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• T cell receptors distinguish between the wild type and anchor-modified gp100 209 melanoma antigens. • The clinical candidate SILv44 recognizes the WT antigen with stronger affinity and potency than the anchor-modified antigen. • Higher affinity for the wild type antigen explains the SILv44′s superior tumor control in mouse models of melanoma. • Anchor modified peptides should be used cautiously, as the presumption that they are wild type surrogates may be wrong. Although there are exceptions and outliers, T cell functional responses generally correlate with the affinity of a TCR for a peptide/MHC complex. In one recently described outlier case, the most promising clinical candidate in a series of TCRs specific for the gp100 209 melanoma antigen bound with the weakest solution affinity and produced the least amount of cytokine in vitro. Hypotheses for this outlier behavior included unusual cytokine expression patterns arising from an atypical TCR binding geometry. Studying this instance in more detail, we found here that outlier behavior is attributable not to unusual cytokine patterns or TCR binding, but the use of a position 2 anchor-modified peptide variant in in vitro experiments instead of the wild type antigen that is present in vivo. Although the anchor-modified variant has been widely used in basic and clinical immunology as a surrogate for the wild type peptide, prior work has shown that TCRs can clearly distinguish between the two. We show that when this differential recognition is accounted for, the functional properties of gp100 209 -specific TCRs track with their affinity towards the peptide/MHC complex. Beyond demonstrating the correlates with T cell function for a clinically relevant TCR, our results provide important considerations for selection of TCRs for immunotherapy and the use of modified peptides in immunology. [ABSTRACT FROM AUTHOR]

Summary: For patients with untreated hepatic veno‐occlusive disease (VOD)/sinusoidal obstruction syndrome (SOS) with multi‐organ dysfunction (MOD), mortality is >80%. We conducted a pooled analysis of three studies that assessed Day 100 survival in relationship to MOD severity, with dialysis and/or ventilator dependence representing the most severe organ dysfunction. All patients in the analysis were diagnosed using Baltimore criteria/biopsy. This analysis of patients with VOD/SOS and MOD after haematopoietic cell transplantation (HCT; n = 651) demonstrated higher Day 100 survival rates amongst defibrotide‐treated patients with VOD/SOS with less versus more severe forms of MOD. Even patients with severe forms of MOD post‐HCT benefitted from defibrotide. [ABSTRACT FROM AUTHOR]

To study the contribution of T‐cell receptors (TCR) to resulting T‐cell responses, we studied three different human αβ TCRs, reactive to the same gp100‐derived peptide presented in the context of HLA‐A*0201. When expressed in primary CD8 T cells, all receptors elicited classic antigen‐induced IFN‐γ responses, which correlated with TCR affinity for peptide–MHC in the order T4H2 > R6C12 > SILv44. However, SILv44 elicited superior IL‐17A release. Importantly, in vivo, SILv44‐transgenic T cells mediated superior antitumor responses to 888‐A2 + human melanoma tumor cells upon adoptive transfer into tumor‐challenged mice while maintaining IL‐17 expression. Modeling of the TCR ternary complexes suggested architectural differences between SILv44 and the other complexes, providing a potential structural basis for the observed differences. Overall, the data reveal a more prominent role for the T‐cell receptor in defining host T‐cell physiology than traditionally assumed, while parameters beyond IFN‐γ secretion and TCR affinity ultimately determine the reactivity of tumor‐reactive T cells. [ABSTRACT FROM AUTHOR]

Pediatric patients requiring kidney transplant after hematopoietic cell transplant receive multiple courses of immunosuppression placing them at risk for infection. To elucidate potential risk factors for infection, we compared the immunosuppressive regimens and infectious complications of pediatric kidney transplant recipients at a single institution who had previously undergone hematopoietic cell transplant from different donors to similar patients reported in the literature. Among the initial four post-hematopoietic cell transplant kidney transplant patients reviewed, viremia episodes were universal, including BK virus, Epstein-Barr virus, and human herpesvirus-6, with one death from presumed BK virus encephalitis. No viremia was reported in five similar cases in the literature. Risk factors for increased infection include use of lymphodepleting serotherapy in HCT conditioning, multiple HCTs, limited immune reconstitution time between transplants, increased pre- KTx viral burden, and use of T-cell-depleting versus -suppressive induction immunosuppression for KTx. These findings suggest that pediatric post- HCT KTx recipients are at increased risk for viral infections, likely benefitting from thorough pre- KTx evaluation of immune reconstitution and preferential use of non-T-cell-depleting induction therapy for KTx. We applied these recommendations to one subsequent post- HCT patient requiring KTx at our institution with excellent outcomes one year post- KTx. [ABSTRACT FROM AUTHOR]

Hepatic veno-occlusive disease/sinusoidal obstruction syndrome ( VOD/ SOS) is a progressive, potentially fatal complication of conditioning for haematopoietic stem cell transplant ( HSCT). The VOD/ SOS pathophysiological cascade involves endothelial-cell activation and damage, and a prothrombotic-hypofibrinolytic state. Severe VOD/ SOS (typically characterized by multi-organ dysfunction) may be associated with >80% mortality. Defibrotide is approved for treating severe hepatic VOD/ SOS post- HSCT in the European Union, and for hepatic VOD/ SOS with renal or pulmonary dysfunction post- HSCT in the United States. Previously, defibrotide (25 mg/kg/day in 4 divided doses for a recommended ≥21 days) was available through an expanded-access treatment protocol for patients with VOD/ SOS. Data from this study were examined post-hoc to determine if the timing of defibrotide initiation post- VOD/ SOS diagnosis affected Day +100 survival post- HSCT. Among 573 patients, defibrotide was started on the day of VOD/ SOS diagnosis in approximately 30%, and within 7 days in >90%. The relationship between Day +100 survival and treatment initiation before/after specific days post-diagnosis showed superior survival when treatment was initiated closer to VOD/ SOS diagnosis with a statistically significant trend over time for better outcomes with earlier treatment initiation ( P < 0·001). These results suggest that initiation of defibrotide should not be delayed after diagnosis of VOD/ SOS. [ABSTRACT FROM AUTHOR]

Hepatic veno-occlusive disease, or sinusoidal obstruction syndrome (VOD/SOS), is a serious and potentially fatal complication of conditioning for hematopoietic stem cell transplantation (HSCT) or of chemotherapy regimens alone. Defibrotide is a complex mixture of single-stranded polydeoxyribonucleotides that is approved in the United States for treating hepatic VOD/SOS with renal or pulmonary dysfunction post-HSCT and in the European Union, Israel, and South Korea for treating severe hepatic VOD/SOS post-HSCT. Defibrotide was previously available in the United States as an investigational drug through a treatment protocol (treatment IND) study. Interim results of that large, treatment IND study of patients with VOD/SOS and with or without multiorgan dysfunction (MOD; also known as multiorgan failure) are presented here. Defibrotide was administered i.v. at 6.25 mg/kg every 6 hours (25 mg/kg/day), with a recommended treatment duration of at least 21 days. Enrolled patients (n = 681) were diagnosed with VOD/SOS based on Baltimore or modified Seattle criteria or liver biopsy analysis. Among the 573 HSCT recipients, 288 (50.3%; 95% confidence interval [CI], 46.2% to 54.4%) were alive at day +100 post-HSCT. Day +100 survival for the pediatric (≤16 years) and adult (>16 years) subgroups was 54.5% (95% CI, 49.1% to 60.0%; n = 174 of 319) and 44.9% (95% CI, 38.8% to 51.0%; n = 114 of 254), respectively. In the MOD subgroup, 159 of 351 patients (45.3%; 95% CI, 40.1% to 50.5%) of patients were alive at day +100 post-HSCT. Treatment with defibrotide was generally well tolerated, and drug-related toxicities were consistent with previous studies. Adverse events were reported in 69.6% of safety-evaluable patients (399 of 573). Other than VOD/SOS and associated MOD symptoms, the most commonly reported treatment-emergent adverse event was hypotension (13.8%). Day +100 survival results observed in this trial were consistent with results seen in previous trials of defibrotide for VOD/SOS in adult and pediatric patients. These data support the potential benefit of defibrotide in treating a VOD/SOS patient population that includes those with and without MOD. [ABSTRACT FROM AUTHOR]

Allogeneic hematopoietic stem cell transplantation has demonstrated efficacy for numerous inherited metabolic disorders (IMDs). Umbilical cord blood transplant (UCBT) is increasingly used as a graft source in IMDs, but little is known of the impact of cord blood unit (CBU)/recipient HLA allelic disparity on key outcomes following UCBT for IMD. We reviewed outcomes of 106 consecutive first, single UCBTs for IMD at the University of Minnesota with regard to CBU/recipient HLA allelic matching (HLA-A, -B, -C, and -DRB1). The median age at UCBT was 1 year, and 87 patients (82%) received myeloablative conditioning. Primary diagnoses were Hurler syndrome (41%), cerebral adrenoleukodystrophy (35%), metachromatic leukodystrophy/globoid cell leukodystrophy (9%), and other (16%). The 5-year overall survival (OS) for the entire cohort was 70% (95% confidence interval, 59% to 79%). Rates of severe acute and chronic graft-versus-host disease were low (6% for each). CBU/recipient HLA conventional matching was based on antigen-level matching at HLA-A and -B, and on allele-level matching at HLA-DRB1. Of 46 conventional matched UCBTs, 20 (43%) were mismatched at 1 or more alleles. Of 49 conventional 5/6 UCBTs, 30 (61%) were mismatched at ≥2 alleles and 19 (39%) were mismatched at ≥3 alleles. Within the 6/6 conventional match stratum, comparisons of key outcomes between allele-matched and allele-mismatched UCBT were as follows: 5-year OS, 88% versus 42% ( P  < .01); 1-year engrafted survival (ES) with ≥90% donor chimerism, 73% versus 60% ( P  = .33); graft failure, 8% versus 30% ( P  = .05); and transplantation-related mortality (TRM), 8% versus 30% ( P  = .04). For patients undergoing conventional 5/6 HLA-matched UCBT, better allelic matching was associated with similar outcomes: 5-year OS, 77% versus 74% ( P  = .72); 1-year ES, 73% versus 47% ( P  = .06); graft failure, 17% versus 42% ( P  = .05); and TRM, 10% versus 16% ( P  = .54). On multivariable analyses, fewer allele-level mismatches within each conventional match stratum continued to predict more favorable outcomes following UCBT. These data provide evidence that allele-level HLA matching considerations within a conventional HLA match stratum may better predict outcomes of interest after UCBT for IMD. Larger studies are warranted to confirm these findings and explore other allele-level HLA match dynamics. [ABSTRACT FROM AUTHOR]

Background: Little is known about the role of advance directives (AD) in end-of-life (EOL) care for adolescents and young adults (AYA) undergoing hematopoietic stem cell transplant (HSCT). Objective: The study objective was to describe the frequency, type, and influence of AD on the use of life-sustaining treatment (LST) in AYA patients undergoing HSCT. Methods: We performed a retrospective chart review of 96 patients aged 14-26 undergoing HSCT between April 2011 and January 2015 at the University of Minnesota. LST was defined as the use of positive pressure ventilation (PPV), dialysis, or CPR. Results: Of the 96 patients, survival was 72.9%, and 23% had an AD. Of the 26 patients who died, 13 (50%) had an AD. Among the 19 patients who died in the ICU, there was no significant difference in PPV, dialysis, withholding or withdrawing of LST, or timing of do not resuscitate (DNR) orders between those with ADs preferring LST ( n = 5), those naming proxies only ( n = 4), and those without ADs ( n = 10). Patients with ADs expressing preference for LST were significantly more likely to receive CPR than those with proxies or those without ADs ( p = 0.02). Conclusion: A minority of AYA patients undergoing HSCT had ADs. Patients received care that was strongly associated with their preferences. With the exception of CPR, the use of LST did not differ between those with ADs and those without. [ABSTRACT FROM AUTHOR]

Abstract: We report two patients who underwent cardiac transplantation at a young age and subsequently required a HCT for varied indications. Despite the challenges associated with HCT following cardiac transplant, including need for altered immunosuppression, toxicities related to chemotherapy exposure, and infection risks, both patients are currently alive and well. There is a paucity of such successful cases documented in the literature, and these cases highlight the critical importance of an experienced, multidisciplinary team when caring for this patient population. [ABSTRACT FROM AUTHOR]

Abstract: Allogeneic hematopoietic stem cell transplantation for patients with a hemoglobinopathy can be curative but is limited by donor availability. Although positive results are frequently observed in those with an HLA-matched sibling donor, use of unrelated donors has been complicated by poor engraftment, excessive regimen-related toxicity, and graft-versus-host disease (GVHD). As a potential strategy to address these obstacles, a pilot study was designed that incorporated both a reduced-intensity conditioning and mesenchymal stromal cells (MSCs). Six patients were enrolled, including 4 with high-risk sickle cell disease (SCD) and 2 with transfusion-dependent thalassemia major. Conditioning consisted of fludarabine (150 mg/m2), melphalan (140 mg/m2), and alemtuzumab (60 mg for patients weighing > 30 kg and .9 mg/kg for patients weighing <30 kg). Two patients received HLA 7/8 allele matched bone marrow and 4 received 4-5/6 HLA matched umbilical cord blood as the source of HSCs. MSCs were of bone marrow origin and derived from a parent in 1 patient and from an unrelated third-party donor in the remaining 5 patients. GVHD prophylaxis consisted of cyclosporine A and mycophenolate mofetil. One patient had neutropenic graft failure, 2 had autologous hematopoietic recovery, and 3 had hematopoietic recovery with complete chimerism. The 2 SCD patients with autologous hematopoietic recovery are alive. The remaining 4 died either from opportunistic infection, GVHD, or intracranial hemorrhage. Although no infusion-related toxicity was seen, the cotransplantation of MSCs was not sufficient for reliable engraftment in patients with advanced hemoglobinopathy. Although poor engraftment has been observed in nearly all such trials to date in this patient population, there was no evidence to suggest that MSCs had any positive impact on engraftment. Because of the lack of improved engraftment and unacceptably high transplant-related mortality, the study was prematurely terminated. Further investigations into understanding the mechanisms of graft resistance and development of strategies to overcome this barrier are needed to move this field forward. [Copyright &y& Elsevier]

Umbilical cord blood has rapidly become a valuable alternative stem cell source for allogeneic haematopoietic stem cell transplantation. Extensive research over the last 20 years has established the safety and efficacy of umbilical cord blood transplantation in both children and adults with a variety of malignant and non-malignant diseases. This research has clearly shown that this stem cell source has several unique characteristics resulting in distinct advantages and disadvantages when compared to transplantation with unrelated bone marrow or peripheral blood stem cells. This article reviews the most recent literature comparing the outcomes after umbilical cord blood transplantation with other alternative stem cell sources. [ABSTRACT FROM AUTHOR]

Transplant decisions for children with acute lymphoblastic leukemia (ALL) in second complete remission (CR2) are often based on the type of available donor. In many cases, allogeneic hematopoietic cell transplantation (HCT) is considered only if a human leukocyte antigen (HLA) matched sibling donor (MSD) is available. The role of unrelated donor (URD) HCT in this patient population is not well established. As advances in supportive care and donor selection have improved, the use of URD HCT in such patients should be reevaluated. We analyzed the outcomes of 87 consecutive children with ALL in CR2 who underwent allogeneic HCT at the University of Minnesota between 1990 and 2007. Donor sources included MSD bone marrow (n = 32), well and partially matched (M, n = 18) and mismatched (MM, n = 16) URD bone marrow and URD umbilical cord blood (UCB, n = 21). Although the incidence of neutrophil recovery was similar in all groups, the overall incidence of grades II-IV acute graft-versus-host disease (aGVHD) and chronic GVHD (cGVHD) was 37% and 9%, respectively, with a higher incidence of aGVHD in recipients of URD grafts. Leukemia-free survival (LFS) at 5 years was lower in recipients of MM-URD grafts, but was comparable in all other groups. Although relapse at 5 years was highest in recipients of MSD (50%), results were not significantly different compared to recipients of M-URD (17%), MM-URD (6%), and UCB (33%) (P = .17). The development of grades II-IV aGVHD and a first remission >3 years were associated with a lower risk of relapse (relative risk [RR] 0.2, P = .03; RR 0.2. P = .01 respectively). Together, these results support the continued investigation of URD HCT for ALL in CR2, and suggest the timing of HCT in these children should be based primarily on the risk of relapse with conventional chemotherapy and not on the type of donor available. [Copyright &y& Elsevier]

Voriconazole is a widely used antifungal agent in immunocompromised patients, but its utility is limited by its variable exposure and narrow therapeutic index. Population pharmacokinetic (PK) models have been used to characterize voriconazole PK and derive individualized dosing regimens. However, determinants of temporal within‐patient variability of voriconazole PK were not well established. We aimed to characterize temporal variability of voriconazole PK within individuals and identify predictive clinical factors. This study was conducted as a part of a single‐institution, phase I study of intravenous voriconazole in children undergoing hematopoietic cell transplantation (NCT02227797). We analyzed voriconazole PK study data collected at week 1 and again at week 2 after the start of voriconazole therapy in 59 pediatric patients undergoing HCT (age <21 years). Population PK analysis using nonlinear mixed effect modeling was performed to analyze temporal within‐individual variability of voriconazole PK by incorporating a between‐occasion variability term in the model. A 2‐compartment linear elimination model incorporating body weight and cytochrome P450 2C19 phenotype described the data. The ratio of individual voriconazole clearance between weeks 1 and 2 ranged from 0.11 to 3.3 (−9.1 to +3.3‐fold change). Incorporation of covariate effects by serum C‐reactive protein and albumin levels decreased between‐occasion variability of clearance as compared to the model without them (coefficient of variation, 41.2% and 59.5%, respectively) and improved the model fit (P <.05). As significant covariates on voriconazole PK, C‐reactive protein and albumin concentrations may potentially serve as useful biomarkers as part of therapeutic drug monitoring. [ABSTRACT FROM AUTHOR]

Summary: Hepatic veno‐occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) is a potentially life‐threatening complication of haematopoietic stem cell transplant (HSCT) conditioning and chemotherapy. Defibrotide is approved for treatment of hepatic VOD/SOS with pulmonary or renal dysfunction [i.e., multi‐organ dysfunction (MOD)] after HSCT in the United States and severe VOD/SOS after HSCT in patients aged older than 1 month in the European Union. Defibrotide was available as an investigational drug by an expanded‐access treatment programme (T‐IND; NCT00628498). In the completed T‐IND, the Kaplan–Meier estimated Day +100 survival for 1000 patients with documented defibrotide treatment after HSCT was 58·9% [95% confidence interval (CI), 55·7–61·9%]. Day +100 survival was also analysed by age and MOD status, and post hoc analyses were performed to determine Day +100 survival by transplant type, timing of VOD/SOS onset (≤21 or >21 days) and timing of defibrotide treatment initiation after VOD/SOS diagnosis. Day +100 survival in paediatric patients was 67·9% (95% CI, 63·8–71·6%) and 47·1% (95% CI, 42·3–51·8%) in adults. All patient subgroups without MOD had higher Day +100 survival than those with MOD; earlier defibrotide initiation was also associated with higher Day +100 survival. The safety profile of defibrotide in the completed T‐IND study was similar to previous reports. [ABSTRACT FROM AUTHOR]

During the workup for transplantation, the patient's sister (age 20 years at the time of sister's HLH diagnosis) was found to have the same compound heterozygote mutations in I RAB27A i and grayish hair. Similar to our patient, isolated neuroinflammation presenting before HLH diagnosis is a subject of a recent analysis of 38 patients.[11] Median age of neurologic presentation was 6.5 years and patients progressed to HLH at a mean of 3 years after neurologic presentation. Griscelli syndrome type 2 (GS2) is caused by mutations of the I RAB27A i gene and can be complicated by hemophagocytic lymphohistiocytosis (HLH) at a very young age. [Extracted from the article]

• BuCy-based conditioning is associated with greater regimen-related toxicity but earlier CD3 donor engraftment. • BuFlu-based conditioning is associated with lower toxicity but higher rates of graft failure and immune cytopenias. • Newer approaches and modification of conditioning regimen are needed to optimize benefits. Hematopoietic stem cell transplantation (HCT) is a primary treatment for various inherited metabolic disorders (IMDs). Achieving stable and sustained engraftment while minimizing transplantation-related morbidity and mortality is critical to optimizing outcomes for IMDs. Traditional regimens have used myeloablative approaches, primarily busulfan and cyclophosphamide (BuCy), which is associated with significant regimen-related toxicity. Alternatively, reduced-toxicity regimens, such as busulfan and fludarabine (BuFlu), have been proposed to offer similar efficacy with reduced toxicities. We compared transplantation-related outcomes with BuCy-based and BuFlu-based conditioning in patients with IMDs. We retrospectively analyzed the University of Minnesota's transplantation database for patients with IMDs who underwent HCT using a BuCy (with alemtuzumab) or BuFlu (with antithymocyte globulin) preparative regimen between March 2008 and September 2017. Overall survival (OS), event-free survival (EFS), and incidence of neutrophil and platelet recovery were determined using standard definitions. Complications such as graft failure, sinusoidal obstruction syndrome, hemorrhagic cystitis, and respiratory failure were compared. Graft failure includes primary and secondary aplastic graft failure with and without autologous recovery. The incidence of viral infections post-transplantation in the 2 regimens was also determined. A total of 99 patients underwent HCT for IMDs during the study period. Sixty-four patients received BuCy conditioning, and the other 35 received BuFlu. Hurler syndrome (46%) and adrenoleukodystrophy (43%) were the most common IMDs, and umbilical cord blood was the most common graft source (74%). One-year OS was similar in the 2 groups (81.2% in BuCy versus 85.5% in BuFlu; P =.8), with an EFS of 75% versus 63%, respectively. The 2 groups also had similar incidences of grade III-IV acute GVHD (9% versus 6%; P =.5) and chronic GVHD (9% versus 7%; P =.67). Neutrophil and platelet recovery were similar in the 2 groups, with a significantly shorter duration of hospital stay noted in the BuFlu cohort (median, 21 days versus 34 days; P =.002). The cumulative incidence of graft failure was significantly higher in the BuFlu group (29% versus 14%; P =.08), as was the rate of second HCT (27% versus 3%; P =.001). The incidences of adenoviral infection (14% versus 0%; P =.02) and hemorrhagic cystitis (23% versus 3%; P =.01) were higher in the BuCy group. T cell engraftment occurred significantly sooner with BuCy conditioning until 1-year post-transplantation, but donor myeloid engraftment was similar in the 2 groups. Our data indicate that reduced-toxicity conditioning is associated with lower rates of infection and other transplantation-related complications but is concerning for a higher rate of graft failure in patients with IMDs. Alternate immunosuppressive agents and novel techniques should be considered to minimize toxicities and reduce complications. [ABSTRACT FROM AUTHOR]

The Primary Immune Deficiency Treatment Consortium (PIDTC) performed a retrospective analysis of 662 patients with severe combined immunodeficiency (SCID) who received a hematopoietic cell transplantation (HCT) as first-line treatment between 1982 and 2012 in 33 North American institutions. Overall survival was higher after HCT from matched-sibling donors (MSDs). Among recipients of non-MSD HCT, multivariate analysis showed that the SCID genotype strongly influenced survival and immune reconstitution. Overall survival was similar for patients with RAG, IL2RG, or JAK3 defects and was significantly better compared with patients with ADA or DCLRE1C mutations. Patients with RAG or DCLRE1C mutations had poorer immune reconstitution than other genotypes. Although survival did not correlate with the type of conditioning regimen, recipients of reduced-intensity or myeloablative conditioning had a lower incidence of treatment failure and better T- and B-cell reconstitution, but a higher risk for graft-versus-host disease, compared with those receiving no conditioning or immunosuppression only. Infection-free status and younger age at HCT were associated with improved survival. Typical SCID, leaky SCID, and Omenn syndrome had similar outcomes. Landmark analysis identified CD4+ and CD4+CD45RA+ cell counts at 6 and 12 months post-HCT as biomarkers predictive of overall survival and long-term T-cell reconstitution. Our data emphasize the need for patient-tailored treatment strategies depending upon the underlying SCID genotype. The prognostic significance of CD4+ cell counts as early as 6 months after HCT emphasizes the importance of close follow-up of immune reconstitution to identify patients who may need additional intervention to prevent poor long-term outcome. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine the effect of a pretransplant cranial boost (CB) on post-transplant central nervous system (CNS) relapse and survival in acute lymphoblastic leukemia (ALL) patients undergoing allogeneic hematopoietic stem cell transplantation (HSCT) using a total body irradiation (TBI)-containing preparation regimen. Two hundred thirteen ALL patients were treated consecutively at our institution with allogeneic HSCT. Conditioning included TBI (1320 cGy in 8 fractions given twice daily) and cyclophosphamide (120 mg/kg) with or without fludarabine (75 mg/m 2 ). Patients were divided into 4 groups based on history of CNS disease and whether a CB was given. Of the 160 patients with no history of CNS disease, none received a CB (CNS−/CB−). Of the 53 patients with prior CNS disease, 41 had not received prior cranial irradiation. Thirty of these 41 received a CB of 900 to 1000 cGy in 5 daily fractions (CNS+/CB+), whereas the other 11 did not receive a CB because of physician preference (CNS+/CB−). The remaining 12 patients with prior CNS involvement had previously received cranial irradiation and thus were not candidates for a CB (CNS + PriorRT). Two-year CNS relapse risk, overall survival (OS), and disease-free survival (DFS) were calculated using Kaplan-Meier analysis. Seven patients experienced post-transplant CNS relapse: 4 in the CNS−/CB− group, 2 in the CNS+/CB− group, and 1 in the CNS + PriorRT group. None of the 30 patients who received a CB relapsed in the CNS. Two-year CNS relapse risk was 0% in the CNS+/CB+ group compared with 21% (95% CI, 0% to 45%) in the CNS+/CB− group ( P  = .03). Two-year OS and DFS did not differ between the groups. In conclusion, among ALL patients with prior CNS leukemia, there was a trend toward a reduced risk of post-transplant CNS relapse in patients who received a CB. However, the addition of a CB did not appear to have an impact on OS or DFS. [ABSTRACT FROM AUTHOR]

Sustained donor engraftment after allogeneic hematopoietic cell transplantation (HCT) converts to healthy donor hemoglobin synthesis and halts disease symptoms in patients with sickle cell disease and thalassemia major. A disease-free survival probability that exceeds 90% has been reported when HCT using an HLA-matched sibling donor is performed in young patients with low-risk disease or treatment-related risk factors. Alternate donor HCT and HCT in adults is performed infrequently because of a higher risk profile. Transplant-specific risks include conditioning regimen-related toxicity, graft-versus-host disease, graft rejection with marrow aplasia or disease recurrence, and infections associated with immunosuppression and delayed immune reconstitution. The magnitude of risk depends on patient age, clinical status of the underlying disease (eg, organ injury from vasculopathy and iron overload), donor source, and intensity of the conditioning regimen. These risks are commonly monitored and reported in the short term. Documenting very late outcomes is important, but these data are rarely reported because of challenges imposed by patient drop-out and insufficient resources. This report summarizes long-term follow-up results after HCT for hemoglobin disorders, identifies gaps in knowledge, and discusses opportunities for future investigations. This consensus summary will be followed by a second article detailing comprehensive long-term follow-up recommendations to aid in maintaining health in these individuals and identifying late complication risks that could facilitate interventions to improve outcomes. [ABSTRACT FROM AUTHOR]

Existing literature shows mixed conclusions regarding the impact of ABO incompatibility on outcomes after hematopoietic stem cell transplantation. Because the future for umbilical cord blood (UCB) expansion technologies is bright, we assessed whether this typically overlooked graft characteristic impacted various outcomes after UCB transplantation (UCBT) for nonmalignant disorders (NMDs). A prospectively maintained institutional blood and marrow transplant program database was queried for all patients undergoing first UCBT for NMDs. UCB and recipient ABO compatibility was considered as matched, major mismatched, minor mismatched, or bidirectional mismatched. The impact of ABO incompatibility was assessed on overall survival, graft failure, acute and chronic graft-versus-host disease (GVHD), time to neutrophil and platelet recovery, day 0 to day 100 RBC transfusion burden, and donor hematopoietic chimerism. Through December 2014, 270 patients have undergone first UCBT for various NMDs. In both univariable and multivariable analyses, ABO compatibility status did not appear to impact any outcomes assessed, although a trend toward increased grades III to IV acute GVHD was seen in recipients of major mismatched units. When considering UCBT for treatment of NMDs, ABO compatibility between the donor unit and intended recipient does not appear to be an important consideration in the UCB unit choice. [ABSTRACT FROM AUTHOR]

Acute kidney injury (AKI) is a well-documented complication of pediatric hematopoietic stem cell transplantation (HSCT). Dialysis after HSCT is associated with a lower overall survival (OS); however, the association between less severe AKI and OS is unclear. We retrospectively studied 205 consecutive pediatric HSCT patients to determine the incidence and impact of all stages of AKI on OS in pediatric HSCT recipients. We used the peak pRIFLE grade during the first 100 days to classify AKI (ie, R = risk, I = injury, F = failure, L = loss of function, E = end-stage renal disease) and used the modified Schwartz formula to estimate glomerular filtration rate. AKI was observed in 173 of 205 patients (84%). The 1-year OS rate decreased significantly with an increasing severity of pRIFLE grades ( P < .01). There was no difference in the OS between patients without AKI and the R/I group. Regardless of the dialysis status, stages F/L/E had significantly lower rates of OS compared with patients without AKI or R/I ( P < .01). There was no difference in OS among patients with dialysis and F/L/E without dialysis ( P = .65). Stages F/L/E predicted mortality independent of acute graft-versus-host disease, gender, and malignancy. The OS of children after HSCT decreases significantly with an increasing severity of AKI within the first 100 days post-transplant. Although our data did not show an increased risk of mortality with stages R/I, stages F/L/E predicted mortality regardless of dialysis. Prevention and minimization of AKI may improve survival after pediatric HSCT. [ABSTRACT FROM AUTHOR]

Abstract: It is not unusual for children to require dialysis for fluid and electrolyte management after hematopoietic cell transplantation (HCT). Previous studies have documented high mortality in children who require dialysis after HCT, but recent data are lacking. The purpose of this study was to compare the incidence of dialysis after pediatric HCT and the survival of patients who received dialysis in 2 decades, 1990-1999 and 2000-2009. A total of 1427 patients age <21 years who underwent a first HCT at the University of Minnesota between January 1990 and December 2009 were reviewed using prospectively collected data from the institutional HCT database. The incidence of dialysis during the first 100 days post-HCT and survival at 1 year post-HCT in the 2 cohorts were determined. Comparisons between patients who did and did not require dialysis were made using the χ2 and Fisher exact tests as appropriate. Kaplan-Meier estimates and 95% confidence intervals for 1-year post-HCT overall survival were reported by dialysis group and compared using the log-rank test. Predictors of overall survival among patients requiring dialysis were assessed using univariate and multivariate Cox regression analyses. The incidence of dialysis was not significantly different in the 2 cohorts (8.2% for 1990-1999 versus 8.9% for 2000-2009; P = .6326). Patients requiring dialysis were significantly more likely to survive to or past 1 year in the 2000-2009 cohort compared with the 1990-1999 cohort (23% versus 11%; P < .0001). Multivariate analyses found that older age at the time of HCT, primary disease type, pulmonary hemorrhage, and HCT in 1990-1999 were associated with increased mortality in the dialyzed population. The use of cyclosporine was associated with increased survival in the patients who received dialysis. Dialysis is an important complication of pediatric HCT with an incidence that has remained constant over the last 2 decades. Survival was improved in the 2000-2009 cohort regardless of dialysis status. Despite a recent significant reduction in mortality in patients requiring dialysis, mortality remains higher in these patients than in those who do not need dialysis. [Copyright &y& Elsevier]

Abstract: Risk-adapted therapy has been the cornerstone of treatment for pediatric B precursor acute lymphoblastic leukemia (B-ALL). Recently, age ≥13 years at diagnosis has been identified as a very high-risk feature for chemotherapy treated pediatric patients with B-ALL. Whether age at time of transplantation is associated with poor outcomes in adolescents and young adults (AYA) is unknown. We hypothesized that AYA receiving allogeneic hematopoietic cell transplantation (allo-HCT) would have greater relapse and inferior survival compared with children age <13 years. We reviewed the outcomes in 136 consecutive patients (age 0-30 years) with B-ALL who underwent myeloablative allo-HCT at our institution, including 79 children age <13 years (58%) and 57 AYA age 13-30 years (42%). Overall survival at 5 years was significantly lower in the AYA group (hazard ratio, 1.74; 95% confidence interval [CI], 1.04-2.95; P = .03). In addition, the AYA patients had a greater risk of transplantation-related mortality at 1 year (hazard ratio, 2.23; 95% CI, 1.01-4.90; P = .05), but no difference in relapse (relative risk, 0.85; 95% CI, 0.41-1.76; P = .66). Based on this analysis, AYA patients undergoing allo-HCT for B-ALL have significantly inferior survival and greater transplantation-related mortality compared with children age <13 years, but no difference in relapse, suggesting that allo-HCT may overcome relapse in AYA. Further improvements in peritransplantation care are needed to limit complications in AYA patients. [Copyright &y& Elsevier]

Mycophenolate mofetil (MMF) is an immunosuppressant routinely used in allogeneic hematopoietic cell transplantation (alloHCT) to promote stem cell engraftment and prevent acute graft vs host disease. Administered as a prodrug, MMF is converted by esterases to the active moiety, mycophenolic acid (MPA). The impact of clinical covariates on unbound MPA exposure was investigated with a population pharmacokinetic approach. Pharmacokinetic data were obtained from routine area under the curve (AUC) monitoring of unbound MPA drug levels in 36 pediatric (n = 31) and young adult (n = 5) patients undergoing alloHCT for a variety of malignant and nonmalignant disorders. Unbound MPA pharmacokinetics were well described by a 2-compartment model with linear elimination and first-order absorption. The important clinical covariates affecting unbound MPA pharmacokinetics were weight, estimated creatinine clearance, and total bilirubin. Unbound MPA clearance was reduced, and exposure (AUC0-8) increased in individuals with decreased renal function. In individuals with severe hepatic dysfunction (total bilirubin >10 mg/dL) unbound MPA clearance was approximately 3-fold lower compared with patients with normal to mild hepatic impairment. In alloHCT recipients with renal dysfunction or severe hepatic injury, dose reductions may be necessary to prevent toxicity and ensure optimal immunosuppression. [ABSTRACT FROM PUBLISHER]

Human parainfluenza viruses (HPIVs) are uncommon, yet high-risk pathogens after hematopoietic stem cell transplant (HCT). We evaluated 5178 pediatric and adult patients undergoing HCT between 1974 and 2010 to determine the incidence, risk factors, response to treatment, and outcome of HPIV infection as well as any change in frequency or character of HPIV infection over time. HPIV was identified in 173 patients (3.3%); type 3 was most common (66%). HPIV involved upper respiratory tract infection (URTI; 57%), lower respiratory tract infection (LRTI; 9%), and both areas of the respiratory tract (34%), at a median of 62 days after transplantation. In more recent years, HPIV has occurred later after HCT, whereas the proportion with nosocomial infection and mortality decreased. Over the last decade, HPIV was more common in older patients and in those receiving reduced intensity conditioning (RIC). RIC was a significant risk factor for later (beyond day +30). HPIV infections, and this association was strongest in patients with URTI. HCT using a matched unrelated donor (MURD), mismatched related donor (MMRD), age 10 to 19 years, and graft-versus-host disease (GVHD) were all risk factors for HPIV infections. LRTI, early (<30 days), age 10 to 19 years, MMRD, steroid use, and coinfection with other pathogens were risk factors for mortality. The survival of patients with LRTI, especially very early infections, was poor regardless of ribavirin treatment. HPIV incidence remains low, but may have delayed onset associated with RIC regimens and improving survival. Effective prophylaxis and treatment for HPIV are needed. [Copyright &y& Elsevier]

Enterococcal bloodstream infections are associated with an increased risk of mortality during the first year after hematopoietic stem cell transplantation, especially in patients with vancomycin-resistant enterococci (VRE) strains. Colonization with VRE and delayed engraftment are significant risk factors for VRE bacteremia.Background. Enterococci are an important cause of healthcare-associated infections. We retrospectively analyzed risk factors and outcome of vancomycin-resistant enterococci (VRE) and vancomycin-sensitive enterococci (VSE) infections.Methods. Seven hundred fifty-two patients who received hematopoietic stem cell transplants from 2004 through 2008 at the University of Minnesota were included.Results. Ninety-three patients had enterococcal bloodstream infection (BSI) during the first year after transplant. Vancomycin resistance was observed in 66% and 31% of isolates in adults and children, respectively. Cumulative incidence of VRE and VSE bacteremia was 6.6% (95% confidence interval [CI], 4.8%–8.4%) and 5.7% (95% CI, 4.0%–7.4%), respectively. Colonization with VRE before or after transplant was a risk factor for VRE bacteremia (odds ratio [OR], 3.3 [95% CI, 1.3–8.3] and 7.0 [95% CI, 4.0–14.8], respectively). Delay in engraftment increased the incidence of VRE bacteremia from 4.5% (95% CI, 2.9–6.6) if engrafted before day 21 and to 15% (95% CI, 3.2%–38%) if engrafted between days 36 and 42. In adults, mortality 30 days after infection was 38% for both VRE (95% CI, 25%–54%) and VSE cases (95% CI, 21%–62%). The hazard ratio for all-cause mortality up to 1 year after transplant was 4.2 (95% CI, 3.1–6.9) and 2.7 (95% CI, 1.4–5.1) for patients with VRE and VSE BSIs, respectively, compared to patients without enterococcal BSI. In pediatric patients, mortality 30 days after VRE and VSE bacteremia was 20% (95% CI, 5.4%–59%) and 4.5% (95% CI, .6%–28%), respectively.Conclusion. High rates of vancomycin resistance and association of enterococcal infections with significant mortality warrant further efforts to optimize prevention and management of these infections. [ABSTRACT FROM AUTHOR]

Rapid lymphocyte recovery after bone marrow or peripheral blood transplantation is associated with improved survival. However, the impact of early lymphocyte recovery has not been examined after umbilical cord blood transplant (UCBT). We evaluated lymphocyte recovery in 360 consecutive patients with hematologic malignancy that underwent UCBT between 2001 and 2007. Uniform myeloablative (MA), reduced intensity conditioning (RIC) and graft-versus-host disease prophylaxis regimens were used. In multivariate analysis, an absolute leukocyte count (ALC) >200 × 106/L at day 30 (n = 73) after MA conditioning was associated with superior 2-year overall survival (OS) (73% versus 61%; P = .02) (relative risk [RR]: 2.29; 95% confidence interval [CI]: 1.15-4.56), progression-free survival (PFS) (68% versus 54%; P = .05) (RR: 1.96; 95% CI: 0.99-3.86) and less transplant-related mortality (8% versus 28%, P < .01) (RR: 4.38; 95% CI: 1.65-11.60) compared to ≤200 × 106/L (n = 43). Similarly, an ALC >200 × 106/L at day 42 (n = 105) after RIC was associated with superior 2-year OS (59% versus 41%, P < .01) (RR: 2.10; 95% CI: 1.3-3.41) and PFS (46% versus 36%, P = .05) (RR: 1.58; 95% CI: 1.01-2.49) compared to ≤200 × 106/L (n = 55). There was no significant relationship between ALC and relapse. Rapid lymphocyte recovery early after UCBT predicts better survival in patients with hematologic malignancies. [ABSTRACT FROM AUTHOR]

Pericardial effusion (PE) is a rare but life-threatening complication that can occur following hematopoietic stem cell transplant (HCT). The incidence in pediatric post-HCT population has been reported to be between 9%-37%. The underlying etiology is unclear and small studies have reported high morbidity and mortality in patients who develop PE post-HCT. Various studies have attempted to analyze the risk factors associated with occurrence of PE after HCT but detailed analysis is limited due to low incidence. We retrospectively analyzed the University of Minnesota's Blood and Marrow Transplant database for occurrence of PE after HCT in patients less than 18 years between January 1, 2005 and December 31, 2018. Data was analyzed to compare the overall survival (OS) in patients who developed PE with those who did not. Risk factors analyzed included age, graft versus host disease (GVHD), type of conditioning regimen, graft source, underlying disease and human leukocyte antigen matching using univariate analysis. Multivariate analysis was performed using logistic regression model. A total of 770 patients underwent HCT during the study period, of which 162 (21%) developed PE. The median age of transplant for patients who developed PE was 8 years with about 60% males (n=98). Median time to development of PE after HCT was 69 days. Children who developed PE post-HCT had a significantly poor survival (2-year OS of 66%, confidence interval (CI): 58-73% vs 78%, CI: 75-81% in controls; p<0.01). There was a higher risk of grade III-IV acute GVHD in the PE cohort (relative risk (RR) of 14% (CI: 8-19%) vs 4%(CI: 3-6%) in those without PE). In univariate analysis, use of myeloablative conditioning as compared to non-myeloablative or reduced intensity conditioning (RR of 24% (CI: 20-27%) vs 11% (CI: 7-16%); p<0.01), use of umbilical cord blood (UCB) stem cells compared to bone marrow or peripheral blood stem cells (RR: 24% (CI: 20-28%) vs 18% (CI: 14-21%); p<0.01), and underlying malignant disorders were significantly associated with development of PE (RR: 26% (CI: 20-31%)) and inherited metabolic disorders (RR: 23% (CI: 17-28%) vs 15% in non-malignant disorders (CI: 11-20%); p<0.01). A higher risk was also noted in those with metabolic disorders (In multivariate analysis, use of myeloablative conditioning showed a significantly higher risk of development of PE (hazard ratio of 2.16 (CI: 1.33-3.50); p<0.01). Pericardial effusion after HCT is associated with a higher mortality and higher risk of severe acute GVHD. The high-risk group (underlying malignancy, receiving myeloablative conditioning and UCB transplant) should be monitored closely for development of PE. [ABSTRACT FROM AUTHOR]

Prolonged thrombocytopenia after hematopoietic stem cell transplant is a common complication, especially after umbilical cord blood transplant (UCBT). Romiplostim is a thrombopoietin receptor agonist that is FDA approved for chronic ITP. Its effect on platelet recovery after UCBT remains unknown. The primary objective of the study was to determine the maximum tolerated dose (MTD) of romiplostim in patients who failed to achieve platelet recovery by day +28 after UCBT. Secondary objectives were to determine if romiplostim influences the speed of platelet recovery, decreases the risk of thrombocytopenia related complications or affects the incidence of bone marrow fibrosis or relapse. This was a single center dose escalation trial of weekly romiplostim in patients >18 years who failed to achieve an untransfused platelet count (PLT) of 20 × 109/L by day +28 after myeloablative (MA) or non-myeloablative (NMA) UCBT. A total of 20 patients were enrolled. Romiplostim was administered at the assigned dose as 6 weekly injections beginning by day +42 post UCBT with an end date by day +100. Four dose levels (4, 6, 8, and 10 mcg/kg/dose) were evaluated. There was no intra-patient dose escalation. The MTD of romiplostim was determined by the Continual Reassessment Method, with a goal to identify a dose level with desired toxicity rate of ≤ 20%. Historical controls were selected from our database based on age, gender, underlying disease, and transplant type (1:1 matching). Median age of the patients was 59.5 years and 40% were male. Ten patients had AML, 5 ALL, 3 MDS, 1 NHL and 1 MM. Two patients received 4, two 6, four 8 and the remaining 12 received 10 mcg/kg/dose. Only 5 patients completed the full 6 doses. Of the 15 patients who received less than 6 doses, 12 were due to a PLT>100, 2 due to PLT>400 (× 109/L), and 1 was due to the subject developed right upper extremity edema (no thrombosis). All romiplostim treated patients achieved platelet engraftment to 20 × 10^9/L at a median of 45 days post UCBT compared to 85% of controls at a median of 49 days (p=0.07). Similarly, 90% of romiplostim treated patients achieved platelet engraftment to 50 × 10^9/L at a median of 48 days compared to 70% of controls at a median of 52 days (p=0.04) (fig 1). Three patients experienced serious AEs requiring discontinuation of the drug: 2 had a PLT>400 × 109 /L and 1 developed right upper extremity edema. Bleeding episodes or transfusions improved with the use of the drug. All dose levels appear to be effective with low toxicity. Therefore, the MTD of romiplostim was 10mcg/kg/dose. There were no BM findings suggestive of increased fibrosis or relapse by day +100. Our results indicate that romiplostim is safe and potentially effective therapy to improve platelet recovery after UCBT, with the MTD being 10mcg/kg/dose. Further studies in larger numbers of patients are needed to confirm these observations. [ABSTRACT FROM AUTHOR]

Adoptive immunotherapy using banked virus-specific T-lymphocytes (VSTs) derived from partially HLA-matched donors has been successful in restoring antiviral immunity after hematopoietic stem cell transplantation (HSCT), although broad availability of this therapy is currently limited, and best methods for donor-recipient matching remain unclear. To determine the feasibility and efficacy of third-party VSTs for the treatment of immunocompromised pediatric patients with refractory viral infections in a multicenter phase I/II consortium study. There are two arms to this study. Arm A are pediatric subjects who had infections with CMV, EBV, and/or adenovirus after hematopoietic stem cell transplant (HSCT) and had failed antiviral therapy, or who had toxicities related to anti-viral drug-related. Arm B enrolls patients with primary immunodeficiency disorders with refractory viral infection prior to HSCT. A VST bank containing products generated from 40 donors at Children's National was utilized, and antiviral HLA mapping was applied to identify the most suitable product for each patient referred. Patients received a dose of 2 × 10^7 VSTs/m2, with optional additional doses given 28 days after the initial VST infusion. Viral PCRs were monitored for efficacy, and VST persistence and expansion in vivo was measured via IFN-g ELISpot and flow cytometry. Twenty-three patients were enrolled from 11 study sites to date. Twenty-two were treated in Arm A (after HSCT), at a median time of 95 days post-HSCT (range 16-476). Fourteen patients were treated for adenovirus and 9 for CMV. Patients received a median of 1 infusion (range 1-3). Infused VSTs were matched at a median of 3/10 HLA alleles (range 2-5), and 22 had confirmation of antiviral activity through at least one shared HLA allele. Of 18 evaluable patients, 14 had antiviral responses at 1-month post-infusion (4/5 with CMV, and 10/13 with adenovirus, Figure 1), including 7 who had complete resolution of viremia. No GVHD was observed after infusion, and 17 of 23 (74%) are virus free up to 15 months post-infusion. Virus-specific T-cell activity was higher by day 45 (mean 177 IFN-g SPW) post-infusion than at baseline (mean 13 IFN-g SPW, p=0.045). VSTs remained detectable for up to 3 months via flow cytometry staining of discordant HLA alleles (Figure 2). Third-party VSTs utilized from a single bank can be distributed and administered in a multicenter consortium setting, and are safe and feasible for the treatment of refractory viral infections in pediatric patients. Preliminary efficacy data shows high rates of response and long-term survival. Studies of targeting strategies and characterization of T-cell epitopes are ongoing. [ABSTRACT FROM AUTHOR]

With >36 years of data collected, PIDTC prospective (6901) and retrospective (6902) natural history studies provide an unprecedented opportunity to study hematopoietic cell transplantation (HCT) outcomes for SCID over time. Patients in this 6901/6902 analysis met PIDTC diagnostic criteria for SCID and underwent HCT. Categorial variables were analyzed between decades (a) 1982-89 (b) 1990-99 (c) 2000-09 (d) 2010-18 using the chi-square test. Continuous outcomes were compared using the Kruskal-Wallis test. Kaplan-Meier method was used for estimates of overall survival (OS). 896 children with typical (n=742) and atypical (n=154) SCID requiring HCT between 1982-2018 were enrolled. Diagnosis of SCID for reasons other than family history or newborn screening was common (60%) in early cohorts (a-c) dropping to 30% in cohort (d). Distribution of SCID genotypes changed over time (Fig 1), and novel/unknown genotypes also decreased from (a) 53% to (d) 13%, p<0.001. Due to the rise of gene therapy, there were fewer patients with adenosine deaminase deficient SCID receiving HCT in cohort (d) compared to prior decades. Median age at HCT has decreased, from 193 to 112 days of life, p<0.001. While marrow was the most common stem cell source in the 1980's (95%), currently peripheral blood stem cells and cord blood are given to 46% of patients (p<0.001). The increased use of unrelated donors parallels a decrease in mismatched related donors (Fig 2a; p<0.001). In univariate analysis, use of conditioning has increased from 12% in the 1980's to 65% currently (Fig 2b, p<0.001); contributing factors that will be evaluated in upcoming multivariate analyses include genotype, typical vs atypical SCID, and donor type. Day +100 cumulative incidence of grades 3-4 acute graft-versus-host disease (GVHD) has dropped, from 9.6% to 5.9% (p=0.02). OS has markedly improved in the last decade (Fig 3a), with 1- and 5-year OS being 90 and 87%, respectively (p=0.02). In particular, gains have been made in OS when using alternative donors (p=0.02) (Fig 3c,d) while OS for matched sibling HCT remains high (Fig 3b). This longitudinal data set, spanning the implementation of NBS and advancements in diagnostics and supportive care, highlights improved OS after HCT for SCID, including alternative donors. Exploration of decreased toxicity approaches that maintain high OS and engraftment are warranted. [ABSTRACT FROM AUTHOR]

Background Immune mediated cytopenias (IMC) – isolated or combined hemolytic anemia, thrombocytopenia, and neutropenia - are increasingly recognized as potentially serious complications following allogeneic hematopoietic cell transplantation (HCT) for non-malignant disorders (NMD). However, IMC incidence, severity, response to therapy, and risk factors are not well defined. Methods Pediatric patients undergoing HCT for NMD between 2010 and 2017 at a single institution were identified, excluding those experiencing graft failure or death prior to day +100. Demographics and HCT characteristics were obtained from a prospectively-maintained database. A retrospective chart review identified cases of IMC with positive direct Coombs test, anti-platelet antibody, and/or anti-granulocyte antibody; and documented treatment and response. IMC severity was defined by months to resolution: mild (0-3), moderate (3-6), or severe (>6). Results Of 271 NMD HCT recipients, 52 (19%) exhibited IMC at a median of 130 days post-HCT (range, 30-279); 23 (44% of cases) had multiple cell lines affected. IMC disease was mild, moderate, or severe in 44%, 25%, and 31%, respectively, with no deaths attributed to IMC. For those with moderate or severe IMC, all received steroid therapy, with a response rate of 34%. An average of 2.0 unique agents were used to achieve IMC resolution, at a median of 117 days (range 17 – 639). Univariate analysis revealed statistically significant associations between IMC and younger age at HCT (median 3.7 vs. 7.0 years, p<0.01), inherited metabolic disorder or hemoglobinopathy as indication for HCT (p<0.01), reduced toxicity conditioning (p<0.01), and use of serotherapy in conditioning (p=0.04). While presence of acute graft-versus-host disease (GvHD) was not associated, those with IMC were more likely to receive steroids for GvHD prophylaxis (p<0.01). Following HCT, a decline in peripheral blood donor CD3+ chimerism by at least 10% from day +60 to +100 was more common in those with IMC (p<0.01), with a trend toward lower peripheral blood CD3+ donor chimerism at day +100 (71% IMC vs 88.5% no IMC, p = 0.1). Lower absolute CD4 count at days +100 (median 100 vs. 163) and +180 (median 170 vs. 276) were observed (p<0.01) with no differences in CD8 or CD19. Conclusion Immune mediated cytopenias following HCT for NMD in a large pediatric cohort was common at 19%, with limited steroid responsiveness, use of multiple immunosuppressive agents and duration of therapy exceeding 3 months for the majority affected. Patient and transplant characteristics associated with IMC were consistent with previous reports, though we expand these findings with observation of declining donor T-lymphoid chimerism and CD4 counts by day +100, prior to median onset of IMC. While, the pathogenesis of IMC post-HCT for NMD remains elusive, further research may identify approaches to prevent this HCT complication. [ABSTRACT FROM AUTHOR]

Introduction Hematopoietic stem cell transplantation (HSCT) is a primary treatment for various inherited metabolic diseases (IMDs). Achieving stable and sustained engraftment while minimizing transplant related morbidity and mortality is critical in optimizing outcome for IMDs. Traditional regimens have used myeloablative approaches, primarily Busulfan and Cyclophosphamide (BuCy), which is associated with significant regimen related toxicity (RRT). Alternatively, reduced toxicity regimens, such as Busulfan and Fludarabine (BuFlu), have been proposed to offer similar efficacy with reduced toxicities. Objective To compare outcomes with BuCy and BuFlu based conditioning in patients with IMDs. Methods We retrospectively analyzed University of Minnesota's transplant database for patients with IMDs who underwent HSCT using BuCy (with alemtuzumab) or BuFlu (with ATG) preparative regimen from March, 2008 to September,2017. Overall survival (OS) and incidence of neutrophil and platelet recovery was determined using standard definitions. Complications such as graft failure, sinusoidal obstruction syndrome, hemorrhagic cystitis and respiratory failure were compared. Graft failure includes primary and secondary aplastic graft failure, with and without autologous recovery. Incidence of viral infections post-transplant comparing two regimens were also determined. Results Total of 99 patients underwent HSCT for IMDs during the study period. Sixty-four received BuCy conditioning and 35 received BuFlu. Hurler syndrome (46%) and adrenoleukodystrophy (43%) were most common IMDs and umbilical cord blood was the most common graft source (74%). One-year OS was similar in both groups (81.2% in BuCy vs. 85.5% in BuFlu; p=0.8) with a similar incidence of grade 3-4 acute GVHD(9% vs. 6%; p=0.5) and chronic GVHD(9% vs. 7%; p=0.67). Neutrophil and platelet recovery were similar in both groups with significantly shorter duration of hospital stay noted in BuFlu cohort (median 21 d vs. 34 d, p = 0.002). Cumulative incidence of graft failure was higher with BuFlu group (29% vs 14%, p = 0.08). Significantly higher rates of second HCT was noted following BuFlu cohort (27% vs. 3%, p = 0.001). Incidence of adenoviral infection (14% vs. 0%, p=0.02) and hemorrhagic cystitis (23% vs. 3%, p=0.01) were higher in the BuCy group. T-cell engraftment occurred significantly sooner with BuCy conditioning until 1-year post transplant, donor myeloid engraftment was similar in both groups. Conclusions Reduced toxicity conditioning leads to lower rates of infections and other transplant related complications, but is associated with higher rate of graft failure in patients with IMDs. Alternate immune suppressive agents should be considered to reduce graft failure and minimize toxicities. Alternate donor options, including expanded UCB, should also be considered to improve engraftment in patients with IMDs. [ABSTRACT FROM AUTHOR]