Summary
Chimeric antigen receptor T‐cell (CAR T‐cell) therapy is associated with significant toxicities secondary to immune activation, including a rare but increasingly recognised severe toxicity ...resembling haemophagocytic lymphohistiocytosis (carHLH). We report the development of carHLH in 14·8% of paediatric patients and young adults treated with CD19‐specific CAR T‐cell therapy with carHLH, occurring most commonly in those with high disease burden. The diagnosis and treatment of carHLH required a high index of suspicion and included multidrug immunomodulation with variable response to therapies. Compared to patients without carHLH, patients with carHLH had both reduced response to CAR T‐cell therapy (P‐value = 0·018) and overall survival (P‐value = < 0·0001).
Antigen-independent homeostasis of memory CD8 T cells is vital for sustaining long-lived T cell-mediated immunity. In this study, we report that maintenance of human memory CD8 T cell effector ...potential during in vitro and in vivo homeostatic proliferation is coupled to preservation of acquired DNA methylation programs. Whole-genome bisulfite sequencing of primary human naive, short-lived effector memory (T
), and longer-lived central memory (T
) and stem cell memory (T
) CD8 T cells identified effector molecules with demethylated promoters and poised for expression. Effector-loci demethylation was heritably preserved during IL-7- and IL-15-mediated in vitro cell proliferation. Conversely, cytokine-driven proliferation of T
and T
memory cells resulted in phenotypic conversion into T
cells and was coupled to increased methylation of the CCR7 and Tcf7 loci. Furthermore, haploidentical donor memory CD8 T cells undergoing in vivo proliferation in lymphodepleted recipients also maintained their effector-associated demethylated status but acquired T
-associated programs. These data demonstrate that effector-associated epigenetic programs are preserved during cytokine-driven subset interconversion of human memory CD8 T cells.
Summary
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.
A pediatric patient with acute myeloid leukemia was referred to our institution for investigational therapy after disease relapse following a mismatched unrelated donor hematopoietic cell transplant ...(HCT). Prior to second HCT, the patient’s serum was negative for antibodies to class I and class II HLA. Eight days after receiving a maternal donor haploidentical transplant, the patient became platelet refractory and highly sensitized to multiple class I HLA. Serum from the patient’s mother was positive for the strongest antibodies present in the patient, suggesting the antibodies were donor-derived. Patient sera showed magnified and expanded sensitization over time in the context of 100% donor chimerism and despite undetectable circulating B cells. Escalating sensitization suggests active transfer of rituximab-resistant antibody-producing passenger lymphocytes from a haploidentical donor to a transplant recipient at the time of progenitor cell infusion. Evaluation of donor sensitization status may be a consideration prior to HLA mismatched HCT.
Background
CD19-specific chimeric antigen receptor (CAR) T-cell therapy has shown promising disease responses in patients with high-risk B-cell malignancies. However, its use may be related to ...complications such as immune-mediated complications, infections, and end-organ dysfunction. The incidence of post-CAR T-cell therapy acute kidney injury (AKI) in the children, adolescent, and young adult (CAYA) patient population is largely unreported.
Methods
The objectives of this study were to determine the incidence of AKI in CAYA patients with high-risk B-cell malignancies treated with CD19-CAR T-cell therapy, evaluate potential risk factors for developing AKI, and determine patterns of kidney function recovery. We conducted a retrospective analysis of 34 CAYA patients treated with CD19-CAR T-cell at a single institution.
Results
There was a cumulative incidence of any grade AKI by day 30 post-infusion of 20% (
n
= 7), with four cases being severe AKI (stages 2–3) and one patient requiring kidney replacement therapy. All episodes of AKI developed within the first 14 days after receiving CAR T-cell therapy and 50% of patients with AKI recovered kidney function to baseline within 30 days post-infusion. No evaluated pre-treatment risk factors were associated with the development of subsequent AKI; there was an association between AKI and cytokine release syndrome and neurotoxicity. We conclude that the risk of developing AKI following CD19-CAR T-cell therapy is highest early post-infusion, with most cases of AKI being severe.
Conclusions
Frequent monitoring to facilitate early recognition and subsequent management of kidney complications after CD19-CAR T-cell therapy may reduce the severity of AKI in the CAYA patient population.
Graphical abstract
A higher resolution version of the Graphical abstract is available as
Supplementary information
Abstract
Background
Despite preventive measures, infections continue to pose significant risks to pediatric allogeneic hematopoietic cell transplantation (allo-HCT) recipients. The gut microbiota has ...been linked to clinical outcomes following adult allo-HCT. This study evaluated whether similar disruptions or differing microbiota patterns were associated with infection risk in pediatric allo-HCT.
Methods
In a prospective observational study, fecal samples were obtained from 74 children before conditioning and upon neutrophil recovery. Microbiome signatures identified through sequencing were examined for their associations with infections or acute graft-versus-host disease (aGVHD) in the first-year post-HCT using Cox proportional hazards analysis.
Results
Microbiome disruption in adults, did not predict infection risk in pediatric allo-HCT. Unique microbiota signatures were associated with different infections or aGVHD. A ratio of strict and facultative anaerobes (eg, Lachnoclostridium, Parabacteroides) prior to conditioning predicted bacteremia risk (Cox hazard ratio HR, 3.89). A distinct ratio of oral (eg, Rothia, Veillonella) to intestinal anaerobes (eg, Anaerobutyricum, Romboutsia) at neutrophil recovery predicted likelihood of bacterial infections (Cox HR, 1.81) and viral enterocolitis (Cox HR, 1.96).
Conclusions
Interactions between medical interventions, pediatric hosts, and microbial communities contribute to microbiota signatures that predict infections. Further multicenter study is necessary to validate the generalizability of these ratios as biomarkers.
Gut microbial communities can predict which children after hematopoietic cell transplantation will have infections or acute graft-versus-host disease. These ratios of gut community members can be used to focus prevention and treatment on children at highest risks for complications.
In patients with acute leukemia, detection of minimal residual disease (MRD) before allogeneic hematopoietic cell transplantation (HCT) correlates with risk of relapse. However, the level of MRD that ...is most likely to preclude cure by HCT is unclear, and the benefit of further chemotherapy to reduce MRD before HCT is unknown. In 122 children with very-high-risk acute lymphoblastic leukemia (ALL; n = 64) or acute myeloid leukemia (AML, n = 58), higher MRD levels at the time of HCT predicted a poorer survival after HCT (P = .0019); MRD was an independent prognostic factor in a multivariate analysis (P = .0035). However, the increase in risk of death associated with a similar increment of MRD was greater in ALL than in AML, suggesting that a pretransplantation reduction of leukemia burden would have a higher impact in ALL. At any given MRD level, survival rates were higher for patients treated in recent protocols: the 5-year overall survival for patients with ALL was 49% if MRD was detectable and 88% if it was not and the corresponding rates for patients with AML were 67% and 80%, respectively. Although MRD before HCT is a strong prognostic factor, its impact has diminished and should not be regarded as a contraindication for HCT.
Purpose
Alemtuzumab is a humanized monoclonal antibody against CD52 which is predominantly present on T and B lymphocytes. Alemtuzumab has been used as part of conditioning regimens for prophylaxis ...against rejection and GVHD. While the mechanism of action is well understood, the pharmacokinetics of this drug in children needed to be studied in more detail especially in the setting of ex vivo T-cell-depleted hematopoietic cell transplantation (HCT).
Methods
Serum alemtuzumab levels were measured at various time points in 13 patients who underwent haploidentical HCT utilizing ex vivo donor T-cell depletion. Alemtuzumab was administered subcutaneously at a cumulative dose of 45 mg/m
2
from days − 13 to − 11. A one-compartmental model was used to fit the data using non-linear mixed effects modeling.
Results
We determined the median half-life to be 11 days. Alemtuzumab clearance increased with increasing baseline lymphocyte count (
p
= 0.008). Additionally, clearance increased with weight and age (
p
≤ 0.035). AUC of alemtuzumab did not have any significant relationship with type of leukemia, overall survival, engraftment, immune reconstitution, mixed chimerism or GVHD, although the number of subjects in this pilot study was limited.
Conclusion
Absolute lymphocyte count and body weight affect alemtuzumab clearance. We also demonstrate feasibility of body-surface area-based dosing of alemtuzumab in pediatric HCT patients. Further studies are needed to evaluate the role of monitoring alemtuzumab serum concentrations to balance the prevention of graft rejection and GVHD with the promotion of rapid donor immune reconstitution.
PDF
