Donor-derived multiple leukemia antigen-specific T-cell therapy to prevent relapse after transplant in patients with ALL.

Hematopoietic stem cell transplant (HSCT) is a curative option for patients with high-risk acute lymphoblastic leukemia (ALL), but relapse remains a major cause of treatment failure. To prevent disease relapse, we prepared and infused donor-derived multiple leukemia antigen-specific T cells (mLSTs) targeting PRAME, WT1, and survivin, which are leukemia-associated antigens frequently expressed in B- and T-ALL. Our goal was to maximize the graft-versus-leukemia effect while minimizing the risk of graft-versus-host disease (GVHD). We administered mLSTs (dose range, 0.5 × 107 to 2 × 107 cells per square meter) to 11 patients with ALL (8 pediatric, 3 adult), and observed no dose-limiting toxicity, acute GVHD or cytokine release syndrome. Six of 8 evaluable patients remained in long-term complete remission (median: 46.5 months; range, 9-51). In these individuals we detected an increased frequency of tumor-reactive T cells shortly after infusion, with activity against both targeted and nontargeted, known tumor-associated antigens, indicative of in vivo antigen spreading. By contrast, this in vivo amplification was absent in the 2 patients who experienced relapse. In summary, infusion of donor-derived mLSTs after allogeneic HSCT is feasible and safe and may contribute to disease control, as evidenced by in vivo tumor-directed T-cell expansion. Thus, this approach represents a promising strategy for preventing relapse in patients with ALL.

Prolonged cytopenias after immune effector cell therapy and lymphodepletion in patients with leukemia, lymphoma and solid tumors.

BACKGROUND AIMS: The success of chimeric antigen receptor (CAR) T-cell therapy in treating B-cell malignancies has led to the evaluation of CAR T-cells targeting a variety of other malignancies. Although the efficacy of CAR T-cells is enhanced when administered post-lymphodepleting chemotherapy, this can trigger bone marrow suppression and sustained cytopenia after CD19.CAR T-cell therapy. Additionally, systemic inflammation associated with CAR T-cell activity may contribute to myelosuppression. Cytopenias, such as neutropenia and thrombocytopenia, elevate the risk of severe infections and bleeding, respectively. However, data on the incidence of prolonged cytopenias after immune effector therapy in the solid tumor context remain limited. OBJECTIVE: We compared the incidence of prolonged cytopenias after immune effector therapy including genetically modified T-cells, virus-specific T-cells (VSTs) and NKT-cells, as well non-gene-modified VSTs for leukemia, lymphoma, and solid tumors (ST) to identify associated risk factors. METHODS: A retrospective analysis was conducted of 112 pediatric and adult patients with relapsed and/or refractory cancers who received lymphodepleting chemotherapy followed by immune effector therapy. Patients treated with 13 distinct immune effector cell therapies through 11 single-center clinical trials and 2 commercial products over a 6-year period were categorized into 3 types of malignancies: leukemia, lymphoma and ST. We obtained baseline patient characteristics and adverse events data for each participant, and tracked neutrophil and platelet counts following lymphodepletion. RESULTS: Of 112 patients, 104 (92.9%) experienced cytopenias and 88 (79%) experienced severe cytopenias. Patients with leukemia experienced significantly longer durations of severe neutropenia (median duration of 14 days) compared with patients with lymphoma (7 days) or ST (11 days) (P = 0.002). Patients with leukemia also had a higher incidence of severe thrombocytopenia (74.1%), compared with lymphoma (46%, P = 0.03) and ST (14.3%, P < 0.0001). Prolonged cytopenias were significantly associated with disease type (63% of patients with leukemia, 44% of patients with lymphoma, and 22.9% of patients with ST, P = 0.006), prior hematopoietic stem cell transplant (HSCT) (66.7% with prior HSCT versus 38.3% without prior HSCT, P = 0.039), and development of immune effector cell-associated neurotoxicity syndrome (ICANS) (75% with ICANS versus 38% without ICANS, P = 0.027). There was no significant association between prolonged cytopenias and cytokine release syndrome. CONCLUSIONS: Immune effector recipients often experience significant cytopenias due to marrow suppression following lymphodepletion regardless of disease, but prolonged severe cytopenias are significantly less common after treatment of patients with lymphoma and solid tumors.

Hematopoietic stem cell transplantation for B-thalassemia major with alemtuzumab.

While matched related donor (MRD) allogeneic hematopoietic stem cell transplantation (HSCT) is a curative option for transfusion-dependent beta-thalassemia (TDT), the use of alternative sources has increased, resulting in the exploration of novel transplant-conditioning regimens to reduce the contribution of graft-versus-host disease (GVHD) and graft failure (GF) to transplant-related morbidity and mortality. Alemtuzumab is a CD52 monoclonal antibody that has been successfully incorporated into myeloablative conditioning regimens for other hematologic conditions, yet there have been limited studies regarding the use of alemtuzumab in HSCT for TDT. The purpose of this study was to evaluate engraftment, incidence of GVHD, and transplant related morbidity and mortality in patients with TDT who received alemtuzumab in addition to standard busulfan-based conditioning. The primary endpoint was severe GVHD-free, event-free survival (GEFS). Our cohort included 24 patients with a median age of 6.8 years (range 1.5-14.9). Eleven patients received a 10/10 MRD HSCT, eleven 10/10 unrelated donor (UD), and two mismatched UD. All patients achieved primary engraftment. For all patients, 5-year GEFS was 77.4% and 5-year overall survival (OS) was 91%. The 5-year cumulative incidence of GF (attributed to poor graft function) without loss of donor chimerism was 13.8% (95% CI: 4.5, 35.3). We report low rates of significant acute GVHD grade II-IV (12.5%) and chronic GVHD (4.4%). Younger age and MRD were associated with significantly improved GEFS, OS and EFS. Our results show that the use of alemtuzumab promotes stable engraftment, may reduce rates of severe GVHD, and results in acceptable GEFS, OS, and EFS.

Clinical effects of administering leukemia-specific donor T cells to patients with AML/MDS after allogeneic transplant.

Relapse after allogeneic hematopoietic stem cell transplantation (HCT) is the leading cause of death in patients with acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS). Infusion of unselected donor lymphocytes (DLIs) enhances the graft-versus-leukemia (GVL) effect. However, because the infused lymphocytes are not selected for leukemia specificity, the GVL effect is often accompanied by life-threatening graft-versus-host disease (GVHD), related to the concurrent transfer of alloreactive lymphocytes. Thus, to minimize GVHD and maximize GVL, we selectively activated and expanded stem cell donor-derived T cells reactive to multiple antigens expressed by AML/MDS cells (PRAME, WT1, Survivin, and NY-ESO-1). Products that demonstrated leukemia antigen specificity were generated from 29 HCT donors. In contrast to DLIs, leukemia-specific T cells (mLSTs) selectively recognized and killed leukemia antigen-pulsed cells, with no activity against recipient's normal cells in vitro. We administered escalating doses of mLSTs (0.5 to 10 × 107 cells per square meter) to 25 trial enrollees, 17 with high risk of relapse and 8 with relapsed disease. Infusions were well tolerated with no grade >2 acute or extensive chronic GVHD seen. We observed antileukemia effects in vivo that translated into not-yet-reached median leukemia-free and overall survival at 1.9 years of follow-up and objective responses in the active disease cohort (1 complete response and 1 partial response). In summary, mLSTs are safe and promising for the prevention and treatment of AML/MDS after HCT. This trial is registered at www.clinicaltrials.com as #NCT02494167.

Assessment of ST2 for risk of death following graft-versus-host disease in pediatric and adult age groups.

Assessment of prognostic biomarkers of nonrelapse mortality (NRM) after allogeneic hematopoietic cell transplantation (HCT) in the pediatric age group is lacking. To address this need, we conducted a prospective cohort study with 415 patients at 6 centers: 170 were children age 10 years or younger and 245 were patients older than age 10 years (both children and adults were accrued from 2013 to 2018). The following 4 plasma biomarkers were assessed pre-HCT and at days +7, +14, and +21 post-HCT: stimulation-2 (ST2), tumor necrosis factor receptor 1 (TNFR1), regenerating islet-derived protein 3α (REG3α), and interleukin-6 (IL-6). We performed landmark analyses for NRM, dichotomizing the cohort at age 10 years or younger and using each biomarker median as a cutoff for high- and low-risk groups. Post-HCT biomarker analysis showed that ST2 (>26 ng/mL), TNFR1 (>3441 pg/mL), and REG3α (>25 ng/mL) are associated with NRM in children age 10 years or younger (ST2: hazard ratio [HR], 9.13; 95% confidence interval [CI], 2.74-30.38; P = .0003; TNFR1: HR, 4.29; 95% CI, 1.48-12.48; P = .0073; REG3α: HR, 7.28; 95% CI, 2.05-25.93; P = .0022); and in children and adults older than age 10 years (ST2: HR, 2.60; 95% CI, 1.15-5.86; P = .021; TNFR1: HR, 2.09; 95% CI, 0.96-4.58; P = .06; and REG3α: HR, 2.57; 95% CI, 1.19-5.55; P = .016). When pre-HCT biomarkers were included, only ST2 remained significant in both cohorts. After adjustment for significant covariates (race/ethnicity, malignant disease, graft, and graft-versus-host-disease prophylaxis), ST2 remained associated with NRM only in recipients age 10 years or younger (HR, 4.82; 95% CI, 1.89-14.66; P = .0056). Assays of ST2, TNFR1, and REG3α in the first 3 weeks after HCT have prognostic value for NRM in both children and adults. The presence of ST2 before HCT is a prognostic biomarker for NRM in children age 10 years or younger allowing for additional stratification. This trial was registered at www.clinicaltrials.gov as #NCT02194439.

Hematopoietic Cell Transplantation Cures Adenosine Deaminase 2 Deficiency: Report on 30 Patients.

PURPOSE: Deficiency of adenosine deaminase 2 (DADA2) is an inherited inborn error of immunity, characterized by autoinflammation (recurrent fever), vasculopathy (livedo racemosa, polyarteritis nodosa, lacunar ischemic strokes, and intracranial hemorrhages), immunodeficiency, lymphoproliferation, immune cytopenias, and bone marrow failure (BMF). Tumor necrosis factor (TNF-α) blockade is the treatment of choice for the vasculopathy, but often fails to reverse refractory cytopenia. We aimed to study the outcome of hematopoietic cell transplantation (HCT) in patients with DADA2. METHODS: We conducted a retrospective study on the outcome of HCT in patients with DADA2. The primary outcome was overall survival (OS). RESULTS: Thirty DADA2 patients from 12 countries received a total of 38 HCTs. The indications for HCT were BMF, immune cytopenia, malignancy, or immunodeficiency. Median age at HCT was 9 years (range: 2-28 years). The conditioning regimens for the final transplants were myeloablative (n = 20), reduced intensity (n = 8), or non-myeloablative (n = 2). Donors were HLA-matched related (n = 4), HLA-matched unrelated (n = 16), HLA-haploidentical (n = 2), or HLA-mismatched unrelated (n = 8). After a median follow-up of 2 years (range: 0.5-16 years), 2-year OS was 97%, and 2-year GvHD-free relapse-free survival was 73%. The hematological and immunological phenotypes resolved, and there were no new vascular events. Plasma ADA2 enzyme activity normalized in 16/17 patients tested. Six patients required more than one HCT. CONCLUSION: HCT was an effective treatment for DADA2, successfully reversing the refractory cytopenia, as well as the vasculopathy and immunodeficiency. CLINICAL IMPLICATIONS: HCT is a definitive cure for DADA2 with > 95% survival.

Toward Functional Immune Monitoring in Allogeneic Stem Cell Transplant Recipients.

Serious viral infections, due to delayed immune reconstitution, are a leading cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT). Thus, many transplant centers prospectively track cellular immune recovery by evaluating absolute cell numbers and the phenotypic profile of reconstituting T cell subsets to identify individuals who are at highest risk of infection. Conventional assessments, however, fail to measure either the antigen specificity or functional capacity of reconstituting cells-both factors that correlate with endogenous antiviral protection. In this pilot study, we sought to address this limitation by prospectively investigating the tempo of endogenous immune reconstitution in a cohort of 23 pediatric HSCT patients using both quantitative (flow cytometry) and qualitative (IFNγ ELISpot) measures, which we correlated with either the presence or absence of infections associated with cytomegalovirus, adenovirus, Epstein-Barr virus, BK virus, human herpes virus 6, respiratory syncytial virus, parainfluenza, influenza, and human metapneumovirus. We present data spanning 12 months post-transplant demonstrating the influence of conditioning on immune recovery and highlighting the differential impact of active viral replication on the quantity and quality of reconstituting cells. Judicious use of standard (phenotypic) and novel (functional) monitoring strategies can help guide the clinical care and personalized management of allogenic HSCT recipients with infections.

Genetic and mechanistic diversity in pediatric hemophagocytic lymphohistiocytosis.

The HLH-2004 criteria are used to diagnose hemophagocytic lymphohistiocytosis (HLH), yet concern exists for their misapplication, resulting in suboptimal treatment of some patients. We sought to define the genomic spectrum and associated outcomes of a diverse cohort of children who met the HLH-2004 criteria. Genetic testing was performed clinically or through research-based whole-exome sequencing. Clinical metrics were analyzed with respect to genomic results. Of 122 subjects enrolled over the course of 17 years, 101 subjects received genetic testing. Biallelic familial HLH (fHLH) gene defects were identified in only 19 (19%) and correlated with presentation at younger than 1 year of age (P < .0001). Digenic fHLH variants were observed but lacked statistical support for disease association. In 28 (58%) of 48 subjects, research whole-exome sequencing analyses successfully identified likely molecular explanations, including underlying primary immunodeficiency diseases, dysregulated immune activation and proliferation disorders, and potentially novel genetic conditions. Two-thirds of patients identified by the HLH-2004 criteria had underlying etiologies for HLH, including genetic defects, autoimmunity, and malignancy. Overall survival was 45%, and increased mortality correlated with HLH triggered by infection or malignancy (P < .05). Differences in survival did not correlate with genetic profile or extent of therapy. HLH should be conceptualized as a phenotype of critical illness characterized by toxic activation of immune cells from different underlying mechanisms. In most patients with HLH, targeted sequencing of fHLH genes remains insufficient for identifying pathogenic mechanisms. Whole-exome sequencing, however, may identify specific therapeutic opportunities and affect hematopoietic stem cell transplantation options for these patients.

Factors Impacting Time to Engraftment in Patients With High-risk Neuroblastoma Following Autologous Stem Cell Transplant.

BACKGROUND: Despite advances in supportive measures, myeloablative chemotherapy with stem cell rescue remains limited by toxicity and treatment-related mortality. The purpose of this study was to identify factors influencing the rate of hematopoietic recovery following autologous stem cell transplant in high-risk neuroblastoma. PROCEDURE: We retrospectively studied 54 patients with high-risk neuroblastoma who received a single autologous stem cell transplant between 2006 and 2016. Race, sex, conditioning regimen, chemotherapy delays and bone marrow involvement were analyzed using Kaplan-Meier Log-Rank test while the amount of cells infused, age, and length of hospital stay were analyzed using univariate Cox Proportional Hazards Regression. RESULTS: The conditioning regimen administered was significant (P=0.016) for time to engraftment of neutrophils, with busulfan/melphalan (Bu/Mel) at 16.6 days, and carboplatin/etoposide/melphalan at 12.1 days. A delay of chemotherapy during induction (n=24) was significant (P<0.001) for time to platelet engraftment of >75,000/µL. Female patients had a longer time to engraftment (P=0.029). CONCLUSION: Patients receiving Bu/Mel as a conditioning regimen, patients who had a delay in induction chemotherapy and patients of female sex were found to be significant for delayed engraftment of neutrophils, platelets, and hemoglobin, respectively, in patients with high-risk neuroblastoma undergoing autologous stem cell transplant. Knowing these factors may lead to new expectations and possible interventions to decrease the morbidity and mortality of treatment and recovery.

Therapeutic Plasma Exchange does not Improve Renal Function in Hematopoietic Stem Cell Transplantation-Associated Thrombotic Microangiopathy: An Institutional Experience.

Transplantation-associated thrombotic microangiopathy (TA-TMA) is a complication of hematopoietic stem cell transplant (HSCT) that causes severe multiorgan injury. The kidneys are almost universally affected. There is no proven therapy, but therapeutic plasma exchange (TPE) is commonly used to treat TA-TMA at Texas Children's Hospital (TCH). To date, there have been no studies assessing the long-term efficacy of TPE in preventing the development of chronic kidney disease (CKD) in TA-TMA patients. In this study we retrospectively analyzed the incidence of CKD in TA-TMA pediatric patients treated with TPE to determine if this treatment modality improves renal morbidity. We reviewed records between January 2007 and June 2017 of pediatric HSCT patients diagnosed with TA-TMA, identified through an internal database maintained at TCH. To be included patients must have completed a course of TPE per the "TPE in TA-TMA" institutional protocol at TCH. CKD was defined as kidney damage for at least 3 months and stratified into stages 1 through 5 according to estimated glomerular filtration rate. Stages 4 and 5 were considered "severe CKD." In the 10-year timeframe 15 patients with TA-TMA completed a course of TPE per our institutional protocol and were subsequently followed for a median of 963 days. Fourteen patients developed CKD, and 5 of these 14 patients developed severe CKD. The cumulative incidence of severe CKD development was 33% (95% confidence interval. 11% to 57%). 6 patients required dialysis, and 2 patients received a renal transplant. 5 patients received eculizumab in addition to TPE. In our patients a TPE course of at least 7 weeks (and up to 25 weeks) was not effective in the prevention of CKD. Our data indicate a need for alternative therapeutic measures to prevent the development of CKD in TA-TMA patients.

Hematopoietic stem cell transplantation rescues the hematological, immunological, and vascular phenotype in DADA2.

Deficiency of adenosine deaminase 2 (DADA2) is caused by biallelic deleterious mutations in CECR1 DADA2 results in variable autoinflammation and vasculopathy (recurrent fevers, livedo reticularis, polyarteritis nodosa, lacunar ischemic strokes, and intracranial hemorrhages), immunodeficiency and bone marrow failure. Tumor necrosis factor-α blockade is the treatment of choice for the autoinflammation and vascular manifestations. Hematopoietic stem cell transplantation (HSCT) represents a potential definitive treatment. We present a cohort of 14 patients from 6 countries who received HSCT for DADA2. Indication for HSCT was bone marrow dysfunction or immunodeficiency. Six of 14 patients had vasculitis pre-HSCT. The median age at HSCT was 7.5 years. Conditioning regimens were myeloablative (9) and reduced intensity (5). Donors were HLA-matched sibling (n = 1), HLA-matched unrelated (n = 9), HLA-mismatched unrelated (n = 3), and HLA haploidentical sibling (n = 1). All patients are alive and well with no new vascular events and resolution of hematological and immunological phenotype at a median follow-up of 18 months (range, 5 months to 13 years). Plasma ADA2 enzyme activity normalized in those tested post-HSCT (7/7), as early as day +14 (myeloid engraftment). Post-HSCT hematological autoimmunity (cytopenias) was reported in 4 patients, acute graft-versus-host disease grade 1 in 2, grade 2 in 3, and grade 3-4 in 1, and moderate chronic graft-versus-host disease in 1 patient. In conclusion, in 14 patients, HSCT was an effective and definitive treatment of DADA2.

Purtscher-like retinopathy: A rare presentation of hematopoietic stem cell transplant-associated thrombotic microangiopathy.

Hematopoietic stem cell transplant (HSCT)-associated (TA) thrombotic microangiopathy (TMA) is an acquired disorder and a potentially life-threatening complication after allogeneic HSCT. TA-TMA causes endothelial damage and results in micro-thrombi in capillaries and arterioles. Early detection and treatment of complications associated with TA-TMA might improve outcomes. Purtscher-like retinopathy (PLR) is associated with micro-thrombi that occlude the retinal arteries and cause retinal injury. PLR has been associated with multiple entities, including HUS and TTP, but has not previously been described in the setting of TA-TMA. Here, we describe an 18-year-old male who underwent a mismatched unrelated donor HSCT for relapsed acute lymphoblastic leukemia. The patient was diagnosed with TA-TMA based on standard defined criteria. He presented with acute onset of blurred vision with findings of multiple white retinal patches, retinal hemorrhages, and macular edema, thought initially to be hypertensive retinopathy. However, on further evaluation using fluorescein angiography and optical coherence tomography, the diagnosis was determined to be PLR. The patient was treated with intravitreal steroid injections (triamcinolone acetonide) with dramatic improvement of vision. The aim of this report is to make clinicians aware of PLR as a potential ocular complication associated with TA-TMA and that prompt intervention might reverse visual impairment.

Current Allogeneic Hematopoietic Stem Cell Transplantation for Pediatric Acute Lymphocytic Leukemia: Success, Failure and Future Perspectives-A Single-Center Experience, 2008 to 2016.

Hematopoietic stem cell transplantation (HSCT) is the only curative option for a subset of patients with high-risk or relapsed acute lymphoblastic leukemia (ALL). Given evolving practices, it is important to continually evaluate outcomes for pediatric ALL following HSCT. Outcomes after HSCT are influenced by the type of donor used as this determines the degree and method of T cell depletion used and, consequently, specific transplant-related morbidities. We retrospectively analyzed HSCT data from our center for transplants performed between January 2008 and May 2016, comparing outcomes among different donor types. One hundred and twenty-four pediatric patients underwent HSCT from a matched sibling donor (MSD; n = 48), an unrelated matched donor (UMD; n = 56), or a haploidentical donor (n = 20). We observed a similar 3-year event-free survival (EFS) for MSD recipients (of .64) and for UMD recipients (.62), but a significantly lower EFS for recipients of haploidentical transplants (.35; P = .01). Relapse was the main cause of HSCT failure and was significantly higher in the haploidentical donor group (.47 versus .19 for MSD and .24 for UMD; P = .02). Treatment-related mortality was evenly distributed among the donor groups (.17, .16, and .15 for the MSD, UMD, and haploidentical groups, respectively). Rates of infection-related mortality were lower than previously reported. Relapse is the main obstacle for successful HSCT in the contemporary era, and this effect is most evident in recipients of haploidentical donor grafts. Newer methods to improve graft-versus-leukemia effect are being evaluated and will need to be incorporated into the management of high-risk patients.

Outcomes after Allogeneic Transplant in Patients with Wiskott-Aldrich Syndrome.

Wiskott-Aldrich syndrome (WAS) is a rare X-linked disorder characterized by a triad of immunodeficiency, eczema, and thrombocytopenia. Currently, hematopoietic stem cell transplantation (HSCT) is the most reliable curative treatment with excellent results for patients with HLA-matched family or unrelated donors. However, even after fully myeloablative preparative regimens, mixed donor chimerism is a potential concern. We performed a retrospective chart review of 12 children who underwent allogeneic HSCT for WAS to report our experience. The median age at transplant was 10.5 months (range, 3 to 39). The median nucleated cell dose from the marrow was 4.55 × 109/kg (range, .3 to 7.9). The median times to neutrophil and platelet engraftment were 19 days (range, 13 to 27) and 18.5 days (range, 12 to 31), respectively. The rate of overall survival was 92% with median follow-up of 67 months (range, 3 to 146). Two patients developed grade IV acute graft-versus-host disease, and 1 died on day +99. Five of 12 patient's (42%) had mixed donor chimerism (range, 12% to 85%) at day +180. None of the pretransplant patient parameters was predictive of mixed chimerism. Nonetheless, of these 5 patients, 2 had normalization of the platelet count despite the mixed chimerism, 2 had full donor chimerism after receiving a second transplant with the same donor, and 1 remains transfusion dependent awaiting a second transplant. Hence, even with a significant rate of mixed chimerism, HSCT provides substantial benefit to WAS patients, with excellent overall survival.

High Incidence of Autoimmune Disease after Hematopoietic Stem Cell Transplantation for Chronic Granulomatous Disease.

There is a lack of consensus regarding the role and method of hematopoietic stem cell transplantation (HSCT) on patients with chronic granulomatous disease (CGD). Long-term follow-up after HSCT in these patient population is essential to know its potential complications and decide who will benefit the most from HSCT. We report the outcome of HSCT and long-term follow-up in 24 patients with CGD, transplanted in our center from either related (n = 6) or unrelated (n = 18) donors, over a 12-year period (2003 to 2015), using high-dose alemtuzumab in the preparative regimen. We evaluated the incidence and timing of adverse events and potential risk factors. We described in detailed the novel finding of increased autoimmunity after HSCT in patients with CGD. At a median follow-up of 1460 days, 22 patients were full donor chimeras, and 2 patients had stable mixed chimerism. All assessable patients showed normalization of their neutrophil oxidative burst test. None of the patients developed grades II to IV acute graft-versus-host disease, and no patient had chronic graft-versus-host disease. Twelve of 24 patients developed 17 autoimmune diseases (ADs). Severe ADs (cytopenia and neuropathy) occurred exclusively in the unrelated donor setting and mainly in the first year after HSCT, whereas thyroid AD occurred in the related donor setting as well and more than 3 years after HSCT. Two patients died due to infectious complications after developing autoimmune cytopenias. One additional patient suffered severe brain injury. The remaining 21 patients have long-term Lansky scores ≥ 80. The outcome of HSCT from unrelated donors is comparable with related donors but might carry an increased risk of developing severe AD. A lower dose of alemtuzumab may reduce this risk and should be tested in further studies.

Immunoglobulin prophylaxis in pediatric hematopoietic stem cell transplant.

BACKGROUND: After allogeneic hematopoietic stem cell transplantation (HSCT), patients have an increased susceptibility to infections, thought to be due in part to hypogammaglobulinemia. Thus, prophylactic administration of intravenous immunoglobulins (IVIG) has been administered to patients after HSCT as standard of care. This study compares the viral infection rate between dosing IVIG by IgG levels versus by routine monthly administration in pediatric patients after HSCT. PROCEDURE: In this retrospective chart review, we abstracted from electronic medical records data on pediatric patients undergoing HSCT from 2010 to 2012 for 6 months post-HSCT. We compared rates of infection between patients treated with routine IVIG prophylaxis and patients given IVIG prophylaxis based on IgG tough levels (IgG levels were checked every 2 weeks). RESULTS: Data were available and reviewed for 50 patients dosed with IVIG every 28 days (Group 1) and 100 patients dosed with IVIG based on IgG level > 400 mg/dl (Group 2). There was no significant difference in age (P = 0.98) or sex (P = 0.42), reason for HSCT, alemtuzumab use (P = 0.602), or reduced intensity conditioning (P = 1.00). Significantly more haploidentical donors were in Group 1 (P = 0.04), otherwise there was no significant difference in donor type between groups. Significantly less acute graft versus host disease occurred (P = <0.001) in Group 2 (P = <0.001). PCR documented viral infections were not significantly different (P = 0.412) (Table 1). Group 2 patients received significantly less IVIG (P < 0.001). CONCLUSION: Dosing IVIG to maintain an IgG level > 400 mg/dl is a cost-effective and safe way to prevent viral infections in pediatric patients undergoing HSCT.

Allogeneic hematopoietic cell transplant following crizotinib monotherapy for relapsed/refractory anaplastic large cell lymphoma.

Relapsed ALK-positive ALCL often is responsive to CRZ monotherapy. The subsequent role of allogeneic HCT after achieving second remission is poorly understood. We report 6 children who underwent allogeneic HCT for relapsed ALCL after CRZ. Age at transplant ranged from 10.7 to 22.6 years. Follow-up ranged from 0.9 to 4.5 years. All patients engrafted. Three of 4 patients that received a reduced-toxicity conditioning regimen containing fludarabine, alemtuzumab, and low-dose irradiation showed progressive mixed chimerism. Five patients remain in remission. One patient developed isolated CNS relapse 3.6 years after HCT despite a lack of previous CNS involvement. No acute transplant-related complications were experienced. One patient developed chronic renal disease secondary to transplant-associated microangiopathy and one patient chronic GVHD secondary to DLI. Ultimately, allogeneic HCT appears safe and potentially curative after remission induction with CRZ. The role of conditioning therapy, ablative or reduced intensity, remains uncertain for patients' post-CRZ monotherapy, and further studies may be warranted.

Intravesicular cidofovir for BK hemorrhagic cystitis in pediatric patients after hematopoietic stem cell transplant.

BK virus hemorrhagic cystitis is a complication of HCST. Response to IV cidofovir is unpredictable, and treatment carries risk of toxicity. We report the largest series of pediatric patients with BKHC after HSCT successfully treated with intravesicular cidofovir. There was no significant decrease in urine or plasma BK PCR. There was significant decrease in pain score on days 3 and 7, with associated decrease in morphine use. No patients experienced toxicities associated with IV cidofovir. Intravesicular cidofovir appears to be safe and effective for symptomatic treatment of BKHC in pediatric patients after HSCT.

PGM3 mutations cause a congenital disorder of glycosylation with severe immunodeficiency and skeletal dysplasia.

Human phosphoglucomutase 3 (PGM3) catalyzes the conversion of N-acetyl-glucosamine (GlcNAc)-6-phosphate into GlcNAc-1-phosphate during the synthesis of uridine diphosphate (UDP)-GlcNAc, a sugar nucleotide critical to multiple glycosylation pathways. We identified three unrelated children with recurrent infections, congenital leukopenia including neutropenia, B and T cell lymphopenia, and progression to bone marrow failure. Whole-exome sequencing demonstrated deleterious mutations in PGM3 in all three subjects, delineating their disease to be due to an unsuspected congenital disorder of glycosylation (CDG). Functional studies of the disease-associated PGM3 variants in E. coli cells demonstrated reduced PGM3 activity for all mutants tested. Two of the three children had skeletal anomalies resembling Desbuquois dysplasia: short stature, brachydactyly, dysmorphic facial features, and intellectual disability. However, these additional features were absent in the third child, showing the clinical variability of the disease. Two children received hematopoietic stem cell transplantation of cord blood and bone marrow from matched related donors; both had successful engraftment and correction of neutropenia and lymphopenia. We define PGM3-CDG as a treatable immunodeficiency, document the power of whole-exome sequencing in gene discoveries for rare disorders, and illustrate the utility of genomic analyses in studying combined and variable phenotypes.