effective option for those children with acute leukemia (AL) who need an allograft and lacking an immediately available HLA-identical donor. With this approach, recipients can benefit immediately after transplantation from the anti-leukemia effect mediated by donor natural killer (NK) and γd T cells, which can also protect against infections. A further improvement of the results achievable with this platform could achieved with a faster adaptive T-cell immunity recovery, which play a key role to augment the graft-versus-leukemia effect and the capacity to fight infections. In light of these considerations, we designed a phase I/II trial aimed at testing the safety and efficacy of post-transplant infusion of donor-derived T cells transduced with the new iC9 suicide gene (BPX-501) in children with either malignant or non-malignant disorders (NCT02065869). Remarkably, after the activation and transduction with the retroviral iC9 construct, BPX501 cells switch the phenotype towards a preferential CD45RO pattern. Patients and methods: The phase I portion of the trial consisted of a classical 3+3 design with 3 cohorts, receiving escalating doses of BPX-501 cells of 2.5x105, 5x105, and 1x106 cells/kg, respectively. Patients included in the phase II portion were planned to receive the recommended dose identified during the phase I part of the study.Enrollment of patients started in December 2014; so far, 25 patients with AL in morphological complete remission (CR) have been enrolled. Twenty patients had acute lymphoblastic leukemia (ALL) and 5 acute myeloid leukemia (AML). Details on patient, donor and transplant characteristics are reported in table 1. All patients transplanted in CR1 had either poor cytogenetic/molecular characteristics or high levels of minimal residual disease at the end of induction therapy, both factors predicting a high relapse rate. All patients were given a fully myeloablative conditioning regimen (table 1). Before haplo-HSCT, children received rabbit anti-thymocyte globulin (ATG NEOVII, 12 mg/Kg over 3 days, from day -4 to day -2) to prevent both graft-versus-host disease (GvHD) and graft failure, and Rituximab (200 mg/ m2 on day -1) to prevent EBV-related lymphoproliferative disorders. No post-transplantation GvHD prophylaxis was administered. Results: All patients engrafted and no secondary graft failure was recorded. Median time to neutrophil and platelet recovery was 18 days (range 10-22) and 11 days (range 9-13), respectively. Once documented the engraftment of donor cells, BPX-501 T lymphocytes were infused at a median time of 17 days (range 13-52) after the allograft. Two patients were enrolled in the phase I portion of the study; one each received 2.5x105 and 1x106 cells/kg. The remaining 23 children were treated in the phase II, where the recommended dose was 1x106 cells/kg. However, since we did not observe any acute GvHD requiring the infusion of the dimerizing agent (Rimiducid/AP1903) activating iC9 gene in the first 15 children receiving 1x106 cells/kg, we decided to emend the protocol to further increase the BPX501 cell dose infused to 2 and 4x106 cells/kg. Thus, the last 6 patients were enrolled in these 2 last dose levels (3 patients each). Six and 3 patients developed grade II-IV acute and chronic GvHD, respectively. In one child, given 4x106 cells/kg, we infused rimiducid for steroid-resistant grade II skin acute GvHD, with complete resolution of the disease in 24 hours. The cumulative incidence of grade II-III acute and chronic GvHD are shown in figure 1A and B, respectively. Median follow-up of these 25 children is 8 months (range 1-19 months). One of them died due to chronic GvHD-associated bronchiolitis obliterans and one child with ALL transplanted in CR2 relapsed; the cumulative incidence of non-relapse mortality and leukemia recurrence are shown in figure 1C. The probability of disease-free survival at 15 months is 87% (figure 1D). Once infused, BPX501 cells expanded and persisted over time in both peripheral blood and bone marrow. Conclusion: Overall, these data indicate that the infusion of BPX-501 cells in children with AL given selectively manipulated haplo-HSCT results in low non-relapse mortality and chronic GvHD. Although the median observation time is still limited, the cumulative incidence of disease recurrence is promising. Table 1 Table 1. Figure 1 Figure 1. Disclosures Stanson: Bellicum pharmaceuticals: Employment. Moseley:Bellicum Pharmaceuticals: Employment, Membership on an entity's Board of Directors or advisory committees.

Introduction. Allogeneic HSCT currently represents the only consolidated curative approach for Fanconi anemia (FA) patients, with best results observed in the HLA-identical sibling setting. For patients lacking an HLA-matched related or unrelated donor, haploidentical HSCT virtually assures the opportunity for nearly all patients to benefit from HSCT, offering the advantage of immediate accessibility to the transplant procedure. In order to overcome the limitation of delayed immune recovery, historically associated with this type of allograft, in the last few years we developed a novel method of ex vivo graft manipulation, consisting of the negative depletion of T-cell receptor (TCR) αβ+ T-lymphocytes and CD19 B-cells from peripheral blood stem cells (PBSC) grafts (ClinicalTrial.gov identifier: NCT01810120) (Bertaina el al., Blood 2014). Here we report our analysis in a subgroup of FA patients given TCRαβ/CD19-depleted haploidentical HSCT at our Institution. Patients and methods. Ten consecutive FA patients (6 girls and 4 boys) underwent a TCRαβ/CD19-depleted HSCT from an HLA-haploidentical relative between September 2011 and July 2015. Median age at diagnosis was 6.6 (range 2.7-22.0) years and median age at time of transplantation was 8.1 (range 4.4-22.2) years. The conditioning regimen included Cyclophosphamide 300 mg/m2/day and Fludarabine 30 mg/m2/day for 4 consecutive days (days -6 to -3), with 200 cGy single-dose TBI. Pretransplantation Fresenius® ATG was administered at a dose of 4 mg/kg/day for 3 consecutive days (days -5 to -3) in order to prevent both graft failure and graft-versus-host disease (GVHD). All patients received Rituximab 200 mg/m2 to reduce the risk of Epstein-Barr virus-related post-transplant lymphoproliferative disorders. Selective removal of TCRαβ+ and B-cells was performed on G-CSF-mobilized donor PBSC through labeling with biotinylated anti-TCRαβ antibodies and anti-CD19 antibodies, followed by incubation with anti-biotin antibodies conjugated to paramagnetic beads (CliniMACS; Miltenyi Biotec, Bergisch Gladbach, Germany). No immunosuppressive therapy was administered as post-transplantation prophylaxis against GVHD. Results. The TCRαβ/CD19-depletedgrafts contained a median of 20.40 x106/kg (range 15.80-33.40) CD34+ cells, 5.60 x106/kg (range 1.78-69.60) CD3+ lymphocytes, 0.021 x106/kg (range 0.002-0.043) TCRαβ+ lymphocytes, 5.60 x106/kg (range 1.78-69.60) TCRγδ+ lymphocytes, 0.036 x106/kg (range 0.013-0.079) CD20+ lymphocytes, and 45.30 x106/kg (range 16.2-177.0) NK cells. Engraftment with sustained full donor chimerism was achieved in 9 out of 10 patients, the cumulative incidence of graft rejection being 10% (95% CI, 0-26.8). The patient who rejected his first allograft achieved a complete engraftment after a second HSCT from one-antigen mismatched unrelated donor. No secondary graft failures were observed. The median time for neutrophil and platelet engraftment was 12 days (range, 9-15) and 9 days (range, 8-12), respectively. No patient experienced acute or chronic GVHD in the follow-up period. No transplant-related deaths occurred in our cohort. With a median follow-up of 28 months (range 13.2-39.1), the Kaplan-Meier estimates of OS and DFS were both 100%, while the EFS probability was 90% (95% CI, 47.3-98.5). Discussion. These data suggest that haploidentical HSCT after removal of TCRαβ+ and CD19+ lymphocytes is able to guarantee engraftment with excellent OS and DFS in patients affected by FA. Moreover, given the very low incidence of both acute and chronic GVHD, which has been shown to contribute to the increased risk of developing late post-transplantation malignancies in FA patients, this approach can be considered a very attractive option for FA patients in need of an allograft and lacking an HLA-identical family donor. Disclosures No relevant conflicts of interest to declare.

Background Nosocomial infection is among the most important causes of morbidity, prolonged hospital stay, increased hospital costs, and mortality in neonates, particularly those born preterm. The vast majority of scientific articles dealing with nosocomial infections address bacterial or fungal infections, and viral agents are often disregarded. This analysis reviews the medical literature in an effort to establish the incidence, types of pathogens, and clinical features of noncongenital neonatal viral infections. Methods This analysis was performed using the worldwide database of health care–associated outbreaks ( http://www.outbreak-database.com ). Items analyzed included causative pathogens, types of infection, source of outbreaks, and measures taken to stop outbreaks. Results The outbreak database contained a total of 590 neonatal outbreaks, of which 64 were originated by viruses, 44 of which (68.75%) were reported from neonatal intensive care units (NICUs). The 5 most frequent viral agents were rotavirus (23.44%), respiratory syncytial virus (17.19%), enterovirus (15.63%), hepatitis A virus (10.94%), and adenovirus (9.38%). Conclusion Our analysis of the viral origins of nosocomial infections in NICUs can be a valuable tool in the investigation of neonatal infections. The mortality rates reported in this analysis demonstrate the significance of noncongenital viral infections in NICUs and the need for more effective outbreak prevention strategies.

Context:Agenesis of the internal carotid artery and hypoplasia of the internal carotid artery are rare congenital abnormalities, involving less than 0.01% of the general population. Congenital hypopituitarism is also a rare condition; thus, the association of the two entities is unlikely to be casual. We describe one pediatric case of agenesis of the internal carotid artery with hypopituitarism and review other known cases.Evidence Acquisition and Synthesis:In this brief clinical case seminar, we summarize the current understanding of this association based on a MEDLINE search of all peer-reviewed publications (original articles and reviews) on this topic between 1980 and 2011. We found nine other cases, mainly diagnosed during childhood. Defects of pituitary function varied among cases; in four, midline anomalies were present.Conclusion:There are two theories that are not mutually exclusive to explain the association of congenital vascular malformation and pituitary hypoplasia with hypopituitarism: the first involves hemodynamic mechanisms, and the second, complex neural-crest differentiation and/or migration disorders. Whatever the real physiopathological mechanism responsible for this condition, it could be considered as a new clinical entity.

Background: Immune recovery is crucial for patients treated with allogeneic HSCT and in particular of those receiving a T-cell depleted haplo-HSCT. We recently developed a novel method of graft manipulation based on physical elimination of α/β T cells and B-lymphocytes for preventing graft-versus-host disease (GvHD) and EBV-related lymphoproliferative disorders, respectively. Thanks to this approach, we successfully conducted a prospective trial in children with malignant or non-malignant disorders (ClinicalTrial.gov identifier: NCT01810120). Although patients enrolled in this trial had faster immune recovery and lower incidence of infections than those given haplo-HSCT after infusion of positively selected CD34+ cells, reconstitution of adaptive T-cell immunity remains suboptimal. We therefore designed a phase I/II trial aimed at testing the effect on post-transplant immune recovery of adoptive infusion (within 14 + 4 days after transplantation) of BPX-501 cells in children given haplo-HSCT after depletion of α/β T and B cells (ClinicalTrials.gov identifier: NCT02065869). Patients and methods: As of July 25th 2015, 23 children have been infused with BPX-501 cells. The 9 children included in the phase I portion of the study were given 2.5x105, 5x105, and 1x106 BPX-501 cells/kg, respectively, while the 14 included in the phase II received 1x106 BPX-501 cells/kg. This analysis refers to the 16 patients with a minimum follow-up of 90 days; 7 children had acute leukemia and 9 non-malignant disorders. Basic phenotype of circulating lymphocytes was assessed by flow cytometry on fresh heparinized peripheral blood samples at 10, 20, 30, 60, 90, 120 and 150 days post haplo-HSCT, respectively. The following antibodies were used: anti-TCRαβ FITC/anti-TCRγδ PE/anti-CD3 PerCP-Cy™5.5 (WT31, 11F2, SK7), anti-CD4 APC Cy7 (RPA-T4), anti-CD19 BV 510 (SJ25C1), anti-CD3 BV 421 (UCHT1), anti-CD56 PeCy7 (B159), anti-CD16 APC (B73.1), anti-CD8 APC (RPA-T8) from BD Biosciences (San Diego, CA, USA). Antigen-driven activation of peripheral mononuclear cells was evaluated by standard lymphoproliferation assay (LPA) with 3H-thymidine pulsing on day 4 and harvesting 18 hours later. Antigens included PHA or CMV, EBV and AdV whole viral lysate. Results were scored positive with stimulation indexes (SI) >10 for PHA and >3 for viral antigens. Results: None of the patients died from transplant-related complications. Chimerism analysis investigated through short tandem repeats showed that in all but 4 patients, cells were of donor origin before the infusion of BPX-501 cells. In the 4 patients, there was a reversion to complete donor chimerism after infusion of BPX-501 cells. At early time points after haplo-HSCT, gδ T cells predominated over αβ T lymphocytes; subsequently, this latter population became the more largely represented. The number of both CD3+ T lymphocytes and of BPX-501 cells is shown in Panel A of Figure 1, reconstitution of whole T cells in historical children given haplo-HSCT after depletion of α/β T cells is also shown. The number of CD3+ T lymphocytes reached greater than 0.5x109/L 2 months after infusion of BPX-501 cells. Remarkably, while usually immune recovery after transplantation is characterized by prevalence of CD8+ cells, in our patients the physiological predominance of CD4+ lymphocytes was maintained (Panel B of Figure 1. Reconstitution of natural killer cells (NK) is shown in Panel C of Figure 1. As compared to patients receiving CD34+ selected cell haplo-HSCT, children included in this study had a faster reconstitution of mature KIR+/NKG2A- NK cells. Serum levels of IgA and IgM over time are shown in Panel D of Figure 1: there was a recovery of newly synthetized Ig at 3 months. The analysis of the function of T cells showed that the proliferative response to a polyclonal mitogen or to CMV lysate was comparable to that of a healthy control in 50% of patients as early as day + 60 after haplo-HSCT and BPX-501; on day +150, all patients reached a normal SI. Response to both EBV and AdV antigens was slightly delayed, but progressively improved over time (see also Figure 2). Conclusions: Overall, these data indicate that infusion of BPX-501 cells is able to accelerate the recovery of adaptive T-cell immunity since these cells, once infused, expand in vivo and persist over time, potentially contributing to protect patients from infections. Figure 1. Figure 1. Figure 2. Figure 2. Disclosures Moseley: Bellicum Pharmaceuticals: Employment, Equity Ownership.

Background: T-cell depleted haplo-HSCT is an established treatment for children with primary immune deficiencies (PID). However, children given this type of allograft are exposed to the risk of fatal events due to viral infections because of the prolonged impairment of adaptive immunity. We recently developed a novel method of selective T-cell depletion based on physical elimination of α/β T cells (ClinicalTrial.gov identifier: NCT01810120), which was shown to be safe and more effective than transplantation of positively-selected CD34+ cells for preventing life-threatening infections. However, we recorded some severe and even fatal viral infections, which prompted us to explore innovative approaches to accelerate the recovery of adaptive immunity. For this purpose, we designed an ongoing phase I/II trial aimed at testing the safety and the efficacy of post-transplant infusion of BPX-501 cells in children with malignant or non-malignant disorders (ClinicalTrials.gov identifier: NCT02065869). We report 3 cases of children with either severe combined immune deficiency (SCID) or Wiskott-Aldrich syndrome (WAS), who were enrolled in the dose escalation phase of the study and who cleared cytomegalovirus (CMV) or Adenovirus (AdV) infections likely due to the contribution of the BPX-501 cells. Patients and methods: Patient #1, affected by SCID, was transplanted from the HLA-haploidentical father. Before transplantation she had CMV-DNAemia which was treated with ganciclovir until donor stem cell infusion. She was given 2.5 x 105/kg BPX-501 cells on day 17 after transplantation. Patient #2, also affected by SCID, was transplanted from the HLA-haploidentical mother. Before transplantation she had AdV-DNAemia and high load of the virus in stools. She was given 5 x 105/kg BPX-501 cells on day 15 after transplantation. Patient #3 was affected by WAS and referred to the transplant unit; in the months preceding haplo-HSCT the child had developed CMV retinitis and hepatitis with high levels of CMV-DNAemia. This patient was transplanted from the father and received 1 x 106/kg BPX-501 cells on day 15 after haplo-HSCT. Basic phenotype of circulating lymphocytes was assessed by flow cytometry on fresh heparinized peripheral blood samples at 10, 20, 30, 60, 90, 120 and 150 days post haplo-HSCT, respectively. Since BPX-501 cells are CD3+/CD19+, it was easy to track the presence of these genetically modified cells. CMV specific reconstitution was also monitored through the INF gamma ELISPOT assay. In particular, peripheral blood mononuclear cells were stimulated for 16hrs in the presence of peptide libraries derived from pp65, IE1 and IE2 CMV-specific antigens. Results: The increase in the number of both CD3+ T lymphocytes and BPX-501 cells over time after transplantation together with the modifications of DNAemia of both CMV and AdV in the 3 patients are reported in Panel A, B and C, respectively, of Figure 1. In all of these patients, the pre-existing viral infection was progressively cleared once the BPX-501 cells were infused. These cells expanded in vivo and are still persisting, contributing to the recovery of adoptive immunity. The median time to reach an absolute number of α/β CD3+ cells greater than 0.5x109/L was 90, 90 and 30 days, respectively. None of these patients experienced either acute or chronic Graft-versus-Host Disease (GvHD) and no organ inflammatory-related toxicity was recorded. All children are alive and disease free, without infections, at day +200, +180 and +160, respectively. The 2 patients with CMV infection showed a specific response for at least one CMV-derived antigen; indeed, one patient showed a prevalence in pp65 response, whereas in the second one, we observed a specific anti-CMV response against all three tested antigens (Figure 1 - Panel D). Conclusions: Infusion of BPX-501 cells is able to accelerate the recovery of adaptive T-cell immunity in children with PID given haplo-HSCT after depletion of α/β T cells, thus rendering the procedure safer even in children with active infections at time of transplantation. These cells, once infused, expand in vivo and persist over time, contributing to the clearance of viral infections, without inducing GvHD. Figure 1. Figure 1. Disclosures Moseley: Bellicum Pharmaceuticals: Employment, Equity Ownership.