Pediatric Hematopoietic Cell Transplant Recipients Research Articles

Efficacy of Brincidofovir in Pediatric Stem Cell Transplant Recipients With Adenovirus Infections.

Adenovirus (AdV) infections are of particular concern in pediatric hematopoietic stem cell transplantation (HSCT) recipients as therapeutic options are limited. Brincidofovir (BCV) is the lipid-conjugated pro-drug of cidofovir (CDV) with oral bioavailability and higher intracellular concentrations of the active drug. In this retrospective, single-center analysis, we included allogeneic pediatric HSCT recipients with refractory AdV infections because of contraindications or insufficient response to CDV. Common posttransplant viruses were monitored at least weekly by PCR in blood, stool, and urine. Each of the 8 patients received 6 to 12 doses of BCV. BCV treatment was initiated between days +5 and +77. AdV DNAemia and intestinal AdV infection disappeared completely in 6/8 patients. Early AdV DNAemia before day +21 did not result in increased mortality. One patient with a systemic, acyclovir-resistant HSV-1 infection responded rapidly to BCV. Four patients did not survive. AdV infection-related death in 2 patients was accompanied by >1 × 109/mL AdV copy numbers in the blood. Two more patients died of graft-vs-host disease and acute respiratory distress syndrome, respectively, both not related to AdV. AdV DNAemia and intestinal infection subsided completely in 75% of pediatric HSCT recipients treated with BCV. AdV DNAemia exceeding 1 × 109/mL and a poor lymphocyte recovery of <250/µL were associated with high mortality. Early AdV DNAemia before day +21, however, did not result in a worse outcome. Although access to BCV is currently suspended, further clinical trials are needed to clarify the role of BCV in HSCT recipients with AdV infections and its potential benefit in preventing AdV DNAemia in immunocompromised patients.

Early Cumulative Fluid Balance and Outcomes in Pediatric Allogeneic Hematopoietic Cell Transplant Recipients With Acute Respiratory Failure: A Multicenter Study.

ObjectivesTo evaluate the associations between early cumulative fluid balance (CFB) and outcomes among critically ill pediatric allogeneic hematopoietic cell transplant (HCT) recipients with acute respiratory failure, and determine if these associations vary by treatment with renal replacement therapy (RRT).MethodsWe performed a secondary analysis of a multicenter retrospective cohort of patients (1mo - 21yrs) post-allogeneic HCT with acute respiratory failure treated with invasive mechanical ventilation (IMV) from 2009 to 2014. Fluid intake and output were measured daily for the first week of IMV (day 0 = day of intubation). The exposure, day 3 CFB (CFB from day 0 through day 3 of IMV), was calculated using the equation [Fluid in – Fluid out] (liters)/[PICU admission weight](kg)*100. We measured the association between day 3 CFB and PICU mortality with logistic regression, and the rate of extubation at 28 and 60 days with competing risk regression (PICU mortality = competing risk).Results198 patients were included in the study. Mean % CFB for the cohort was positive on day 0 of IMV, and increased further on days 1-7 of IMV. For each 1% increase in day 3 CFB, the odds of PICU mortality were 3% higher (adjusted odds ratio (aOR) 1.03, 95% CI 1.00-1.07), and the rate of extubation was 3% lower at 28 days (adjusted subdistribution hazard ratio (aSHR) 0.97, 95% CI 0.95-0.98) and 3% lower at 60 days (aSHR 0.97, 95% CI 0.95-0.98). When day 3 CFB was dichotomized, 161 (81%) had positive and 37 (19%) had negative day 3 CFB. Positive day 3 CFB was associated with higher PICU mortality (aOR 3.42, 95% CI 1.48-7.87) and a lower rate of extubation at 28 days (aSHR 0.30, 95% CI 0.18-0.48) and 60 days (aSHR 0.30, 95% 0.19-0.48). On stratified analysis, the association between positive day 3 CFB and PICU mortality was significantly stronger in those not treated with RRT (no RRT: aOR 9.11, 95% CI 2.29-36.22; RRT: aOR 1.40, 95% CI 0.42-4.74).ConclusionsAmong critically ill pediatric allogeneic HCT recipients with acute respiratory failure, positive and increasing early CFB were independently associated with adverse outcomes.

Incidence of CMV Infection and Disease and Adverse Events Associated with Antiviral Therapy in a Retrospective Cohort of Allogeneic Hematopoietic Cell Transplant Recipients at an Academic Children's Hospital.

Cytomegalovirus (CMV) is a significant source of morbidity and mortality among transplant recipients; the epidemiology is less understood in pediatric hematopoietic cell transplantation (HCT) cohorts. Furthermore, there is a paucity of data related to CMV prophylactic and preemptive strategies. A single-center retrospective observational cohort of allogeneic HCT recipients at the Children's Hospital of Philadelphia January 1, 2004-December 31, 2017 was constructed. Subjects were followed for 180 days after transplant to determine whether they had CMV infection or disease. Data on antiviral therapy were collected as were outcomes of CMV disease and adverse events (AEs) related to the antiviral therapy. Between January 2004 and March 2017, 345 allogeneic HCTs in 333 patients undergoing CMV surveillance testing were identified. CMV DNAemia was detected during the 180-day follow-up in 89 (25.8%) HCTs. CMV recipient-positive transplants were most likely to have CMV infection (47%). Infection rates were high for those receiving a CMV-specific prophylaxis regimen (50%). CMV DNAemia progressed to CMV disease 11.2% of the time. Of 224 subjects receiving CMV-specific prophylaxis, 19.2% experienced ≥1 AE. Of 53 receiving preemptive therapy during any CMV DNAemia episode, 32.1% experienced ≥1 AE. CMV infection is common in pediatric allogeneic HCT recipients. The CMV-specific prophylaxis regimen employed in this cohort did not effectively prevent DNAemia, progression to CMV disease was uncommon, and AEs from prophylaxis and preemptive therapy were frequent. Novel approaches that reduce the impact of CMV on pediatric allogeneic HCT recipients are needed.

#50: Cytomegalovirus Retinitis Among Pediatric Hematopoietic Stem Cell and Solid Organ Transplantation Recipients: A Contemporary Review

Abstract Background Cytomegalovirus infection can cause significant morbidity and mortality after transplantation. Cytomegalovirus retinitis (CMVR) can be a major complication of tissue invasive CMV disease in transplant recipients. There are little data regarding the contemporary incidence and outcomes of CMVR among pediatric transplant recipients. Methods We performed a retrospective cohort analysis of allogeneic hematopoietic (allo-HCT) and solid organ transplant (SOT) recipients who received medical care at Nationwide Children’s Hospital (NCH) from 1/1/10–11/30/20 and had a diagnosis of CMVR to describe the incidence, timing post-transplant, ocular manifestations, management, and outcomes. Basic demographic and clinical data, pre-transplant donor/recipient CMV serostatus, and post-transplant CMV infection data were collected. Graft-specific CMV surveillance and prophylaxis strategies were performed according to NCH hospital guidelines. During the study period, quantitative plasma CMV PCR assays included copies/mL (2010–2013) and WHO international standard IU/mL (2013–2020). Results During the 10-year study period, 347 patients underwent allo-HCT (N=214) or SOT (N=133; heart N=46, liver N=36, kidney N= 52; 1 patient had concomitant kidney and liver transplantation); median age was 8.6 years [range 0.1–25.9] and 198 (56.5%) were male. In total, 98 patients had CMV DNAemia post-transplant, and CMVR was diagnosed in 3 (HCT=2, SOT=1), for an overall CMVR incidence of 0.86% among all transplant recipients and occurring in 3% of patients with CMV DNAemia. No CMVR was diagnosed in patients without CMV DNAemia. An ophthalmologic examination was performed in 58 (59%) of patients with any DNAemia compared with 67 (27%) of patients without DNAemia. CMVR was diagnosed on funduscopic examination a median of 183 days [range 34–512] post-transplant based on visual symptomatology (N=2) or by routine eye screening prompted by DNAemia (N=1). CMV DNAemia at the time of CMVR was 1,463 copies/mL, 3,000, and 14,204 IU/mL; all patients had prolonged (&amp;gt;3 months) CMV detection before CMVR. One SOT recipient had concomitant pathology confirming CMV gastrointestinal tract disease. Two of the 3 CMVR cases occurred in the setting of genotypic UL94 CMV resistance mutations (A594V, H520Q)(Figure 1). Two patients were already receiving CMV antiviral therapy (maribavir N=1; valganciclovir=1) at the time of CMVR diagnosis. After the CMVR diagnosis, all patients were prescribed systemic foscarnet. Adjunctive therapies included concurrent intravitreal antiviral therapy (ganciclovir N=1; foscarnet N=1) and adoptive immunotherapy with CMV antiviral specific T-cells (N=1, HCT). Improvement of ocular symptoms occurred in 2 patients at 15 and 20 days after starting targeted CMV antiviral therapy; one patient developed permanently impaired vision. Conclusion CMVR remains as an important complication in transplant recipients. Although CMVR incidence was low in our cohort of transplant recipients, it occurred most frequently in cases of CMV resistance, prolonged DNAemia, and led to permanent visual impairment in 1 of 3 patients. The development of resistant CMV may have a role in the occurrence, progression, and severity of CMVR. Additional pediatric-specific data are needed to better characterize CMVR and inform optimal prevention strategies.

Malyglycemia Is Associated with Increased Infection in Pediatric Hematopoietic Stem Cell Transplant Recipients

▪Background: Malglycemia, defined as hypoglycemia, hyperglycemia, or glycemic variability is common in adult hematopoietic stem cell transplant (HSCT) recipients. It is associated with increased rates of infection, acute graft-versus-host disease (GVHD), organ dysfunction, time to engraftment, and mortality. Malglycemia in pediatric HSCT has not been well studied and may have unique incidence, risk factors and clinical implications. Therefore, this study aimed to identify the incidence of and risk factors for malglycemia inpediatric, adolescent and young adult (AYA) HSCT patients, and to characterize associated impacts on outcomes.Methods: Medical records for 351 pediatric/AYA patients, age 0-26 years (average 8.0 years, interquartiles 3.0, 15.0; 59.3% male), who underwent first HSCT from 2007-2016 at Children's Hospital Colorado were retrospectively reviewed. Patients with pre-existing diabetes mellitus (n=5) and patients with inadequate blood glucose data (n=2) were excluded, resulting in a final cohort of 344 patients. The goal was to identify risk factors for malglycemia and to determine its association with clinically significant infection in the first 100 days after HSCT. Malglycemia was defined as presence of mean blood glucose ≥126 mg/dL and/or standard deviation ≥29 mg/dL for each patient, assessed for the following intervals: pre-HSCT (days -14 to 0), days 0-30, days 0-100, and overall (days -14 to +100).Results: Malglycemia occurred in 43.9% of patients, with 22.3% experiencing malglycemia in the two weeks prior to HSCT, 22.3% in the first 30 days post-HSCT, and 22.6% in the first 100 days post-HSCT. In univariate analysis, the rate of malglycemia was higher among patients who underwent allogeneic than autologous transplant (pre-HSCT 35.6% vs 8.4%, p<0.001; days 0-30 25.8% vs 16.1%, p=0.056; days 0-100 27.6% vs 13.6%, p=0.004). In multivariate analysis, age ≥12 years was a risk factor for pre-HSCT malglycemia (p<0.0001), and post-HSCT steroids and treatment with tacrolimus were risk factors for post-HSCT (day 0-100) malglycemia (p<0.0001, p=0.034). Additional factors that did not have an association with malglycemia in multivariate analysis included body mass index, underlying diagnosis category (malignant vs non-malignant), pre-HSCT treatment with insulin, asparaginase, steroids, or radiation, HSCT type (autologous vs allogeneic), preparative regimen, post-HSCT treatment with total parenteral nutrition or radiation. Malglycemia at any time was associated with increased infection (p=0.008-0.042). After adjusting for age, pre-HSCT radiation, HSCT type, GVHD diagnosis (grades II-IV and/or chronic) and post-HSCT steroids, for each 10 mg/dL increase in pre-HSCT glucose, there was a 29.3% increase in any post-HSCT infection (p=0.007) and specifically a 28.8% increase in serious bacterial infection (SBI) (p<0.0001) and a 29.7% increase in viremia/viruria (p=0.002); similar findings existed at other time intervals analyzed (Table 1). Additionally, after adjusting for HSCT type and presence of GVHD, for every 10 mg/dL increase in mean glucose over days 0-100, the average number of hospitalized days from 0-100 increased by 2.7 days (p<0.0001) and days in the intensive care unit (ICU) increased by 1 day (p<0.0001). Similarly, patients with malglycemia during days 0-100 averaged 12.9 more hospital days (p<0.0001) and 3.9 more ICU days (p<0.0001) in the first 100 days post-HSCT than patients without malglycemia, regardless of HSCT type or GVHD diagnosis.Conclusion : Malglycemia occurs frequently in the pediatric/AYA HSCT population and is more common in adolescent patients. When controlling for HSCT type, presence of GVHD and treatment with steroids, malglycemia is an independent risk factor leading to increased rates of serious bacterial infections and viremia/viruria. Mechanistically, the temporal relationship between pre-HSCT mean glucose increases and higher rates of infection support a causal link. The underlying pathophysiology by which malglycemia may influence outcomes such as infection is likely multifactorial, but data suggests that hyperglycemia drives immune system impairment and supports a pro-inflammatory state. Understanding the morbidities associated with malglycemia, and the underlying pathophysiology, should inform future studies evaluating the utility of intensive glucose control in improving pediatric/AYA HSCT outcomes. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Hospitalizations for vaccine-preventable infections among pediatric hematopoietic cell transplantation recipients in the first 5 years after transplantation.

Despite recommendations for vaccination after hematopoietic cell transplantation (HCT), immunization rates remain low leaving children at high risk for vaccine preventable infections (VPIs). However, the burden from VPIs in pediatric HCT recipients is not well known. We describe the prevalence, risk factors, and outcomes of VPI-associated hospitalizations at centers participating in the Pediatric Health Information System database. Children <18 years who underwent allogeneic or autologous-HCT between 1/1/2010-31/12/2018, were identified and prevalence of overall VPI and of each infection were determined at five time-points within 5 years post-HCT. In total, 684 of 9591 pediatric HCT recipients had a VPI-associated hospitalization, most frequently in the first 6-12 months, for an overall prevalence of 7.1% (95% CI: 6.6-7.7%). Influenza, varicella, and invasive pneumococcal infections were the most frequent. Multivariable analyses identified younger age (OR = 0.96 [95% CI: 0.93-0.99]; p = 0.013), primary immune deficiency (PID) (OR = 1.78 [95% CI: 1.11-2.84]; p = 0.016), and GVHD (OR = 1.62 [95% CI: 1.05-2.48]; p = 0.028) as independent risk factors during the initial HCT-hospitalization. Children with VPI had longer duration of hospitalization (55[51] vs 36[24] days, p < 0.001), higher rates of ICU admission (42 vs 26%, p < 0.001), and mortality (11% [n = 17) vs 6% [n = 519]; p = 0.003). Continued efforts to improve vaccination early post-HCT are warranted.

Adrenocortical Function in Children With Brain Tumors and Pediatric Hematopoietic Cell Transplantation Recipients.

Adrenocortical insufficiency (AI) is a clinical condition defined by deficient production of glucocorticoids that can result in life-threatening complications. We examined the prevalence of AI in children with brain tumors and those undergoing hematopoietic cell transplantation. Adrenocorticotropic hormone stimulation (stim) testing was used for the assessment of adrenocortical function. On the basis of 155 stim tests in 117 patients, AI was diagnosed in 27.4% of patients with brain tumors and in 21% of hematopoietic cell transplantation recipients. A number of risk factors associated with AI were identified. Adrenocorticotropic hormone stim testing led to a definitive diagnosis of AI or recovery of adrenal function and unambiguous medical management.

Association of persistent tachycardia with early myocardial dysfunction in children undergoing allogeneic hematopoietic cell transplantation.

Cancer survivors who have undergone hematopoietic cell transplantation (HCT) are at risk for myocardial dysfunction. Children who receive allogenic HCT encounter systemic inflammation resulting in tachycardia and hypertension. The effect of these abnormalities on myocardial function is not known. The aim of this study was to determine whether cardiac dysfunction early after HCT can be predicted by tachycardia or hypertension, within a retrospective single-center sample of pediatric HCT recipients. Early tachycardia or hypertension was defined as a majority of values taken from infusion date to 90 days post-infusion being abnormal. Ejection fraction <53% determined systolic dysfunction. A composite score of accepted pediatric diastolic abnormalities determined diastolic dysfunction. Among 80 subjects (median age 8 years), early tachycardia, systolic dysfunction, and diastolic dysfunction were present in 64%, 25%, and 48% of the sample, respectively. In multivariable models, early tachycardia was an independent predictor of early systolic dysfunction (OR = 12.6 [1.4-112.8], p = 0.024) and diastolic dysfunction (OR = 3.9 [1.3-11.5], p = 0.013). Tachycardia and cardiac dysfunction are common and associated with one another in the early period after pediatric HCT. Future studies may elucidate the role of tachycardia and myocardial dysfunction early after HCT as important predictors of future cardiovascular dysfunction.

Cytomegalovirus Infection and the Implications of Drug-Resistant Mutations in Pediatric Allogeneic Hematopoietic Stem Cell Transplant Recipients: A Retrospective Study from a Tertiary Hospital in China

IntroductionDrug-resistant cytomegalovirus (CMV) infection remains a challenge in the management of pediatric recipients of hematopoietic stem cell transplantation (HSCT). In this study, we retrospectively reviewed the clinical data on pediatric recipients of HSCT and identified known and unknown drug-resistant CMV variants.MethodsA total of 221 children underwent allogeneic HSCT between October 2017 and November 2019 at Shenzhen Children’s Hospital; of these, 35 patients were suspected of having drug-resistant CMV infections and were tested for drug-resistant mutations in the UL97 and UL54 genes by Sanger sequencing.ResultsMutations in UL97 or UL54, or in both, were detected in 11 patients. Most of these mutations have not been previously reported. The UL97 mutation (A582V) was detected in only one patient who also harbored two UL54 mutations (T760X and R876W). One patient with both the G604S and T691A mutations in the UL54 gene died of CMV pneumonia. We investigated the risk factors associated with the development of drug-resistant CMV infection. Patients in whom both the donor and recipient had positive CMV serostatuses were less likely to have drug-resistant mutations (Fisher’s exact test, p < 0.05).ConclusionNewly and previously detected CMV mutations in UL97 and UL54 may be associated with the development of drug-resistant CMV infection. The detection of these mutations may provide guidance for the management of post-transplant CMV infections.Supplementary InformationThe online version contains supplementary material available at 10.1007/s40121-021-00452-4.

Deciphering an Adenovirus F41 Outbreak in Pediatric Hematopoietic Stem Cell Transplant Recipients by Whole-Genome Sequencing.

Human adenovirus (HAdV) represents a major cause of mortality and morbidity in pediatric recipients of allogeneic hematopoietic stem cell transplants (HSCT). HAdV species F type 41 (HAdV-F41) infections in HSCT patients are scarce, whereas HAdV-F41 circulates commonly in healthy individuals. Between March and July 2018, HAdV-F41 infections were identified in four children (A, B, C, and E) who received allogeneic HSCT and one child before HSCT (D) at Robert Debré Hospital, Paris, France. We report here the clinical course of HAdV-F41 infection and the phylogenetic investigation to identify interpatient transmission. HAdV DNA was quantified in stool and plasma samples by real-time PCR. HAdV type was determined by sequencing of the fiber and hexon genes. Phylogenetic investigation was done with whole-genome sequences obtained by next-generation sequencing. HAdV loads in stool samples ranged from 6.60 to 10.10 log10 copies/ml. HAdV-F41 detection in plasma was observed in four patients, but no disseminated disease was reported. Two patients died, but neither death was attributed to HAdV. While sequencing limited to the fiber gene suggested a cluster with four patients, phylogenetic analysis with whole-genome sequencing (WGS) and HVR7 revealed a cluster that included three patients (C, D, and E), suggesting an interpatient transmission in that cluster and two other independent infections. HAdV-F41 levels in stool specimens of pediatric HSCT patients are high and represent a risk of interpatient transmission. WGS helped to identify related cases. Prompt detection of HAdV in stool and control measures are warranted to limit any risk of nosocomial transmission.

Hippocampal Atrophy in Pediatric Transplant Recipients with Human Herpesvirus 6B.

The aim of this study was to determine whether human herpesvirus 6B (HHV-6B) infection can impair the hippocampus in pediatric hematopoietic stem cell transplant (HSCT) recipients. Study subjects were pediatric HSCT recipients monitored for HHV-6B infection who underwent brain MRI before and after transplantation. Volumetric analysis of the hippocampus was performed. Of the 107 patients that received HSCT at Nagoya University Hospital Between July 2008 and April 2014, 20 were eligible for volumetric analysis. Eight patients had HHV-6B infection, of whom two had encephalopathy at the time of HHV-6B infection. None of the 12 patients without HHV-6B infection had encephalopathy. The median ratio of the right hippocampal volume from before to after transplantation was 0.93 in patients with HHV-6B infection and 1.02 in without HHV-6B infection (p = 0.007). The median ratio of the left hippocampal volume ratio in patients with and without HHV-6B infection was 0.92 and 1.00, respectively (p = 0.003). Among the eight patients with HHV-6B infection, four had a marked reduction in hippocampal volume (volume ratio < 0.90). Only one of these patients had neurological symptoms at the time of HHV-6B infection. The reduction in the hippocampal volume ratio was higher in pediatric HSCT recipients with HHV-6B infection than those without viral infection. Neurological follow-up may be required for pediatric HSCT recipients with HHV-6B infection.

A Pilot Study of RNA Sequencing to Improve the Diagnostic Yield of Bronchoalveolar Lavage Specimens in Pediatric Allogeneic Hematopoietic Stem Cell Transplant Recipients

Background: Pulmonary complications often cause morbidity and mortality in pediatric allogeneic hematopoietic stem cell transplant (HSCT) recipients. While detection of infection and initiation of appropriate antimicrobial therapy improves survival, present techniques oftentimes do not detect infections in bronchoalveolar lavage (BAL) samples because of pretreatment with antimicrobial therapies and the need for a priori knowledge of likely viral pathogens, decreasing the yield of BAL. Objective: We evaluated whether RNA-based massively parallel sequencing (MPS) would improve detection of infections in BAL fluid in pediatric allogeneic HSCT recipients. Results: Nine patients underwent 10 BAL (1 patient underwent 2 BAL) and had sufficient BAL fluid for inclusion in this study. Clinical microbiological testing identified infections in 7 patients, and MPS identified infections in 5 patients, although some of these detected organisms were not detected by clinical testing. Results were fully concordant in 5 patients, fully discordant in 3 patients, and partially discordant in 2 patients. Bacterial, viral, and fungal infections were detected via both techniques. Conclusion: This suggests that MPS in conjunction with routine clinical testing increases the yield of detection of infectious organisms in the BAL fluid.

Low CD4 count may be a risk factor for non-tuberculous mycobacteria infection in pediatric hematopoietic cell transplant recipients.

HCT leaves patients in a relative state of immune deficiency both during their initial transplant admission and for several years following discharge. NTM are generally harmless colonizers of the outside environment, but for immunocompromised patients, they can cause significant disease due to a paucity of T-cell defense. While routine prophylaxis against NTM is recommended for patients with low CD4 counts in certain clinical settings (eg, AIDS), this is not yet established for HCT patients despite their higher risk. Here we build upon our prior work to determine risk factors for NTM in pediatric HCT patients by comparing NTM patient characteristics to matched HCT controls. We followed 272 patients across a 13-year time period, with 11 cases of NTM. Patients with NTM had a significantly lower CD4 count at Day 365 than matched HCT controls (105.5±97.0 cells/µl vs. 856.2±446.1 cells/µl, respectively; p=.001). No other potential risk factors (eg, CMV, GvHD, disease type) were found to be statistically significant, including use of T-cell depleting agents. This is consistent with an average diagnosis of NTM at Day +323 (ie, outside immediate post-transplant period). All-cause mortality was similar between NTM and control HCT groups, with an NTM attributable mortality of <10%. Since reduced CD4 counts are associated with NTM, and cost and morbidity are high, azithromycin prophylaxis for CD4 count <200 cells/µl in high-risk patients should be considered.

Steroid-dependent acute GVHD after allogeneic hematopoietic cell transplantation: risk factors and clinical outcomes

AbstractAcute graft-versus-host disease (aGVHD) has various risk factors and outcomes. We defined distinct aGVHD treatment response groups based on response to first-line corticosteroids: steroid sensitive (SS), steroid resistant (SR), and the rarely studied steroid dependent (SD) aGVHD. In 1143 consecutive adult and pediatric allogeneic hematopoietic cell transplant recipients, 385 (34%) developed aGVHD, with 10% having SS aGVHD, 9% SD aGVHD, and 14% SR aGVHD. The only factor significantly associated with SD in comparison with SS was older age (odds ratio [OR], 3.9; 95% confidence interval [CI], 1.4-11.3, when comparing 18- to 60-year-olds with <18-year-olds). Factors significantly associated with SR in comparison with SS were unrelated donor (OR, 3.0; 95% CI, 1.2-7.4) and Minnesota high-risk aGVHD (OR, 2.4; 95% CI, 1.3-4.6). SR aGVHD was independently associated with higher risk for 2-year overall mortality (hazards ratio [HR], 1.8; 95% CI, 1.2-2.8) and nonrelapse mortality (NRM; HR, 2.1; 95% CI, 1.2-3.9). SS and SD GVHD groups had similar overall survival and NRM. The cumulative incidence of chronic GVHD was highest in the SD group, followed by the SR and SS groups (46%, 41%, and 29%, respectively). SD and SS GVHD had similar prognoses, both markedly better than those of the SR groups.

Continuous Renal Replacement Therapy: A Review of Use and Application in Pediatric Hematopoietic Stem Cell Transplant Recipients.

Hematopoietic stem cell transplant (HSCT) is a curative therapy for malignant and non-malignant conditions. However, complications post-HSCT contribute to significant morbidity and mortality in this population. Acute kidney injury (AKI) is common in the post-allogeneic transplant phase and contributes to morbidity in this population. Continuous renal replacement therapy (CRRT) is used often in the setting of AKI or multiorgan dysfunction in critically ill children. In addition, CRRT can be useful in many disease processes related to transplant and can potentially improve outcomes in this population. This review will focus on the use of CRRT in critically ill children in the post-HSCT setting outside the realm of acute renal failure and highlight the benefits and applications of this modality in this high-risk population.

Risk factors for chronic kidney disease following acute kidney injury in pediatric allogeneic hematopoietic cell transplantation.

Risk factors associated with the progression of acute kidney injury to chronic kidney disease in pediatric allogeneic hematopoietic cell transplantation (AlloHCT) recipients are not well described. We retrospectively investigated the risk factors for the progression to CKD in 275 AlloHCT recipients. AKI and CKD grading was defined according to the Kidney Disease Improving Global Outcomes classification. PRI90 was defined as persistent renal insufficiency (estimated GFR < 90 ml/min/1.73 m2) 90 days after the first episode of AKI. The median age was 9.1 years. Incidence of stages 1, 2, and 3 AKI were 43%, 41%, and 15%, respectively. 86.1% met our study criteria for PRI90. Of the 236 PRI90 patients, 213 and 152 patients were evaluable for CKD at 1 and 3 years, respectively. The incidence of CKD at 1 and 3 years was 63.1% and 62.9%, respectively. On multivariable analysis, estimated GFR at initial episode of AKI (<80 ml/min/1.73 m2) and estimated GFR (<70 ml/min/1.73 m2) at PRI90 was a risk factor associated with CKD development and both risk factors were associated with significantly lower overall survival. To conclude, eGFR at the time of AKI and PRI90 may be considered for screening pediatric AlloHCT recipients at risk for the progression to CKD.

CYP51A1 polymorphism and voriconazole-associated hepatotoxicity in children undergoing hematopoietic cell transplant.

Fungal CYP51A (14α-sterol demethylase) is the target of an azole antifungal, voriconazole (VCZ), which also partially inhibits human CYP51A1. Hepatotoxicity is a common adverse effect of azoles, which is reported to be caused by altered gene expressions secondary to cholesterol synthesis inhibition by azoles. This is a post-hoc analysis of a previously conducted phase 1 dose-finding study of prophylactic VCZ in 56 pediatric hematopoietic cell transplant recipients. We explored an association between variants in human CYP51A1 (rs2282976 and rs6465348) and VCZ-induced hepatotoxicity. Genotype A/G or G/G in rs6465348 showed lower odds of hepatotoxicity after adjusting for VCZ area-under-the-curve (OR: 0.10, 95% CI: 0.01 – 0.79, vs. A/A).

436 - Risk Factors for CMV Viremia Among Pediatric Hematopoietic Stem Cell Transplantation Recipients at a Single Institution

436 - Risk Factors for CMV Viremia Among Pediatric Hematopoietic Stem Cell Transplantation Recipients at a Single Institution

431 - Extracellular Vesicle Proteome Reflects BK Viral Infection and Cystitis Status in Pediatric Hematopoietic Stem Cell Transplant (HSCT) Recipients

431 - Extracellular Vesicle Proteome Reflects BK Viral Infection and Cystitis Status in Pediatric Hematopoietic Stem Cell Transplant (HSCT) Recipients

An Immune Recovery-Based Revaccination Protocol for Pediatric Hematopoietic Stem Cell Transplant Recipients: Revaccination Outcomes Following Pediatric HSCT

Following hematopoietic stem cell transplant (HSCT), patients are at increased risk of vaccine-preventable diseases (VPDs) and experience worse outcomes of VPDs compared to immunocompetent patients. Therefore, patients are routinely vaccinated post-HSCT to restore VPD immunity. Published guidelines recommend revaccination based on time post-HSCT, although optimal revaccination timing and the value of using other clinical and laboratory variables to guide revaccination remain unclear. An institutional immune recovery-based protocol to guide timing of revaccination is used at Children's Hospital Colorado. This protocol incorporates time from transplant, time off immunosuppressive therapy and intravenous immunoglobulin replacement, absence of active graft-versus-host disease (GVHD), and minimum absolute CD4 count, absolute lymphocyte count (ALC), and immunoglobulin G (IgG) levels. The objective of this study is to evaluate the performance of this immune recovery-based revaccination protocol by determining rates of seroprotective vaccine responses achieved and describing demographic, clinical, and laboratory markers associated with protective antibody titers post-revaccination. Rates of seroprotection following revaccination were retrospectively determined for patients who received autologous or allogeneic HSCTs at Children's Hospital Colorado from 2007 to 2017. Percent seropositivity after revaccination was determined for ten VPDs: measles, mumps, rubella, varicella, tetanus, diphtheria, Haemophilus influenzae type B (Hib), poliovirus, hepatitis B virus (HBV), and Streptococcus pneumoniae. The impact of covariates, including post-HSCT vaccine timing, patient demographics, clinical features (diagnosis, donor and conditioning regimen data, GVHD, cytomegalovirus disease), and laboratory parameters (CD4 count, ALC, IgG level), on rates of seroprotection post-revaccination was determined using Wilcoxon rank sum, Fisher's exact, or chi-square tests, as appropriate. One hundred-twelve unique patients among 427 HSCT recipients had available data for both revaccination timing and vaccine titers. Among these, high rates of seroprotection were achieved after revaccination for rubella (100%), diphtheria (100%), tetanus (100%), and Hib (98%). More modest rates of seroprotection were achieved after revaccination with HBV (87%) and pneumococcal conjugate (85%) vaccines. Seroprotection was lower after revaccination with measles (76%), pneumococcal polysaccharide (72%), mumps (67%), and varicella (25%) vaccines. Greater rates of seroprotection were associated with younger age (hepatitis B vaccine, P = .04), lack of prior rituximab treatment (pneumococcal conjugate vaccine, P = .005), lack of total body irradiation (pneumococcal conjugate vaccine, P = .03), and receipt of a non-cord blood transplant (pneumococcal polysaccharide vaccine, P = .04). These results suggest that a revaccination protocol that incorporates both time post-HSCT and patient-specific indicators of immunologic recovery can achieve high rates of seroprotection against most VPDs. Seroprotection rates for HBV and PCV were notably among the highest reported in children post-HSCT, suggesting that an immune recovery-based protocol may improve seroprotection for some VPDs that frequently are associated with lower vaccine responses post-HSCT. Seroprotection rates for other VPDs remained suboptimal after revaccination. Therefore, evaluation of additional strategies, such as the use of novel markers of immune competence and new vaccines, to further optimize protection against VPDs in this population is warranted.