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Extracellular vesicles (EVs) deliver bioactive macromolecules (i.e. proteins, lipids and nucleic acids) for intercellular communication in multicellular organisms. EVs are secreted by all cell types including immune cells. Immune cell-derived EVs modulate diverse aspects of the immune system to either enhance or suppress immune activities. The extensive effects of immune cell-derived EVs have become the focus of great interest for various nano-biomedical applications, ranging from the medical use of nanoplatform-based diagnostic agents to the development of therapeutic interventions as well as vaccine applications, and thus may be ideal for ‘immune-theranostic’. Here, we review the latest advances concerning the biological roles of immune cell-derived EVs in innate and acquired immunity. The intercellular communication amongst immune cells through their EVs is highlighted, showing that all immune cell-derived EVs have their unique function(s) in immunity through intricate interaction(s). Natural-killer (NK) cell-derived EVs, for example, contain potent cytotoxic proteins and induce apoptosis to targeted cancer cells. On the other hand, cancer cell-derived EVs bearing NK ligands may evade immune surveillance and responses. Finally, we discuss possible medical uses for the immune cell-derived EVs as a tool for immune-theranostic: as diagnostic biomarkers, for use in therapeutic interventions and for vaccination.

The American Society of Pediatric Hematology/Oncology (ASPHO) recognized recent changes in medical practice and the potential impact on pediatric hematology-oncology (PHO) workforce. ASPHO surveyed society members and PHO Division Directors between 2010 and 2016 and studied PHO workforce data collected by the American Board of Pediatrics and the American Medical Association to characterize the current state of the PHO workforce. The analysis of this information has led to a comprehensive description of PHO physicians, professional activities, and workplace. It is important to continue to collect data to identify changes in composition and needs of the PHO workforce.

CD22 is a B-lineage differentiation antigen that has emerged as a leading therapeutic target in acute lymphoblastic leukemia (ALL).Properties of CD22 expression relevant to therapeutic targeting were characterized in primary samples obtained from children and young adults with relapsed and chemotherapy refractory B-precursor (pre-B) ALL.CD22 expression was demonstrated in all subjects (n = 163) with detection on at least 90% of blasts in 155 cases. Median antigen site density of surface CD22 was 3,470 sites/cell (range 349-19,653, n = 160). Blasts from patients with known 11q23 (MLL) rearrangement had lower site density (median 1,590 sites/cell, range 349-3,624, n = 20 versus 3,853 sites/cell, range 451-19,653, n = 140; P = 0.0001) and 6 of 21 cases had sub-populations of blasts lacking CD22 expression (22%-82% CD22 +). CD22 expression was maintained in serial studies of 73 subjects, including those treated with anti-CD22 targeted therapy. The levels of soluble CD22 in blood and marrow by ELISA were low and not expected to influence the pharmacokinetics of anti-CD22 directed agents.These characteristics make CD22 an excellent potential therapeutic target in patients with relapsed and chemotherapy-refractory ALL, although cases with MLL rearrangement require close study to exclude the presence of a CD22-negative blast population.

Summary Background Chimeric antigen receptor (CAR) modified T cells targeting CD19 have shown activity in case series of patients with acute and chronic lymphocytic leukaemia and B-cell lymphomas, but feasibility, toxicity, and response rates of consecutively enrolled patients treated with a consistent regimen and assessed on an intention-to-treat basis have not been reported. We aimed to define feasibility, toxicity, maximum tolerated dose, response rate, and biological correlates of response in children and young adults with refractory B-cell malignancies treated with CD19-CAR T cells. Methods This phase 1, dose-escalation trial consecutively enrolled children and young adults (aged 1–30 years) with relapsed or refractory acute lymphoblastic leukaemia or non-Hodgkin lymphoma. Autologous T cells were engineered via an 11-day manufacturing process to express a CD19-CAR incorporating an anti-CD19 single-chain variable fragment plus TCR zeta and CD28 signalling domains. All patients received fludarabine and cyclophosphamide before a single infusion of CD19-CAR T cells. Using a standard 3 + 3 design to establish the maximum tolerated dose, patients received either 1 × 10 6 CAR-transduced T cells per kg (dose 1), 3 × 10 6 CAR-transduced T cells per kg (dose 2), or the entire CAR T-cell product if sufficient numbers of cells to meet the assigned dose were not generated. After the dose-escalation phase, an expansion cohort was treated at the maximum tolerated dose. The trial is registered with ClinicalTrials.gov, number NCT01593696. Findings Between July 2, 2012, and June 20, 2014, 21 patients (including eight who had previously undergone allogeneic haematopoietic stem-cell transplantation) were enrolled and infused with CD19-CAR T cells. 19 received the prescribed dose of CD19-CAR T cells, whereas the assigned dose concentration could not be generated for two patients (90% feasible). All patients enrolled were assessed for response. The maximum tolerated dose was defined as 1 × 10 6 CD19-CAR T cells per kg. All toxicities were fully reversible, with the most severe being grade 4 cytokine release syndrome that occurred in three (14%) of 21 patients (95% CI 3·0–36·3). The most common non-haematological grade 3 adverse events were fever (nine [43%] of 21 patients), hypokalaemia (nine [43%] of 21 patients), fever and neutropenia (eight [38%] of 21 patients), and cytokine release syndrome (three [14%) of 21 patients). Interpretation CD19-CAR T cell therapy is feasible, safe, and mediates potent anti-leukaemic activity in children and young adults with chemotherapy-resistant B-precursor acute lymphoblastic leukaemia. All toxicities were reversible and prolonged B-cell aplasia did not occur. Funding National Institutes of Health Intramural funds and St Baldrick's Foundation.

The diagnostic criteria for paediatric mastocytosis are largely based on adult studies and bone marrow findings are not well described in children. We evaluated use of the World Health Organization (WHO) criteria for the diagnosis of systemic disease in paediatric mastocytosis. In addition, we identified unique clinico-histopathological features within the biopsies. One hundred and thirteen children with paediatric mastocytosis were evaluated at the National Institutes of Health between 1986 and 2013. Complete bone marrow evaluations were performed in 50 cases. Seven children had repeat procedures. Bone marrows were analysed by histopathology, flow cytometry and for KIT D816V. Bone marrow biopsies displayed mild atypical haematopoietic maturation, increased haematogones and hypocellularity in a sub-set of patients with urticaria pigmentosa, diffuse cutaneous mastocytosis and indolent systemic mastocytosis. Hypocellularity was most pronounced in those with urticaria pigmentosa. Haematogones were highest, on average, in patients with diffuse cutaneous mastocytosis or mastocytomas. There was no evidence of peripheral blood cytopenias, myelodysplastic syndrome, myeloproliferative neoplasm or leukaemia within this cohort. The WHO criteria are applicable for the diagnosis of systemic mastocytosis in paediatrics. Although unsuspected bone marrow findings typically seen in myeloproliferative disorders are frequent in paediatric mastocytosis, patients within this study remained clinically stable without progression to a more aggressive variant.

Chronic red blood cell transfusion can prevent many of the manifestations of sickle cell disease. The medical costs of chronic transfusion and management of associated side effects, especially iron overload, are considerable. This study was undertaken to evaluate the financial impact of chronic transfusion for stroke prevention in patients with sickle cell anemia. Outpatient charges pertaining to hospital-based Medicare uniform bill (UB-92) codes, professional fees, and iron chelation were evaluated. Data were collected on 21 patients for a total of 296 patient months (mean, 14; median, 14 months/patient). Charges ranged from $9828 to $50 852 per patient per year. UB-92, chelation, and physician-related charges accounted for 53%, 42%, and 5% of total charges, respectively. Of UB-92 charges, 58% were associated with laboratory fees and 16% were related to the processing and administration of blood. Charges for patients who required chelation therapy ranged from $31 143 to $50 852 per patient per year (mean, $39 779; median, $38 607). Deferoxamine accounted for 71% of chelation-related charges, which ranged from $12 719 to $24 845 per patient per year (mean, $20 514; median, $21 381). The financial impact of chronic transfusion therapy for sickle cell disease is substantial with charges approaching $400 000 per patient decade for patients who require deferoxamine chelation. These data should be considered in reference to cost and efficacy analyses of alternative therapies for sickle cell disease, such as allogeneic bone marrow transplantation.

The association of neurofibromatosis 1 (NF1), juvenile xanthogranulomas (JXG), and juvenile myelomonocytic leukemia (JMML) has been previously reported. We describe herein this triad in a Caucasian male infant with a pathogenic mutation in the NF1 gene (neurofibromin). The clinical course from initial presentation to final diagnosis is detailed; the physical features and hematologic characteristics are discussed. The patient underwent bone marrow transplantation and is currently in remission. Children with concurrent cutaneous cafe-au-lait and JXG lesions should be evaluated and monitored closely for the possible development of JMML.

Background. Previous reports have suggested activity of the nucleoside analogues 2-chlorodeoxyadenosine (2-CdA) and 2'-deoxycoformycin (2'-DCF) in Langerhans cell histocytosis (LCH). Procedure. To assess the efficacy of 2-CdA and 2'-DCF as salvage therapy for LCH, a survey of members of the Histiocyte Society and a literature review were undertaken. Twenty-three patients treated with 2-CdA and 4 treated with 2'-DCF were found, age range 2 months to 49 years, Results. All 15 survey patients had multiorgan involvement, and 14 were heavily pretreated. Doses of 2-CdA ranged from 0.1 mg/kg/day continuous infusion for 5-7 days (majority of patients) to 13 mg/m 2 /day for 5 days, for 1-6 courses. One of the 15 patients had an early death, 5 had no response (NR), 3 had partial response (PR), and 6 achieved complete response (CR). Among 8 : 2-CdA; Langerhans published patients, 7 achieved stable CR and 1 NR. Among 4 patients treated with 2'-DCF (4 mg/m 2 /week for 8 weeks then q 2 weekly), 2 achieved CR for 16+ and 18+ months and 2 PR for 2 and 5 months. Toxicity consisted mainly of combined myelo- and immunosuppression but no significant infections occurred and there were no toxic deaths. A cumulative thrombocytopenia was noted, which in 1 case took up to 6 months to resolve. Transient gastrointestinal toxicity and elevation of liver enzymes was seen, and 2 patients developed renal tubular acidosis. The peripheral neuropathy reported in adult patients receiving high doses was not seen. Conclusions. 2-CdA and 2'-DCF appear to have a useful role in LCH and are worthy of prospective trial in patients unresponsive to routine therapy.

Background and Methods It is uncertain whether mortality rates among patients who have undergone bone marrow transplantation return to the level of the mortality rates of the general population. We analyzed the characteristics of 6691 patients listed in the International Bone Marrow Transplant Registry. All the patients were free of their original disease two years after allogeneic bone marrow transplantation. Mortality rates in this cohort were compared with those of an age-, sex-, and nationality-matched general population. Cox proportional-hazards regression was used to identify risk factors for death more than two years after transplantation (late death). Results Among patients who were free of disease two years after transplantation, the probability of living for five more years was 89 percent (95 percent confidence interval, 88 to 90 percent). Among patients who underwent transplantation for aplastic anemia, the risk of death by the sixth year after transplantation did not differ significantly from ...

Although most children with ALL can be cured by chemotherapy approaches, allogeneic hematopoietic cell transplant (HCT) therapy offers a better chance of cure to selected high-risk patients in first remission and most children who relapse. Although transplant-related mortality has decreased significantly in the past decade, relapse remains high after HCT for ALL; developing strategies to decrease relapse and improve survival are vital. Recent studies have shown that relapse risk can be accurately defined using measurements of minimal residual disease (MRD) both pre- and post-HCT and by knowing whether patients get GVHD in the first 2 months after transplant. With these risk definitions in hand, investigators are now applying novel agents and immunotherapeutic methods in attempt to lower MRD before transplant and modulate the GVL effect after transplant. With powerful new immunological approaches coming on line, the transplant process itself will likely expand to include pre and/or post-HCT interventions aimed at reducing relapse.

In the National Cancer Institute's Second Workshop on the Biology, Prevention, and Treatment of Relapse after Hematopoietic Stem Cell Transplantation, the Scientific/Educational Session on the Biology of Relapse discussed recent advances in understanding some of the host-, disease-, and transplantation-related contributions to relapse, emphasizing concepts with potential therapeutic implications. Relapse after hematopoietic stem cell transplantation (HSCT) represents tumor escape, from the cytotoxic effects of the conditioning regimen and from immunologic control mediated by reconstituted lymphocyte populations. Factors influencing the biology of the therapeutic graft-versus-malignancy (GVM) effect—and relapse—include conditioning regimen effects on lymphocyte populations and homeostasis, immunologic niches, and the tumor microenvironment; reconstitution of lymphocyte populations and establishment of functional immune competence; and genetic heterogeneity within the malignancy defining potential for clonal escape. Recent developments in T cell and natural killer cell homeostasis and reconstitution are reviewed, with implications for prevention and treatment of relapse, as is the application of modern genome sequencing to defining the biologic basis of GVM, clonal escape, and relapse after HSCT.

HA22 is a recombinant immunotoxin that kills CD22-expressing cells by ADP-ribosylating and inactivating elongation factor-2 (EF2). HA22 is composed of an Fv that binds to CD22 fused to a portion of Pseudomonas exotoxin A. HA22 is very active in drug-resistant hairy cell leukemia but is less active in children with acute lymphoblastic leukemia. To understand why some patients do not respond to HA22, we isolated an HA22-resistant lymphoma cell line and showed that resistance was due to the inability of HA22 to ADP-ribosylate and inactivate EF2. We analyzed the diphthamide synthesis genes and found that the WDR85 gene was deleted. We show that WDR85 knockdown conferred HA22 resistance to sensitive cells and that sensitivity was restored by introduction of a WDR85 cDNA into resistant cells. Analysis of EF2 in the mutant cells revealed a novel form of diphthamide with an additional methyl group that prevented ADP-ribosylation and inactivation of EF2. The abnormal methylation appeared to be catalyzed by DPH5. Inactivation of the WDR85 gene could be a mechanism of immunotoxin resistance in patients undergoing immunotoxin therapy.

Substantial progress has been made in the treatment of leukemia in childhood. Despite this, leukemia remains a leading cause of pediatric cancer-related mortality and the prognosis is guarded for individuals with relapsed or refractory disease. Standard therapies are associated with a wide array of acute and long-term toxicities and further treatment intensification may not be tolerable or beneficial. The curative potential of allogeneic stem cell transplantation is due in part to the graft-versus-leukemia effect, which provides evidence for the therapeutic capacity of immune-based therapies. In recent years there have been significant advances in the development and application of immunotherapy in the treatment of leukemias, including the demonstration of activity in chemotherapy-resistant cases. This review summarizes immunotherapeutic approaches in the treatment of pediatric leukemia including current results and future directions.

There is a paucity of pharmacokinetic studies describing weight-based dosing of intravenous voriconazole in obese patients. In this case report, we describe the pharmacokinetics of intravenous voriconazole in an obese CYP2C19 homozygous poor metabolizer and review previously reported data regarding the use of intravenous voriconazole in obese patients. A 17-year-old obese Hispanic male patient (body mass index 35 kg/m(2) ) received intravenous voriconazole for the treatment of suspected aspergillosis. After 2.5 days of voriconazole 4 mg/kg intravenously every 12 hours based on adjusted body weight, the voriconazole area under the serum concentration-time curve over the course of a single (12-hr) dosing interval and trough concentration were 86,100 ng · hr/ml and 6.2 µg/ml, respectively. Six days later, the voriconazole dosage was decreased. A trough concentration measured just before the dosage reduction (after 8.5 days of voriconazole 4 mg/kg intravenously every 12 hours based on adjusted body weight) remained elevated at 5.8 µg/ml. Genotyping revealed a CYP2C19 homozygous poor metabolizer (CYP2C19*2/*2). Voriconazole was subsequently discontinued due to QTc prolongation. These data and those from two recent publications suggest that voriconazole does not distribute extensively into human adipose tissue and that obese patients should be dosed on an adjusted body weight basis. If an obese patient dosed on total body weight is also a CYP2C19 poor metabolizer, serum voriconazole concentrations will be further elevated, potentially leading to drug-induced toxicity.

Background: Moxetumomab pasudotox (Moxe) is a recombinant immunotoxin that targets CD22. Moxe showed high clinical activity in a phase II trial against hairy cell leukemia (Kreitman et al, 2012) and a phase III trial has recently completed enrollment. Moxe also demonstrated objective responses in 30% of children with multiply relapsed acute lymphoblastic leukemia (ALL) (Wayne et al AACR 2014). In a xenograft model with the ALL cell line KOPN-8, Moxe as monotherapy clears the murine bone marrow (BM) from leukemia blasts (Mueller et al, CCR 2016). However, mice eventually relapse and die of progressive disease. Goal: To characterize the ALL cells responsible for relapse and to devise a relapse-preventing treatment. Methods/Results: The ALL cell lines KOPN-8 and REH were transduced with luciferase. The systemic bioluminescence signal in KOPN-8 bearing mice was abrogated after three i.v. bolus-doses of Moxe. Relapse was subsequently detected at various, apparently randomly distributed BM sites which possibly were the origin of systemic relapse. The systemic relapse remained Moxe-sensitive for several treatment cycles, but the bioluminescence signal at the discrete BM sites persisted. After several treatment cycles a Moxe-resistant systemic relapse emerged and mice died of progressive disease as determined by bioluminescence and flow cytometry. The Moxe-resistant cells showed a loss of CD10, and a 2.5-fold decrease in surface CD19 and CD22. CD22 mRNA levels and total CD22 protein by Western Blot were reduced up to 7-fold, indicating a profound reduction of intracellular CD22 in resistant cells. RNA deep sequencing revealed a global transcriptional change including down-regulation of B-cell specific genes suggesting a less mature state of KOPN-8 in the Moxe resistant blasts. We had previsouly demonstrated an epigenetic mechanism of Moxe resistance in vitro (Hu et al, Leuk Res 2013). Because most of the genetically homogeneous KOPN-8 cells growing in murine BM were Moxe sensitive but cells at discrete sites persisted, we hypothesized that locally induced epigenetic changes might partially explain the resistance. We therefore combined Moxe with the DNA-methyltransferase inhibitor 5-Azacytidine (5-AZA). KOPN-8 bearing mice treated with Moxe or 5-AZA alone survived longer than untreated mice, but eventually died from leukemia. However, mice that received the combination of 5-AZA and Moxe were disease free at 4 months after treatment by flow cytometry and histopathology. The combination of 5-AZA and Moxe also improved responses over each agent alone in a second ALL xenograft model with the ALL cell line REH. Conclusion: The relapse of KOPN-8 after treatment with Moxe, possibly from discrete BM sites is consistent with BM-niche induced resistance. This niche-induced resistance is further supported by locally persisting cells after repeated treatment cycles, while blasts that repopulate other BM sites remain rIT-sensitive. That relapse at discrete BM-sites is prevented by 5-AZA suggests that epigenetic modifications contribute to induction of localized resistance in vivo. rIT-resistant KOPN-8 relapse shows a profound reduction in total CD22 which may contribute to resistance to CD22-directed rIT. The marked increase of Moxeefficacy in vivo by the addition of 5-AZA makes this combination a promising approach for further clinical testing in children and adults with ALL. Disclosures Wayne: Kite Pharma: Honoraria, Other: Travel support, Research Funding; Spectrum Pharmaceuticals: Honoraria, Other: Travel Support, Research Funding; Pfizer: Consultancy, Honoraria, Other: Travel Support; Medimmune: Honoraria, Other: Travel Support, Research Funding; NIH: Patents & Royalties. Pastan:NIH: Patents & Royalties: Co-Inventor on NIH Patent.

Acquired drug resistance is a major reason for relapse and death in acute lymphoblastic leukemia (ALL). Improving outcomes by targeting mechanisms of acquired drug resistance is a potential solution. DNA methyltransferase inhibitors (DNMTi) and histone deacetylase inhibitors (HDACi) have been shown to reverse drug resistance gene signatures and restore chemosensitivity in relapsed ALL. We report results investigating decitabine (DNMTi) (10-15 mg/m2/dose) and vorinostat (HDACi) (180 mg/m2/dose) with vincristine, dexamethasone, mitoxantrone and PEG-asparaginase (UKALL R3 backbone) for relapsed/refractory ALL. Twenty-three patients with refractory or ≥2nd relapse B-ALL were enrolled (Table 1). Median age was 12 (range, 1-21) years. Toxicity was graded according to CTCAE v4.0. The most common grade (Gr) 3-4 toxicities included hypokalemia (65%), anemia (61%), febrile neutropenia (57%), hypophosphatemia (43%), hyperbilirubinemia (39%), thrombocytopenia (39%), neutropenia (35%), sepsis (30%), lung infection (30%) and infection/infestations-other (30%). Non-hematologic dose limiting toxicity (DLT) was defined as any Gr 3 or 4 adverse event that was at least possibly attributed to decitabine and/or vorinostat with the exception of nausea (Gr 3), vomiting (Gr 3), transaminase elevation that returned to Gr ≤1 or baseline prior to the end of the course, fatigue, fever/infection, electrolyte abnormalities that were transient and not associated with clinical sequelae, albumin, alkaline phosphatase, GGT and anorexia. Hematologic DLT was defined as an absence of peripheral blood count recovery within 6 weeks of starting chemotherapy. Any patient who experienced a DLT after receiving at least 1 dose of decitabine or vorinostat was evaluable for DLT. Patients who did not experience a DLT had to receive a pre-determined amount of protocol therapy as outlined in the study to be evaluable for DLT. Seventeen of 23 patients were evaluable for DLT. Three patients experienced DLTs as follows: Gr 3 cholestasis, Gr 3 steatosis, Gr 4 hyperbilirubinemia (n=1); Gr 4 seizure, Gr 4 somnolence, Gr 3 delirium (n=1); and Gr 3 pneumonitis, Gr 3 hypoxia, Gr 3 hyperbilirubinemia (n=1). The study was suspended and amended after the first 5 patients enrolled (decitabine, 15mg/m2), due to significant infectious toxicities [4 of 5 patients reporting invasive fungal infections: C. kruseii (n=2), C. lusitaniae (n=1), and C. guillermondii (n=1)] and two DLTs (reported above). The treatment schema was modified to lower the dose of decitabine (10mg/m2/dose) and to reduce the duration from days 1-7/15-21 to 1-5/15-19. The duration of vorinostat was also reduced from days 3-10/17-24 to 2-7/16-21 (Figure 1). In addition, anti-fungal prophylaxis with either an echinocandin or amphotericin agent was required. Despite these dose modifications, infectious complications remained common with 17/23 (74%) patients reporting Gr ≥3 infections including invasive fungal disease in 35% (8/23). In analyzing all 23 patients, the complete response rate (CR + CR with incomplete blood count recovery) was 39% (9/23). Fourteen patients (61%) were able to complete full protocol therapy and evaluable for response. The remaining 9 patients did not complete therapy, primarily due to treatment-related toxicities, and were not evaluable. Nine of the 14 patients (64%) achieved a complete response with the remaining 5 reporting stable disease (36%). Minimal residual disease (MRD) testing via flow cytometry was performed on 7 of 9 patients who achieved a CR with a median level of 0.087% MRD (range, 0.00% to 1.6%) detected. Overall survival at 6 months was 35.1% (95% CI, 16.0 - 54.9) and 23.4% (95% CI, 7.8 - 43.6) at 1-year. Death was reported in 18/23 (78%) patients at a median of 10 weeks from study start (range, 3-138). Cause of death was attributed to refractory leukemia (n=8), treatment related toxicity (n=5), infection (n=3) and transplant-related toxicity (n=2). Despite encouraging response rates including low MRD, the combination of decitabine and vorinostat with intensive chemotherapy in this patient population was determined not to be feasible. A future follow-up study with a less intensive chemotherapy backbone is needed to determine if these two promising epigenetic agents can be successfully incorporated into the treatment of pediatric ALL. This study is registered at http://www.clinicaltrials.gov as NCT01483690. Disclosures Wayne: Kite Pharma: Honoraria, Other: Travel support, Research Funding; Spectrum Pharmaceuticals: Honoraria, Other: Travel Support, Research Funding; Pfizer: Consultancy, Honoraria, Other: Travel Support; Medimmune: Honoraria, Other: Travel Support, Research Funding; NIH: Patents & Royalties.

Background: Acute lymphoblastic leukemia (ALL) exhibits a bimodal age distribution with 60% of cases occurring in children and adolescents (45 y; Howlader SEER Cancer Statistics 2015). Most adults and 15-20% of children will relapse following initial therapy with subsequent poor outcomes. (Bassan, JCO 2012; Locatelli, Blood 2012). Promising results have been observed in studies of anti-CD19 CAR T cells in patients with B cell malignancies, including those treated with KTE-C19, a CD28/CD3ζ anti-CD19 CAR T cell studied in the multicenter ZUMA-1 trial (Neelapu ASCO 2016). However, studies of anti-CD19 CAR T cell therapy in R/R ALL have also observed high incidences of severe CRS in patients with high leukemic burden (Lee, Lancet 2015; Maude NEJM 2014). We present a preliminary analysis of the phase 1 portions of ZUMA-3 and ZUMA-4 which to date have enrolled adult and pediatric patients, respectively with high leukemic burden (M3 marrow). Methods: The primary objective of phase 1 of these multicenter trials is to evaluate the safety of KTE-C19. Eligible patients with R/R ALL are aged ≥18 y (ZUMA-3) or 2-21 y (ZUMA-4) with ≥25% marrow blasts, and adequate renal, hepatic, and cardiac function. Patients are required to have an Eastern Cooperative Oncology Group performance score 0-1 (ZUMA-3) or a Lansky or Karnofsky performance status of >80% (ZUMA-4). Patients with Ph+ ALL and low-burden central nervous system disease are eligible. Patients with Burkitt lymphoma or chronic myeloid leukemia in blast crisis, extramedullary disease only, active graft-versus-host disease, or clinically significant infection are not eligible. KTE-C19 is administered at a target dose of either 1 or 2 × 106 anti-CD19 CAR T cells/kg after low-dose conditioning with fludarabine (25 mg/m2/day for 3 days) and cyclophosphamide (900 mg/m2/day [CyFlu]; Wayne ASCO 2016; Shah ESMO 2016). Results: As of July 8, 2016, 6 patients have enrolled and 5 patients (3 adult and 2 pediatric) have been treated with KTE-C19. KTE-C19 was successfully manufactured in a centralized, streamlined 6-8-day process for 5 patients with approximately a 2-week turnaround time from the time of apheresis to delivery of KTE-C19 to site for patient infusion (Choi, ASGCT 2016). In one 2-year-old patient with peripheral white blood cells >150,000/μL and >99% leukemic blasts in the apheresis collection, KTE-C19 could not be manufactured. All 5 treated patients had high burden disease with a median 85% of marrow blasts (range, 48%-100%) at screening. All 5 patients received bridging chemotherapy prior to dosing with KTE-C19. No patient experienced a dose-limiting toxicity. Cytokine release syndrome (CRS) was reported in all adult (grade 1, n=1; grade 2, n=2) and pediatric (grade 2, n=2) patients; neurotoxicity (NT) was reported in adults only (grade 3, n=2; grade 4, n=1). CRS and NT were successfully managed to resolution with either tocilizumab, corticosteroids, and/or siltuximab in addition to other supportive care for all 5 patients. MRD- remission has been observed in all 5 patients who received KTE-C19 by day 28, with some remissions occurring as early as day 7. Four of 5 patients have had a CR/CR with partial hematologic recovery to date, and 1 of 5 patients with MRD- remission was showing recovering counts. CAR T cells expanded in blood within 2 weeks after infusion and were also detected in bone marrow and/or cerebrospinal fluid. Additional patients and clinical and correlative biomarker data will be presented. Conclusions: The administered dose of KTE-C19 after low-dose CyFlu conditioning has been tolerable and to date appears safe for further analysis in adult and pediatric patients with high leukemic burden R/R ALL. Initial results demonstrate promising efficacy, and the central manufacturing process is deemed feasible. The phase 1 portions of ZUMA-3 and ZUMA-4 are ongoing with planned expansion to phase 2. Clinical trial information: NCT02614066 (ZUMA-3); NCT02625480 (ZUMA-4). Disclosures Shah: Pfizer: Consultancy, Speakers Bureau; Bayer: Honoraria, Speakers Bureau; Plexus Communications: Honoraria; Rosetta Genomics: Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Baxalta: Honoraria, Speakers Bureau. Lee:Juno: Honoraria. Wierda:Novartis: Research Funding; Abbvie: Research Funding; Acerta: Research Funding; Gilead: Research Funding; Genentech: Research Funding. Schiller:Incyte Corporation: Research Funding. Gökbuget:Pfizer: Honoraria, Research Funding; Amgen: Honoraria, Research Funding. Sabatino:Kite: Employment, Equity Ownership. Bot:Kite Pharma: Employment, Equity Ownership. Rossi:Kite Pharma: Employment, Equity Ownership. Jiang:Kite Pharma: Employment, Equity Ownership. Navale:Kite Pharma: Employment, Equity Ownership. Stout:Kite Pharma: Employment, Equity Ownership. Aycock:Kite Pharma: Employment, Equity Ownership. Wiezorek:Kite Pharma: Employment, Equity Ownership. Jain:Kite Pharma: Employment, Equity Ownership. Wayne:Spectrum Pharmaceuticals: Honoraria, Other: Travel Support, Research Funding; Kite Pharma: Honoraria, Other: Travel support, Research Funding; Pfizer: Consultancy, Honoraria, Other: Travel Support; Medimmune: Honoraria, Other: Travel Support, Research Funding; NIH: Patents & Royalties.

We have created and are validating a targeted gene panel that utilizes 20ng of FFPE DNA and 10 ng of FFPE RNA in a simple, 3-tube Ion AmpliSeq assay suitable for sequencing on the Ion Torrent platform with rapid turn around time ( Citation Format: Timothy J. Triche, Jackie Biegel, Alex Judkins, Tracy Busse, Alan Wayne, Deepa Bhojwani, Shahab Asgharzadeh, Matthew Oberley, David Parham. A comprehensive gene panel for precise diagnosis and treatment of childhood cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1384.

TPS7075Background: ALL is the most common childhood malignancy. While approximately 80% of patients achieve durable complete remissions (CR) following initial treatment, the 20% of patients with relapsed or refractory disease have poor outcomes and require effective new therapies. An ongoing study at the National Cancer Institute (NCI) using anti-CD19 CAR T cells with CD28/CD3-zeta signaling domains showed complete remissions in 14 of 20 pediatric subjects with r/r ALL. (NCT01593696; Lee, Lancet 2015). KTE-C19 is an autologous, anti-CD-19 CAR T cell therapy that utilizes the same construct investigated in the NCI studies, manufactured in a streamlined 6 - 8 day process. Here we describe a phase 1/2 study evaluating KTE-C19 in pediatric and adolescent patients with r/r ALL. Methods: Subjects with r/r ALL will be treated with fixed dose fludarabine and cyclophosphamide conditioning chemotherapy followed by a single infusion of KTE-C19 at a target dose of 2 x 106 anti-CD19 CAR T cells/kg. Phase 1 will enroll...

Juvenile chronic myelogenous leukemia (JCML) is a myeloproliferative disease in which morbidity and mortality are primarily caused by nonhematopoietic organ failure from myelomonocytic infiltration or by failure of the normal bone marrow. Morphologic evidence of maturation arrest, karyotypic abnormalities, and progression to blast crisis are infrequent events. Viral infections and other reactive processes can initially mimic the clinical course of JCML, creating diagnostic problems. Because of the rarity of JCML and technical limitations, formal clonality studies have not been reported previously. Nine female JCML patients were identified by clinical criteria, characteristic ‘spontaneous’ in vitro cell growth, and negative cultures and titers for various viral agents. Peripheral blood and bone marrow samples were obtained at the time of diagnosis for cell separation and RNA and DNA isolation. To assess clonality, X-chromosome inactivation patterns were evaluated using three different, recently developed polymerase chain reaction-based clonality assays. All nine female JCML patients showed evidence for monoclonal origin of mononuclear cells at the time of diagnosis. Cell separation studies further traced the monoclonal origin back to at least the most primitive myeloid progenitor cell. Reversion to a polyclonal state was demonstrated after bone marrow transplant and also in one patient following treatment with 13-cis retinoic acid. This demonstration of clonality in JCML delineates it from the reactive processes and provides a basis for molecular genetic strategies to identify causally associated mutations.

Immune targeting of B-cell malignancies using chimeric antigen receptors (CARs) is a promising new approach, but critical factors impacting CAR efficacy remain unclear. To test the suitability of targeting CD22 on precursor B-cell acute lymphoblastic leukemia (BCP-ALL), lymphoblasts from 111 patients with BCP-ALL were assayed for CD22 expression and all were found to be CD22-positive, with median CD22 expression levels of 3500 sites/cell. Three distinct binding domains targeting CD22 were fused to various TCR signaling domains ± an IgG heavy chain constant domain (CH2CH3) to create a series of vector constructs suitable to delineate optimal CAR configuration. CARs derived from the m971 anti-CD22 mAb, which targets a proximal CD22 epitope demonstrated superior antileukemic activity compared with those incorporating other binding domains, and addition of a 4-1BB signaling domain to CD28.CD3ζ constructs diminished potency, whereas increasing affinity of the anti-CD22 binding motif, and extending the CD22 binding domain away from the membrane via CH2CH3 had no effect. We conclude that second-generation m971 mAb-derived anti-CD22 CARs are promising novel therapeutics that should be tested in BCP-ALL.

Modern multiagent chemotherapy regimens have increased the cure rate in acute lymphoblastic leukemia (ALL). In pediatric ALL, refinements of doses and schedules of chemotherapy combinations have increased the cure rate from less than 40% in the 1960s to 80% in 2000 without the addition of any novel chemotherapy drugs or targeted therapies.1–3 The pediatric regimens have included induction, consolidation, maintenance, and CNS treatment phases. Using similar strategies in adult ALL has improved the cure rates from less than 20% to 35% to 50%.4–6 The addition of asparaginase to pediatric chemotherapy regimens further improved the cure rates. Using similar regimens in adult ALL seems to improve the cure rates but at the expense of significant toxicity, particularly in patients age 45 years or older.7 Further intensification of existing chemotherapy regimens is unlikely to increase the cure rate and may significantly increase toxicities. Survivors of childhood ALL are at risk of multiple late effects related in part to the intensity of their therapy.8 Therefore, novel anti-ALL agents are needed to overcome chemotherapy resistance and reduce nonspecific toxicities. Targeted therapy in ALL has shown promise in both children and adults. In Philadelphia chromosome–positive ALL, the discovery of the activity of BCR-ABL tyrosine kinase inhibitors and their addition to intensive chemotherapy has increased survival rates from less than 10% to approximately 50% in adults and from approximately 35% to 80% in children.9–12 Targeted therapy using monoclonal antibodies against cell surface markers of ALL cells has shown promising results.13–15 Herein, we will review the results and status of investigational monoclonal antibody–based therapies in ALL.

Manipulation of hematopoietic stem/progenitor cells (HSPCs) ex vivo is of clinical importance for stem cell expansion and gene therapy applications. However, most cultured HSPCs are actively cycling, and show a homing and engraftment defect compared with the predominantly quiescent noncultured HSPCs. We previously showed that HSPCs make contact with osteoblasts in vitro via a polarized membrane domain enriched in adhesion molecules such as tetraspanins. Here we show that increased cell cycling during ex vivo culture of HSPCs resulted in disruption of this membrane domain, as evidenced by disruption of polarity of the tetraspanin CD82. Chemical disruption or antibody-mediated blocking of CD82 on noncultured HSPCs resulted in decreased stromal cell adhesion, homing, and engraftment in nonobese diabetic/severe combined immunodeficiency IL-2γnull (NSG) mice compared with HSPCs with an intact domain. Most leukemic blasts were actively cycling and correspondingly displayed a loss of domain polarity and decreased homing in NSG mice compared with normal HSPCs. We conclude that quiescent cells, unlike actively cycling cells, display a polarized membrane domain enriched in tetraspanins that mediates homing and engraftment, providing a mechanistic explanation for the homing/engraftment defect of cycling cells and a potential new therapeutic target to enhance engraftment.

Background Despite high cure rates for pediatric B-lineage acute lymphoblastic leukemia (B-ALL), short-term and long-term toxicities and chemoresistance are shortcomings of standard chemotherapy. Immunotherapy and chemoimmunotherapy based on monoclonal antibodies (mAbs) that target cell surface antigens with restricted expression in pediatric B-ALL may offer the potential to reduce toxicities and prevent or overcome chemoresistance. The receptor tyrosine kinase ROR1 has emerged as a candidate for mAb targeting in select B-cell malignancies. Methodology and Principal Findings Using flow cytometry, Western blotting, immunohistochemistry, and confocal immunofluorescence microscopy, we analyzed the cell surface expression of ROR1 across major pediatric ALL subtypes represented by 14 cell lines and 56 primary blasts at diagnosis or relapse as well as in normal adult and pediatric tissues. Cell surface ROR1 expression was found in 45% of pediatric ALL patients, all of which were B-ALL, and was not limited to any particular genotype. All cell lines and primary blasts with E2A-PBX1 translocation and a portion of patients with other high risk genotypes, such as MLL rearrangement, expressed cell surface ROR1. Importantly, cell surface ROR1 expression was found in many of the pediatric B-ALL patients with multiply relapsed and refractory disease and normal karyotype or low risk cytogenetics, such as hyperdiploidy. Notably, cell surface ROR1 was virtually absent in normal adult and pediatric tissues. Conclusions and Significance Collectively, this study suggests that ROR1 merits preclinical and clinical investigations as a novel target for mAb-based therapies in pediatric B-ALL. We propose cell surface expression of ROR1 detected by flow cytometry as primary inclusion criterion for pediatric B-ALL patients in future clinical trials of ROR1-targeted therapies.

Background The prognosis of patients with homozygous β-thalassemia (thalassemia major) has been improved by transfusion and iron-chelation therapy. We analyzed outcome and prognostic factors among patients receiving transfusions and chelation therapy who had reached the age at which iron-induced cardiac disease, the most common cause of death, usually occurs. Methods Using the duration of life without the need for either inotropic or antiarrhythmic drugs as a measure of survival without cardiac disease, we studied 97 patients born before 1976 who were treated with regular transfusions and chelation therapy. We used Cox proportional-hazards analysis to assess the effect of prognostic factors and life-table analysis to estimate freedom from cardiac disease over time. Results Of the 97 patients, 59 (61 percent) had no cardiac disease; 36 (37 percent) had cardiac disease, and 18 of them had died. Univariate analysis demonstrated that factors affecting cardiac disease-free survival were age at the start of che...

Genetic deficiency of adenosine deaminase (ADA) can cause profound lymphopenia and result in the clinical presentation of severe combined immune deficiency (SCID). However, because of the ubiquitous expression of ADA, ADA-deficient patients often present also with nonimmunologic clinical problems, affecting the skeletal, central nervous, endocrine, and gastrointestinal systems. We now report that myeloid dysplasia features and bone marrow hypocellularity are often found in patients with ADA-SCID. As a clinical correlate to this finding, we have observed vulnerability to antibiotic-induced myelotoxicity and prolonged neutropenia after nonmyeloablative chemotherapy. We have also noted that, in the absence of enzyme replacement therapy, absolute neutrophil counts of patients with ADA deficiency vary inversely with the accumulation of deoxynucleotides. These data have significant implications for the application of standard and investigational therapies to patients with ADA-SCID and support further studies to investigate the possibility that ADA deficiency is associated with a stem cell defect. These trials were registered at www.clinicaltrials.gov as #NCT00018018 and #NCT00006319.

Chronic active EBV disease (CAEBV) is a lymphoproliferative disorder characterized by markedly elevated levels of antibody to EBV or EBV DNA in the blood and EBV RNA or protein in lymphocytes in tissues. We present our experience with CAEBV during the last 28 years, including the first 8 cases treated with hematopoietic stem cell transplantation in the United States. Most cases of CAEBV have been reported from Japan. Unlike CAEBV in Japan, where EBV is nearly always found in T or natural killer (NK) cells in tissues, EBV was usually detected in B cells in tissues from our patients. Most patients presented with lymphadenopathy and splenomegaly; fever, hepatitis, and pancytopenia were common. Most patients died of infection or progressive lymphoproliferation. Unlike cases reported from Japan, our patients often showed a progressive loss of B cells and hypogammaglobulinemia. Although patients with CAEBV from Japan have normal or increased numbers of NK cells, many of our patients had reduced NK-cell numbers. Although immunosuppressive agents, rituximab, autologous cytotoxic T cells, or cytotoxic chemotherapy often resulted in short-term remissions, they were not curative. Hematopoietic stem cell transplantation was often curative for CAEBV, even in patients with active lymphoproliferative disease that was unresponsive to chemotherapy. These studies are registered at http://www.clinicaltrials.gov as NCT00032513 for CAEBV, NCT00062868 and NCT00058812 for EBV-specific T-cell studies, and NCT00578539 for the hematopoietic stem cell transplantation protocol.

Immunotoxins are antibody-toxin fusion proteins directed to kill cancer cells displaying specific target antigens on their surface. Remarkably, immunotoxins directed to CD22 on hairy cell leukemia have produced complete remissions in approximately 60% of patients enrolled in phase I/II trials. For reasons that are not yet clear, 40% of patients responded less well. In addition, patients with other CD22-positive malignancies have not yet achieved complete remissions. In trying to understand 'resistance' to immunotoxin therapy, a number of challenging issues have been raised. These include insufficient dosing, the production of neutralizing anti-immunotoxin antibodies, poor access to malignant cells, and resistance to toxin killing. In designing immunotoxins, we employ truncated Pseudomonas exotoxin, which enzymatically inactivates protein synthesis and produces cell death in sensitive cells. To begin to address toxin resistance we have explored combination therapy with the BH3-only mimetic, ABT-737. Our results indicate that immunotoxin-ABT combinations often exhibit greater killing activity than either compound alone and in some instances overcome resistance. Expression of high levels of prosurvival Bcl-2 proteins may contribute to toxin resistance.

Long-term remission in a child with refractory EBV + hydroa vacciniforme-like T-cell lymphoma through sequential matched EBV + -related allogeneic hematopoietic SCT followed by donor-derived EBV-specific cytotoxic T-lymphocyte immunotherapy

The National Cancer Institute's First International Workshop on the Biology, Prevention, and Treatment of Relapse after Allogeneic Hematopoietic Stem Cell Transplantation was organized and convened to identify, prioritize, and coordinate future research activities related to relapse after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Each of the Workshop's 6 Working Committees has published individual reports of ongoing basic, translational, and clinical research and recommended areas for future research related to the areas of relapse biology, epidemiology, prevention, and treatment. This document summarizes each committee's recommendations and suggests 3 major initiatives for a coordinated research effort to address the problem of relapse after allo-HSCT: (1) to establish multicenter correlative and clinical trial networks for basic/translational, epidemiologic, and clinical research; (2) to establish a network of biorepositories for the collection of samples before and after allo-HSCT to aid in laboratory and clinical studies; and (3) to further refine, implement, and study the Workshop-proposed definitions for disease-specific response and relapse and recommendations for monitoring of minimal residual disease. These recommendations, in coordination with ongoing research initiatives and transplantation organizations, provide a research framework to rapidly and efficiently address the significant problem of relapse after allo-HSCT. Biol Blood Marrow Transplant 17: 443-454 (2011) Published by Elsevier Inc. on behalf of American Society for Blood and Marrow Transplantation

Introduction Subcutaneous panniculitis-like T-cell lymphoma (SPTL-AB) and cutaneous gamma/delta T-cell lymphoma (CGD-TCL) are rare T-cell lymphomas with varying clinical courses. There is no standard treatment, although chemotherapy and hematopoietic stem cell transplantation are commonly used. We describe results using bexarotene for children and adults with these disorders. Methods We identified 15 patients (12 adults, 3 children) who were treated with bexarotene between 2000 and 2010 from the Memorial Sloan-Kettering Cancer Center lymphoma database, the Stanford Cancer Center Registry, and the National Cancer Institute (NCI) pediatric lymphoma database. There were 8 females and 7 males, with a median age of 45 years (range, 3 years to 85 years). All patients had stage IV disease. Two of 15 and 4 of 15 patients had documented CGD-TCL and SPTL-AB, respectively; others were presumed to have SPTL-AB. Bexarotene was administered at flat doses corresponding to 91 to 339 mg/m 2 /d. Two of 15 patients received concurrent denileukin diftitox. Two children received bexarotene as maintenance therapy and were not evaluable for response. Results Among those treated with bexarotene alone, the overall response rate (ORR) was 82% (6/11 complete response [CR], 3/11 partial response [PR]). One of the 2 patients treated with concomitant denileukin diftitox responded for an ORR of 10/13 (77%), including 54% CR and 23% PR. Median progression-free survival was 38.4 months; median duration of response was 26.3 months. Six patients developed hypothyroidism and 9 developed hyperlipidemia; one patient developed dose-limiting hypertriglyceridemia. One pediatric patient developed insulin-dependent diabetes mellitus. Conclusions In this retrospective series, bexarotene showed a high response rate in SPTL-AB and CGD-TCL. It was generally well-tolerated with durable responses; therefore, bexarotene represents a promising therapy for children and adults with these disorders.

A 60-year-old man with beta-thalassemia intermedia and degenerative joint disease was successfully treated by total hip arthroplasty. The operation was complicated by severe bleeding associated with marked bone marrow hyperplasia. Despite autologous cell salvage, massive homologous transfusion was required. Special orthopaedic and perioperative complications stem from beta-thalassemia syndromes. Management may be complicated by anemia, medullary hyperplasia, organ dysfunction associated with iron overload, and susceptibility to infection. The orthopaedic manifestations of beta-thalassemia may be mitigated by chronic transfusions.

PURPOSE A nonrandomized, single-arm trial was conducted to assess the efficacy of multimodality therapy including intensive chemotherapy with multiple alkylating agents in the treatment of children with Evans stage III neuroblastoma older than 1 year at diagnosis. PATIENTS AND METHODS Twenty-five patients with a median age of 18 months at diagnosis were treated with multimodality therapy including surgery and chemotherapy using either nitrogen mustard (mechlorethamine), doxorubicin, cisplatin, dacarbazine (DTIC), vincristine, and cyclophosphamide (MADDOC) or cisplatin and cyclophosphamide induction followed by maintenance MADDOC (induction MADDOC) protocols. Sixteen of 25 patients also received radiotherapy to the tumor bed and primary lymph nodes. Event-free survival (EFS) was compared with that reported previously in the literature. N-myc amplification was evaluated prospectively and the Shimada classification was evaluated retrospectively as potential prognostic factors. RESULTS We report a 72% EFS (95% confidence interval +/- 18%) with a median follow-up of 85 months. EFS was significantly worse for patients with tumors demonstrating N-myc amplification (P = .018). Patients classified as favorable according to the Shimada system experienced a significantly better EFS (P = .04), but unfavorable patients still maintained a 60% EFS. CONCLUSION Intensive multimodality treatment including MADDOC and induction MADDOC chemotherapy provides a very good EFS for children older than 1 year who have stage III neuroblastoma. Children classified as favorable according to the Shimada system have a better prognosis. Patients whose tumors demonstrate N-myc amplification have a poor prognosis despite therapy.

An 8-year-old girl developed ataxia-telangiectasia. Western blotting of lysate revealed absence of the ATM protein, and 2 mutations in the ATM gene were found. Subsequently, the patient developed increased respiratory symptoms. Open lung biopsy revealed lymphocytic interstitial pneumonitis, which is not characteristic of ataxia-telangiectasia. There was a therapeutic response to glucocorticosteroid treatment.

Background Blastic plasmacytoid dendritic cell neoplasm is a rare malignancy that typically follows a highly aggressive clinical course in adults, whereas experience in children with this disease is very limited.Design and Methods This retrospective study analyzed the pathological and clinical findings of nine cases of blastic plasmactyoid dendritic cell neoplasm presenting in patients under the age of 18 years who were reviewed at our institution. We also identified 20 well-documented additional pediatric cases in the literature.Results In the combined analysis, the overall survival rate among the 25 patients with available follow-up, all having received chemotherapy, was 72% (follow-up ranging from 9 months to 13 years, with a median of 30 months). The event-free survival rate was 64%. Nine patients were alive 5 years after the original diagnosis, although only three of them had undergone hematopoietic stem cell transplantation – one in first complete remission and two in second remission. Of the seven patients who lacked cutaneous disease at presentation, 100% survived, including five who were alive more than 5 years after diagnosis, although only two had undergone stem cell transplantation. Among the 18 patients who presented with cutaneous disease and for whom follow-up data were available, only 11 survived (61%). Detailed immunophenotypic characterization and clinical features of all cases are presented. Unexpectedly, three of four cases of blastic plasmacytoid dendritic cell neoplasm tested showed focal positivity for S-100. S-100 was negative in 28 cases of acute myeloid leukemia evaluated for this marker.Conclusions In contrast to adult cases, in which long-term survival depends on stem cell transplantation in first complete remission, blastic plasmacytoid dendritic cell neoplasms in children are clinically less aggressive. Treatment with high-risk acute lymphoblastic leukemia-type chemotherapy appears to be effective, and stem cell transplantation may be reserved for children who relapse and achieve a second remission. Outcomes were more favorable in cases that lacked cutaneous disease at presentation, although a comparison of cutaneous and non-cutaneous cases might be confounded by differences in treatment regimens. Focal expression of S-100 may be seen in concert with other markers of plasmacytoid dendritic cells.

Acute lymphoblastic leukaemia (ALL) remains the most frequent cause of cancer-related mortality in paediatrics and outcome is poor for patients who have high-risk ALL or relapse. HA22 (CAT-8015) is an immunotoxin composed of an anti-CD22 variable fragment linked to a 38 kDa truncated protein derived from Pseudomonas exotoxin A. Using a bone marrow mesenchymal cell culture assay to support ALL cell viability, we investigated the in vitro cytotoxicity of HA22 against ALL blasts from newly diagnosed (n = 13) and relapsed patients (n = 22). There was interpatient variability in sensitivity to HA22. Twenty-four of 35 patient samples tested were sensitive (median 50% lethal concentration 3 ng/ml, range 1-80 ng/ml). Blasts from the other 11 patients were not killed by 500 ng/ml HA22. The median 50% lethal concentration was 20 ng/ml for all patients. There was no significant difference in HA22 sensitivity between diagnosis and relapse samples but peripheral blood ALL blasts were more sensitive to HA22 than those from bone marrow (P = 0.008). Thus, HA22, at concentrations achievable in patients, is highly cytotoxic to B-lineage ALL cells. These results provide a strong rationale for clinical testing of this agent in children with drug-resistant ALL and offers the potential to reduce morbidities of treatment while improving outcome.

Despite great progress in the curative treatment of leukemia in pediatrics, current therapies are associated with multiple toxicities and the prognosis after relapse is guarded. Novel approaches are needed to overcome resistance to standard therapy and decrease adverse effects. The efficacy of allogeneic stem cell transplantation and the demonstration of a graft-versus-leukemia effect suggest that immune-based therapies can be effective in the treatment of childhood leukemia. Efforts to apply new immunotherapy approaches to the treatment of leukemia in pediatrics have recently begun. The optimal reagents, methods, and regimens have yet to be fully defined. Ongoing clinical trials offer promise in that regard.

Acute and chronic graft versus host disease are frequent and potentially severe complications of allogeneic hematopoietic stem cell transplantation and are among the leading causes of non-relapse transplant-related mortality. For patients with steroid refractory disease, prognosis is particularly poor and although a variety of treatment options are available, responses are commonly transient and the side effects often intolerable. Since it was first introduced for the treatment of cutaneous T-cell lymphoma, extracorporeal photo-apheresis has been utilized as an immunomodulatory therapy for certain autoimmune diseases and solid organ transplant rejection. Recently, extracorporeal photo-apheresis has become a promising alternative for patients with graft versus host disease with disabling or potentially lethal complications. Here we review the experience of extracorporeal photo-apheresis for the treatment of steroid refractory acute and chronic graft versus host disease based on the current literature.

Allogeneic bone marrow (BM) and cytokine mobilized peripheral blood stem cell (PBSC) transplantation can be curative for patients with malignant and nonmalignant hematologic diseases. Siblings are most often selected as a donor match; however, research on sibling donors is limited and has focused primarily on conventional BM donors. This exploratory study describes the experiences of PBSC sibling donors at a single institution. Through retrospective interviews, 14 sibling donors shared their perceived needs and concerns before and after their stem cell collection. Donors identified fears about the donation procedure, and expressed the need for more information about transplant outcome and complications. The inclusion of the sibling donors themselves, rather than the report of their parents or health-care providers and the qualitative nature of the structured design allowed sibling donors to describe their concerns and thoughts without being restrained by the beliefs of the participant’s parents, researcher or sibling’s medical team. Suggestions for visual educational tools, psychosocial interventions and future research are provided.

Hematopoietic Stem Cell Transplant (HSCT) represents the second most frequent major organ transplant in the United States. Compared with other family members, siblings are more likely to be immunologically matched with the recipient and therefore are often the most suitable donors. Due to a dearth of information on the positive and adverse effects of HSCT on pediatric sibling donors, we sought to examine available data. Eight published reports assessing the pediatric sibling donor experience were identified in the literature. Studies were predominately small (n < 44) and cross-sectional. Results suggest a range of psychological distress responses with higher distress in pediatric donor than non-donor siblings. Recommendations include future longitudinal research on sibling donor psychosocial adjustment, identification of sibling donors at high risk for maladaptive responses, and development of educational and psychosocial interventions for this overlooked pediatric population.

BACKGROUND: Antibodies to neutrophil-specific antigens are the best characterized cause of transfusion-related acute lung injury (TRALI). CASE REPORT: A double-apheresis platelet (PLT) component was divided and transfused into two patients. One experienced chills, rigors, and dyspnea and the other experienced chills and headache. Transient leukopenia developed in both patients. RESULTS: Evaluation of donor plasma revealed an anti-HNA-2a and no HLA Class I antibodies. The donor had donated 26 previous apheresis PLT components. The 27 donations resulted in 39 separate transfusions and 12 transfusion reactions in 9 patients. Five reactions occurred immediately after the transfusion, 10 within 1 hour, and all within 2.5 hours. Nine of the reactions involved symptoms or signs of pulmonary dysfunction. The symptoms were mild to moderate in nature. None of the inpatients required intensive care transfer nor did any outpatients require hospital admission. Recipient white blood cell (WBC) counts were measured within 8 hours after 38 of 39 transfusions. Leukopenia occurred in 9 of 12 (75%) transfusions with reactions and in 9 of 26 (35%) transfusions without. The reactions did not correlate with pretransfusion WBC count. CONCLUSIONS: Neutrophil antibodies cause a wide variety of transfusion reactions that do not necessarily meet the definition of TRALI. Donors of blood products causing even mild pulmonary reactions or leukopenia should be tested for neutrophil-specific antibodies.

Introduction Remission induction rates after a second or greater relapse is a critical endpoint in phase II trials of childhood acute lymphoblastic leukemia (ALL). A robust benchmark is crucial for identification of novel multi-agent regimens worthy of further study. The Therapeutic Advances in Childhood Leukemia and Lymphoma (TACL) consortium previously reported the response rates of children with multiply relapsed and refractory (R/R) ALL treated between 1995 and 2004, which provided a benchmark for clinical trials. To define more recent treatment patterns and test the robustness of this benchmark, we performed a retrospective cohort review of children with R/R ALL who experienced second or greater treatment failure at TACL consortium sites between 2005 and 2013. Patients and Methods Eligible patients were identified at participating TACL institutions. This cohort was comprised of patients with medullary R/R B-cell precursor ALL who experienced at least 2 treatment failures or relapsed after hematopoietic stem cell transplant. Patient demographic data and details of the initial and R/R disease characteristics were abstracted from medical records and entered into a central database. This study was approved by the IRB of each participating institution. Treatment failure was defined by the presence or re-emergence of circulating blasts, M2/M3 BM, or extramedullary (EM) disease despite therapy. Complete remission (CR) was defined as M1 marrow, no EM disease and evidence of peripheral count recovery. For the purpose of statistical analysis, patients who met these criteria without platelet recovery (CRp) or normal blood count recovery (CRi) were included as CR. Univariate and multivariate logistic regression were utilized to evaluate the risk of re-induction failure. Predictors included in this preliminary analysis were NCI risk criteria at diagnosis, duration of the prior remission, the treatment attempt number, and the EM and BM status at the start of each therapy attempt. Results This report includes 214 patients. Fifty-six percent were male. At initial diagnosis, 32% were at least 10 years old, 26% had initial white blood cell (WBC) counts over 50,000/µL, and 39% were classified as high risk by the NCI risk criteria (Table 1). Therapy involved various combinations of agents and ranged between 2 and 10 attempts. The CR rate was 42% for third treatment attempt and 24% for fourth and subsequent treatment attempts (Table 2). Treatment failures were significantly associated with increased number of treatment attempts (p < 0.001), shorter duration of previous CR (p < 0.001) and NCI risk category at diagnosis (p = 0.018). Conclusion This preliminary analysis found similar CR rates in patients with third treatment failure compared to the 1st TACL retrospective study of the prior decade (42% vs. 44%, Ko et al, 2010) and an Austrian report with a small cohort of patients (Reismuller et al, 2013). Further analysis will be performed in comparison to the initial TACL retrospective study cohort once enrollment to this study has been completed (approximately 400 patients). A robust, contemporary historical control may serve as an alternative to a randomized control when outcome with past therapies in unacceptably poor. | Characteristic | | No of patients | % | | ------------------------------ | --------------------------- | -------------- | -- | | Age, years | < 1 (infants) | 18 | 8 | | | 1-9 | 126 | 59 | | | 10 and over | 70 | 33 | | WBC count/uL | < 50K | 128 | 60 | | | 50K and over | 56 | 26 | | | Unknown | 30 | 14 | | NCI risk criteria at diagnosis | Non-infants, standard risk | 82 | 38 | | Non-infants, high risk | 84 | 39 | | Non-infants, unknown | 30 | 14 | | Infants | 18 | 8 | | Sex | Female | 94 | 44 | | | Male | 120 | 56 | | CNS disease | Yes | 42 | 20 | | | No | 148 | 69 | | | Unknown | 24 | 11 | | Karyotype1 | Normal | 68 | 30 | | | 11q23 (MLL gene) rearranged | 19 | 8 | | | Hypodiploidy | 7 | 3 | | | Hyperdiploidy | 26 | 12 | | | iAMP21 | 2 | 1 | | | t(12;21) | 6 | 3 | | | t(1;19) | 7 | 3 | | | t(9;22) | 15 | 7 | | | Other | 46 | 21 | | | Unknown | 28 | 12 | * 1 Karyotype is available for 214 unique patients; 2 entries were reported for 7 patients, and 4 entries were reported for 1 patient. Table 1. Patient Characteristics at Initial Diagnosis of Patients with ALL who received at least two treatment attempt (n = 214 patients) | | Third treatment attempt | Fourth through tenth treatment attempt | | ------------------------- | ------------------------------- | -------------------------------------- | --- | | Duration of preceding CR | Response | Total | % | Response | Total | % | | Not achieved (refractory) | 24 | 63 | 38 | 20 | 86 | 23 | | < 18 months duration | 28 | 78 | 36 | 11 | 49 | 22 | | 18 to 36 months duration | 9 | 15 | 60 | 3 | 5 | 60 | | ≥ 36 months duration | 8 | 8 | 100 | | 1 | | | All patients combined | 69 | 164 | 42 | 34 | 141 | 24 | Table 2. Achievement of CR/CRp/CRi After Treatment of R/R ALL by Preceding Remission Duration and Treatment Attempt Disclosures Sun: Gateway for Cancer Researchy: Research Funding; Amgen: Research Funding. Wilkes: Healthcare Research and Quality: Research Funding; Alex's Lemonade Stand Foundation: Research Funding. Gaynon: Bristol Meyers Squibb: Membership on an entity's Board of Directors or advisory committees; Sigma Tau: Speakers Bureau; JAZZ: Speakers Bureau. Wayne: Medimmune: Honoraria, Other: travel support, Research Funding; NIH: Patents & Royalties; Kite Pharma: Honoraria, Other: travel support; Pfizer: Honoraria; Spectrum Pharmaceuticals: Honoraria, Other: travel support, Research Funding. Whitlock: Amgen: Honoraria.