Researcher: Weiguo Cui (Lead Collaborator) - Julie-An Talano, MD (Project Director) 

Project Title: Dissecting the Cellular Mechanisms of Dicerential Outcomes of CD20-19 CAR-T Therapy in Acute Lymphoblastic Leukemia (ALL) 

Year Funded: 2020 
Hospital Affiliation: Children’s of Wisconsin 
Location: Milwaukee, Wisconsin 

Summary: 

Dr. Talano and her team are dissecting the cellular mechanisms of differential outcomes of CAR-T (Chimeric Antigen Receptor Therapy) in acute lymphoblastic leukemia. By collecting samples from pediatric cancer patients who have received engineered T cells to aid in their recovery, they can better understand how the immune system works to fight cancer. 

Project Details: 
Chimeric antigen receptor (CAR) based adoptive cell transfer immunotherapy has generated substantial enthusiasm in treating childhood leukemia especially ALL. Despite the promising success in CAR-T therapy, a number of outstanding issues deserve further investigation most importantly the factors that cause excessive cytokine release and relapse. To tackle these issues, we will use the patient samples 

from a recently opened CD20-19 CAR-T clinical trial in pediatrics ALL to “lineage trace” the CAR programed T cells prior to and after adoptive transfer at various time points. To do this, we will employ a newly developed approach that combines single cell RNA sequencing to TCR sequencing. Given that each T cell has a unique TCR sequence, we can use this information as a cellular barcode to track T cell 

dicerentiation trajectory over time. In addition, the single cell transcriptomics will enable us to delineate the various composition of T cell lineages, which include at least naïve, ecector and memory CD8 T cells, as well as Th1, Th2, Th17 CD4 T cells and Tregs. 

Taken together this deep phenotyping and lineage tracing method will not only generate the atlas of CAR-T cell lineage composition and functional progression, but also reveal cellular mechanisms related to the therapeutic edcacy and adverse effects. We propose that the optimal ratio between functional ecector cells and Treg cells positively correlates with increased cancer control and limited side effects, whereas the increased ratio likely leads to excessive cytokine release and the decreased ratio may cause refractory to the CAR-T therapy.