Infections in children following chimeric antigen receptor T-cell therapy for B-cell acute lymphoblastic leukemia.

BACKGROUND: CD19-directed chimeric antigen receptor T-cell (CAR-T) therapy is transforming care for pediatric patients with relapsed or refractory B-cell acute lymphoblastic leukemia (B-ALL). There are limited pediatric-specific data concerning the infection risks associated with CD19 CAR-T therapy and the adequacy of current antimicrobial prophylaxis guidelines for these patients. METHODS: We describe the antimicrobial prophylaxis used and the types of infectious occurring in the first 100 days following CAR-T therapy for relapsed or refractory B-cell ALL in children and adolescents (≤18 years) at our centre. RESULTS: Twenty-seven patients received their first CAR-T infusion (CTI) during the study period. Almost all patients (96%) had a comprehensive Infectious Diseases review prior to CTI, which informed a personalised prophylaxis or fever/sepsis plan in six (22%). Overall, six (22%) patients had one or more infections during the study period including five (19%, 0.9 per 100 days-at-risk) from days 0-30 and three (n = 20, 15%, 0.6 per 100 days-at-risk) from days 31-100. Bacterial blood stream infections were the most common type of infection encountered during both time periods, and one patient had probable pulmonary aspergillosis. There were no infection-related deaths. CONCLUSION: Our study contributes important information on the spectrum of infections encountered in pediatric patients with B-ALL post CAR-T therapy. Overall, the burden of infectious complications post CAR-T therapy in our cohort is lower than previously reported in the literature. Results suggest that our prophylaxis recommendations are effective in this population.

Density of antibiotic use and infectious complications in pediatric allogeneic hematopoietic cell transplantation.

BACKGROUND: Antibiotics, while an essential component of supportive care in allogeneic hematopoietic cell transplantation (allo-HCT), can have adverse effects and select for antibiotic resistance. Understanding of patterns of use will inform antimicrobial stewardship (AMS) interventions. METHODS: Retrospective, single-center cohort of children undergoing first allo-HCT (n = 125). Antibiotic prescription and infection data were included from the date conditioning was commenced until 30 days post allo-HCT. Antibiotic use was reported as length of therapy (LOT) (number of days a patient received an antibiotic) and days of therapy DOT (aggregating all antibiotics prescribed per day). Infections were classified as microbiologically documented infection (MDI) or clinically documented infections. RESULTS: At least one course of antibiotics was administered to 124 (99%) patients. The LOT was 636 per 1000 patient days and DOT was 959 per 1000 patient days. The median duration of cumulative antibiotic exposure per patient was 24 days (interquartile range [IQR] 20-30 days). There were 131 days of fever per 1000 patient days with patients febrile for a median of 4 days (IQR 1-7 days). Piperacillin-tazobactam was used for 116 (94%) of patients with an LOT of 532 per 1000 patient days. A total of 119 MDI episodes occurred in 74 (59%) patients, including blood stream infection in 30 (24%) and a proven/probable invasive fungal infection in 4 (3%). CONCLUSION: Pediatric HCT patients receive prolonged courses of broad-spectrum antibiotics relative to the frequency of fever and bacterial infections. This study has identified opportunities for AMS intervention to improve outcomes for our HCT patients.

Umbilical Cord Blood Cell Clearance Post-Infusion in Immune-Competent Children with Cerebral Palsy.

Umbilical cord blood cells have therapeutic potential for neurological disorders, through a paracrine mechanism of action. A greater understanding of the safety and immunological effects of allogeneic donor cord blood cells in the context of a healthy recipient immune system, such as in cerebral palsy, is needed. This study aimed to determine how quickly donor cord blood cells were cleared from the circulation in children with cerebral palsy who received a single intravenous infusion of 12/12 human leucocyte antigen (HLA)-matched sibling cord blood cells. Twelve participants with cerebral palsy aged 2-12 years received cord blood cell infusions as part of a phase I trial of umbilical blood infusion for cerebral palsy. Digital droplet PCR analysis of DNA copy number variants specific to donor and recipient was used to assess donor DNA clearance at five timepoints post-infusion, a surrogate measure of cell clearance. Donor cells were cleared by 3 months post-infusion in 11/12 participants. When detected, donor DNA was at a fraction of 0.01-0.31% of total DNA with no signs of graft-versus-host disease in any participant. The donor DNA clearance times provided by this study have important implications for understanding the safety of allogeneic cord blood cell infusion for cerebral palsy and translational tissue engineering or regenerative medicine research in other disorders.