Plasma microbial cell-free DNA following chimeric antigen receptor T cell therapy in pediatric patients with relapsed/refractory leukemia.

Chimeric antigen receptor (CAR) T cell therapy is a promising treatment for pediatric patients with relapsed or refractory B cell acute lymphoblastic leukemia (R/R B ALL). Cytokine release syndrome (CRS) is a common toxicity after CAR T cell therapy and fever is often the first symptom. Differentiating CRS from infection after CAR T cell therapy can be challenging. Plasma microbial cell free DNA (mcfDNA) is a novel diagnostic tool which allows for qualitative and quantitative assessment of over 1000 organisms. This pilot study sought to characterize mcfDNA results in pediatric patients with R/R B ALL in the first 2 months after CAR T cell therapy.