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AbstractCompared with the general population, hematopoietic cell transplantation (HCT) survivors are at elevated risk for developing solid subsequent neoplasms (SNs). The Center for International Blood and Marrow Transplant Research (CIBMTR) is a key resource for quantifying solid SN incidence following HCT, but the completeness of SN ascertainment is uncertain. Within a cohort of 18 450 CIBMTR patients linked to the California Cancer Registry (CCR), we evaluated the completeness of solid SN data reported to the CIBMTR from 1991 to 2018 to understand the implications of using CIBMTR data alone or combined with CCR data to quantify the burden of solid SNs after HCT. We estimated the cumulative incidence of developing a solid SN, accounting for the competing risk of death. Within the cohort, solid SNs were reported among 724 patients; 15.6% of these patients had an SN reported by CIBMTR only, 36.9% by CCR only, and 47.5% by both. The corresponding cumulative incidence of developing a solid SN at 10 years following a first HCT was 4.0% (95% confidence interval [CI], 3.5-4.4) according to CIBMTR data only, 5.3% (95% CI, 4.9-5.9) according to CCR data only, and 6.3% (95% CI, 5.7-6.8) according to both sources combined. The patterns were similar for allogeneic and autologous HCT recipients. Linking detailed HCT information from CIBMTR with comprehensive SN data from cancer registries provides an opportunity to optimize SN ascertainment for informing follow-up care practices and evaluating risk factors in the growing population of HCT survivors.

Hematopoietic cell transplantation (HCT) uses cytotoxic chemotherapy and/or radiation followed by intravenous infusion of stem cells to cure malignancies, bone marrow failure and inborn errors of immunity, hemoglobin and metabolism. Lung injury is a known complication of the process, due in part to disruption in the pulmonary microenvironment by insults such as infection, alloreactive inflammation and cellular toxicity. How microorganisms, immunity and the respiratory epithelium interact to contribute to lung injury is uncertain, limiting the development of prevention and treatment strategies. Here we used 278 bronchoalveolar lavage (BAL) fluid samples to study the lung microenvironment in 229 pediatric patients who have undergone HCT treated at 32 childrens hospitals between 2014 and 2022. By leveraging paired microbiome and human gene expression data, we identified high-risk BAL compositions associated with in-hospital mortality (P = 0.007). Disadvantageous profiles included bacterial overgrowth with neutrophilic inflammation, microbiome contraction with epithelial fibroproliferation and profound commensal depletion with viral and staphylococcal enrichment, lymphocytic activation and cellular injury, and were replicated in an independent cohort from the Netherlands (P = 0.022). In addition, a broad array of previously occult pathogens was identified, as well as a strong link between antibiotic exposure, commensal bacterial depletion and enrichment of viruses and fungi. Together these lung-immune system-microorganism interactions clarify the important drivers of fatal lung injury in pediatric patients who have undergone HCT. Further investigation is needed to determine how personalized interpretation of heterogeneous pulmonary microenvironments may be used to improve pediatric HCT outcomes.

Consolidation with autologous hematopoietic stem cell transplantation (HSCT) has improved survival for patients with central nervous system tumors (CNSTs). The impact of the autologous graft CD34+ dose on patient outcomes is unknown. We wanted to analyze the relationship between CD34+ dose, total nucleated cell (TNC) dose, and clinical outcomes, including overall survival (OS), progression-free survival (PFS), relapse, non-relapse mortality (NRM), endothelial-injury complications (EIC), and time to neutrophil engraftment in children undergoing autologous HSCT for CNSTs. A retrospective analysis of the CIBMTR database was performed. Children aged 3.6×106/kg CD34+ cells experienced superior PFS (p = .04) and OS (p = .04) compared to children receiving ≤3.6 × 106/kg. Relapse rates were lower in patients receiving >3.6 × 106/kg CD34+ cells (p = .05). Higher CD34+ doses were not associated with increased NRM (p = .59). Stratification of CD34+ dose by quartile did not reveal any statistically significant differences between quartiles for 3-year PFS (p = .66), OS (p = .29), risk of relapse (p = .57), or EIC (p = .87). There were no significant differences in patient outcomes based on TNC, and those receiving a TNC >4.4 × 108/kg did not experience superior PFS (p = .26), superior OS (p = .14), reduced risk of relapse (p = .37), or reduced NRM (p = .25). Children with medulloblastoma had superior PFS (p < .001), OS (p = .01), and relapse rates (p = .001) compared to those with other CNS tumor types. Median time to neutrophil engraftment was 10 days versus 12 days in the highest and lowest infused CD34+ quartiles, respectively. For children undergoing autologous HSCT for CNSTs, increasing CD34+ cell dose was associated with significantly improved OS and PFS, and lower relapse rates, without increased NRM or EICs.

Adult hematopoietic stem cell transplantation (HSCT) recipients are at a high risk of adverse outcomes after COVID-19. Although children have had better outcomes after COVID-19 compared to adults, data on risk factors and outcomes of COVID-19 among pediatric HSCT recipients are lacking. We describe outcomes of HSCT recipients who were ≤21 years of age at COVID-19 diagnosis and were reported to the Center for International Blood and Marrow Transplant Research between March 27, 2020, and May 7, 2021. The primary outcome was overall survival after COVID-19 diagnosis. We determined risk factors of COVID-19 as a secondary outcome in a subset of allogeneic HSCT recipients. A total of 167 pediatric HSCT recipients (135 allogeneic; 32 autologous HSCT recipients) were included. Median time from HSCT to COVID-19 was 15 months (interquartile range [IQR] 7-45) for allogeneic HSCT recipients and 16 months (IQR 6-59) for autologous HSCT recipients. Median follow-up from COVID-19 diagnosis was 53 days (range 1-270) and 37 days (1-179) for allogeneic and autologous HSCT recipients, respectively. Although COVID-19 was mild in 87% (n = 146/167), 10% (n = 16/167) of patients required supplemental oxygen or mechanical ventilation. The 45-day overall survival was 95% (95% confidence interval [CI], 90-99) and 90% (74-99) for allogeneic and autologous HSCT recipients, respectively. Cox regression analysis showed that patients with a hematopoietic cell transplant comorbidity index (HCT-CI) score of 1-2 were more likely to be diagnosed with COVID-19 (hazard ratio 1.95; 95% CI, 1.03-3.69, P = .042) compared to those with an HCT-CI of 0. Pediatric and early adolescent and young adult HSCT recipients with pre-HSCT comorbidities were more likely to be diagnosed with COVID-19. Overall mortality, albeit higher than the reported general population estimates, was lower when compared with previously published data focusing on adult HSCT recipients.

PurposeUltrahigh resolution (UHR) HLA matching is reported to result in better outcomes following unrelated donor hematopoietic cell transplantation, improving survival and reducing post-transplant complications. However, most studies included relatively small numbers of patients. Here we report the findings from a large, multicenter validation study.MethodsUHR HLA typing was available on 5,140 conventionally 10 out of 10 HLA-matched patients with malignant disease transplanted between 2008 and 2017.ResultsAfter UHR HLA typing, 82% of pairs remained 10 out of 10 UHR-matched; 12.3% of patients were 12 out of 12 UHR HLA-matched. Compared with 12 out of 12 UHR-matched patients, probabilities of grade 2-4 acute graft-versus-host disease (aGVHD) were significantly increased with UHR mismatches (overall P = .0019) and in those patients who were HLA-DPB1 T-cell epitope permissively mismatched or nonpermissively mismatched (overall P = .0011). In the T-cell-depleted subset, the degree of UHR HLA mismatch was only associated with increased transplant-related mortality (TRM) (overall P = .0068). In the T-cell-replete subset, UHR HLA matching was associated with a lower probability of aGVHD (overall P = .0020); 12 out of 12 UHR matching was associated with reduced TRM risk when compared with HLA-DPB1 T-cell epitope permissively mismatched patients, whereas nonpermissive mismatching resulted in a greater risk (overall P = .0003).ConclusionThis study did not confirm that UHR 12 out of 12 HLA matching increases the probability of overall survival but does demonstrate that aGVHD risk, and in certain settings TRM, is lowest in UHR HLA-matched pairs and thus warrants consideration when multiple 10 out of 10 HLA-matched donors of equivalent age are available.

Transplant-associated thrombotic microangiopathy (TA-TMA) is a severe complication of hematopoietic stem cell transplantation (HSCT). A single-center prospective screening study has shown that the incidence of TA-TMA is much higher than prior retrospective studies that did not systematically screen. These data have not been replicated in a multicenter study. Our objective was to determine the incidence and risk factors for TA-TMA and compare outcomes of pediatric HSCT patients with and without TA-TMA. Patients were prospectively screened for TA-TMA at participating centers using a simple to implement and inexpensive strategy from the start of the preparative regimen through day +100. TA-TMA was diagnosed if ≥4 of 7 laboratory/clinical markers diagnostic for TA-TMA were present concurrently or if tissue histology showed TA-TMA. A total of 614 patients (359 males; 58%) received prospective TA-TMA screening at 13 pediatric centers. TA-TMA was diagnosed in 98 patients (16%) at a median of 22 days (interquartile range, 14-44) posttransplant. Patients with TA-TMA had significantly increased bloodstream infections (38% [37/98] vs 21% [107/51], P ≤ .001), mean total hospitalization days (68; 95% confidence interval [CI], 63-74 vs 43; 95% CI, 41-45; P ≤ .001), and number of days spent in the intensive care unit (10.1; 95% CI, 6.4-14; vs 1.6; 95% CI, 1.1-2.2; P ≤ .001) in the first 100 days after HSCT compared with patients without TA-TMA. Overall survival was significantly higher in patients without TA-TMA (93%; 490/516) compared with patients with TA-TMA (78%; 76/98) (P ≤ .001). These data support the need for systematic screening for TA-TMA and demonstrate the feasibility and efficacy of an easy to implement strategy to do so.

Post-transplant cyclophosphamide (PTCy) has significantly increased the successful use of haploidentical donors with a relatively low incidence of graft-versus-host disease (GVHD). Given its increasing use, we sought to determine risk factors for GVHD after haploidentical hematopoietic cell transplantation (haplo-HCT) using PTCy. Data from the Center for International Blood and Marrow Transplant Research on adult patients with acute myeloid leukemia, acute lymphoblastic leukemia, myelodysplastic syndrome, or chronic myeloid leukemia who underwent PTCy-based haplo-HCT (2013 to 2016) were analyzed and categorized into 4 groups based on myeloablative (MA) or reduced-intensity conditioning (RIC) and bone marrow (BM) or peripheral blood (PB) graft source. In total, 646 patients were identified (MA-BM = 79, MA-PB = 183, RIC-BM = 192, RIC-PB = 192). The incidence of grade 2 to 4 acute GVHD at 6 months was highest in MA-PB (44%), followed by RIC-PB (36%), MA-BM (36%), and RIC-BM (30%) (P = .002). The incidence of chronic GVHD at 1 year was 40%, 34%, 24%, and 20%, respectively (P < .001). In multivariable analysis, there was no impact of stem cell source or conditioning regimen on grade 2 to 4 acute GVHD; however, older donor age (30 to 49 versus

Critically ill pediatric allogeneic hematopoietic cell transplant (HCT) patients may benefit from early and aggressive interventions aimed at reversing the progression of multiorgan dysfunction. Therefore, we evaluated 25 early risk factors for pediatric intensive care unit (PICU) mortality to improve mortality prognostication. We merged the Virtual Pediatric Systems and Center for International Blood and Marrow Transplant Research databases and analyzed 936 critically ill patients ≤21 years of age who had undergone allogeneic HCT and subsequently required PICU admission between January 1, 2009, and December 31, 2014. Of 1532 PICU admissions, the overall PICU mortality rate was 17.4% (95% confidence interval [CI], 15.6% to 19.4%) but was significantly higher for patients requiring mechanical ventilation (44.0%), renal replacement therapy (56.1%), or extracorporeal life support (77.8%). Mortality estimates increased significantly the longer that patients remained in the PICU. Of 25 HCT- and PICU-specific characteristics available at or near the time of PICU admission, moderate/severe pre-HCT renal injury, pre-HCT recipient cytomegalovirus seropositivity,

Pediatric allogeneic hematopoietic cell transplant (HCT) survival is limited by the development of post-transplant infections. In this overview, we discuss a clinical approach to the prompt recognition and treatment of fever and hypotension in pediatric HCT patients. Special attention is paid to individualized hemodynamic resuscitation, thorough diagnostic testing, novel anti-pathogen therapies, and the multimodal support required for recovery. We present three case vignettes that illustrate the complexities of post-HCT sepsis and highlight best practices that contribute to optimal transplant survival in children.

BackgroundWe examined the impact of vancomycin-resistant Enterococcus (VRE) bloodstream infection (BSI) on outcomes of allogeneic hematopoietic cell transplantation (HCT) utilizing the Center for International Blood and Marrow Transplant Research database.MethodsAdult and pediatric patients (N = 7128) who underwent first HCT for acute leukemia or myelodysplastic syndrome from 2008 through 2012 were analyzed as 3 groups-VRE BSI, non-VRE BSI, without BSI-according to BSI status at 100 days (D100) after allogeneic HCT. Multivariable models examined the effect of VRE BSI for overall survival (OS) and nonrelapse mortality (NRM) at 1 year.ResultsOf 7128 patients, 258 (3.2%) had VRE BSI, 2398 (33.6%) had non-VRE BSI, and 4472 (63%) had no BSI. The median time to VRE BSI and non-VRE BSI were D11 and D15, respectively. Compared with non-VRE BSI patients, VRE BSI patients were older, had advanced-stage acute leukemia, and received umbilical cord blood (UCB) allografts. In multivariable models, VRE BSI was associated with lower OS (relative risk [RR], 2.9;(99% confidence interval [CI], 2.2-3.7) and increased NRM (RR, 4.7; 99% CI, 3.6-6.2) (P < .0001) for both. Other predictors for worse OS and increased NRM were non-VRE BSI, older age, advanced disease stage, UCB allograft, - mismatch, comorbidity index ≥3, and cytomegalovirus seropositivity (P < .001 for all variables).ConclusionsVRE BSI is associated with lowest OS and highest NRM compared with patients without BSI or non-VRE BSI. Novel interventions that address the pathophysiology of VRE BSI have the potential of improving survival after HCT.

We studied 1110 patients with β-thalassemia major aged ≤25 years who received transplants with grafts from HLA-matched related (n = 677; 61%), HLA-mismatched related (n = 78; 7%), HLA-matched unrelated (n = 252; 23%), and HLA-mismatched unrelated (n = 103; 9%) donors between 2000 and 2016. Ninety percent of transplants were performed in the last decade. Eight-five percent of patients received ≥20 transfusions and 88% were inadequately chelated. All patients received myeloablative-conditioning regimen. Overall and event-free survival were highest for patients aged ≤6 years and after HLA-matched related and HLA-matched unrelated donor transplantation. The 5-year probabilities of overall survival for patients aged ≤6 years, 7 to 15 years, and 16 to 25 years, adjusted for donor type and conditioning regimen were 90%, 84%, and 63%, respectively (P < .001). The corresponding probabilities for event-free survival were 86%, 80%, and 63% (P < .001). Overall and event-free survival did not differ between HLA-matched related and HLA-matched unrelated donor transplantation (89% vs 87% and 86% vs 82%, respectively). Corresponding probabilities after mismatched related and mismatched unrelated donor transplantation were 73% vs 83% and 70% vs 78%. In conclusion, if transplantation is considered as a treatment option it should be offered early (age ≤6 years). An HLA-matched unrelated donor is a suitable alternative if an HLA-matched relative is not available.

Presumably, reduced-intensity/nonmyeloablative conditioning (RIC/NMA) for allogeneic hematopoietic cell transplantation (alloHCT) results in reduced infections compared with myeloablative conditioning (MAC) regimens; however, published evidence is limited. In this Center for International Blood and Marrow Transplant Research study, 1755 patients (aged ≥40 years) with acute myeloid leukemia in first complete remission were evaluated for infections occurring within 100 days after T-cell replete alloHCT. Patients receiving RIC/NMA (n = 777) compared with those receiving MAC (n = 978) were older and underwent transplantation more recently; however, the groups were similar regarding Karnofsky performance score, HCT-comorbidity index, and cytogenetic risk. One or more infections occurred in 1045 (59.5%) patients (MAC, 595 [61%]; RIC/NMA, 450 [58%]; P = .21) by day 100. The median time to initial infection after MAC conditioning occurred earlier (MAC, 15 days [range,

Limited data exist on characteristics of central nervous system viruses (CNS-V) in allogeneic hematopoietic stem cell transplant (HCT) recipients. Between 2007 and 2015, the Center for International Blood and Marrow Transplant Research (CIBMTR) received information on 27,532 patients undergoing HCT. Of these, centers reported 165 HCT recipients with CNS-V detected in cerebrospinal fluid within 6 months after HCT. CNS viruses predominantly included human herpes virus 6 (HHV-6) (73%), followed by Epstein-Barr Virus (10%), cytomegalovirus (3%), varicella zoster virus (3%), herpes simplex virus (3%) and Adenovirus (3%). Median time of viral detection in CNS was 31 days after HCT; and viral detection was earlier in patients with CNS HHV-6. Concurrent viremia occurred in 52% of patients. Cord blood transplant recipients (CBT) accounted for the majority (53%) of patients with CNS-V. Myeloablative conditioning (65%), use of fludarabine (63%), or use of anti-thymocyte globulin (61%) were also predominant. Overall survival from the time of detection of CNS-V was 50% at 6 months and 30% at 5 years. Infections were the leading cause of death (32%). In summary, CBT recipients predominated in the population with CNS-V. Outcomes after CNS-V were poor with significant mortality seen in the first 6 months.

We analyzed CIBMTR data to evaluate the incidence of non-relapse mortality (NRM) and association with overall survival (OS) for bacterial blood stream infections (BSIs) occurring within 100 days of alloHCT in 2 different phases: pre-/peri-engraftment (BSI very early phase, BSI-VEP) and BSI post-engraftment (BSI occurring between 2 weeks after engraftment and day 100, late early phase, BSI-LEP). Of the 7128 alloHCT patients, 2656 (37%) had ≥1 BSI by day 100. BSI-VEP, BSI-LEP, and BSI-Both constituted 56% (n = 1492), 31% (n = 824), and 13% (n = 340) of total BSI, respectively. Starting in 2009, we observed a gradual decline in BSI incidence through 2012 (61-48%). Patients with BSI-VEP were more likely to receive a myeloablative conditioning (MAC) regimen with total body irradiation (TBI). NRM was significantly higher in patients with any BSI (RR 1.82 95% CI 1.63-2.04 for BSI-VEP, RR 2.46, 95% CI 2.05-2.96 for BSI-LEP, and RR 2.29, 95% CI 1.87-2.81 for BSI-Both) compared with those without BSI. OS was significantly lower in patients with any BSI compared with patients without BSI (RR 1.36, 95% CI 1.26-1.47 for BSI-VEP; RR 1.83, 95% CI 1.58-2.12 for BSI-LEP: RR 1.66, 95% CI 1.43-1.94 for BSI-Both). BSIs within day 100 after alloHCT are common and remain a risk factor for mortality.

Data are limited on whether to adjust high-dose chemotherapy before autologous hematopoietic cell transplant (autoHCT) in obese patients. This study explores the effects of dose adjustment on the outcomes of obese patients, defined as body mass index (BMI) ≥ 30 kg/m2. Dose adjustment was defined as a reduction in standard dosing ≥20%, based on ideal, reported dosing and actual weights. We included 2 groups of US patients who had received autoHCT between 2008 and 2014. Specifically, we included patients with multiple myeloma (MM, n = 1696) treated with high-dose melphalan and patients with Hodgkin or non-Hodgkin lymphomas (n = 781) who received carmustine, etoposide, cytarabine, and melphalan conditioning. Chemotherapy dose was adjusted in 1324 patients (78%) with MM and 608 patients (78%) with lymphoma. Age, sex, BMI, race, performance score, comorbidity index, and disease features (stage at diagnosis, disease status, and time to transplant) were similar between dose groups. In multivariate analyses for MM, adjusting for melphalan dose and for center effect had no impact on overall survival (P = .894) and treatment-related mortality (TRM) (P = .62), progression (P = .12), and progression-free survival (PFS; P = .178). In multivariate analyses for lymphoma, adjusting chemotherapy doses did not affect survival (P = .176), TRM (P = .802), relapse (P = .633), or PFS (P = .812). No center effect was observed in lymphoma. This study demonstrates that adjusting chemotherapy dose before autoHCT in obese patients with MM and lymphoma does not influence mortality. These results do not support adjusting chemotherapy dose in this population.

This Center for International Blood and Marrow Transplant Research report describes the use of hematopoietic stem cell transplantation (HSCT) in pediatric patients with cancer, 4408 undergoing allogeneic (allo) and3076 undergoing autologous (auto) HSCT in the United States between 2008 and 2014. In both settings, there was a greater proportion of boys (n = 4327; 57%), children < 10 years of age (n = 4412; 59%), whites (n = 5787; 77%), and children with a performance score ≥ 90% at HSCT (n = 6187; 83%). Leukemia was the most common indication for an allo-transplant (n = 4170; 94%), and among these, acute lymphoblastic leukemia in second complete remission (n = 829; 20%) and acute myeloid leukemia in first complete remission (n = 800; 19%) werethe most common. The most frequently used donor relation, stem cell sources, and HLA match were unrelated donor (n = 2933; 67%), bone marrow (n = 2378; 54%), and matched at 8/8 HLA antigens (n = 1098; 37%) respectively. Most allo-transplants used myeloablative conditioning (n = 4070; 92%) and calcineurin inhibitors and methotrexate (n = 2245; 51%) for acute graft-versus-host disease prophylaxis. Neuroblastoma was the most common primary neoplasm for an auto-transplant (n = 1338; 44%). Tandem auto-transplants for neuroblastoma declined after 2012 (40% in 2011, 25% in 2012, and 8% in 2014), whereas tandem auto-transplants increased for brain tumors (57% in 2008 and 77% in 2014). Allo-transplants from relatives other than HLA-identical siblings doubled between 2008 and 2014 (3% in 2008 and 6% in 2014). These trends will be monitored in future reports of transplant practices in the United States.

Patients with prior invasive fungal infection (IFI) increasingly proceed to allogeneic hematopoietic cell transplantation (HSCT). However, little is known about the impact of prior IFI on survival. Patients with pre-transplant IFI (cases; n=825) were compared with controls (n=10247). A subset analysis assessed outcomes in leukemia patients pre- and post 2001. Cases were older with lower performance status (KPS), more advanced disease, higher likelihood of AML and having received cord blood, reduced intensity conditioning, mold-active fungal prophylaxis and more recently transplanted. Aspergillus spp. and Candida spp. were the most commonly identified pathogens. 68% of patients had primarily pulmonary involvement. Univariate and multivariable analysis demonstrated inferior PFS and overall survival (OS) for cases. At 2 years, cases had higher mortality and shorter PFS with significant increases in non-relapse mortality (NRM) but no difference in relapse. One year probability of post-HSCT IFI was 24% (cases) and 17% (control, P

Alternative graft sources (umbilical cord blood [UCB], matched unrelated donors [MUD], or mismatched unrelated donors [MMUD]) enable patients without a matched sibling donor to receive potentially curative hematopoietic cell transplantation (HCT). Retrospective studies demonstrate comparable outcomes among different graft sources. However, the risk and types of infections have not been compared among graft sources. Such information may influence the choice of a particular graft source. We compared the incidence of bacterial, viral, and fungal infections in 1781 adults with acute leukemia who received alternative donor HCT (UCB, n= 568; MUD, n = 930; MMUD, n = 283) between 2008 and 2011. The incidences of bacterial infection at 1 year were 72%, 59%, and 65% (P