State of the CAR-T: Risk of Infections with chimeric antigen receptor T-Cell therapy and determinants of SARS-CoV-2 vaccine responses

Document Type

Review Article


Pathology and Microbiology; Pathology and Laboratory Medicine


Chimeric antigen receptor T-cell (CAR-T) therapy has shown unprecedented response rates in patients with relapsed/refractory (R/R) hematological malignancies. While CAR-T therapy renders hope to heavily pre-treated patients, the rapid commercialization and cumulative immunosuppression predispose patients to infections for a prolonged period. CAR-T poses distinctive short- and long-term toxicities and infection risks among patients who receive CAR-T after multiple prior treatments, often including hematopoietic cell transplantation. The acute toxicities include cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome. The long-term B-cell depletion, hypogammaglobulinemia, and cytopenia further predispose patients to severe infections and abrogate the remission success achieved by the living drug. These on-target-off-tumor toxicities deplete B-cells across the entire lineage and further diminish immune responses to vaccines. Early observational data suggest that patients with hematologic malignancies may not mount an adequate humoral and cellular response to SARS-CoV-2 vaccines. In this review, we summarize the immune comprising factors indigenous to CAR-T recipients. We discuss the immunogenic potential of different SARS-CoV-2 vaccines based on the differences in the manufacturing platforms among CAR-T recipients. Given the lack of data related to the safety and efficacy of SARS-CoV-2 vaccines in this distinctively immunosuppressed cohort, we summarize the infection risks associated with FDA-approved CAR-T constructs and the potential determinants of vaccine responses. The review further highlights the potential need for booster vaccine dosing and the promise for heterologous prime-boosting in CAR-T recipients.

Publication (Name of Journal)

Transplantation and Cellular Therapy