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Background: In 2014, germline signal transducer and activator of transcription (STAT) 3 gain-of-function (GOF) mutations were first described to cause a novel multisystem disease of early-onset lymphoproliferation and autoimmunity. Objective: This pivotal cohort study defines the scope, natural history, treatment, and overall survival of a large global cohort of patients with pathogenic STAT3 GOF variants. Methods: We identified 191 patients from 33 countries with 72 unique mutations. Inclusion criteria included symptoms of immune dysregulation and a biochemically confirmed germline heterozygous GOF variant in STAT3. Results: Overall survival was 88%, median age at onset of symptoms was 2.3 years, and median age at diagnosis was 12 years. Immune dysregulatory features were present in all patients: lymphoproliferation was the most common manifestation (73%); increased frequencies of double-negative (CD4−CD8−) T cells were found in 83% of patients tested. Autoimmune cytopenias were the second most common clinical manifestation (67%), followed by growth delay, enteropathy, skin disease, pulmonary disease, endocrinopathy, arthritis, autoimmune hepatitis, neurologic disease, vasculopathy, renal disease, and malignancy. Infections were reported in 72% of the cohort. A cellular and humoral immunodeficiency was observed in 37% and 51% of patients, respectively. Clinical symptoms dramatically improved in patients treated with JAK inhibitors, while a variety of other immunomodulatory treatment modalities were less efficacious. Thus far, 23 patients have undergone bone marrow transplantation, with a 62% survival rate. Conclusion:: STAT3 GOF patients present with a wide array of immune-mediated disease including lymphoproliferation, autoimmune cytopenias, and multisystem autoimmunity. Patient care tends to be siloed, without a clear treatment strategy. Thus, early identification and prompt treatment implementation are lifesaving for STAT3 GOF syndrome.

BACKGROUND: The DNA-repair enzyme Artemis is essential for rearrangement of T- and B-cell receptors. Mutations in DCLRE1C, which encodes Artemis, cause Artemis-deficient severe combined immunodeficiency (ART-SCID), which is poorly responsive to allogeneic hematopoietic-cell transplantation. METHODS: We carried out a phase 1–2 clinical study of the transfusion of autologous CD34+ cells, transfected with a lentiviral vector containing DCLRE1C, in 10 infants with newly diagnosed ART-SCID. We followed them for a median of 31.2 months. RESULTS: Marrow harvest, busulfan conditioning, and lentiviral-transduced CD34+ cell infusion produced the expected grade 3 or 4 adverse events. All the procedures met pre-specified criteria for feasibility at 42 days after infusion. Gene-marked T cells were detected at 6 to 16 weeks after infusion in all the patients. Five of 6 patients who were followed for at least 24 months had T-cell immune reconstitution at a median of 12 months. The diversity of T-cell receptor β chains normalized by 6 to 12 months. Four patients who were followed for at least 24 months had sufficient B-cell numbers, IgM concentration, or IgM isohemagglutinin titers to permit discontinuation of IgG infusions. Three of these 4 patients had normal immunization responses, and the fourth has started immunizations. Vector insertion sites showed no evidence of clonal expansion. One patient who presented with cytomegalovirus infection received a second infusion of gene-corrected cells to achieve T-cell immunity sufficient for viral clearance. Autoimmune hemolytic anemia developed in 4 patients 4 to 11 months after infusion; this condition resolved after reconstitution of T-cell immunity. All 10 patients were healthy at the time of this report. CONCLUSIONS: Infusion of lentiviral gene-corrected autologous CD34+ cells, preceded by pharmacologically targeted low-exposure busulfan, in infants with newly diagnosed ART-SCID resulted in genetically corrected and functional T and B cells. (Funded by the California Institute for Regenerative Medicine and the National Institute of Allergy and Infectious Diseases; ClinicalTrials.gov number, NCT03538899.)

Shearer et al in 2014 articulated well-defined criteria for the diagnosis and classification of severe combined immunodeficiency (SCID) as part of the Primary Immune Deficiency Treatment Consortium's (PIDTC's) prospective and retrospective studies of SCID.Because of the advent of newborn screening for SCID and expanded availability of genetic sequencing, revision of the PIDTC 2014 Criteria was needed.We developed and tested updated PIDTC 2022 SCID Definitions by analyzing 379 patients proposed for prospective enrollment into Protocol 6901, focusing on the ability to distinguish patients with various SCID subtypes.According to PIDTC 2022 Definitions, 18 of 353 patients eligible per 2014 Criteria were considered not to have SCID, whereas 11 of 26 patients ineligible per 2014 Criteria were determined to have SCID. Of note, very low numbers of autologous T cells (0.05 × 10The PIDTC 2022 Definitions describe SCID and its subtypes more precisely than before, facilitating analyses of SCID characteristics and outcomes.

Hematopoietic cell transplantation (HCT) is an established cure for sickle cell disease (SCD) supported by long-term survival, but long-term organ function data are lacking. We sought to describe organ function and assess predictors for dysfunction in a retrospective cohort (n = 247) through the Sickle cell Transplant Advocacy and Research alliance. Patients with1-year follow-up or graft rejection/second HCT were excluded. Organ function data were collected from last follow-up. Primary measures were organ function, comparing pre- and post-HCT. Bivariable and multivariable analyses were performed for predictors of dysfunction. Median age at HCT was 9.4 years; the majority had HbSS (88.2%) and severe clinical phenotype (65.4%). Most received matched related (76.9%) bone marrow (83.3%) with myeloablative conditioning (MAC; 57.1%). Acute and chronic graft-versus-host disease (GVHD) developed in 24.0% and 24.8%. Thirteen patients (5.3%) died ≥1 year after HCT, primarily from GVHD or infection. More post-HCT patients had low ejection or shortening fractions than pre-HCT (0.6% → 6.0%, P = .007 and 0% → 4.6%, P = .003). The proportion with lung disease remained stable. Eight patients (3.2%) had overt stroke; most had normal (28.3%) or stable (50.3%) brain magnetic resonance imaging. On multivariable analysis, cardiac dysfunction was associated with MAC (odds ratio [OR] = 2.71; 95% confidence interval [CI], 1.09-6.77; P = .033) and severe acute GVHD (OR = 2.41; 95% CI, 1.04-5.62; P = .041). Neurologic events were associated with central nervous system indication (OR = 2.88; 95% CI, 2.00-4.12; P.001). Overall organ dysfunction was associated with age ≥16 years (OR = 2.26; 95% CI, 1.35-3.78; P = .002) and clinically severe disease (OR = 1.64; 95% CI, 1.02-2.63; P = .043). In conclusion, our results support consideration of HCT at younger age and use of less intense conditioning.

Hemophagocytic lymphohistiocytosis (HLH) is a rare but severe form of immune dysregulation often presenting as unremitting fever, cytopenia, hepatosplenomegaly, coagulopathy, and elevation of typical HLH biomarkers. HLH is universally fatal, if left untreated. The HLH-2004 criteria are widely used to diagnose this condition, but there is growing concerns across different settings that its application may result in undertreatment of certain patients. There is an expanding spectrum of genetic conditions that can be complicated by HLH. This review summarizes the current concepts in HLH, the lessons learned from the past, and provide an overview of the latest diagnostic and treatment modalities.

Adenosine deaminase (ADA) deficiency causes ∼13% of cases of severe combined immune deficiency (SCID). Treatments include enzyme replacement therapy (ERT), hematopoietic cell transplant (HCT), and gene therapy (GT). We evaluated 131 patients with ADA-SCID diagnosed between 1982 and 2017 who were enrolled in the Primary Immune Deficiency Treatment Consortium SCID studies. Baseline clinical, immunologic, genetic characteristics, and treatment outcomes were analyzed. First definitive cellular therapy (FDCT) included 56 receiving HCT without preceding ERT (HCT); 31 HCT preceded by ERT (ERT-HCT); and 33 GT preceded by ERT (ERT-GT). Five-year event-free survival (EFS, alive, no need for further ERT or cellular therapy) was 49.5% (HCT), 73% (ERT-HCT), and 75.3% (ERT-GT; P < .01). Overall survival (OS) at 5 years after FDCT was 72.5% (HCT), 79.6% (ERT-HCT), and 100% (ERT-GT; P = .01). Five-year OS was superior for patients undergoing HCT at

Granulocyte transfusions are sometimes used as adjunctive therapy for the treatment of infection in patients with chronic granulomatous disease (CGD). However, granulocyte transfusions can be associated with a high rate of alloimmunization, and their role in CGD patients undergoing hematopoietic cell transplantation (HCT) or gene therapy (GT) is unknown. We identified 27 patients with CGD who received granulocyte transfusions pre- (within 6months) and/or post-HCT or GT in a retrospective survey. Twelve patients received granulocyte transfusions as a bridge to cellular therapy. Six (50%) of these patients had a complete or partial response. However, six of 10 (60%) patients for whom testing was performed developed anti-HLA antibodies, and three of the patients also had severe immune-mediated cytopenia within the first 100days post-HCT or GT. Fifteen patients received granulocyte transfusions post-HCT only. HLA antibodies were not checked for any of these 15 patients, but there were no cases of early immune-mediated cytopenia. Out of 25 patients who underwent HCT, there were 5 (20%) cases of primary graft failure. Three of the patients with primary graft failure had received granulocyte transfusions pre-HCT and were subsequently found to have anti-HLA antibodies. In this small cohort of patients with CGD, granulocyte transfusions pre-HCT or GT were associated with high rates of alloimmunization, primary graft failure, and early severe immune-mediated cytopenia post-HCT or GT. Granulocyte transfusions post-HCT do not appear to confer an increased risk of graft failure.

BACKGROUND Previous studies have explored posthematopoietic cell transplant (HCT) outcomes by race in adults; however, pediatric data addressing this topic are scarce. PROCEDURE This retrospective registry study included 238 White (W) and 57 Black (B) children with hematologic malignancies (HM) receiving first allogeneic HCT between 2010 and 2019 at one of the five Florida pediatric HCT centers. RESULTS We found no differences between W and B children in transplant characteristics, other than donor type. There was a significant difference in use of human leukocyte antigen (HLA)-mismatched donors (HLA-MMD) (53% W, 71% B, p = .01). When comparing HLA-MMD use to fully HLA-matched donors, B had relative risk (RR) of 1.47 (95% CI 0.7-3) of receiving a mismatched unrelated donor (MMUD), RR of 2.34 (95% CI 1.2-4.4) of receiving a mismatched related donor (MMRD), and RR of 1.9 (95% CI 0.99-3.6) of receiving a mismatched cord blood donor (MMCBD) HCT, respectively. There was no significant difference in the incidence of aGVHD (48% W, 35% B), p = .1, or cGVHD (19% W, 28% B, p = .1), or primary cause of death. Overall 24-month survival was 61% (95% CI 55%-68%) for W, and 60% (95% CI 48-75) for B children, log-rank p = .7. While HLA matching improved survival in W children, the number of B children receiving HLA-matched HCT was too small to identify the impact of HLA matching on survival. CONCLUSIONS In this contemporary cohort of children with HM, we found that B children were more likely to receive HLA-MMD transplants, but this did not adversely affect survival or GVHD rates.

Recently, primary immune regulatory disorders have been described as a subset of inborn errors of immunity that are dominated by immune mediated pathology. As the pathophysiology of disease is elucidated, use of biologic modifiers have been increasingly used successfully to treat disease mediated clinical manifestations. Hematopoietic cell transplant (HCT) has also provided definitive therapy in several PIRDs. Although biologic modifiers have been largely successful at treating disease related manifestations, data are lacking regarding long term efficacy, safety, and their use as a bridge to HCT. This review highlights biologic modifiers in the treatment of several PIRDs and there use as a therapeutic bridge to HCT.

Chronic granulomatous disease (CGD) is a primary immune deficiency due to defects in phagocyte respiratory burst leading to severe and life-threatening infections. Patients with CGD also suffer from disorders of inflammation and immune dysregulation including colitis and granulomatous lung disease, among others. Additionally, patients with CGD may be at increased risk of systemic inflammatory disorders such as hemophagocytic lymphohistiocytosis (HLH). The presentation of HLH often overlaps with symptoms of systemic inflammatory response syndrome (SIRS) or sepsis and therefore can be difficult to identify, especially in patients with a primary immune deficiency in which incidence of infection is increased. Thorough evaluation and empiric treatment for bacterial and fungal infections is necessary as HLH in CGD is almost always secondary to infection. Simultaneous treatment of infection with anti-microbials and inflammation with immunosuppression may be needed to blunt the hyperinflammatory response in secondary HLH. Herein, we present a series of X-linked CGD patients who developed HLH secondary to or with concurrent disseminated CGD-related infection. In two patients, CGD was a known diagnosis prior to development of HLH and in the other two CGD was diagnosed as part of the evaluation for HLH. Concurrent infection and HLH were fatal in three; one case was successfully treated, ultimately receiving hematopoietic stem cell transplantation. The current literature on presentation, diagnosis, and treatment of HLH in CGD is reviewed.

FPBCC was formed in 2018 by five pediatric transplant programs in Florida. One of the key objectives of the consortium is to provide outcome analyses by combining HCT data from all the participating centers in order to identify areas for improvement. In this first FPBCC landscape report we describe the patient and transplant characteristics of pediatric patients undergoing first allo and auto HCT between 2014 and 2016 in Florida. The source of data was eDBtC of the CIBMTR. Over the span of 3 years, a total of 230 pediatric patients underwent allo-HCT and 104 underwent auto-HCT at the participating centers. The most significant predictor of survival in allo-HCT recipients with malignant disorders was the degree of HLA- match, while in the recipients of allo-HCT with non-malignant disorders the predictors of survival included age, donor relationship and degree of HLA match. Our analyses identified the need to improve reporting of primary cause of death and improve on donor selection process given that the degree of HLA match remains the most important predictor of survival. This first FPBCC-wide review describes the trends in pediatric HCT activity between 2014 and 2016 among the participating centers in Florida and confirms feasibility of using eDBtC data platform and collaborative approach in order to identify areas for improvement in outcomes.

Precision therapy is a concept in which medical treatment is tailored to the patient's individual needs based on individual characteristics and mechanism of disease. Primary immunodysregulatory disorders are an expanding group of primary immunodeficiency diseases that are characterized by early onset autoimmunity and autoinflammation. Precision therapy allows for the alteration of the aberrant immune response leading to clinical improvement of disease related manifestations. This article reviews targeted precision-based therapy for treatment of cytotoxic T-lymphocyte antigen haploinsufficiency, lipopolysaccharide-responsive beige-like anchor deficiency, activated PI3K deficiency syndrome, signal transducer and activator of transcription- 1 and -3 - gain-of-function disorders, and disorders of inflammasome activation.

Hemophagocytic lymphohistiocytosis (HLH) is a rare but severe form of immune dysregulation often presenting as unremitting fever, cytopenia, hepatosplenomegaly, coagulopathy, and elevation of typical HLH biomarkers. HLH is universally fatal, if left untreated. The HLH-2004 criteria are widely used to diagnose this condition, but there is growing concerns across different settings that its application may result in undertreatment of certain patients. There is an expanding spectrum of genetic conditions that can be complicated by HLH. This review summarizes the current concepts in HLH, the lessons learned from the past, and provide an overview of the latest diagnostic and treatment modalities.

BackgroundAllogeneic hematopoietic cell transplantation for hemophagocytic lymphohistiocytosis (HLH) disorders is associated with substantial morbidity and mortality.ObjectiveThe effect of conditioning regimen groups of varying intensity on outcomes after transplantation was examined to identify an optimal regimen or regimens for HLH disorders.MethodsWe studied 261 patients with HLH disorders transplanted between 2005 and 2018. Risk factors for transplantation outcomes by conditioning regimen groups were studied by Cox regression models.ResultsFour regimen groups were studied: (1) fludarabine (Flu) and melphalan (Mel) in 123 subjects; (2) Flu, Mel, and thiotepa (TT) in 28 subjects; (3) Flu and busulfan (Bu) in 14 subjects; and (4) Bu and cyclophosphamide (Cy) in 96 subjects. The day 100 incidence of veno-occlusive disease was lower with Flu/Mel (4%) and Flu/Mel/TT (0%) compared to Flu/Bu (14%) and Bu/Cy (22%) (P< .001). The 6-month incidence of viral infections was highest after Flu/Mel (72%) and Flu/Mel/TT (64%) compared to Flu/Bu (39%) and Bu/Cy (38%) (P< .001). Five-year event-free survival (alive and engrafted without additional cell product administration) was lower with Flu/Mel (44%) compared to Flu/Mel/TT (70%), Flu/Bu (79%), and Bu/Cy (61%) (P= .002). The corresponding 5-year overall survival values were 68%, 75%, 86%, and 64%, and did not differ by conditioning regimen (P= .19). Low event-free survival with Flu/Mel is attributed to high graft failure (42%) compared to Flu/Mel/TT (15%), Flu/Bu (7%), and Bu/Cy (18%) (P< .001).ConclusionsGiven the high rate of graft failure with Flu/Mel and the high rate of veno-occlusive disease with Bu/Cy and Flu/Bu, Flu/Mel/TT may be preferred for HLH disorders. Prospective studies are warranted.

Introduction: Inborn errors of immunity such as hemophagocytic lymphohistiocytosis (HLH) and chronic granulomatous disease (CGD) are characterized by hyperinflammation. Hematopoietic cell transplantation (HCT) in the setting of hyperinflammation leads to high morbidity and mortality. Consequently, there is increasing use of less intense conditioning regimens, which can increase risk of mixed chimerism or graft failure. We sought to study the effect of common regimens on outcomes after HCT using data reported to the Center for International Blood and Marrow Transplant Research. Methods : 365 patients aged Results : Patient demographics were similar across the three treatment groups. Patients with HLH were more likely to receive the Flu/Mel regimen. Although unrelated donor HCTs were predominant across the treatment groups, cord blood graft was more common in the Bu/Cy group. Conditioning regimens changed over the study period with most Flu/Mel/TT and Flu/Bu regimens used after 2010. Consequently, outcomes were censored 2-years post-HCT to account for differences in follow-up. The day-100 incidence of VOD was higher with Bu/Cy (18%) compared to Flu/Mel (4%) and Flu/Mel/TT or Flu/Bu (7%) regimens (p Conclusion : The data does not support the use of a reduced intensity Flu/Mel regimen for hyperinflammatory inborn errors of immunity. Although we did not observe differences in event-free survival between Bu/Cy and Flu/Mel/TT or Flu/Bu regimens, lower incidences of VOD and bacterial infections favor Flu/Mel/TT or Flu/Bu regimens. Disclosures Pulsipher: Bellicum: Honoraria; Jasper: Honoraria; Novartis: Honoraria; Miltenyi: Honoraria, Research Funding; Mesoblast: Honoraria; Adaptive: Research Funding. Stenger:ISCT: Membership on an entity's Board of Directors or advisory committees; Bluebird Bio: Research Funding.

Myeloid neoplasms in children with sickle cell disease have been rarely reported, and the exact underlying connection between these two conditions is not clearly understood. Whether the acute myeloid leukemia in hydroxyurea-treated sickle cell patients is co-incidental or related to therapy remains an unanswered question. Herein, we report a 14-year-old girl of Haitian descent with sickle beta zero thalassemia on chronic hydroxyurea therapy who developed FMS-like tyrosine kinase 3 (FLT3)-mutated acute myeloid leukemia and underwent a complete disease remission following a combination chemotherapy with sorafenib and was subsequently treated using a T cell replete unmanipulated haploidentical bone marrow transplantation followed by post-transplant cyclophosphamide.

Wiskott-Aldrich syndrome (WAS) is an X-linked disease caused by mutations in the WAS gene, leading to thrombocytopenia, eczema, recurrent infections, autoimmune disease, and malignancy. Hematopoietic cell transplantation (HCT) is the primary curative approach, with the goal of correcting the underlying immunodeficiency and thrombocytopenia. HCT outcomes have improved over time, particularly for patients with HLA-matched sibling and unrelated donors. We report the outcomes of 129 patients with WAS who underwent HCT at 29 Primary Immune Deficiency Treatment Consortium centers from 2005 through 2015. Median age at HCT was 1.2 years. Most patients (65%) received myeloablative busulfan-based conditioning. With a median follow-up of 4.5 years, the 5-year overall survival (OS) was 91%. Superior 5-year OS was observed in patients 95%) vs low-level (5%-49%) donor myeloid engraftment. In summary, HCT outcomes for WAS have improved since 2005, compared with prior reports. HCT at a younger age continues to be associated with superior outcomes supporting the recommendation for early HCT. High-level donor myeloid engraftment is important for platelet reconstitution after either myeloablative or busulfan-containing reduced intensity conditioning. (This trial was registered at www.clinicaltrials.gov as #NCT02064933.)

IntroductionInflammatory bowel disease (IBD) affects approximately 1/3 of patients with chronic granulomatous disease (CGD). Comprehensive investigation of the effect of allogeneic hematopoietic cell transplantation (HCT) on CGD IBD and the impact of IBD on transplant outcomes is lacking.MethodsWe collected data retrospectively from 145 patients with CGD who had received allogeneic HCT at 26 Primary Immune Deficiency Treatment Consortium (PIDTC) centers between January 1, 2005 and June 30, 2016.ResultsForty-nine CGD patients with IBD and 96 patients without IBD underwent allogeneic HCT. Eighty-nine percent of patients with IBD and 93% of patients without IBD engrafted (p = 0.476). Upper gastrointestinal acute GVHD occurred in 8.5% of patients with IBD and 3.5% of patients without IBD (p = 0.246). Lower gastrointestinal acute GVHD occurred in 10.6% of patients with IBD and 11.8% of patients without IBD (p = 0.845). The cumulative incidence of acute GVHD grades II-IV was 30% (CI 17-43%) in patients with IBD and 20% (CI 12-29%) in patients without IBD (p = 0.09). Five-year overall survival was equivalent for patients with and without IBD: 80% [CI 66-89%] and 83% [CI 72-90%], respectively (p = 0.689). All 33 surviving evaluable patients with a history of IBD experienced resolution of IBD by 2years following allogeneic HCT.ConclusionsIn this cohort, allogeneic HCT was curative for CGD-associated IBD. IBD should not contraindicate HCT, as it does not lead to an increased risk of mortality. This study is registered at clinicaltrials.gov NCT02082353.

BACKGROUND: Langerhans cell histiocytosis (LCH) is a rare myeloid neoplasm characterized by the presence of abnormal CD1a-positive (CD1a(+))/CD207(+) histiocytes. Hemophagocytic lymphohistiocytosis (HLH) represents a spectrum of hyperinflammatory syndromes typified by the dysregulated activation of the innate and adaptive immune systems. Patients with LCH, particularly those with multisystem (MS) involvement, can develop severe hyperinflammation mimicking that observed in HLH. Nevertheless, to the authors' knowledge, little is known regarding the prevalence, timing, risk factors for development, and outcomes of children and young adults who develop HLH within the context of MS-LCH (hereafter referred to LCH-associated HLH). METHODS: To gain further insights, the authors conducted a retrospective, multicenter study and collected data regarding all patients diagnosed with MS-LCH between 2000 and 2015. RESULTS: Of 384 patients with MS-LCH, 32 were reported by their primary providers to have met the diagnostic criteria for HLH, yielding an estimated 2-year cumulative incidence of 9.3% +/- 1.6%. The majority of patients developed HLH at or after the diagnosis of MS-LCH, and nearly one-third (31%) had evidence of an intercurrent infection. Patient age

Rationale Chronic granulomatous disease (CGD) is a primary immune deficiency due to defects in the phagocyte oxidative burst leading to life-threatening infections and inflammatory disorders. Due to high mortality and morbidity, hematopoietic cell transplantation (HCT) is now considered a potentially curative option. We evaluated outcomes of HCT at our institution over 13 years. Methods Retrospective chart review of CGD HCTs performed at John Hopkins All Children's Hospital between August 2005-October 2018. Results Eight patients (median age=2.2 years, range=1.1-4.3 years) with CGD underwent HCT: 6 patients had X-linked (CYBB, gp91phox), 2 patients had autosomal recessive (CYBA, p22phox). Pre-HCT infections were controlled including; pneumonia (n=3, 2 Aspergillus, 2 requiring lobectomy) and staphylococcal lymphadenitis/skin abscesses(n=3). Five of eight (62%) had inflammatory disease pre-HCT: lung granulomas (n=2), autoimmune hepatitis (n=3), and colitis (n=2). Myeloablative conditioning was used in 3 and reduced intensity/toxicity (RIC) in 5. Four received matched related donor and 4 received matched unrelated-donor HCTs. Median neutrophil engraftment was 18.5 days (range=10-21 days). Overall survival was 87.5%. One patient died (day +21) from disseminated Trichosporon. All patients achieved primary engraftment; 42% (3/7) maintained full donor chimerism (≥99%) with normalization of DHR, median follow-up 4.3 years (range=4-8.3 years); 42% (3/7) are mixed chimera (58-84% myeloid donor), median follow-up of 0.9 years (range=0.8-1.2 years). One patient who received RIC (Fludarabine/Melphalan/Campath) had secondary graft failure 1 year after HCT, has since developed inflammatory colitis, uveitis, and pneumonitis and is awaiting second HCT. There was no grade III-IV GVHD; 2 had acute grade I GVHD. Post-HCT complications included EBV viremia (without PTLD) in 1, pericarditis in 1, autoimmune cytopenias in 1 and hypothyroidism in 1. Conclusions Patients with CGD are at high risk of early mortality. HCT is a viable treatment option but has considerable risk, often deterring providers and patients from pursuing HCT early. Our institution's experience shows safety and efficacy with early HCT approach.

The purpose was to describe the incidence and risk factors of congestive heart failure (CHF) among children with acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). We included 2053 children (≤18 years) with first primary ALL and AML diagnosed 1992-2010 and registered in the Pediatric Oncology Group of Ontario Networked Information System. We identified CHF events through linked administrative databases. At 10 years, the cumulative incidence of CHF was 1.7% in ALL and 7.5% in AML. Factors associated with CHF in ALL were female gender, age1 year at cancer diagnosis, irradiation and cumulative anthracycline dose ≥250 mg/m

Background Children with Langerhans cell histiocytosis (LCH) and single-bone CNS-risk lesions have been reported to be at increased risk of diabetes insipidus (DI), central nervous system neurodegeneration (CNS-ND), and recurrence of disease. However, it is unknown whether the addition of chemotherapy or radiotherapy changes outcomes in these patients. Methods Ten pediatric institutions across North America and Europe contributed data of their patients with LCH and single-bone CNS-risk lesions. Clinical information on age, sex, specific craniofacial site involvement, and intracranial extension at diagnosis, therapy, and disease course was collected for all eligible patients. Results The final analysis included 93 eligible children who were either treated with systemic therapy (chemotherapy, chemo-radiotherapy, or radiotherapy) or local therapy (biopsy, curettage, and/or intralesional steroids). Fifty-nine patients had systemic and 34 had local therapy. The 5-year event-free survival (EFS) and overall survival (OS) were 80 ± 5% and 98 ± 2% in the systemic therapy group versus 85 ± 6% and 95 ± 5% in the local therapy group. There was no statistically significant difference between either group with regard to EFS (P = 0.26) and OS (P = 0.78). On multivariable analysis, there was no significant difference among the two treatment groups after adjusting for site and intracranial soft tissue extension, nor any trend favoring systemic therapy (HR = 2.26, 95% CI = 0.77-6.70; P = 0.14). Conclusion Systemic therapy may not reduce the risk of recurrence or late sequelae in children with LCH and single-bone CNS-risk lesions as compared to local treatment.

Hematopoietic stem cell transplantation (HSCT) is currently the only available curative therapy for X-linked inhibitor of apoptosis (XIAP) deficiency. Myeloablative conditioning regimens are associated with high mortality rates. Reduced-intensity conditioning (RIC) is recommended in order to decrease treatment-related toxicities, but RIC regimens increase the risk for mixed donor-recipient chimerism that may progress to graft loss. We report our experience with a patient with XIAP deficiency who was successfully treated with allogeneic HSCT using a RIC protocol. Post-transplant chimerism was vigilantly monitored and maintained with donor lymphocyte infusions and a stem cell boost to a level that prevented hemophagocytic lymphohistiocytosis recurrence.

Haemophagocytic lymphohistiocytosis (HLH) is a life threatening complication of Epstein-Barr virus (EBV) infection. The anti-CD20 antibody rituximab depletes B cells, leading to improved outcomes for patients with EBV-associated B-lymphoproliferative disorders. To gather data on the use of rituximab in EBV-HLH, we performed a retrospective investigation involving 42 EBV-HLH patients who had received treatment with rituximab-containing regimens. On average, patients received 3 rituximab infusions (range 1-10) at a median dose of 375 mg/m(2) . In all patients, rituximab was administered with other HLH-directed medications, including steroids, etoposide and/or ciclosporin. Rituximab-containing regimens appeared well tolerated and improved clinical status in 43% of patients. Examination of laboratory data obtained prior to and within 2-4 weeks after the first rituximab dose revealed significant reductions in EBV load (median load pre-rituximab: 114,200 copies/ml, median post-rituximab: 225 copies/ml, P = 0.0001) and serum ferritin levels (median ferritin pre-rituximab: 4260 μg/l, median post-rituximab: 1149 μg/l, P = 0.001). Thus, when combined with conventional HLH-directed therapies, rituximab improves symptoms, reduces viral load and diminishes inflammation. These data support the incorporation of rituximab into future prospective clinical trials for patients with EBV-HLH.

Introduction: Langerhans cell histiocytosis (LCH) is a monoclonal disorder characterized by proliferation and accumulation of atypical Langerhans cells and in up to 55% of all cases somatic mutations in BRAF proves to be the driver. Although uncommon, it is potentially fatal and carries significant morbidity. Bone involvement in LCH can be destructive, painful and often associated with pathologic fractures. There is no consensus in the treatment strategies for bone LCH which could vary from simple curettage with biopsy and/or intralesional steroids to more toxic systemic chemotherapy. However, the number of treatments for this disease is limited and other options need to be explored. Bisphosphonates are osteoclast inhibitors that can target certain osteoclast markers expressed by the multinucleated giant cells in the skin, bone and lymph nodes LCH lesions and can potentially be used to alleviate bone pain and possibly control the progression of disease activity. Purpose: To evaluate the efficacy and safety of bisphosphonates in treating bone LCH and extra-osseous disease. Methods: An international multicenter retrospective chart review was conducted in children and adults with LCH who received bisphosphonates between 1995 and 2014. Results: Eighteen patients were identified from 4 centers. All received bisphosphonates therapy either at diagnosis or at ≥ 1st reactivation. Median age at start of bisphosphonates was 23.7 years (range 5.7-38.3 years), and median follow-up time post-bisphosphonate therapy was 2.8 years (range 0.9-5.0 years). Patients had either single system bone disease or bone lesions as part of their multisystem disease. Patients were treated with different bisphosphonates with majority received zoledronic acid (n=10), followed by pamidronate (n=4) and alendronate (n= 3); one patient received both pamidronate and zoledronic acid. All patients reported significant reduction in pain to either no or mild pain after administration of bisphosphonates. Thirteen of 18 patients (72%) achieved complete remission (CR) in their bone lesions, including lesions in skin (n=1), lung (n=1) and pituitary (n=1); 2 had partial response and 3 had no response. Among the 13 CR patients, 12 had no active disease for a median of 4.1 years (range 2.8 - 5.1 years) and 1 developed radiographic neurodegeneration after 2 years. Bisphosphonate therapy was well tolerated by all patients with no major toxicity. Progression-free survival (PFS) was 75 ± 11% at 3 years, with a trend favoring better PFS (P=0.24) in patients with no or first reactivation compared with those having ≥ 2 reactivations. Conclusion: Bisphosphonates is a well-tolerated medication that can significantly improve bone pain in patients with bone LCH, and may even be effective in treating extra-osseous disease. A prospective randomized trial evaluating the role of bisphosphonates in multifocal bone LCH is warranted. Disclosures No relevant conflicts of interest to declare.

Hematopoietic stem cell transplantation (HSCT) is currently the only available curative therapy for X-linked inhibitor of apoptosis (XIAP) deficiency. Myeloablative conditioning regimens are associated with high mortality rates. Reduced-intensity conditioning (RIC) is recommended in order to decrease treatment-related toxicities, but RIC regimens increase the risk for mixed donor-recipient chimerism that may progress to graft loss. We report our experience with a patient with XIAP deficiency who was successfully treated with allogeneic HSCT using a RIC protocol. Post-transplant chimerism was vigilantly monitored and maintained with donor lymphocyte infusions and a stem cell boost to a level that prevented hemophagocytic lymphohistiocytosis recurrence.