Mahadeo, Kris M.

Abstract Background Pediatric patients undergoing hematopoietic cell transplantation (HCT) may develop life-threatening complications and need for ICU admission (ICU). They may display more severe and/or unique manifestations of organ dysfunction syndromes, including acute respiratory failure, sepsis and delirium, compared to the general pediatric In this interim analysis of the POEM study, the utility of a p-MODS screening tool as a predictor of endotheliopathies and/or ICU is reported. Methods: NCT05090345 is a prospective multi-center registry/biorepository trial of children and adolescents/young adults (AYA) undergoing HCT to assess the impact of endotheliopathies on morbidity and mortality. Patients undergoing all HCT types are prospectively monitored for 100 days post-HCT for sinusoidal obstructive syndrome (SOS), thrombotic microangiopathy (TMA), capillary leak syndrome (CLS), diffuse alveolar hemorrhage (DAH) and ICU. The risk of p-MODS was assessed within 7 days of HCT admission and weekly for 4 weeks, to dynamically evaluate organ function across 8 systems: respiratory, cardiovascular, renal, hepatic, hematologic, neurologic, immune, and gastrointestinal. Each system was graded on a 0–5 scale based on clinical and laboratory parameters, with total pMODS calculated using the worst score per organ. Descriptive statistics were used to compare p-MODS score between groups with “events” (defined as endotheliopathy or ICU) versus “no events”. The “no event” comparison group was matched 1:1 by diagnosis, age, gender and HCT type. Results: Among all subjects (n=151), the median age was 11.3 (range: 0.2–26.9) years and the majority (64%) male and Caucasian ( 60%) and 20% Black. Most patients (86.8%) underwent allogeneic HCT. Common indications were hematologic malignancy (45%), solid tumors (19%) and hemoglobinopathies (8.6%).Events (n=50) were observed in 35 of 151 patients, including ICU (n=26), SOS (n=19), TMA (n=3) CLS (n=1) and DAH (n=1). Events occurred at a median of 16 (range: –7 to 85) days post-HCT. Median time to ICU was 15 (range: –7 to 82) days post-HCT. The median pMODS score at the time of ICU was 10 (range: 1–22). All three patients with TMA had preceding ICU admissions and 4 of 19 patients with SOS required ICU management. The median time to onset of endotheliopathy was 17 (range: 6–33) days post-HCT. The median pMODS score at the time of event was 11 (range: 7–18), compared to a median of 8 (range: 5–21) the week prior to onset. Patients who developed events exhibited progressively higher scores compared to matched controls starting at week 1 (p < 0.05). This difference became more pronounced over time, reaching statistical significance at week 2 (p < 0.001). Since physiologic decline may precede overt events, we next analyzed pMODS score change between Day 0 and week 1. A significant difference was observed with median increase of 2 (range: –2 to 16) in the event group versus 1 (range: –3 to 7) in the control group (p = 0.01). Analysis of individual organ system scores revealed notable differences between the event and control groups by Week 1, prior to median event onset. The event group had higher rates of indicators of organ dysfunction in 6 of 8 organ system. The event group had more subjects with acute kidney injury, elevated delirium scores, need for respiratory support, increased bilirubin, moderate to significant weight gain and infections. However, rates of neutropenia and lymphopenia were comparable between groups. Conclusion In this interim analysis, a significant increase in pMODS between Day 0 and week 1 post-HCT may reflect early physiologic decline, with notable changes in respiratory status, acute kidney injury, elevated CAPD scores, and infectious burden. These findings highlight the potential utility of pMODS as an early screening tool to identify pediatric HCT recipients at risk for clinical deterioration. Prospective and dynamic monitoring of pMODS may support timely intervention and improve outcomes in this vulnerable population.

OBJECTIVES: The last decade has seen improved outcomes for children requiring extracorporeal life support as well as for children undergoing hematopoietic cell transplantation. Thus, given the historically poor survival of hematopoietic cell transplantation patients using extracorporeal life support, the Pediatric Acute Lung Injury and Sepsis Investigators’ hematopoietic cell transplantation and cancer immunotherapy subgroup aimed to characterize the utility of extracorporeal life support in facilitating recovery from critical cardiorespiratory illnesses in pediatric hematopoietic cell transplantation patients. DATA SOURCES: All available published data were identified using a set of PubMed search terms for pediatric extracorporeal life support and hematopoietic cell transplantation. STUDY SELECTION: All articles that provided original reports of pediatric hematopoietic cell transplantation patients who underwent extracorporeal life support were included. Sixty-four manuscripts met search criteria. Twenty-four were included as primary reports of pediatric hematopoietic cell transplantation patients who underwent extracorporeal life support (11 were single case reports, four single institution case series, two multi-institution case series, and seven registry reports from Extracorporeal Life Support Organization, Pediatric Heath Information System, and Virtual Pediatric Systems). DATA EXTRACTION: All 24 articles were reviewed by first and last authors and a spread sheet was constructed including sample size, potential biases, and conclusions. DATA SYNTHESIS: Discussions regarding incorporation of available evidence into our clinical practice were held at biannual meetings, as well as through email and virtual meetings. An expert consensus was determined through these discussions and confirmed through a modified Delphi process. CONCLUSIONS: Extracorporeal life support in hematopoietic cell transplantation patients is being used with increasing frequency and potentially improving survival. The Pediatric Acute Lung Injury and Sepsis Investigators hematopoietic cell transplantation-cancer immunotherapy subgroup has developed a framework to guide physicians in decision-making surrounding extracorporeal life support candidacy in pediatric hematopoietic cell transplantation patients. In addition to standard extracorporeal life support considerations, candidacy in the hematopoietic cell transplantation population should consider the following six factors in order of consensus agreement: 1) patient comorbidities; 2) underlying disease necessitating hematopoietic cell transplantation; 3) hematopoietic cell transplantation toxicities, 4) family and patient desires for goals of care; 5) hematopoietic cell transplantation preparatory regimen; and 6) graft characteristics. Although risk assessment may be individualized, data are currently insufficient to clearly delineate ideal candidacy. Therefore, we urge the onco-critical care community to collaborate and capture data to provide better evidence to guide physicians’ decision-making in the future.

Acute lymphoblastic leukemia (ALL) is the most common pediatric malignancy. Advancements in technology that enhance our understanding of the biology of the disease, risk-adapted therapy, and enhanced supportive care have contributed to improved survival rates. However, additional clinical management is needed to improve outcomes for patients classified as high risk at presentation (eg, T-ALL, infant ALL) and who experience relapse. The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for pediatric ALL provide recommendations on the workup, diagnostic evaluation, and treatment of the disease, including guidance on supportive care, hematopoietic stem cell transplantation, and pharmacogenomics. This portion of the NCCN Guidelines focuses on the frontline and relapsed/refractory management of pediatric ALL.

The proton-coupled folate transporter (PCFT-SLC46A1) is required for intestinal folate absorption and is mutated in the autosomal recessive disorder, hereditary folate malabsorption (HFM). This report characterizes properties and requirements of the R376 residue in PCFT function, including a R376Q mutant associated with HFM. Gln, Cys, and Ala substitutions resulted in markedly impaired transport of 5-formyltetrahydrofolate (5-FTHF) and 5-methyltetrahydrofolate (5-MTHF) due to an increase in Km and decrease in Vmax in HeLa R1–11 transfectants lacking endogenous folate transport function. In contrast, although the influx Km for pemetrexed was increased, transport was fully preserved at saturating concentrations and enhanced for the like-charged R376K- and R376H-PCFT. Pemetrexed and 5-FTHF influx mediated by R376Q-PCFT was markedly decreased at pH 5.5 compared with wild-type PCFT. However, while pemetrexed transport was substantially preserved at low pH (4.5–5.0), 5-FTHF transport remained very low. Electrophysiological studies in Xenopus oocytes demonstrated that 1) the R376Q mutant, like wild-type PCFT, transports protons in the absence of folate substrate, and in this respect has channel-like properties; and 2) the influx Km mediated by R376Q-PCFT is increased for 5-MTHF, 5-FTHF, and pemetrexed. The data suggest that mutation of the R376 residue to Gln impairs proton binding which, in turn, modulates the folate-binding pocket and depresses the rate of conformational alteration of the carrier, a change that appears to be, in part, substrate dependent.